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NEW ZEALAND HEALTH TECHNOLOGY ASSESSMENT (NZHTA) Department of Public Health and General Practice Christchurch School of Medicine and Health Sciences Christchurch, New Zealand
Transportation of emergency patients Dr Robert Weir
NZHTA TECHNICAL BRIEF March 2007 Volume 6 Number 4
This report should be referenced as follows: Weir, R. Transportation of emergency patients. NZHTA Technical Brief 2007; 6(4) Titles in this Series can be found on the NZHTA website: http://nzhta.chmeds.ac.nz/ publications 2007 New Zealand Health Technology Assessment (NZHTA) ISBN 978-1-877455-03-2 (Print) ISBN 978-1-877455-04-9 (Web) ISSN 1175-7884
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CONTRIBUTIONS BY AUTHORS
It was authored by Dr Robert Weir (Director), who conducted the critical appraisals, prepared the report and coordinated the project.
ACKNOWLEDGEMENTS
This Technical Brief was commissioned by the New Zealand Ministry of Health.
The literature search strategy was developed and undertaken by Susan Bidwell (Information Specialist). Cath Turnbull (Administrator) provided document formatting. Internal peer review was provided by Dr Martin Than.
DISCLAIMER
NZHTA takes great care to ensure the accuracy of the information supplied within the project timeframe, but neither NZHTA nor the University of Otago can accept responsibility for any errors or omissions that may occur. NZHTA and the University of Otago along with their employees accept no liability for any loss of whatever kind, or damage, arising from the reliance in whole or part, by any person, corporate or natural, on the contents of this paper. This document is not intended to be used as personal health advice; people seeking individual medical advice are referred to their physician. The views expressed in this report are those of NZHTA and do not necessarily represent those of the University of Otago, or the New Zealand Ministry of Health.
COPYRIGHT
This work is copyright. Apart from any use as permitted under the Copyright Act 1994 no part may be reproduced by any process without written permission from New Zealand Health Technology Assessment. Requests and inquiries concerning reproduction and rights should be directed to the Director, New Zealand Health Technology Assessment, Christchurch School of Medicine and Health Sciences, P O Box 4345, Christchurch, New Zealand.
CONTACT DETAILS
New Zealand Health Technology Assessment (NZHTA) Department of Public Health and General Practice Christchurch School of Medicine and Health Sciences PO Box 4345 Christchurch New Zealand Tel: +64 3 364 3696 Fax: +64 3 364 3697 Email: [email protected]
Website: http://nzhta.chmeds.ac.nz
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LEVEL OF EVIDENCE CONSIDERED IN TECHNICAL BRIEFS
Technical Briefs are rapidly produced assessments of the best available evidence for a topic of highly limited scope. They are less rigorous than systematic reviews. Best evidence is indicated by research designs which are least susceptible to bias according to the National Health and Medical Research Council’s (NHMRC) criteria (see Appendix 2). Where methodologically acceptable and applicable, appraised evidence is limited to systematic reviews, meta-analyses, evidence based clinical practice guidelines, health technology assessments and randomised controlled trials (RCTs). Where not available, poorer quality evidence may be considered.
CONFLICT OF INTEREST
None.
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EXECUTIVE SUMMARY
Aim
This technical brief examined four questions:
1. In adults and children with a medical or trauma related emergency, does the presence of a medical doctor on emergency helicopter services improve health outcome when compared with transportation by emergency helicopter without a medical doctor?
2. In adults and children with a medical or trauma related emergency, does the presence of a medical doctor on a road ambulance service improve health outcome when compared with transportation by a road ambulance service without a medical doctor?
3. In adults and children with a medical or trauma related emergency, does the presence of a medical crew able to perform rapid sequence intubation and/or thoracostomy improve health outcome when compared with a medical crew unable to perform rapid sequence intubation and/or tube thoracostomy and/or thoracotomy?
4. In adults and children with a medical or trauma related emergency how does variation in the time from callout to arrival at a medical facility with definitive care influence health outcome?
There are two general strategies about pre-hospital transportation: “scoop and run” and “stay and treat”. Scoop and run consists of short times at the scene with the emphasis being to transport the patient to definitive care as quickly as possible. In contrast, stay and treat involves longer times at the scene in order to start the stabilisation process. The above questions were designed to help address the most appropriate transportation strategy.
Data sources
The literature was searched using the following bibliographic databases: Medline, Embase, Cinahl, Current Contents, Science Citation Index, and Social Science Citation Index. Review databases searched were the Cochrane Database of Systematic Reviews, the Database of Abstracts of Reviews of Effects, the NHS Economic Evaluation Database and the Health Technology Assessment Database. Relevant publications referenced in material obtained in the course of the project were also identified.
Searches were performed between 24 October and 7 November 2006, and were restricted to material in English published from 1980 onwards.
Selection criteria
The selection criteria varied by review question. Selection criteria for each question included:
� primary aim of the study was to evaluate the comparison of interest in each review question
� methods were clearly described
� studies had a relevant control group
� study population included trauma and/or medical emergencies
� minimum sample size of 50
� outcomes included death and days in hospital
� Non-English language articles and publications that had been superseded were excluded.
Criteria were also set for the intervention and comparator based on the review question of interest.
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Data extraction
A single reviewer extracted data and appraised the selected studies. Summaries were presented in the form of evidence tables and full text.
Key results and conclusions
Key results were: 1. There was generally more support for the inclusion of doctors on helicopters in the seven
studies appraised in this section. However, there were uncertainties due to study design issues (levels of evidence ranged between III-1 and III-3), lack of consideration about whether non-doctor groups can be trained to perform certain procedures that would improve patient outcome and whether there may be different clinical scenarios that would favour one crew mix over another.
2. Similar considerations applied in the studies examining the use of doctors on board road ambulances. There were four studies in this section with levels of evidence ranging between III-2 and III-3.
3. When considering the outcome in patients who were treated by crews able to perform rapid sequence intubation and/or thoracostomy with other crews who were not able to perform these procedures, the only studies identified that met the study eligibility criteria included doctors amongst those able to perform the procedures of interest. It was therefore not possible to form conclusions about the effectiveness of non-doctor crews able to perform the procedures of interest when compared with crews that included a doctor. There were five studies in this section with levels of evidence ranging between III-1 and III-3.
4. There was inconsistent data on the association between pre-hospital time and patient outcome. However, the general direction was to support improved outcome in association with shorter pre-hospital times. Two studies provided information to consider whether crew mix or rapid transport had a more significant bearing on outcome. The results were conflicting across these two studies. There were 21 studies in this section with levels of evidence all being III-2.
5. Most of the studies included related to trauma rather than medical emergencies.
6. There was insufficient information to consider subgroups based on injury severity or age group.
While the balance of studies support improved outcome associated with doctors on board emergency transportation, the robustness of these studies and the areas of uncertainty that remain (see under research gaps) provide uncertainty about the best approach. The best study supported the use of doctors on board helicopters. The balance of studies supported improved outcome associated with shorter pre-hospital times. The studies identifying improved outcome frequently assessed the linear relationship between pre-hospital outcome and time, meaning that the focus was on any improvement in outcome rather than a set threshold of pre-hospital time to meet in order to achieve improved outcome.
Further research/reviews required
Some general areas of future research that would be helpful include:
1. Is there some form of interaction between pre-hospital time and pre-hospital crew that has impact on patient outcome? Linked to this is whether the same pre-hospital approach (time and crew) results in improved outcome in all emergency patients or whether the best approach is dependent on the clinical situation.
2. Given differences in procedures performed and clinical assessment processes adopted by doctors compared with non-doctor pre-hospital personnel, to what extent would enhanced procedure training for non-doctor groups be helpful?
3. There are cost differences between the “scoop and run” and “stay and treat” approaches, along with the crew mixes used that ideally should be examined in relation to cost effectiveness of different approaches. However, given current uncertainties in
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effectiveness of the different strategies, incremental cost effectiveness can not be robustly examined at this time.
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TABLE OF CONTENTS
CONTRIBUTIONS BY AUTHORS ....................................................................................................................I ACKNOWLEDGEMENTS ...............................................................................................................................I DISCLAIMER ...............................................................................................................................................I COPYRIGHT ................................................................................................................................................I CONTACT DETAILS .....................................................................................................................................I LEVEL OF EVIDENCE CONSIDERED IN TECHNICAL BRIEFS...........................................................................II CONFLICT OF INTEREST .............................................................................................................................II EXECUTIVE SUMMARY .............................................................................................................................III Aim.......................................................................................................................................................... iii Data sources........................................................................................................................................... iii Selection criteria..................................................................................................................................... iii Data extraction........................................................................................................................................ iv Key results and conclusions..................................................................................................................... iv Further research/reviews required.......................................................................................................... iv TABLE OF CONTENTS ............................................................................................................................... VI ABBREVIATIONS ..................................................................................................................................... VII BACKGROUND ...........................................................................................................................................1 International variation in approach to transporting emergency patients.................................................1 Procedures performed by different groups of transport staff ...................................................................2 Dispatch strategies ...................................................................................................................................2 Golden hour..............................................................................................................................................3 Definitions related to transportation times...............................................................................................3 Traumatic versus non-traumatic medical emergencies ............................................................................3 Study types ................................................................................................................................................4 Scope of evaluation...................................................................................................................................6 Review Questions......................................................................................................................................7 SELECTION CRITERIA.................................................................................................................................8 MAIN SEARCH TERMS ..............................................................................................................................11 SEARCH SOURCES ....................................................................................................................................12 Bibliographic databases .........................................................................................................................12 Review databases....................................................................................................................................12 APPRAISAL METHODOLOGY.....................................................................................................................12 RESULTS..................................................................................................................................................13 Doctor versus no doctor on board helicopter.........................................................................................13 Doctor versus no doctor on board road ambulances .............................................................................35 Comparison of outcomes amongst crews that do and do not perform rapid sequence intubation
and/or thoracostomy.............................................................................................................................47 Outcomes by time from ambulance call out to emergency department delivery.....................................63 OVERVIEW ............................................................................................................................................115 Main findings........................................................................................................................................115 Limitations............................................................................................................................................116 Research gaps.......................................................................................................................................116 Conclusions ..........................................................................................................................................116 REFERENCES .........................................................................................................................................117 APPENDIX 1: SEARCH STRATEGY ...................................................................................................122 APPENDIX 2: LEVELS OF EVIDENCE ................................................................................................130 APPENDIX 3: EXCLUDED RETRIEVED PAPERS: DOCTOR VERSUS NO DOCTOR ON HELICOPTERS ......131 APPENDIX 4: EXCLUDED RETRIEVED PAPERS: DOCTOR VERSUS NO DOCTOR ON ROAD
AMBULANCES............................................................................................................134 APPENDIX 5: EXCLUDED RETRIEVED PAPERS: COMPARISON OF OUTCOMES AMONGST CREWS
THAT DO AND DO NOT PERFORM RAPID SEQUENCE INTUBATION AND/OR
THORACOSTOMY .......................................................................................................136 APPENDIX 6: EXCLUDED RETRIEVED PAPERS: OUTCOMES BY TIME FROM AMBULANCE CALL OUT
TO EMERGENCY DEPARTMENT DELIVERY..................................................................142 APPENDIX 7: INCLUDED PAPERS ....................................................................................................151
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LIST OF TABLES
Table 1. Inclusion/exclusion criteria for the effectiveness of including medical doctors on emergency helicopter transportation.................................................................................. 8 Table 2. Inclusion/exclusion criteria for the effectiveness of including medical doctors on road ambulances ........................................................................................................................ 9 Table 3. Inclusion/exclusion criteria for the effectiveness of including a crew able to perform rapid sequence intubation and/or thoracostomy on pre-hospital emergency transportation ................................................................................................................... 10 Table 4 Inclusion/exclusion criteria for the ideal time between call out and delivery of emergency patients to the emergency department ........................................................... 11 Table 5 Reasons for exclusion of studies before retrieval in full text: doctor versus no doctor on board helicopter ............................................................................................................... 13 Table 6 Reasons for exclusion of studies retrieved in full text: doctor versus no doctor on board helicopter ........................................................................................................................ 13 Table 7 Evidence tables of studies comparing the outcome or patients transported by helicopter with and without a medical doctor on board.................................................................... 18 Table 8 Reasons for exclusion of studies before retrieval in full text: doctor versus no doctor on board road ambulances .................................................................................................... 36 Table 9 Reasons for exclusion of studies retrieved in full text: doctor versus no doctor on board road ambulances .............................................................................................................. 36 Table 10 Evidence tables of studies comparing the outcome of patients transported by road ambulance with and without a medical doctor on board.................................................. 39 Table 11 Reasons for exclusion of studies before retrieval in full text (from additional search): patients transported by crews that do and do not have the ability to perform rapid sequence intubation and/or thoracostomy........................................................................ 47 Table 12 Reasons for exclusion of studies retrieved in full text: patients transported by crews that do and do not have the ability to perform rapid sequence intubation and/or thoracostomy................................................................................................................... 47 Table 13 Evidence tables of studies comparing crews that do and do not perform rapid sequence intubation and/or thoracostomy ....................................................................................... 52 Table 14 Reasons for exclusion of studies before retrieval in full text: time from callout to emergency department delivery ....................................................................................... 63 Table 15 Reasons for exclusion of studies retrieved in full text: time from callout to emergency department delivery ......................................................................................................... 63 Table 16 Evidence tables of studies examining time from ambulance callout to emergency department arrival ............................................................................................................ 73 Table 17 Key results for studies examining time from ambulance callout to emergency department arrival that found an association between prolonged pre-hospital time and poor outcome......................................................................................................................... 112 Table 18 Key results for studies examining time from ambulance callout to emergency department arrival in studies that did not directly compare pre-hospital time with outcome ........... 113 Table 19 Key results for studies examining time from ambulance callout to emergency department arrival in studies that did not find an association between pre-hospital time and outcome.......................................................................................................................... 114
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ABBREVIATIONS
AIS abbreviated injury scale
ALS advanced life support
APACHE acute physiology and chronic health evaluation
ASCOT A severity characterisation of trauma
AUC area under the curve
CI confidence interval
CPR cardiopulmonary resuscitation
DHB District Health Board
ED emergency department
GCS Glasgow Coma Scale
HEMS helicopter emergency medical service
ICU intensive care unit
ISS injury severity score
IV intravenous
MECU mobile emergency care unit
MI myocardial infarction
MTOS Major Trauma Outcome Study
NSW New South Wales
OR odds ratio
Ps probability of survival
RTS revised trauma score
TISS Therapeutic Intervention Scoring System
TRISS Trauma and Injury Severity Score
TS trauma score
UK United Kingdom
USA United States of America
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BACKGROUND
This technical brief was requested by Paul Howard, DHB Funding and Performance Directorate, Ministry of Health, New Zealand Government.
International variation in approach to transporting emergency patients
Variations are seen in the approach to transportation of emergency patients internationally. Some use helicopters with doctors on board, others use helicopters that include nurses or paramedics. Some regions use road ambulance when others would use helicopters and some have used a combination of helicopters supported by ground services (Frankema et al. 2004). At longer distances, there is also variation between fixed wing and rotary wing aircraft. The most appropriate approaches are controversial, particularly in relation to:
1. Staffing of emergency helicopter services
2. Road versus air ambulance transportation.
There is also debate about time spent on the trauma scene (Feero et al. 1995; Sampalis et al. 1993), with Europe tending towards placing more importance on field stabilisation while the North American philosophy tends to be that field stabilisation only contributes to reducing mortality if on-scene time is not prolonged or if the patient would die without immediate intervention (Osterwalder 2002). In some regions, such as Europe and Quebec, field stabilisation is usually achieved by physicians whereas in others paramedics with access to voice control by physicians are used in the field (Sampalis et al. 1993).
The optimal staffing for helicopter transport is controversial (Bartolacci et al. 1998; Cameron 1999) (Cameron and Zalstein 1998; Gisvold 2002; Rhee et al. 1986). Proponents of the inclusion of a physician on helicopter transport suggest improved outcomes can be expected from improved assessment and better use of advanced life support (ALS) skills (Rhee et al. 1986). However, the major advantage from the use of helicopters may be a result of speed (Matsumoto et al. 2006). Under those circumstances, the use of a limited range of ALS skills would be more appropriate, thus obviating the need for physician skills. Some suggest ALS may be more beneficial in certain circumstances, such as blunt trauma (Cameron 1999).
A range of studies exist that compare road with air ambulance. These studies reflect ongoing controversy about the most appropriate use of these two forms of transport (Cameron and Zalstein 1998; Kerr et al. 1999; Nicholl et al. 1995; Thomas et al. 2002).
In the UK the first helicopter ambulance service started in 1987. Since that time air ambulance services operating in the UK have expanded and, interestingly, bear little resemblance to one another, further emphasising the uncertainty about the most appropriate transportation methods in different circumstances. A study set in London reported crew arrangements at the time. The service, which operated from Royal London Hospital, was crewed by two pilots, a registrar and a paramedic (Nicholl et al. 1995). In another study, set in Italy, the helicopter was crewed by an anaesthetist, registered nurse with ICU or pre-hospital emergency experience, a flight co-ordinator with the same skills as the registered nurse and the pilot (Sanson et al. 1999). A national air ambulance service implemented in Norway in 1988 also included anaesthetists on all helicopter services (Nielsen et al. 2002). A study set in Michigan used helicopters crewed by a pilot, flight nurse (with emergency of intensive care experience) and a physician (resident or fellow), (Rhee et al. 1986). Japan has recently started using helicopters with physicians on board to transport emergency patients (Matsumoto et al. 2006).
Some air ambulance services are developed to overcome issues of remoteness. For example, an emergency medical retrieval service was set up in the Argyll and Clyde Health Board, Scotland to support rural community hospitals in the area (Corfield et al. 2006). Transferring patients via helicopter resulted in highly significant differences in transfer times when compared with road/ferry combinations in the regions covered by this service.
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Procedures performed by different groups of transport staff
Procedures performed by different groups vary by region. For example, paramedics in New South Wales intubate without paralysis or sedation. Therefore, only unconscious patients could be intubated. In other regions, paramedics can use paralysing agents and sedation (Garner et al. 1999; Murphy-Macabobby et al. 1992). In Quebec, emergency medical technicians are prohibited from performing any invasive procedures or administering medications. Physicians are dispatched to the trauma scene based on severity of the trauma. Only physicians can intubate, insert intravenous (IV) lines, and administer IV fluids and medications. Emergency technicians are restricted to basic life support procedures including extrication, wound dressing, head and spine immobilisation, oxygen administration, fracture splinting and cardiopulmonary resuscitation (CPR) (Sampalis et al. 1992).
Thoracostomy may be differentially performed by staff groups. There is some controversy concerning relative outcomes of thoracostomy pre-hospital versus in the emergency department setting. Spanjersberg et al. (2005) compared thoracostomies in these two settings and found no difference in complication rates between the two groups.
Intubation frequency and difficulty in the pre-hospital setting has been examined. A study set in the USA found there were 11,951 intubations from 1,544,791 patient care reports (0.77%), (Wang et al. 2005). In a study set in Germany, pre-hospital intubation was performed in 342 of 3669 (9.3%) patients treated by helicopter emergency medical service (HEMS), (Helm et al. 2006). The first attempt was successful in 87.4% of the 342 intubations.
Some studies have raised uncertainties about the use of IV fluids pre-hospital. For example, Sampalis et al. (1997) found that IV fluid replacement was associated with an increase in mortality risk and this association was exacerbated by increased pre-hospital times. A health technology assessment of the issue found no evidence that pre-hospital IV fluid resuscitation was beneficial and some evidence was identified that it may be harmful. However, they commented that this evidence was not conclusive (Dretzke et al. 2004).
Further differences in procedures performed are documented in the studies selected for appraisal in this review.
Dispatch strategies
Dispatch strategies vary internationally and within countries (Garner et al. 1999). In some countries (and studies) there is no consistency in approach between systems. For example, a study comparing a physician with a paramedic crew appeared to use the physician crew on a selective basis (Garner et al. 1999), making interpretation of the study results difficult.
Some have stated that helicopters have a role in transporting critically ill trauma patients over distances greater than 50 km or 30 minutes by road (Cameron and Zalstein 1998; Garner et al. 1999; Ministerial Taskforce on Trauma and Emergency Services 1999).
The following section provides examples of selected dispatch strategies to illustrate the variation in approaches.
The dispatch of CareFlight, a medically staffed helicopter service operating in New South Wales (NSW), is at the discretion of the NSW Ambulance Service. Dispatch is based on injury severity, entrapment, remote location or difficult hoist (needing a rescue hoist for extraction), (Bartolacci et al. 1998).
In Rotterdam, the following criteria are used for the primary deployment of a helicopter transported medical team for trauma patients (Frankema et al. 2004):
� place difficult to reach for ambulances
� in the professional opinion of the dispatcher, the helicopter service provides additional value
� motor vehicle crashes with estimated speed > 30 km/hr
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� frontal collisions outside the built up area of town
� fall from > 6 metres or third floor
� entrapment in vehicle
� death of other occupant
� ejected from vehicle
� explosions
� near drowning or diving accidents
� exposure to toxic chemicals
� inhalation trauma or severe burns
� penetrating injuries to head, neck or trunk
� pelvic, spinal or femur fracture
� comatose (Glasgow Coma Scale ≤ 8)
� systolic blood pressure < 95 mm Hg or pulse > 120 per min
� major estimated blood loss (> 1 litre)
� respiratory distress.
Some centres have a paramedic stationed in ambulance service control to help identify calls that would benefit from helicopter retrieval (Nicholl et al. 1995).
Golden hour
Trunkey classified deaths as immediate, early and late. Immediate deaths were defined as occurring instantaneously or within one hour of the time of injury. Such deaths resulted from severe injuries to the brain, major blood vessels, heart or spinal cord. Early deaths were defined as occurring between one hour and one week following injury. These deaths resulted from major haemorrhage, multiple brain injuries and severe brain damage. These injuries should not result in death if definitive care can be given within one hour (the golden hour) of the time of injury. Late deaths occur more than one week after injury and result from later complications or infections (Trunkey 1983). The data used to support this classification was largely based on wartime findings. There is debate whether the golden hour applies to civilian settings (Lerner and Moscati 2001).
Definitions related to transportation times
There are five phases in the transportation of emergency patients to the emergency department:
1. Activation.
2. Dispatch.
3. Travel.
4. Patient preparation and treatment.
5. Travel.
Activation, dispatch and travel to the scene represent the response time. The retrieval time encompasses all five phases (Ministerial Taskforce on Trauma and Emergency Services 1999).
Traumatic versus non-traumatic medical emergencies
The scope of this review included both traumatic and non-traumatic medical emergencies. The studies examining the staff mix on helicopters tended to focus on study populations resulting from trauma as opposed to medical emergencies. Trauma patients are thought to be good subjects as the predicted mortality can be estimated objectively and compared with the actual mortality (Osterwalder 2003). The
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great majority of studies eligible for the comparison of outcomes by pre-hospital time were also conducted in trauma populations. Reasons for this are explained in more detail in the relevant results section.
Study types
Judgment of skills required for specific trauma incidents
In some studies the judgment and skills shown by physicians were used to evaluate their role on helicopter transport (Dalton et al. 1992; Rhee et al. 1986). These studies can be expected to be somewhat subjective and the added value proposed for physicians may be dependent on who is doing the evaluation. In some cases the added value of the physician may be underestimated and in others it may be overestimated, depending on the study design. It is difficult to extrapolate the findings of these studies to precise estimates of improvement in health outcome. If a delay in transportation to the base hospital occurs as a result of the physician involvement, this may adversely affect outcome and such factors are unlikely to be considered in this type of study. Therefore, this type of study was omitted from this review, in favour of studies that included relevant health outcomes. A variant on the above study design was also identified. In this design, records were retrospectively reviewed and classified into groups indicating whether a physician was required (Nielsen et al. 2002; Snow et al. 1986). Similar considerations apply to those outlined above, so these studies were also excluded. Gries et al. (2006) examined the frequency of defined procedures and conditions that may require physicians to adequately manage emergency situations. In this study it was estimated that patients with life threatening conditions such as acute coronary syndrome, stroke, head trauma, and multiple trauma only occurred once every 0.4-14.5 months and CPR and intubation was carried out once every 0.5-1.5 months. The ranges represent time periods before encountering each specific outcome across both helicopter and ground transportation. Chest tubes were inserted every six months to six years. This was in the context of a service with 82,002 scene calls registered for ground crews during a 54 month period and 47,184 calls for air rescue services over 24 months.
Scientific methods used to compare the predicted mortality with actual mortality
A common method used in the studies selected for this review made use of a comparison between predicted and actual mortality. Most of these studies made use of the Trauma and Injury Severity Score (TRISS). Another, less frequently used comparison was with the ASCOT (A Severity Characterization of Trauma) model. Both these approaches are detailed below.
Study methods involving the TRISS approach evolved for two reasons: understanding the limitations of a retrospective evaluation of helicopter use in relation to patient outcome and the practical difficulties associated with conducting a randomised controlled trial. TRISS incorporates physiologic (trauma score), anatomic (injury severity score) and age (55 years as cut-off) independent variables into a logistic regression model. Predicted mortality can then be compared with actual mortality (Boyd et al. 1987).
The trauma score (TS) includes five components:
1. Systolic blood pressure.
2. Capillary refill.
3. Respiratory rate.
4. Respiratory expansion.
5. Glasgow Coma Scale (GCS).
Boyd et al. (1987) considered the trauma score had a sensitivity of 80% (meaning 20% of patients with severe injury will not be identified with this score) and specificity of 75% (meaning overestimation of severity will occur when physiologic changes are related to factors other than the consequences of hypovolaemia, cerebral oedema or hypoxia). The predictive value is greatly improved when combined with an injury severity score (ISS).
The ISS is based on the abbreviated injury scale (AIS). It was first proposed by Baker et al. (1974) as a method of using the AIS but adjusting for multiple injuries. The AIS is a list of several hundred injuries
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each with a score that can range from 1 (minor injuries) to 6 (nearly always fatal). The ISS takes values from 1-75. If the patient has any AIS 6 injury, the ISS score is automatically 75. Otherwise, the highest AIS severity score in each of six body regions is identified, and the squares of the largest three are added to obtain the ISS.
Age greater than 55 years was shown to be associated with significantly increased mortality given comparable levels of physiologic derangement and anatomic injury severity in the Major Trauma Outcome Study (MTOS), (Boyd et al. 1987).
The probability of survival can be estimated from:
Ps = 1/(1 + e-b)
Where b= b0 + b1(TS) + b2(ISS) + b3(A).
b0….3 are regression coefficients that were initially derived from the patients included in the MTOS. As improvements in trauma care result in decreased mortality, these MTOS coefficients can be expected to change. Different sets of coefficients are used for blunt and penetrating trauma.
A revised trauma score (RTS) evolved out of a critical analysis of patients whose outcome was not predicted by the TRISS methods. Three parameters were used: GCS, systolic blood pressure and respiratory rate. When using the RTS the coefficients are different from those originally proposed. The RTS classification rather than the TS classification was used in the MTOS results published in 1990 (Champion et al. 1990b). The MTOS norms were obtained for adults (15+ years) with either blunt injuries (n=15,754) or penetrating injuries (n=7,423).
Various statistics are calculated using the TRISS methodology. The Z statistic compares outcome in two population subsets (Flora 1978). It quantitates the difference in the actual number of deaths in the test subset with the predicted number of deaths. Z values can be affected by the injury severity match between the study and baseline patient sets. The M statistic is a measure of that match. Values for M range from zero to one. The closer the value is to one, the better is the match of injury severity. Z
values associated with lower values of M (< 0.88) should be viewed with sceptism.
Younge et al. (1997) discussed the use of the W statistic in order to compare trauma survival rates between different institutions and reference databases hampered by different injury severity mixes. The W statistic estimates excess survivors per 100 patients that would be achieved if the study centre treated patients with the same distribution of injury severity as the reference database (e.g. MTOS). It represents the number of excess survivors per 100 patients attending a particular centre that would be achieved if that centre received patients with the same distribution of injury severity as the reference database. The standardising process places undue emphasis on patients with a good probability of survival. In lower strata of survival, which are based on smaller patient numbers in the reference database, the linear regression model over-predicts survival. Overall, the TRISS model tends to over-predict survival when using the MTOS database, meaning the performance of individual centres with a poor prognosis casemix will appear to be poor. This problem is reduced if the W statistic for each probability of survival interval at the study centre is compared with the W statistic for the equivalent interval in the reference database.
As a general comment, the analytic complexity of TRISS based studies is one aspect that lacks appeal to a wide readership. Stratification by severity marker is a method of overcoming this limitation but requires large patient numbers to achieve adequate study power. Other limitations include:
� unmeasured factors (e.g. pre-existing medical conditions, mixture of injury types, injury mechanism, time between injury and assessment of RTS) may account for differences between predicted and actual outcome
� distribution of probability of survival (Ps) may differ within comparative Ps intervals
� choosing different Ps intervals may alter the result.
The MTOS was a retrospective study of injury severity that initially aimed to develop national norms for trauma care that could be used for quality assurance. The study was co-ordinated through the
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American College of Surgeons’ Committee on Trauma and data collection started in 1982. Over 140 hospitals from the USA, Canada, Australia and the UK submitted demographic, aetiologic, injury severity and outcome data. At the time of publishing results in 1990 more than 120,000 trauma patients had been treated at the participating hospitals, including 80,544 trauma patients from 139 USA and Canadian institutions for the period October 1982-1987. These 80,544 patients were the focus of a publication by Champion et al. (1990b). It should be noted that MTOS was not population based, participation was voluntary, participating centres may have tended to have increased trauma care expertise and may have been biased towards more severe trauma.
The ASCOT model was developed by Champion et al. (1990a). This approach combines emergency department admission values of GCS, systolic blood pressure, respiratory rate, patient age and AIS anatomic injury scores in a way that was designed to overcome ISS shortcomings. In his original description, Champion et al. suggested, based on Hosmer-Lemeshow statistics, that ASCOT reliably predicted patient outcome in penetrating injuries and “nearly so” for blunt injured patients. He commented that statistically reliable predictions were not achieved by TRISS in either patient group.
Other more recent studies have compared TRISS, ASCOT and other models (Frankema et al. 2005; Gabbe et al. 2005). Gabbe et al. (2005), estimated the sensitivity, specificity and the area under the curve (AUC) of receiver operating characteristic curves (which is a discriminating estimate of measure performance). The sensitivity, specificity and AUC of TRISS were 19%, 98% and 0.87 respectively. Likewise, the sensitivity, specificity and AUC of ASCOT were 75%, 58% and 0.78 respectively. In contrast in Frankema et al. (2005), the AUC for TRISS was 0.940 and for ASCOT was 0.956. Thus, on the basis of these two studies, it was not clear which of the two measures were better. What is clear is that neither is perfect, indicating potential problems with the estimation of excess unexpected deaths and excess unexpected survivors in the studies that use this approach in this review.
Other measures have been used to compare severity of injury at baseline in some of the included studies. One measure was the APACHE (Acute physiology and chronic health evaluation) II score. Some studies have been conducted evaluating the performance of APACHE II. One study estimated an AUC in receiver operating characteristic curves with mortality as the outcome of interest of 0.84 (95% CI 0.83-0.85), (Suistomaa et al. 2002). Another study estimated an AUC of 0.787 and also noted there were significant differences between observed and predicted mortality (p<0.001), (Moreno and Morais 1997). Vassar et al. (1999) compared TRISS, APACHE II and APACHE III. TRISS and APACHE were described as having poor performance characteristics. In relation to predicting mortality both had poor goodness of fit characteristics (Hosmer-Lemeshow testing). The AUC for APACHE II was 0.87 and for TRISS was 0.82. APACHE had better goodness of fit characteristics and the AUC was 0.89. Similar performance characteristics for APACHE II were found by Muckart et al. (1997). In this study, goodness of fit was poor compared with a new model the authors developed. The AUC for APACHE II was 0.78.
Stratified/multivariate studies
As previously mentioned, there are drawbacks to studies comparing predicted with actual mortality. One method that has been used to overcome some of these limitations is stratification by severity marker. However, this design requires large sample sizes. Multivariate analysis can help with this.
Scope of evaluation
The scope of the systematic review included two broad areas:
1. The usefulness of including medical doctors on emergency transportation.
2. Ideal times between receipt of call out and delivery to base hospital for emergency patients.
The second aspect of the scope was designed to assist with the process of determining the most appropriate form of transport (air or road ambulance) in different locations of New Zealand. The literature was restricted to 1980 onwards.
TRANSPORTATION OF EMERGENCY PATIENTS
7
Review Questions
Question 1
In adults and children with a medical or trauma related emergency, does the presence of a medical doctor on emergency helicopter services improve health outcome when compared with transportation by emergency helicopter without a medical doctor? The health outcomes of interest are death in-transit and in-hospital and time to hospital discharge to the community.
Explanatory notes:
1. The cut off between childhood and adulthood was 16 years.
2. Neonates were excluded.
3. An inpatient stay in a local secondary hospital after discharge from the “definitive care” hospital was included in ‘length of stay’ where possible.
4. Subanalysis for Injury Severity Score, ISS >15.
Question 2
In adults and children with a medical or trauma related emergency, does the presence of a medical doctor on a road ambulance service improve health outcome when compared with transportation by a road ambulance service without a medical doctor? The health outcomes of interest are death in-transit and in-hospital and time to hospital discharge to the community.
Explanatory notes:
1. The cut off between childhood and adulthood was 16 years.
2. Neonates were excluded.
3. An inpatient stay in a local secondary hospital after discharge from the “definitive care” hospital was included in ‘length of stay’ where possible.
4. Subanalysis for Injury Severity Score, ISS >15.
Question 3
In adults and children with a medical or trauma related emergency, does the presence of a medical crew able to perform rapid sequence intubation and/or thoracostomy improve health outcome when compared with a medical crew unable to perform rapid sequence intubation and/or tube thoracostomy and/or thoracotomy? The health outcomes of interest are death in-transit and in-hospital and time to hospital discharge to the community.
Explanatory notes:
1. The cut off between childhood and adulthood was 16 years.
2. Neonates were excluded.
3. An inpatient stay in a local secondary hospital after discharge from the “definitive care” hospital was included in ‘length of stay’ where possible.
4. Subanalysis for Injury Severity Score, ISS >15.
Question 4
In adults and children with a medical or trauma related emergency how does variation in the time from callout to arrival at a medical facility with definitive care influence health outcome? The health outcomes of interest are death in-transit and in-hospital and time to hospital discharge to the community.
TRANSPORTATION OF EMERGENCY PATIENTS
8
Explanatory notes:
1. The cut off between childhood and adulthood was 16 years.
2. Neonates were excluded.
3. An inpatient stay in a local secondary hospital after discharge from the “definitive care” hospital was included in ‘length of stay’ where possible.
4. Subanalysis for Injury Severity Score, ISS >15.
SELECTION CRITERIA
Question 1
The selection criteria for question 1 are set out in Table 1.
Table 1. Inclusion/exclusion criteria for the effectiveness of including medical doctors on
emergency helicopter transportation
Characteristic Criteria
Inclusion criteria
Aim A primary aim of the study was to evaluate the
effectiveness of including medical doctors on emergency
helicopter transportation
Methods The methods were clearly described
Publication type Randomised controlled trials, cohort studies, case control
studies, interrupted time series and systematic reviews of
the above publication types
Population
Adults or children (excluding neonates) who present to
the emergency department after helicopter
transportation
Medical emergencies or trauma related health
emergencies will be included
Sample size At least 50 human patients
Intervention/test Inclusion of a medical doctor on the helicopter
transporting the emergency patient
Comparator
The absence of a medical doctor for the helicopter
transporting the emergency patient
Outcome Death: in transit, death in hospital, days to hospital
discharge
Exclusion criteria
Publication type Non-systematic reviews, case series, letters, editorials,
expert opinion articles, conference proceedings,
comments and articles published in abstract form.
Population Restriction to publication of incidents during
transportation
Comparator Expected outcome based on expert panel
Publication superseded Publication superseded by a later publication with longer
follow-up data and overlap in the patient population
Language Non-English language articles will be excluded
TRANSPORTATION OF EMERGENCY PATIENTS
9
Question 2
The selection criteria for question 2 are set out in Table 2.
Table 2. Inclusion/exclusion criteria for the effectiveness of including medical doctors on road
ambulances
Characteristic Criteria
Inclusion criteria
Aim A primary aim of the study was to evaluate the
effectiveness of including medical doctors on road
ambulances
Methods The methods were clearly described
Publication type Randomised controlled trials, pseudorandomised
controlled trials, cohort studies, case control studies,
interrupted time series and systematic reviews of the
above publication types
Population
Adults or children (excluding neonates) who present to
the emergency department after road ambulance
transportation
Medical emergencies or trauma related health
emergencies will be included
Sample size At least 50 human patients
Intervention/test Inclusion of a medical doctor on the road ambulance
transporting the emergency patient
Comparator
The absence of a medical doctor on the road
ambulance transporting the emergency patient
Outcome Death: in transit, death in hospital, days to hospital
discharge to community
Exclusion criteria
Publication type Non-systematic reviews, case series, letters, editorials,
expert opinion articles, conference proceedings,
comments and articles published in abstract form.
Population Restriction to publication of incidents during
transportation
Comparator Expected outcome based on expert panel
Publication superseded Publication superseded by a later publication with longer
follow-up data and overlap in the patient population
Language Non-English language articles will be excluded
TRANSPORTATION OF EMERGENCY PATIENTS
10
Question 3
The selection criteria for question 3 are set out in Table 3.
Table 3. Inclusion/exclusion criteria for the effectiveness of including a crew able to perform
rapid sequence intubation and/or thoracostomy on pre-hospital emergency
transportation
Characteristic Criteria
Inclusion criteria
Aim A primary aim of the study was to evaluate the
effectiveness of different crew configurations on health
outcome
Methods The methods were clearly described
Publication type Randomised controlled trials, pseudorandomised
controlled trials, cohort studies, case control studies,
interrupted time series and systematic reviews of the
above publication types
Population
Adults or children (excluding neonates) who present to
the emergency department after emergency
transportation
Medical emergencies or trauma related health
emergencies will be included
Sample size At least 50 human patients
Intervention/test Inclusion of a crew able to perform rapid sequence
intubation using muscle relaxants and/or tube
thoracostomy and/or thoracotomy
Comparator
Inclusion of a crew unable to perform rapid sequence
intubation and/or thoracostomy
Outcome Death: in transit, death in hospital, days to hospital
discharge to community
Exclusion criteria
Publication type Non-systematic reviews, case series, letters, editorials,
expert opinion articles, conference proceedings,
comments and articles published in abstract form.
Population Restriction to publication of incidents during
transportation
Comparator Expected outcome based on expert panel
Publication superseded Publication superseded by a later publication with longer
follow-up data and overlap in the patient population
Language Non-English language articles will be excluded
TRANSPORTATION OF EMERGENCY PATIENTS
11
Question 4
The selection criteria for question 4 are set out in Table 4.
Table 4 Inclusion/exclusion criteria for the ideal time between call out and delivery of
emergency patients to the emergency department
Characteristic Criteria
Inclusion criteria
Aim A primary aim of the study was to evaluate the effect of
different transportation times (from call out to arrival at an
emergency department) on health outcome
Methods The methods were clearly described
Publication type Study that includes a control group
Population
Adults or children (excluding neonates) who present to
the emergency department after helicopter
transportation
Medical emergencies or trauma related health
emergencies will be included
Sample size At least 50 human patients
Comparison Comparison of at least two different categories of time
from call out to time of delivery of patients to the
emergency department
Comparison of different methods of transport that have
different mean times of transport
Outcome Death: in transit, death in hospital, days to hospital
discharge
Exclusion criteria
Publication type Non-systematic reviews, letters, editorials, expert opinion
articles, conference proceedings, comments and articles
published in abstract form.
Publication superseded Publication superseded by a later publication with longer
follow-up data and overlap in the patient population
Language Non-English language articles will be excluded
MAIN SEARCH TERMS
Details of the search strategies are presented in Appendix 1.
Medline Subject Headings (MeSH headings): air ambulances, aircraft, “personnel staffing and scheduling”, personnel selection, patient care team, physician’s role, exp physicians, allied health personnel, nurse’s role, nurses, manpower[as floated subheading], time facts, survival analysis, treatment outcome, patient discharge, length of stay, morbidity, mortality, “outcome assessment (health care)”, emergencies, exp emergency medical services, emergency service-hospital, transportation of patients, ambulances
Additional keywords: helicopter$, medivac, medivac, casivac, casevac, evac, aeromedic$, air ambulanc$ , flight ambulanc$, medical practitioner$, medic$ adj qualif$, paramedic$, medic, medics, flight nurse$, doctor$, staff$, physician$, personnel, time adj3 delay$, ((pre-hospital or, pre-hospital) adj (time or care or treatment)), ((call-out or callout) and (arrival or admit$ or hospital or medical
TRANSPORTATION OF EMERGENCY PATIENTS
12
facility or definitive care or emergency department or ED)), scene time, “out of hospital time”, transport adj time$, transfer$ adj time$, survival, outcome, golden hour, golden minute$
SEARCH SOURCES
Bibliographic databases
Medline Embase Cinahl Current Contents Science/Social Science Citation Index PubMed (last 90 days)
Review databases
Cochrane Database of Systematic Reviews Database of Abstracts of Reviews of Effectiveness (DARE) NHS Economic Evaluation Database Health Technology Assessment Database
Articles published in English language only were considered.
The search was restricted to literature published from 1980 onwards. Searching was undertaken between 24 October and 7 November, 2006.
APPRAISAL METHODOLOGY
Summaries of appraisal results are shown in tabular form (known as Evidence Tables) which detail study design, study setting, sample, methods, results, and reported conclusions.
The evidence presented in the selected studies were assessed and classified according to the NHMRC’s revised hierarchy of evidence (Appendix 2).
TRANSPORTATION OF EMERGENCY PATIENTS
13
RESULTS
Doctor versus no doctor on board helicopter
From the search strategy for question one (comparing helicopter transportation with and without medical doctor staffing) we identified, 1068 potentially relevant articles/abstracts of which 58 were retrieved. Of these retrieved articles, 51 were excluded. These excluded papers are presented in Appendix 3. Two additional articles were identified from reference lists. Both these studies were excluded: one was not relevant to the review question and the other used an incorrect comparator. Reasons for exclusion of studies before retrieval in full text are outlined in Table 5. Reasons for exclusion of studies retrieved in full text are detailed in Table 6.
Table 5 Reasons for exclusion of studies before retrieval in full text: doctor versus no doctor
on board helicopter
Reason for exclusion Number
Not relevant to review question aim 894
Methods were not clearly described 0
Wrong publication type 98
Incorrect population 1
Sample size less than 50 4
Incorrect comparator 7
Incorrect outcomes 3
Publication superseded 0
Non-English language 0
Neonatal study 3
Total 1010
Table 6 Reasons for exclusion of studies retrieved in full text: doctor versus no doctor on
board helicopter
Reason for exclusion Number
Not relevant to review question aim 16
Methods were not clearly described 2
Wrong publication type 18
Incorrect population 1
Sample size less than 50 0
Incorrect intervention group 3
Incorrect comparator 6
Incorrect outcomes 3
Publication superseded 0
Non-English language 0
Neonatal study 0
Patient transfer 1
Article unable to be obtained 1
Total 51
Seven retrieved articles were appraised and are listed in the references and Appendix 7. Included papers are presented in the evidence table below. Included studies ranged from level III-1 to III-3 and above according to NHMRC’s hierarchy of evidence, including one pseudorandomised controlled trial, four cohort studies and two before and after studies. Evidence tables for the included studies are found at the end of this section (Table 7). Two of the seven studies were of marginal relevance given the high proportion of patients transferred from a hospital rather than the scene (Burney et al. 1992; Burney et al. 1995). These are presented separately from the remaining five studies.
TRANSPORTATION OF EMERGENCY PATIENTS
14
Baxt et al. 1987
Baxt et al. (1987) conducted a pseudorandomised controlled trial (Level III-1 evidence) comparing mortality in a group of consecutive patients with blunt trauma transported by helicopter with physician and nurse on board with another group with paramedic and nurse on board. There were 574 participants (316 in the physician group and 258 in the comparator group). Actual mortality was compared with predicted mortality using TRISS methodology. The trauma score scale rather than the revised trauma score scale was included in this calculation. Differences in procedures that the different groups could perform were noted and are detailed in Table 7. Actual mortality was not statistically significantly different from predicted mortality in the paramedic group while, in the physician group, actual mortality was significantly lower than predicted (P<0.05). There was a statistically significant difference in the Z statistic between the two groups, supporting reduced mortality in the physician group compared with the paramedic group.
There were potential sources of confounding and bias that should be considered when interpreting this study. Key issues included:
� the study was not truly randomised so is susceptible to confounding. However, significant baseline differences were not observed for transport time, trauma score, ISS, GCS, predicted survival or patient age.
� the key difference between the groups related to the category of patients who survived but were expected to die. There were only 22 patients who were expected to die in the physician group (five survived) and 16 who were expected to die in the paramedic group (none survived).
� the TRISS methodology used in this review did not assess the degree of match in injury severity between the two groups, or adjust for different casemix in the study groups.
� the study did not use all-cause mortality as the outcome (the focus was on mortality due to trauma), resulting in the potential for misclassification of outcome.
Despite the limitations this was the strongest study considering the effectiveness of including doctors on board helicopters.
Garner (2004) noted that the non-doctor team in this study was “considerably more procedurally capable than most Australian paramedics” and observed that despite this, a better outcome was observed in the physician treatment group.
Hamman et al. 1991
Hamman et al. (1991) conducted a before and after study (Level III-3 evidence) comparing mortality in a group of consecutive patients transported by helicopter crewed by physician and nurse (before phase) with another group crewed by paramedic and nurse or two nurses (after phase). There were 145 in the physician group and 114 in the non-physician group. Actual mortality was compared with predicted mortality using TRISS methodology. Differences in procedures that the different groups could perform were noted and are detailed in Table 7. Comparison of actual with predicted mortality showed a lower than predicted mortality in both groups. However, there was no overall difference in patient outcomes between the two groups.
Despite the above results, this study should be viewed cautiously, given a number of significant limitations:
� before and after design is a weak method as factors other than the factor of interest may contribute to the estimated measure of effect
� the study lacked power to detect a difference between the two groups as there were only 32 patients in total who were expected to die based on estimates of the probability of survival
� comparison of injury severity between the two groups is consistent with a poor match in severity between the groups (M statistic 0.87)
� lack of documentation about the timing of deaths and timing of estimation of RTS added to difficulties interpreting the results.
TRANSPORTATION OF EMERGENCY PATIENTS
15
Schmidt et al. 1992
Schmidt et al. (1992) reported on a registry based study (level III-2) that compared mortality in two centres with differing crew configurations on their emergency helicopter services. In the German centre a trauma surgeon was included on all flights, whereas in the USA centre the trauma surgeon was replaced with either a flight nurse or a paramedic. There were 221 participants in the setting with a surgeon and 186 in the setting without a surgeon. Actual mortality was compared with predicted mortality using TRISS methodology. Differences in procedures that the different groups could perform were noted and are detailed in Table 7. The Z statistic was calculated for the comparison between actual and predicted outcome at both centres. This statistic was consistent with improved survival compared with that predicted in the surgeon centre. This improvement was consistent with an additional 1.35 survivors per 100 patients when compared with the MTOS reference population. No such improvement was noted in the non-surgeon centre. However, there were reservations about the degree of match in injury severity between the actual data and the reference population in the non-surgeon setting. There were a lower proportion of deaths in the first six hours in the surgeon present setting.
There were limitations to this study:
� registry based study that resulted in the omission of 37 patients in the surgeon setting due to missing charts or data. This is likely to have resulted in selection bias, in that it seems likely the excluded patients were not representative of the general population, given no deaths occurred amongst these 37 patients.
� the measurement of RTS, a key component of the projected survival populations, occurred at different times in the two centres. This results in variation in the accuracy of the comparison with the reference population, and therefore in the Z statistic.
� there was variation in key time intervals relating to transport. In particular, there was a significantly shorter time between the incident and arrival at the scene in the surgeon setting. This may have resulted in improved prognosis in this setting.
� management was more aggressive in the setting with a surgeon and this increased aggressiveness may have produced the more favourable results, rather than the presence of a surgeon per se. The procedures adopted that reflected this increased aggressiveness could be performed by flight nurses and paramedics as well as surgeons.
More detail about this study is presented in Table 7.
Garner et al. 1999
Garner et al. (1999) reported on a retrospective study set in Australia (level III-2). They compared the outcome (mortality) between groups transported via helicopter with a physician on board versus patients transported with a paramedic on board. All patients were transported directly from the scene to the relevant hospital (hospitals varied by the crew mix on the helicopter). There were 67 patients in the physician group and 140 in the paramedic group. The patients were restricted to those with blunt trauma and an ISS score greater than 10. Actual mortality was compared with predicted mortality using TRISS methodology (MTOS as the reference population) and the adjusted W statistic was also used to directly compare the physician and paramedic groups. The degree of match on injury severity between the MTOS population and the physician and paramedic groups was poor, therefore the adjusted W statistic was appropriately presented. When comparing the physician group with the MTOS population it was estimated that 9.48 (95% CI 3.84-15.12) extra lives per 100 population were saved in the physician group. There was no significant difference in mortality between the MTOS population and the paramedic group. Direct comparison between the paramedic and physician groups suggested 13.44 (95% CI 7.80-19.08) extra lives per 100 population were saved in the physician group. There were differences in the procedures performed between the two groups. These are detailed in Table 7. In general, the physician group treated patients more aggressively and also conducted a number of rapid sequence intubations and tube thoracostomies (the paramedic group did not).
TRANSPORTATION OF EMERGENCY PATIENTS
16
The study had limitations:
� it was a retrospective study
� there were sources of selection bias – with differences in baseline measures between the two study groups (the physician group appeared to manage a more severely injured group) and seven patients who died were excluded from the paramedic group due to missing case sheets
� confounding was a potential problem between the two groups although use of the W statistic should have partially controlled confounding (based on injury severity)
� the degree of match in injury severity with the MTOS study was poor and there were variations in methods adopted in the MTOS study and this study (most notably related to the timing of RTS measurement) which limits the usefulness of the MTOS cohort as a reference population.
Cameron et al. 2005
A retrospective chart review was conducted in Australia (Cameron et al. 2005). This study used a before and after design (Level III-3 evidence) to compare outcome in a period where helicopters included emergency physicians with a subsequent period where the helicopter did not include an emergency physician (intensive care paramedics were used). Given the nature of the data recorded measures of injury severity were restricted to the RTS. Chart abstraction was primarily performed by one person but a 10% sample was validated by another abstractor. There was an excellent level of agreement between the two abstractors. There were 163 patients in the physician group and 211 in the paramedic group. Mortality was measured at 30 days. There were 10 deaths in total and no significant difference was detected between the study groups. There was also no significant difference in the length of stay, although the mean length of stay was only two days and one day respectively in the physician and paramedic groups.
There were significant limitations to this study:
� the effects of a retrospective design were apparent. As the authors documented, they were unable to extract data that would have provided a better indication of injury/illness severity.
� there was no control over potential confounders. Given baseline differences suggestive of a more severe casemix in the physician group this may have led to bias in the comparison.
� the outcome of the group discharged from ED was not obtained.
� the study power was low, particularly for mortality, so the lack of a significant difference in outcome was not surprising.
Studies that included predominantly transfer patients
Burney et al. 1992
Burney et al. (1992) reported on a retrospective cohort study (Level III-2 evidence) that compared outcome following the helicopter transportation of patients by physician/nurse with nurse/nurse. Both groups were studied concurrently during 1987-1988. There were 659 participants (418 in the P/N team and 241 in the N/N team). Most of the transports originated in an emergency department (ED), followed by inpatient units with only 5.5% being from the scene. There was no overall difference in mortality or number of hospital days. No statistically significant differences in these outcomes were observed on subgroup analysis (by clinical category or point of origin of the transport). However, the latter analyses had low study power.
This study had a number of limitations:
� measures of injury severity were not typical of those used in the studies conducted to investigate this review question
� lack of documentation about the procedures available to the two groups, dispatch criteria for the two groups, and number of receiving hospitals involved
TRANSPORTATION OF EMERGENCY PATIENTS
17
� there was variation in baseline characteristics between the two groups in the following variables: age, clinical category and origin of patient
� there was no adequate method of controlling for confounding used (the stratified analyses resulted in loss of study power)
� low proportion of participants were transported from the scene, thus having little relevance to the New Zealand setting.
Details of this study are provided in Table 7.
Burney et al. 1995
Burney et al. (1995) followed their retrospective cohort study with a prospective cohort study (Level III-2 evidence). The same study comparisons were made and the same data collection tools were used (although severity measures were measured more frequently). There were 255 patients in the P/N group and 914 in the N/N group. As previously, the proportion of transports originating from the scene was low (7.6%). There were differences in criteria for the selection of who was to attend the patient particularly in the second year of the study when the physician group attended patients with more complicated injuries. Overall, there was no significant difference in mortality between the two groups (25% in physician group, 21% in nurse group, P=0.12). There was also no difference in the group transported from the scene (mortality of 16% in both groups). Duration of hospital days was assessed separately across each study year. The nurse group was associated with a significantly shorter stay in the second year but this wasn’t surprising given the more complex cases attended by the physician group in that study period.
This study had similar limitations to that conducted by Burney et al. in 1992, except it had the advantage of a prospective approach. If the study was to have 80% power to detect a 5% difference in mortality at the 5% significance level a sample of 2,000 patients would have been required (there were 1,169 patients). The increased complexity of the patients transported by physicians in the second year makes it very difficult to interpret the results of this study.
TRANSPORTATION OF EMERGENCY PATIENTS
18
Ta
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7
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the
in
itia
l in
jurie
s o
r c
om
plic
atio
ns
of
the
in
jurie
s
Follo
w-u
p in
terv
al
Min
imu
m o
f si
x m
on
ths
An
aly
sis
Pre
dic
ted
mo
rta
lity e
stim
ate
d u
sin
g
the
TR
ISS m
eth
od
olo
gy, u
tilis
ing
th
e
mo
st r
ec
en
t c
oe
ffic
ien
ts a
va
ilab
le
at
the
tim
e.
An
aly
tic
me
tho
ds
inc
lud
ed
usi
ng
χ2,
two
ta
iled
Stu
de
nt
t te
st,
Ma
nte
l-
He
an
sze
l te
st a
nd
th
e Z
sta
tist
ic o
f
co
mp
ariso
n b
etw
ee
n p
red
icte
d
an
d a
ctu
al s
urv
iva
l.
Nu
mb
er
of
ac
tua
l de
ath
s b
y t
he
nu
mb
er
pre
dic
ted
to
die
(b
ase
d o
n
Ps
≤ 0
.50)
Pa
ram
ed
ic g
rou
p:
Pre
dic
ted
= 1
9.5
Ac
tua
l=1
9
Z s
tatist
ic 0
.208 (
P>
0.0
5)
Ph
ysi
cia
n g
rou
p:
Pre
dic
ted
16.9
Ac
tua
l 11
Z s
tatist
ic 2
.284 (
P<
0.0
5)
Diffe
ren
ce
in Z
sta
tist
ic b
etw
ee
n t
he
two
gro
up
s: 2
.076 (
P<
0.0
5)
Ind
ica
tin
g a
sta
tist
ica
lly s
ign
ific
an
t
imp
rove
d o
utc
om
e in
th
e p
hysi
cia
n
gro
up
.
Dis
trib
utio
n o
f p
atie
nts
by
pro
ba
bili
ty o
f su
rviv
al
Exp
ec
ted
to
die
bu
t liv
ed
:
Pa
ram
ed
ic: 0
Ph
ysi
cia
n: 5
Exp
ec
ted
to
live
bu
t d
ied
:
Pa
ram
ed
ic: 5
Ph
ysi
cia
n: 3
Exp
ec
ted
to
die
an
d d
ied
:
Pa
ram
ed
ic: 1
4
Ph
ysi
cia
n: 8
Lim
ita
tio
ns
�
No
t tr
uly
ra
nd
om
ise
d: d
isp
atc
h
de
pe
nd
ed
on
ro
tatio
n o
f c
alls
or
wh
ich
he
lico
pte
r w
as
clo
ser
to t
he
sce
ne
at
tim
e o
f d
isp
atc
h.
�
Ce
ntr
al c
om
mu
nic
atio
n d
id n
ot
ap
pe
ar
to b
e a
va
ilab
le f
or
eith
er
sta
ff
gro
up
.
�
The
leve
l of
exp
erie
nc
e o
f b
oth
sta
ff
gro
up
s w
as
un
cle
ar.
�
TRIS
S m
eth
od
olo
gy in
clu
de
d t
he
tra
um
a s
co
re (
TS)
rath
er
tha
n t
he
revis
ed
tra
um
a s
co
re (
RTS
). In
late
r
ye
ars
th
e R
TS s
co
re w
as
co
nsi
de
red
to
be
mo
re a
cc
ura
te t
ha
n t
he
TS s
co
re.
Su
bse
qu
en
t d
eve
lop
me
nts
in T
RIS
S
me
tho
do
log
y m
ad
e u
se o
f th
e M
sta
tist
ic w
hic
h a
llow
s a
n a
sse
ssm
en
t o
f
the
in
jury
se
ve
rity
mix
be
twe
en
stu
dy
gro
up
s a
nd
, if a
pp
rop
ria
te,
the
W
sta
tist
ic, w
hic
h d
ea
ls w
ith
diffe
ren
t
ca
se m
ixe
s a
cro
ss s
am
ple
s.
�
All-
ca
use
mo
rta
lity n
ot
use
d. M
ay
ha
ve
lea
d t
o o
utc
om
e
mis
cla
ssific
atio
n.
�
No
do
cu
me
nta
tio
n o
f b
lind
ing
in t
he
ass
ess
me
nt
of
ca
use
of
de
ath
.
�
Un
cle
ar
if t
he
re w
ere
diffe
ren
ce
s in
the
du
ratio
n o
f fo
llow
-up
be
twe
en
stu
dy g
rou
ps
(alth
ou
gh
all
rec
ord
ed
de
ath
s o
cc
urr
ed
with
in 4
8 h
ou
rs o
f
ad
mis
sio
n).
TRANSPORTATION OF EMERGENCY PATIENTS
19
Ta
ble
7
Ev
iden
ce t
ab
les
of
stu
die
s co
mp
arin
g t
he
ou
tco
me
or
pa
tien
ts t
ran
spo
rted
by
hel
ico
pte
r w
ith
an
d w
ith
ou
t a
med
ica
l d
oct
or
on
boa
rd (
con
tin
ued
)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Ba
xt
an
d M
oo
dy 1
987
)
USA
co
ntin
ue
d
A
na
lyse
s c
om
pa
ring
gro
up
s a
t b
ase
line
.
Me
dia
n p
rob
ab
ility
of
surv
iva
l:
Pa
ram
ed
ic c
rew
: 0.9
5-1
.0
Ph
ysi
cia
n c
rew
: 0.9
5-1
.0
Me
dia
n G
lasg
ow
Co
ma
Sc
ore
of
seve
re
bra
in in
jure
d p
atie
nts
(G
CS≤8
)
Pa
ram
ed
ic c
rew
(n
=44,
17%
of
tota
l): 4
Ph
ysi
cia
n c
rew
(n
=5
4, 1
7%
of
tota
l):
5
Me
an
Tra
um
a S
co
re:
Pa
ram
ed
ic g
rou
p:
14.2
Ph
ysi
cia
n g
rou
p:
14.3
Me
an
In
jury
se
ve
rity
sc
ore
:
Pa
ram
ed
ic g
rou
p:
13.6
Ph
ysi
cia
n g
rou
p:1
3.9
Me
an
pre
dic
ted
su
rviv
al
Pa
ram
ed
ic g
rou
p:
0.9
24
Ph
ysi
cia
n g
rou
p:
0.9
47
Me
an
ag
e
Pa
ram
ed
ic g
rou
p:
27.6
ye
ars
Ph
ysi
cia
n g
rou
p:
27.8
ye
ars
Tra
nsp
ort
tim
es:
Me
an
re
spo
nse
tim
e:
Pa
ram
ed
ic g
rou
p 1
5.5
min
ute
s
Ph
ysi
cia
n g
rou
p:
14.9
min
ute
s
Me
an
sc
en
e t
ime
:
Pa
ram
ed
ic g
rou
p:
18.6
min
ute
s
Ph
ysi
cia
n g
rou
p:
19.1
min
ute
s
Me
an
de
live
ry t
ime
:
Pa
ram
ed
ic g
rou
p:
16.9
min
ute
s
Ph
ysi
cia
n g
rou
p:
16.1
min
ute
s.
B
lind
ed
ch
art
an
aly
sis
ass
ess
ing
ad
he
ren
ce
to
writt
en
me
dic
al
tre
atm
en
t p
roto
co
ls.
1.
Pa
tie
nts
wh
o s
urv
ive
d
Pa
ram
ed
ic g
rou
p18 o
f 23
9 p
atie
nts
with
inc
on
sist
en
cie
s fr
om
th
e
rec
om
me
nd
ed
pro
toc
ols
Ph
ysi
cia
n g
rou
p:
2 o
f 305
pa
tie
nts
with
inc
on
sist
en
cie
s fr
om
th
e
rec
om
me
nd
ed
pro
toc
ols
.
2.
Pa
tie
nts
wh
o d
ied
Pa
ram
ed
ic g
rou
p:
9 o
f 19 p
atie
nts
with
inc
on
sist
en
cie
s fr
om
th
e
rec
om
me
nd
ed
pro
toc
ols
Ph
ysi
cia
n g
rou
p:
0 o
f 11 p
atie
nts
with
inc
on
sist
en
cie
s fr
om
th
e
rec
om
me
nd
ed
pro
toc
ols
.
No
te in
co
nsi
ste
nc
ies
inc
lud
ed
failu
re t
o c
on
du
ct
the
ind
ica
ted
pro
ce
du
re o
r m
ed
ica
l pro
ce
du
re
no
t fo
llow
ed
.
�
Po
ten
tia
l fo
r c
on
fou
nd
ing
, a
lth
ou
gh
ba
selin
e a
na
lyse
s in
dic
ate
litt
le
diffe
ren
ce
in t
ran
spo
rt t
ime
, tr
au
ma
sco
re, in
jury
se
ve
rity
sc
ore
, G
CS,
pre
dic
ted
su
rviv
al a
nd
pa
tie
nt
ag
e
be
twe
en
gro
up
s.
�
Ke
y r
esu
lts
are
ba
sed
on
a s
ma
ll
nu
mb
er
of
pa
tie
nts
wh
o s
urv
ive
d b
ut
we
re e
xpe
cte
d t
o d
ie (
5 o
f 22 in
th
e
ph
ysi
cia
n g
rou
p a
nd
0 o
f 1
6 in
th
e
pa
ram
ed
ic g
rou
p).
�
Un
cle
ar
if R
SI w
as
ava
ilab
le t
o t
he
co
mp
ara
tor
gro
up
Co
mm
en
ts
�
All
pa
tie
nts
att
en
de
d a
sin
gle
tra
um
a
ce
ntr
e.
�
The
TR
ISS m
eth
od
olo
gy w
as
ap
plie
d t
o
the
tw
o s
tud
y g
rou
ps
usi
ng
da
ta t
ha
t
we
re c
olle
cte
d a
t th
e s
am
e t
ime
be
twe
en
th
e t
wo
gro
up
s.
�
Use
d a
pp
rop
ria
te m
eth
od
olo
gy t
o
est
ima
te in
jury
se
ve
rity
.
�
Thre
e p
atie
nts
we
re e
xclu
de
d in
ea
ch
gro
up
du
e t
o t
he
lac
k o
f re
susc
ita
tiv
e
me
asu
res
in t
he
fie
ld.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
A s
tatist
ica
lly s
ign
ific
an
t re
du
ctio
n in
th
e
mo
rta
lity o
f p
atie
nts
with
blu
nt
tra
um
a
tre
ate
d b
y a
me
dic
al h
elic
op
ter
em
erg
en
cy
ca
re s
erv
ice
sta
ffe
d b
y a
nu
rse
/ph
ysi
cia
n
co
mb
ina
tio
n c
ou
ld b
e d
em
on
stra
ted
co
mp
are
d w
ith
th
at
sta
ffe
d b
y a
nu
rse
/pa
ram
ed
ic c
om
bin
atio
n.
* D
iffer
ence
in p
roce
dure
s av
aila
ble
to th
e tw
o st
affin
g gr
oups
TRANSPORTATION OF EMERGENCY PATIENTS
20
Ta
ble
7
Ev
iden
ce t
ab
les
of
stu
die
s co
mp
arin
g t
he
ou
tco
me
or
pa
tien
ts t
ran
spo
rted
by
hel
ico
pte
r w
ith
an
d w
ith
ou
t a
med
ica
l d
oct
or
on
boa
rd (
con
tin
ued
)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Ha
mm
an
et
al.
1991
)
USA
Be
fore
an
d
aft
er
de
sig
n
Leve
l III-
3.
Stu
dy s
ett
ing
.
All
pa
tie
nts
tra
nsp
ort
ed
fro
m a
cc
ide
nt
sce
ne
to
Hu
ma
na
Ho
spita
l U
niv
ers
ity
in
a 1
0 m
on
th p
erio
d in
198
5 (
with
ph
ysi
cia
n)
an
d c
om
pa
red
with
a g
rou
p
tra
nsp
ort
ed
du
rin
g a
10 m
on
th p
erio
d in
1987 (
with
ou
t p
hysi
cia
n).
Pa
rtic
ipa
nts
:
Tota
l sa
mp
le 2
59
Inte
rve
ntio
n (
n=
11
4).
Sto
pp
ed
th
e p
rese
nc
e o
f a
me
dic
al
do
cto
r o
n e
me
rge
nc
y h
elic
op
ter
(tw
o
nu
rse
s o
r n
urs
e +
pa
ram
ed
ic p
rese
nt)
Co
mp
ara
tor
(n=
14
5).
Me
dic
al d
oc
tor
(Fa
cu
lty m
em
be
r o
r a
sec
on
d o
r th
ird
ye
ar
resi
de
nt
ph
ysi
cia
n)
pre
sen
t o
n h
elic
op
ter
(be
fore
ph
ase
of
the
stu
dy).
Nu
rse
als
o o
n b
oa
rd.
Ph
ysi
cia
ns
ab
le t
o p
erf
orm
th
e f
ollo
win
g
ad
ditio
na
l pro
ce
du
res:
cric
oth
yro
ido
tom
ies
an
d t
ub
e
tho
rac
ost
om
ies.
Bo
th in
terv
en
tio
n a
nd
co
mp
ara
tor
gro
up
s in
tub
ate
d, o
bta
ine
d IV
ac
ce
ss,
pe
rfo
rme
d a
dva
nc
ed
CP
R, p
lac
ed
pn
eu
ma
tic
an
tish
oc
k g
arm
en
t,
pe
rfo
rme
d n
ee
dle
th
ora
co
sto
my a
nd
pe
rica
rdio
ce
nte
sis,
im
mo
bili
sed
th
e
ne
ck, sp
linte
d f
rac
ture
s a
nd
dre
sse
d
op
en
wo
un
ds.
Inc
lu/e
xcl c
rite
ria
.
Co
nse
cu
tive
ad
ults
du
rin
g t
he
tw
o
stu
dy p
erio
ds.
Exc
lud
ed
pa
tie
nts
with
an
initia
l an
d
sub
seq
ue
ntly u
nc
ha
ng
ed
RTS
of
0
an
d b
urn
vic
tim
s.
Da
ta c
olle
ctio
n
Dis
tan
ce
tra
nsp
ort
ed
Tim
e a
t sc
en
e
Pro
ce
du
res
pe
rfo
rme
d
RTS
ISS
Ou
tco
me
me
asu
res
Mo
rta
lity
Follo
w-u
p in
terv
al
No
t st
ate
d
An
aly
sis
Me
an
co
mp
ariso
ns
use
d e
ith
er
χ2,
Be
hre
ns-
Fis
he
r t’
, o
r th
e W
elc
h d
f’
test
to
de
term
ine
sim
ilarity
.
Re
gre
ssio
n c
on
sta
nts
we
re d
erive
d
fro
m M
TOS.
The
Z a
nd
M s
tatist
ics
we
re c
alc
ula
ted
.
Nu
mb
er
of
ac
tua
l de
ath
s b
y t
he
nu
mb
er
pre
dic
ted
to
die
(b
ase
d o
n
Ps
≤ 0
.50)
Ph
ysi
cia
n p
rese
nt
gro
up
Pre
dic
ted
: 17
Ac
tua
l: 1
2
% r
ed
uc
tio
n:
30
Z s
tatist
ic -
2.0
3
Ph
ysi
cia
n a
bse
nt
gro
up
Pre
dic
ted
: 15
Ac
tua
l: 8
% r
ed
uc
tio
n:
47
Z s
tatist
ic -
3.1
1
Fre
qu
en
cy o
f p
ote
ntia
lly li
fe
thre
ate
nin
g in
jurie
s n
ot
ad
dre
sse
d
be
fore
arr
iva
l at
ED
Ph
ysi
cia
n p
rese
nt
gro
up
: 12%
Ph
ysi
cia
n a
bse
nt
gro
up
: 6
%
P>
0.0
5
Lim
ita
tio
ns
�
Re
tro
spe
ctive
stu
dy.
�
Be
fore
an
d a
fte
r d
esi
gn
ha
ve
sig
nific
an
t lim
ita
tio
ns
du
e t
o t
he
po
ssib
le c
ha
ng
e o
f fa
cto
rs o
the
r th
an
the
in
terv
en
tio
n.
�
Len
gth
of
follo
w-u
p o
f p
art
icip
an
ts
wa
s n
ot
cle
ar.
�
Un
cle
ar
if t
he
re w
ere
diffe
ren
ce
s in
the
du
ratio
n o
f fo
llow
-up
be
twe
en
stu
dy g
rou
ps.
�
Hig
h p
ote
ntia
l fo
r c
on
fou
nd
ing
.
�
Sig
nific
an
t d
iffe
ren
ce
in a
ge
be
twe
en
the
tw
o g
rou
ps
with
th
e p
hysi
cia
n
ab
sen
t g
rou
p b
ein
g o
f yo
un
ge
r
ove
rall
ag
e a
nd
th
ere
fore
imp
rove
d
ou
tco
me
is f
avo
ure
d in
th
is g
rou
p.
�
Ke
y r
esu
lts
are
ba
sed
on
a s
ma
ll
nu
mb
er
of
pa
tie
nts
wh
o w
ere
exp
ec
ted
to
die
(32 in
to
tal)
th
us
un
de
rpo
we
red
to
de
tec
t a
diffe
ren
ce
in o
utc
om
e b
etw
ee
n t
he
tw
o s
tud
y
gro
up
s.
�
M s
tatist
ic w
as
0.8
7 w
hic
h is
less
th
an
the
ad
vis
ed
cu
t o
ff o
f 0.8
8 a
nd
th
us
ind
ica
tes
a p
oo
r m
atc
h in
inju
ry
seve
rity
be
twe
en
th
e t
wo
gro
up
s. W
sta
tist
ic w
as
no
t c
alc
ula
ted
to
ad
just
for
the
va
ria
tio
n in
ca
sem
ix.
�
Tim
ing
of
de
ath
s w
as
no
t
do
cu
me
nte
d.
�
Un
cle
ar
if R
TS w
as
est
ima
ted
at
the
sam
e t
ime
po
st in
jury
in b
oth
gro
up
s.
RTS
is s
usc
ep
tib
le t
o c
ha
ng
e o
ve
r
tim
e.
TRANSPORTATION OF EMERGENCY PATIENTS
21
Ta
ble
7
Ev
iden
ce t
ab
les
of
stu
die
s co
mp
arin
g t
he
ou
tco
me
or
pa
tien
ts t
ran
spo
rted
by
hel
ico
pte
r w
ith
an
d w
ith
ou
t a
med
ica
l d
oct
or
on
boa
rd (
con
tin
ued
)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Ha
mm
an
et
al.
1991
)
USA
co
ntin
ue
d
A
na
lyse
s c
om
pa
ring
gro
up
s a
t b
ase
line
.
Ave
rag
e a
ge
(ye
ars
):
Ph
ysi
cia
n p
rese
nt:
34
Ph
ysi
cia
n a
bse
nt:
30
P<
0.0
5
Dis
tan
ce
tra
nsp
ort
ed
(m
iles)
Ph
ysi
cia
n p
rese
nt:
21
Ph
ysi
cia
n a
bse
nt:
23
Initia
l tra
um
a s
co
re
Ph
ysi
cia
n p
rese
nt:
7
Ph
ysi
cia
n a
bse
nt:
7
Nu
mb
er
of
org
an
s in
jure
d:
Ph
ysi
cia
n p
rese
nt:
2
Ph
ysi
cia
n a
bse
nt:
2
ISS
Ph
ysi
cia
n p
rese
nt:
15
Ph
ysi
cia
n a
bse
nt:
15
Tim
e a
t sc
en
e (
min
ute
s)
Ph
ysi
cia
n p
rese
nt:
15
Ph
ysi
cia
n a
bse
nt:
15
Nu
mb
er
of
sce
ne
pro
ce
du
res
(% p
er
att
en
da
nc
e)
Ph
ysi
cia
n p
rese
nt:
221
Ph
ysi
cia
n a
bse
nt:
25
6
Nu
mb
er
of
in-f
ligh
t p
roc
ed
ure
s (%
pe
r
att
en
da
nc
e)
Ph
ysi
cia
n p
rese
nt:
8
Ph
ysi
cia
n a
bse
nt:
4
Co
mm
en
ts
�
All
pa
tie
nts
att
en
de
d a
sin
gle
tra
um
a
ce
ntr
e.
�
Ce
ntr
al c
om
mu
nic
atio
n w
as
no
t
do
cu
me
nte
d f
or
eith
er
gro
up
.
�
TRIS
S m
eth
od
olo
gy a
pp
rop
ria
tely
use
d
RTS
sc
ore
.
�
TRIS
S a
na
lysi
s a
pp
rop
riate
ly in
clu
de
d
est
ima
tio
n o
f th
e M
sta
tist
ic.
�
Use
d a
pp
rop
ria
te m
eth
od
olo
gy t
o
est
ima
te in
jury
se
ve
rity
.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
It a
pp
ea
rs t
ha
t e
xpe
rie
nc
ed
nu
rse
s a
nd
pa
ram
ed
ics,
op
era
tin
g w
ith
we
ll-e
sta
blis
he
d
pro
toc
ols
, c
an
pro
vid
e a
gg
ress
ive
ca
re t
ha
t
yie
lds
eq
ua
l ou
tco
me
re
sults
co
mp
are
d w
ith
tho
se o
f a
flig
ht
tea
m t
ha
t in
clu
de
s a
ph
ysi
cia
n.
TRANSPORTATION OF EMERGENCY PATIENTS
22
Ta
ble
7
Ev
iden
ce t
ab
les
of
stu
die
s co
mp
arin
g t
he
ou
tco
me
or
pa
tien
ts t
ran
spo
rted
by
hel
ico
pte
r w
ith
an
d w
ith
ou
t a
med
ica
l d
oct
or
on
boa
rd (
con
tin
ued
)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Ha
mm
an
et
al.
1991
)
USA
co
ntin
ue
d
N
um
be
r o
f e
me
rge
nc
y r
oo
m
pro
ce
du
res
(% p
er
att
en
da
nc
e)
Ph
ysi
cia
n p
rese
nt:
26
Ph
ysi
cia
n a
bse
nt:
20
Blu
nt
ve
rsu
s p
en
etr
atin
g in
jurie
s (%
)
Ph
ysi
cia
n p
rese
nt:
95:5
Ph
ysi
cia
n a
bse
nt:
93
:7
TRANSPORTATION OF EMERGENCY PATIENTS
23
Ta
ble
7
Ev
iden
ce t
ab
les
of
stu
die
s co
mp
arin
g t
he
ou
tco
me
or
pa
tien
ts t
ran
spo
rted
by
hel
ico
pte
r w
ith
an
d w
ith
ou
t a
med
ica
l d
oct
or
on
boa
rd (
con
tin
ued
)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Sc
hm
idt
et
al.
1992
)
USA
an
d G
erm
an
y
Re
gis
try b
ase
d
stu
dy
co
mp
arin
g
mo
rta
lity in
two
ce
ntr
es
Leve
l III-
2.
Stu
dy s
ett
ing
.
Two
se
ttin
gs:
USA
an
d G
erm
an
y. Th
e
USA
se
ttin
g c
on
sist
ed
of
he
lico
pte
rs
cre
we
d b
y f
ligh
t n
urs
e a
nd
pa
ram
ed
ic
(Ju
ly 1
98
8-J
un
e 1
989
). T
he
Ge
rma
n
sett
ing
co
nsi
ste
d o
f h
elic
op
ters
cre
we
d
by t
rau
ma
su
rge
on
an
d p
ara
me
dic
(No
ve
mb
er
198
8-O
cto
be
r 19
89
).
Pa
rtic
ipa
nts
:
Tota
l 407
Inte
rve
ntio
n (
n=
22
1)
Ge
rma
n s
ett
ing
(w
ith
su
rge
on
)
Co
mp
ara
tor
(n=
18
6).
USA
se
ttin
g (
with
ou
t su
rge
on
)
Pre
-ho
spita
l A
LS in
clu
de
d
IV f
luid
s, E
T in
tub
atio
n,
tub
e
tho
rac
ost
om
y/n
ee
dle
de
co
mp
ress
ion
.
Hig
h u
se o
f IV
an
ae
sth
esi
a in
Ge
rma
ny.
Inc
lu/e
xcl c
rite
ria
.
All
pa
tie
nts
with
mu
ltip
le in
jurie
s
tra
nsp
ort
ed
to
th
e t
wo
re
spe
ctive
tra
um
a c
en
tre
s d
urin
g a
on
e y
ea
r
pe
riod
.
Pa
tie
nts
we
re t
ran
spo
rte
d d
ire
ctly
to t
he
tra
um
a c
en
tre
ra
the
r th
an
via
an
inte
rme
dia
te f
ac
ility
.
Exc
lud
ed
pa
tie
nts
with
inc
om
ple
te
or
mis
sin
g c
ha
rts.
Da
ta c
olle
ctio
n
Da
ta r
etr
ieve
d f
rom
tra
um
a r
eg
istr
y
rec
ord
s a
nd
flig
ht
log
s.
Ext
rac
ted
pa
tie
nt
ag
e,
me
ch
an
ism
of
inju
ry, flig
ht
tim
es
fro
m t
he
sc
en
e
to t
he
tra
um
a c
en
tre
, R
TS, IS
S,
AIS
-
85,
mo
rta
lity,
tim
e o
f d
ea
th f
rom
ho
spita
l ad
mis
sio
n a
nd
pre
-ho
spita
l
ALS
re
ce
ive
d.
RTS
me
asu
red
in t
he
fie
ld in
Ge
rma
ny a
nd
up
on
arr
iva
l
at
the
tra
um
a c
en
tre
in U
SA
.
Ou
tco
me
me
asu
res
Mo
rta
lity
Follo
w-u
p in
terv
al
No
t st
ate
d
Nu
mb
er
of
ac
tua
l de
ath
s b
y t
he
nu
mb
er
pre
dic
ted
to
die
(b
ase
d o
n
Ps
≤ 0
.50)
Su
rge
on
gro
up
Z s
tatist
ic +
2.4
59
P<
0.0
25
M s
tatist
ic 0
.89
W s
tatist
ic in
dic
ate
s 1.3
5 a
dd
itio
na
l
surv
ivo
rs f
rom
100
pa
tie
nts
an
aly
sed
co
mp
are
d w
ith
th
e M
TOS
po
pu
latio
n.
No
n-s
urg
eo
n g
rou
p
Z s
tatist
ic +
1.0
49
P>
0.0
5
No
te h
ow
eve
r, M
st
atist
ic o
f 0.8
74
ind
ica
tes
less
th
an
ide
al d
eg
ree
of
ma
tch
in in
jury
se
ve
rity
(a
dvis
ed
cu
t
off
0.8
8)
De
ath
with
in 6
ho
urs
Su
rge
on
pre
sen
t: 4
of
21
de
ath
s
Su
rge
on
ab
sen
t: 1
2 o
f 21 d
ea
ths
P<
0.0
1
Lim
ita
tio
ns
�
Re
tro
spe
ctive
, re
gis
try b
ase
d s
tud
y.
�
Exc
lud
ed
37 p
atie
nts
fro
m t
he
Ge
rma
n s
ett
ing
du
e t
o in
co
mp
lete
or
mis
sin
g c
ha
rts.
Th
is is
a lik
ely
so
urc
e o
f
sele
ctio
n b
ias
giv
en
th
ere
we
re n
o
de
ath
s in
th
is g
rou
p.
�
Va
riatio
n in
tim
ing
of
RTS
est
ima
tio
n
will
re
sult in
va
ria
tio
n in
th
e p
red
icte
d
surv
iva
l in
th
e t
wo
gro
up
s. T
he
refo
re,
co
nc
ern
s e
xis
t a
bo
ut
the
dire
ct
co
mp
ara
bili
ty o
f th
e p
atie
nt
surv
iva
l
da
ta b
etw
ee
n t
he
tw
o g
rou
ps.
�
Un
cle
ar
if t
he
re w
ere
diffe
ren
ce
s in
the
du
ratio
n o
f fo
llow
-up
be
twe
en
stu
dy g
rou
ps.
�
Hig
h p
ote
ntia
l fo
r c
on
fou
nd
ing
.
�
Sig
nific
an
tly s
ho
rte
r tim
e f
rom
inc
ide
nt
to la
un
ch
in t
he
su
rge
on
gro
up
po
ten
tia
lly im
pro
vin
g p
rog
no
sis.
�
Sig
nific
an
tly lo
ng
er
sce
ne
tim
e in
th
e
surg
eo
n g
rou
p.
TRANSPORTATION OF EMERGENCY PATIENTS
24
Ta
ble
7
Ev
iden
ce t
ab
les
of
stu
die
s co
mp
arin
g t
he
ou
tco
me
or
pa
tien
ts t
ran
spo
rted
by
hel
ico
pte
r w
ith
an
d w
ith
ou
t a
med
ica
l d
oct
or
on
boa
rd (
con
tin
ued
)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Sc
hm
idt
et
al.
1992
)
USA
an
d G
erm
an
y
co
ntin
ue
d
A
na
lyse
s c
om
pa
ring
gro
up
s a
t b
ase
line
.
Me
an
ag
e (
ye
ars
)
Su
rge
on
pre
sen
t: 36
(ra
ng
e 1
-90)
Su
rge
on
ab
sen
t: 2
9.5
(ra
ng
e 1
-86)
Blu
nt
me
ch
an
ism
of
inju
ry (
%)
Su
rge
on
pre
sen
t: 10
0
Su
rge
on
ab
sen
t: 8
9.2
Me
an
ISS s
co
re
Su
rge
on
pre
sen
t: 1
8
Su
rge
on
ab
sen
t: 1
9.8
Tota
l de
ath
s:
Su
rge
on
pre
sen
t: 2
1 (
9.5
%)
Su
rge
on
ab
sen
t: 2
1 (
11.3
%)
Me
an
tim
e f
rom
in
cid
en
t to
he
lico
pte
r
lau
nc
h (
min
ute
s)
Su
rge
on
pre
sen
t: 5
.5
Su
rge
on
ab
sen
t: 1
7.5
P<
0.0
5
Me
an
sc
en
e t
ime
(m
inu
tes)
Su
rge
on
pre
sen
t: 1
9.3
Su
rge
on
ab
sen
t: 1
0
P<
0.0
5
Tota
l mis
sio
n t
ime
fro
m in
cid
en
t to
ho
spita
l arr
iva
l (m
inu
tes)
Su
rge
on
pre
sen
t: 4
2.5
Su
rge
on
ab
sen
t: 5
4.5
P>
0.0
5
ISS s
co
res
ha
d s
imila
r d
istr
ibu
tio
ns
at
bo
th c
en
tre
s. S
imila
r d
istr
ibu
tio
ns
of
ag
e
an
d ISS w
ere
als
o o
bse
rve
d a
t b
oth
site
s. U
ne
qu
al d
istr
ibu
tio
n o
f se
ve
re
inju
rie
s to
on
e b
od
y r
eg
ion
wa
s a
lso
no
t
de
mo
nst
rate
d.
An
aly
sis
Me
an
s fo
r a
ge
, IS
S a
nd
flig
ht
tim
es
ca
lcu
late
d.
Dis
trib
utio
ns
of
ISS c
on
stru
cte
d.
Co
mp
ara
bili
ty o
f b
od
y r
eg
ion
s
inju
red
co
mp
are
d u
sin
g t
he
AIS
sco
re.
TRIS
S m
eth
od
s u
sed
(re
fere
nc
e
MTO
S)
to c
om
pa
re b
oth
ce
ntr
es.
Pro
ba
bili
ty o
f su
rviv
al u
sed
to
ca
lcu
late
th
e Z
sta
tist
ic.
The
M a
nd
W s
tatist
ics
we
re c
alc
ula
ted
fo
r
ea
ch
inst
itu
tio
n.
Ad
va
nc
ed
pre
-ho
spita
l ca
re
ET
intu
ba
tio
n
Su
rge
on
pre
sen
t: 3
7.1
%
Su
rge
on
ab
sen
t: 1
3.4
%
P<
0001
Tho
rac
ic c
av
ity d
ec
om
pre
ssio
n
Su
rge
on
pre
sen
t: 9
.1%
Su
rge
on
ab
sen
t: 0
.5%
P<
0.0
01
IV f
luid
infu
sio
n (
me
an
mls
)
Su
rge
on
pre
sen
t: 1
800
Su
rge
on
ab
sen
t: 8
25
P<
0.0
5
Co
mm
en
ts
�
All
pa
tie
nts
att
en
de
d a
sin
gle
tra
um
a
ce
ntr
e in
ea
ch
co
un
try.
�
TRIS
S m
eth
od
olo
gy a
pp
rop
ria
tely
use
d
RTS
sc
ore
.
�
TRIS
S a
na
lysi
s a
pp
rop
riate
ly in
clu
de
d
est
ima
tio
n o
f th
e M
an
d W
sta
tist
ics.
�
Use
d a
pp
rop
ria
te m
eth
od
olo
gy t
o
est
ima
te in
jury
se
ve
rity
.
�
Me
dic
al c
on
tro
l ava
ilab
le b
y r
ad
io in
USA
.
�
Re
sults
ma
y r
efle
ct
mo
re a
gg
ress
ive
the
rap
y in
Ge
rma
ny r
ath
er
tha
n t
he
spe
cific
cre
w c
on
fig
ura
tio
n s
inc
e k
ey
diffe
ren
ce
s in
th
e p
roc
ed
ure
s u
sed
ca
n b
e c
on
du
cte
d b
y p
ara
me
dic
s
an
d f
ligh
t n
urs
es
as
we
ll a
s d
oc
tors
.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
With
on
sc
en
e e
xpe
rie
nc
e a
nd
jud
ge
me
nt
of
a t
rau
ma
su
rge
on
, th
e G
erm
an
ae
rom
ed
ica
l syst
em
pro
vid
ed
mo
re
ag
gre
ssiv
e p
re-h
osp
ita
l re
susc
ita
tio
n,
pa
rtic
ula
rly in
th
e a
rea
s o
f a
irw
ay a
nd
ve
ntila
tio
n m
an
ag
em
en
t.
TRANSPORTATION OF EMERGENCY PATIENTS
25
Ta
ble
7
Ev
iden
ce t
ab
les
of
stu
die
s co
mp
arin
g t
he
ou
tco
me
or
pa
tien
ts t
ran
spo
rted
by
hel
ico
pte
r w
ith
an
d w
ith
ou
t a
med
ica
l d
oct
or
on
boa
rd (
con
tin
ued
)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Ga
rne
r e
t a
l. 19
99
)
Au
stra
lia
Re
tro
spe
ctive
co
ho
rt s
tud
y
Leve
l III-
2.
Stu
dy s
ett
ing
.
He
lico
pte
r tr
an
spo
rta
tio
n o
f p
atie
nts
fro
m t
he
sc
en
e o
ve
r a
28 m
on
th p
erio
d.
Pa
rtic
ipa
nts
(n
=2
07
):
Inte
rve
ntio
n (
n=
67
).
Ph
ysi
cia
n s
taff
ed
NR
MA
Ca
reFl
igh
t
he
lico
pte
r
Co
mp
ara
tor
(n=
14
0).
Pa
ram
ed
ic s
taff
ed
We
stp
ac
Hu
nte
r
reg
ion
he
lico
pte
r.
An
aly
ses
co
mp
arin
g g
rou
ps
at
ba
selin
e.
Me
dia
n a
ge
(ye
ars
)
Ph
ysi
cia
n g
rou
p:
31 (
13
-70
)
Pa
ram
ed
ic g
rou
p:
33 (
2-8
9)
Me
ch
an
ism
of
inju
ry
Mo
tor
ve
hic
le o
cc
up
an
t
Ph
ysi
cia
n g
rou
p:
63%
Pa
ram
ed
ic g
rou
p:
63
%
Mo
tor
bik
e r
ide
r
Ph
ysi
cia
n g
rou
p:
9%
Pa
ram
ed
ic g
rou
p:
11
%
Pe
da
l cyc
list
or
pe
de
stria
n
Ph
ysi
cia
n g
rou
p:
3%
Pa
ram
ed
ic g
rou
p:
5%
Inc
lu/e
xcl c
rite
ria
.
Blu
nt
tra
um
a
ISS ≥
10
Tra
nsp
ort
ed
dire
ctly f
rom
th
e
inc
ide
nt
sce
ne
Inc
ide
nt
oc
cu
rre
d b
etw
ee
n
Jan
ua
ry 1
996 a
nd
Ap
ril 1
998.
Da
ta c
olle
ctio
n
Pa
ram
ed
ic g
rou
p r
etr
osp
ec
tive
ly
ide
ntifie
d f
rom
th
e t
rau
ma
re
gis
try
of
Joh
n H
un
ter
Ho
spita
l, N
ew
ca
stle
.
Ph
ysi
cia
n g
rou
p id
en
tifie
d f
rom
th
e
me
dic
al d
ata
ba
se o
f N
RM
A
Ca
reFl
igh
t/N
SW
Me
dic
al r
etr
ieva
l
Se
rvic
e w
ho
we
re t
ran
spo
rte
d t
o
We
stm
ea
d o
r N
ep
ea
n h
osp
ita
ls in
Syd
ne
y.
Pre
-ho
spita
l ca
se s
he
ets
we
re
exa
min
ed
to
allo
w t
he
ca
lcu
latio
n
of
the
RTS
(firs
t re
co
rde
d d
ata
use
d).
Oth
er
da
ta c
olle
cte
d
inc
lud
ed
de
mo
gra
ph
ics,
me
ch
an
ism
of
inju
ry, re
spo
nse
,
sce
ne
an
d t
ran
spo
rt t
ime
s,
en
tra
pm
en
t a
t th
e s
ce
ne
,
req
uire
me
nt
for
win
ch
extr
ac
tio
n,
flu
ids
ad
min
iste
red
an
d p
roc
ed
ure
s
pe
rfo
rme
d a
t th
e s
ce
ne
or
in t
ran
sit.
Ou
tco
me
me
asu
res
Mo
rta
lity. C
om
pa
red
with
TR
ISS
me
tho
do
log
y u
sin
g c
oe
ffic
ien
ts
de
rive
d f
rom
th
e M
TOS u
sin
g t
he
1990 a
bb
revia
ted
inju
ry s
ca
le.
Co
mp
aris
on
be
twe
en
ob
serv
ed
an
d p
red
icte
d m
ort
alit
y m
ad
e a
t
ho
spita
l dis
ch
arg
e.
Nu
mb
er
of
ac
tua
l de
ath
s b
y t
he
nu
mb
er
pre
dic
ted
to
die
(b
ase
d o
n
Ps
≤ 0
.50)
Ph
ysi
cia
n g
rou
p
Z s
tatist
ic +
2.7
2
P<
0.0
1
M s
tatist
ic 0
.62
Ad
just
ed
W s
tatist
ic 9
.48 (
95%
CI
3.8
4-1
5.1
2)
co
mp
are
d w
ith
th
e
MTO
S p
op
ula
tio
n.
Pa
ram
ed
ic g
rou
p
Z s
tatist
ic -
1.1
6
P=
0.2
5
M s
tatist
ic 0
.68
Ad
just
ed
W s
tatist
ic -
2.3
7 (
95%
CI -
6.8
1 t
o 2
.07)
co
mp
are
d w
ith
th
e
MTO
S p
op
ula
tio
n.
Dire
ct
co
mp
ariso
n b
etw
ee
n
ph
ysi
cia
n a
nd
pa
ram
ed
ic g
rou
p
Ad
just
ed
W s
tatist
ic 1
3.4
4 (
95%
CI
7.8
0-1
9.0
8)
sug
ge
stin
g a
n a
dd
itio
na
l
13 s
urv
ivo
rs p
er
10
0 p
atie
nts
tre
ate
d
in t
he
ph
ysi
cia
n g
rou
p c
om
pa
red
with
th
e p
ara
me
dic
gro
up
.
Lim
ita
tio
ns
�
Re
tro
spe
ctive
stu
dy.
�
Gro
up
s tr
ea
ted
in d
iffe
ren
t h
osp
ita
ls –
pa
ram
ed
ic g
rou
p t
rea
ted
in a
leve
l 6
ho
spita
l, p
hysi
cia
n g
rou
p in
a le
ve
l 5
or
leve
l 6 h
osp
ita
l.
�
Sta
tist
ica
lly s
ign
ific
an
t d
iffe
ren
ce
in
ba
selin
e G
CS a
nd
ISS s
co
res.
co
nsi
ste
nt
with
in
cre
ase
d s
eve
rity
in
the
ph
ysi
cia
n g
rou
p.
�
Un
cle
ar
if t
he
re w
ere
diffe
ren
ce
s in
the
du
ratio
n o
f fo
llow
-up
be
twe
en
stu
dy g
rou
ps.
�
Ob
serv
atio
n s
tud
y is
su
sce
ptib
le t
o
co
nfo
un
din
g a
lth
ou
gh
use
of
the
W
sta
tist
ic h
elp
s a
dju
st f
or
TRIS
S v
aria
ble
s
be
twe
en
th
e s
tud
y p
op
ula
tio
ns.
�
Ce
ntr
al c
om
mu
nic
atio
n w
as
no
t
do
cu
me
nte
d f
or
eith
er
gro
up
.
�
RTS
sc
ore
in t
he
MTO
S s
tud
y w
as
ca
lcu
late
d a
t a
dm
issi
on
ra
the
r th
an
at
the
sc
en
e a
s p
erf
orm
ed
in t
his
stu
dy. Th
e a
pp
roa
ch
use
d in
th
is s
tud
y
ha
s th
e a
dva
nta
ge
of
co
llec
tin
g R
TS
da
ta b
efo
re in
tub
atio
n a
nd
co
mp
arin
g R
TS in
bo
th g
rou
ps
at
ap
pro
xim
ate
ly t
he
sa
me
tim
e.
Ho
we
ve
r, c
om
pa
riso
n w
ith
MTO
S is
no
t so
va
lid g
ive
n t
he
diffe
ren
ce
in
tim
ing
.
�
Se
ve
n p
atie
nts
we
re e
xclu
de
d d
ue
to
mis
sin
g c
ase
sh
ee
ts.
All
7 w
ere
in t
he
pa
ram
ed
ic g
rou
p p
rod
uc
ing
a
sele
ctio
n b
ias.
TRANSPORTATION OF EMERGENCY PATIENTS
26
Ta
ble
7
Ev
iden
ce t
ab
les
of
stu
die
s co
mp
arin
g t
he
ou
tco
me
or
pa
tien
ts t
ran
spo
rted
by
hel
ico
pte
r w
ith
an
d w
ith
ou
t a
med
ica
l d
oct
or
on
boa
rd (
con
tin
ued
)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Ga
rne
r e
t a
l. 19
99
)
Au
stra
lia
co
ntin
ue
d
Fa
lls
Ph
ysi
cia
n g
rou
p:
10%
Pa
ram
ed
ic g
rou
p:
6%
Me
dia
n t
ime
inte
rva
ls (
min
ute
s)
Ca
ll to
sc
en
e a
rriv
al
Ph
ysi
cia
n g
rou
p:
29
Pa
ram
ed
ic g
rou
p:
26
Sc
en
e t
ime
(e
xclu
din
g t
rap
pe
d a
nd
win
ch
ed
pa
tie
nts
)
Ph
ysi
cia
n g
rou
p:
33
Pa
ram
ed
ic g
rou
p:
34
Tra
nsp
ort
tim
e t
o h
osp
ita
l
Ph
ysi
cia
n g
rou
p:
15
Pa
ram
ed
ic g
rou
p:
12
Tota
l pre
-ho
spita
l tim
e
Ph
ysi
cia
n g
rou
p:
86
Pa
ram
ed
ic g
rou
p:
82
Me
dia
n R
TS
Ph
ysi
cia
n g
rou
p:
6.9
0
Pa
ram
ed
ic g
rou
p:
7
.55
Me
dia
n G
CS
Ph
ysi
cia
n g
rou
p: 1
3
Pa
ram
ed
ic g
rou
p:
14
P=
0.0
5
Me
dia
n ISS
Ph
ysi
cia
n g
rou
p:
25
Pa
ram
ed
ic g
rou
p:
18
P=
0.0
5
Follo
w-u
p in
terv
al
No
t st
ate
d
An
aly
sis
Ca
teg
oric
al v
aria
ble
s: χ
2 o
r Fi
she
r’s
exa
ct
test
, a
s a
pp
rop
ria
te.
Co
ntin
uo
us
va
ria
ble
s: M
an
n-
Wh
itn
ey U
te
st.
Co
mp
aris
on
be
twe
en
pre
dic
ted
an
d o
bse
rve
d m
ort
alit
y u
sin
g Z
, W
an
d M
sta
tist
ics.
An
ad
just
ed
W
sta
tist
ic w
as
ca
lcu
late
d b
y t
he
me
tho
d o
f Y
ou
ng
e w
he
n t
he
M
sta
tist
ic in
dic
ate
d a
po
or
ma
tch
with
th
e M
TOS c
oh
ort
an
d t
o
dire
ctly c
om
pa
re t
he
pa
ram
ed
ic
an
d p
hysi
cia
n t
rea
ted
gro
up
s.
Pro
ce
du
res
at
sce
ne
Me
dia
n v
olu
me
of
flu
id in
fuse
d in
pa
tie
nts
wh
o r
ec
eiv
ed
> 5
0m
L
Ph
ysi
cia
n g
rou
p:
250
0
Pa
ram
ed
ic g
rou
p:
825
P<
0.0
01
Me
dia
n v
olu
me
of
flu
id (
mL)
infu
sed
in p
atie
nts
with
initia
l hyp
ote
nsi
on
(syst
olic
BP
<90
mm
Hg
)
Ph
ysi
cia
n g
rou
p:
503
5
Pa
ram
ed
ic g
rou
p:
147
5
P<
0.0
01
Nu
mb
er
of
pa
tie
nts
intu
ba
ted
Ph
ysi
cia
n g
rou
p:
34/6
7 (
1
cric
oth
yro
ido
tom
y, m
usc
le r
ela
xan
t
dru
gs
use
d in
28 o
f th
e 3
4
intu
ba
tio
ns)
Pa
ram
ed
ic g
rou
p:
14
/14
0
P<
0.0
01
Pro
po
rtio
n o
f p
atie
nts
with
GC
S<
9
intu
ba
ted
Ph
ysi
cia
n g
rou
p:
23/2
3
Pa
ram
ed
ic g
rou
p:
14
/36
P<
0.0
01
Tho
rac
ic d
ec
om
pre
ssio
ns
Ph
ysi
cia
n g
rou
p:
8/6
7 (
6 t
ub
e, 2
ne
ed
le)
Pa
ram
ed
ic g
rou
p:
2/1
40 (
bo
th
ne
ed
le)
P<
0.0
1
Co
mm
en
ts
�
TRIS
S m
eth
od
olo
gy a
pp
rop
ria
tely
use
d
RTS
sc
ore
.
�
TRIS
S a
na
lysi
s a
pp
rop
riate
ly in
clu
de
d
est
ima
tio
n o
f th
e M
an
d W
sta
tist
ics.
�
Use
d a
pp
rop
ria
te m
eth
od
olo
gy t
o
est
ima
te in
jury
se
ve
rity
.
�
Diffe
ren
ce
s in
pro
ce
du
res
pe
rfo
rme
d
be
twe
en
stu
dy g
rou
ps.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
Ph
ysi
cia
ns
pe
rfo
rm a
gre
ate
r n
um
be
r o
f
pro
ce
du
res
at
ac
cid
en
t sc
en
es
with
ou
t
inc
rea
sin
g s
ce
ne
tim
e.
This
re
sults
in
sig
nific
an
tly lo
we
r m
ort
alit
y. C
ritic
al c
are
ph
ysi
cia
ns
sho
uld
be
ad
de
d t
o p
ara
me
dic
he
lico
pte
r se
rvic
es
for
sce
ne
re
spo
nse
to
blu
nt
tra
um
a.
TRANSPORTATION OF EMERGENCY PATIENTS
27
Ta
ble
7
Ev
iden
ce t
ab
les
of
stu
die
s co
mp
arin
g t
he
ou
tco
me
or
pa
tien
ts t
ran
spo
rted
by
hel
ico
pte
r w
ith
an
d w
ith
ou
t a
med
ica
l d
oct
or
on
boa
rd (
con
tin
ued
)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Ca
me
ron
et
al.
20
05)
Au
stra
lia
Be
fore
an
d
aft
er
stu
dy.
Re
tro
spe
ctive
ch
art
re
vie
w.
Leve
l III-
3.
Stu
dy s
ett
ing
.
Ca
irn
s B
ase
ho
spita
l. U
ntil 2
00
1
he
lico
pte
rs in
clu
de
d e
me
rge
nc
y
ph
ysi
cia
ns.
Sin
ce
2001 t
he
y h
ave
be
en
sta
ffe
d b
y in
ten
sive
ca
re p
ara
me
dic
s.
Pa
rtic
ipa
nts
(n
=3
74
):
Inte
rve
ntio
n (
n=
16
3)
Sto
pp
ed
th
e p
rese
nc
e o
f a
n
em
erg
en
cy p
hysi
cia
n o
n a
n
em
erg
en
cy h
elic
op
ter
Co
mp
ara
tor
(n=
21
1)
Em
erg
en
cy p
hysi
cia
n o
n b
oa
rd
An
aly
ses
co
mp
arin
g g
rou
ps
at
ba
selin
e
Me
dia
n a
ge
(ye
ars
)
Ph
ysi
cia
n g
rou
p:
34
Pa
ram
ed
ic g
rou
p:
33
Ma
les
(%)
Ph
ysi
cia
n g
rou
p:
64.0
Pa
ram
ed
ic g
rou
p:
65.6
Me
an
RTS
Ph
ysi
cia
n g
rou
p:
7.7
22
Pa
ram
ed
ic g
rou
p:
7.7
30
Inc
lu/e
xcl c
rite
ria
.
An
y p
rim
ary
ta
skin
g o
f th
e
he
lico
pte
r. C
ase
s w
ere
ide
ntifie
d b
y
the
‘m
od
e o
f a
rriv
al’
fie
ld re
co
rde
d
on
th
e E
D in
form
atio
n s
yst
em
Da
ta c
olle
ctio
n
The
RTS
wa
s c
alc
ula
ted
usi
ng
th
e
initia
l clin
ica
l ob
serv
atio
ns
in t
he
me
dic
al r
ec
ord
s a
nd
am
bu
lan
ce
form
s.
Ou
tco
me
me
asu
res
30 d
ay m
ort
alit
y
Len
gth
of
in-h
osp
ita
l sta
y
Tra
nsf
er
rate
s
Ra
tes
of
dis
ch
arg
e d
ire
ctly f
rom
ho
spita
l
An
aly
sis
An
aly
ses
co
mp
arin
g g
rou
ps
at
ba
selin
e.
On
e w
ay a
na
lysi
s o
f va
ria
nc
e w
as
un
de
rta
ke
n a
nd
P v
alu
es
an
d a
χ2
test
with
Ya
tes
co
rre
ctio
n w
ere
ca
lcu
late
d w
he
re a
pp
rop
ria
te.
Ka
pp
a s
tatist
ic w
as
use
d t
o a
sse
ss
inte
r-ra
ter
relia
bili
ty in
th
e c
ha
rt
ext
rac
tio
n.
30 d
ay m
ort
alit
y p
rop
ort
ion
, b
y
stu
dy g
rou
p (
%)
Ph
ysi
cia
n g
rou
p:
2.8
%
Pa
ram
ed
ic g
rou
p:
2.5
%
P=
0.8
Me
an
ho
spita
l le
ng
th o
f st
ay, b
y
stu
dy g
rou
p (
da
ys)
Ph
ysi
cia
n g
rou
p:
2
Pa
ram
ed
ic g
rou
p:
1
P=
0.3
Lim
ita
tio
ns
�
Re
tro
spe
ctive
stu
dy.
�
The
ac
cu
rac
y o
f c
od
ing
th
e m
od
e o
f
arr
iva
l (u
sed
to
ide
ntify
re
leva
nt
pa
tie
nts
) w
as
no
t d
oc
um
en
ted
.
Ho
we
ve
r, t
his
is n
ot
like
ly t
o b
e a
ma
jor
sou
rce
of
bia
s.
�
Un
cle
ar
if t
he
tim
ing
of
the
me
asu
rem
en
ts u
sed
to
ass
ess
RTS
wa
s
the
sa
me
in b
oth
gro
up
s.
�
Me
asu
res
of
inju
ry s
eve
rity
use
d w
ere
diffe
ren
t fr
om
th
e n
orm
al a
pp
roa
ch
.
No
use
of
the
ISS s
o it
wa
s n
ot
po
ssib
le
to a
sse
ss p
rob
ab
ility
of
surv
iva
l w
ith
refe
ren
ce
to
a s
uita
ble
po
pu
latio
n
suc
h a
s M
TOS.
�
Ob
serv
atio
n s
tud
y is
su
sce
ptib
le t
o
co
nfo
un
din
g.
�
Ce
ntr
al c
om
mu
nic
atio
n w
as
no
t
do
cu
me
nte
d f
or
eith
er
gro
up
.
�
Ba
selin
e d
iffe
ren
ce
s in
pa
tie
nts
ad
mitte
d w
ith
hig
he
r p
rop
ort
ion
of
the
ph
ysi
cia
n g
rou
p b
ein
g a
dm
itte
d.
�
Ve
ry lo
w n
um
be
r o
f d
ea
ths
co
nsi
ste
nt
with
low
stu
dy p
ow
er
(10 d
ea
ths
in
tota
l).
�
Au
tho
rs s
ug
ge
ste
d R
TS w
as
a p
oo
r
pre
dic
tor
of
ne
ed
fo
r a
dm
issi
on
an
d
po
stu
late
d t
ha
t A
PA
CH
E m
ay h
ave
be
en
a b
ett
er
me
asu
re.
�
No
fo
llow
-up
of
pa
tie
nts
dis
ch
arg
ed
dire
ctly f
rom
ED
TRANSPORTATION OF EMERGENCY PATIENTS
28
Ta
ble
7
Ev
iden
ce t
ab
les
of
stu
die
s co
mp
arin
g t
he
ou
tco
me
or
pa
tien
ts t
ran
spo
rted
by
hel
ico
pte
r w
ith
an
d w
ith
ou
t a
med
ica
l d
oct
or
on
boa
rd (
con
tin
ued
)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Ca
me
ron
et
al.
20
05)
Au
stra
lia
co
ntin
ue
d
P
rop
ort
ion
dis
ch
arg
ed
fro
m E
D
Ph
ysi
cia
n g
rou
p:
14.7
%
Pa
ram
ed
ic g
rou
p:
33.1
%
P=
0.0
00
1
Pro
po
rtio
n o
f tr
au
ma
pa
tie
nts
ad
mitte
d
Ph
ysi
cia
n g
rou
p:
86.7
%
Pa
ram
ed
ic g
rou
p:
68.9
%
P=
0.0
02
Pro
po
rtio
n o
f n
on
-tra
um
a p
atie
nts
ad
mitte
d
Ph
ysi
cia
n g
rou
p:
83.7
Pa
ram
ed
ic g
rou
p:
64.4
P=
0.0
04
Pro
po
rtio
n o
f tr
au
ma
pa
tie
nts
with
ma
xim
um
RTS
Ph
ysi
cia
n g
rou
p:
89.4
Pa
ram
ed
ic g
rou
p:
90.0
Co
mm
en
ts
�
Two
co
nse
cu
tive
ye
ars
fo
r e
ac
h g
rou
p
we
re e
xam
ine
d in
th
e c
ha
rt r
ev
iew
.
�
A s
ec
on
d r
ev
iew
er
va
lida
ted
th
e
ch
art
ext
rac
tio
n in
40 r
an
do
mly
sele
cte
d c
ha
rts
(10.7
% o
f th
e t
ota
l).
Exc
elle
nt
leve
l of
ag
ree
me
nt
ac
hie
ve
d (
Ka
pp
a 0
.937
).
�
All
pa
tie
nts
tra
nsp
ort
ed
to
th
e s
am
e
ba
se h
osp
ita
l.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
The
sim
ilaritie
s in
ou
tco
me
s fo
r a
dm
itte
d
pa
tie
nts
su
pp
ort
th
e v
iew
th
at
bo
th g
rou
ps
ha
ve
sim
ilar
task
ing
crite
ria
fo
r h
igh
ac
uity
pa
tie
nts
an
d s
ug
ge
st t
ha
t p
ara
me
dic
s a
re
as
eff
ica
cio
us
as
ph
ysi
cia
ns
in d
eliv
erin
g
pre
-ho
spita
l ca
re in
th
is g
rou
p o
f p
atie
nts
.
Ho
we
ve
r, f
or
low
er
ac
uity p
atie
nts
, th
ere
is a
sta
tist
ica
lly s
ign
ific
an
t h
igh
er
rate
of
clin
ica
lly
un
ne
ce
ssa
ry t
ask
ing
s b
y t
he
am
bu
lan
ce
gro
up
. G
ive
n t
he
re
ce
nt
fata
l ae
rom
ed
ica
l
ac
cid
en
ts in
Qu
ee
nsl
an
d it
wo
uld
se
em
pru
de
nt
to r
ed
uc
e c
linic
ally
un
ne
ce
ssa
ry
retr
ieva
ls t
hro
ug
h c
linic
al c
oo
rdin
atio
n w
ith
ap
pro
pria
tely
qu
alif
ied
em
erg
en
cy
ph
ysi
cia
ns.
TRANSPORTATION OF EMERGENCY PATIENTS
29
Ta
ble
7
Ev
iden
ce t
ab
les
of
stu
die
s co
mp
arin
g t
he
ou
tco
me
or
pa
tien
ts t
ran
spo
rted
by
hel
ico
pte
r w
ith
an
d w
ith
ou
t a
med
ica
l d
oct
or
on
boa
rd (
con
tin
ued
)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Bu
rne
y e
t a
l. 19
92)
USA
Re
tro
spe
ctive
co
ho
rt s
tud
y
Leve
l III-
2
Stu
dy s
ett
ing
.
Ae
rom
ed
ica
l tra
nsf
ers
be
twe
en
Se
pte
mb
er
1,
198
7 a
nd
Au
gu
st 3
1, 1
988.
Inc
lud
e t
ran
spo
rt f
rom
oth
er
ED
s
(n=
404
), t
he
sc
en
e (
n=
36)
an
d o
the
r
inp
atie
nt
un
its
(n=
21
8).
Pa
rtic
ipa
nts
:
Tota
l = 6
59
Inte
rve
ntio
n (
n=
41
8)
Ph
ysi
cia
n a
nd
nu
rse
te
am
Co
mp
ara
tor
(n=
24
1)
Two
nu
rse
te
am
.
An
aly
ses
co
mp
arin
g g
rou
ps
at
ba
selin
e.
AP
AC
HE-I
I sc
ore
Ph
ysi
cia
n g
rou
p:
8.0
Nu
rse
gro
up
: 7
.8
RTS
1 s
co
re (
Ob
tain
ed
at
orig
in o
f
tra
nsp
ort
)
Ph
ysi
cia
n g
rou
p:
10.6
7
Nu
rse
gro
up
: 1
0.8
47
RTS
2 s
co
re (
ob
tain
ed
aft
er
arr
iva
l at
rec
eiv
ing
ho
spita
l)
Ph
ysi
cia
n g
rou
p:
10.8
77
Nu
rse
gro
up
: 1
0.9
72
TISS1 s
co
re
Ph
ysi
cia
n g
rou
p:
17.0
Nu
rse
gro
up
: 1
6.0
TISS2 s
co
re
Ph
ysi
cia
n g
rou
p:
14.9
Nu
rse
gro
up
: 1
2.6
P=
0.0
01
Inc
lu/e
xcl c
rite
ria
.
Inc
lud
ed
all
pa
tie
nts
tra
nsf
err
ed
du
rin
g t
he
stu
dy p
erio
d.
Exc
lud
ed
pa
tie
nts
un
de
r 1
6 y
ea
rs
an
d p
atie
nts
tra
nsf
err
ed
to
oth
er
ho
spita
ls
Da
ta c
olle
ctio
n
Se
ve
rity
of
illn
ess
me
asu
red
usi
ng
RTS
, A
PA
CH
E-I
I a
nd
th
e T
he
rap
eu
tic
Inte
rve
ntio
n S
co
rin
g S
yst
em
(TI
SS)
Two
TIS
S s
co
res
we
re o
bta
ine
d:
TISS1=
inte
rve
ntio
ns
ca
rrie
d o
ut
be
fore
th
e a
rriv
al o
f th
e f
ligh
t te
am
TISS2=
inte
rve
ntio
ns
co
ntin
ue
d o
r
initia
ted
by t
he
flig
ht
tea
m
Ou
tco
me
me
asu
res
Ho
spita
l mo
rta
lity
ICU
len
gth
of
sta
y
Ho
spita
l le
ng
th o
f st
ay
Follo
w-u
p in
terv
al
No
t st
ate
d
An
aly
sis
Pa
tie
nts
str
atifie
d in
to t
hre
e g
rou
ps:
ca
rdia
c, tr
au
ma
an
d o
the
r. O
rig
ins
of
the
tra
nsp
ort
an
d t
ran
sfe
r tim
es
we
re in
clu
de
d in
th
e a
na
lysi
s.
Da
ta a
na
lyse
d u
sin
g S
YSTA
T.
Pro
po
rtio
n d
isc
ha
rge
d a
live
(%
)
Ph
ysi
cia
n g
rou
p:
83
Nu
rse
gro
up
: 7
9
P=
0.2
Nu
mb
er
of
ho
spita
l da
ys
Ph
ysi
cia
n g
rou
p:
20.4
Nu
rse
gro
up
: 2
0.3
P=
0.9
45
Ou
tco
me
s w
ere
no
t si
gn
ific
an
tly
diffe
ren
t in
an
y o
f th
e c
linic
al
sub
gro
up
s o
r p
atie
nt
orig
in.
Lim
ita
tio
ns
�
The
orig
in o
f o
ne
pa
tie
nt
wa
s n
ot
ac
co
un
ted
fo
r.
�
On
ly 5
.5%
of
tra
nsp
ort
s o
rig
ina
ted
at
the
sc
en
e.
�
Sc
an
t d
eta
ils p
rovid
ed
ab
ou
t th
e
an
aly
sis
pro
ce
du
re in
th
e m
eth
od
s
sec
tio
n o
f th
e p
ap
er.
�
No
de
tails
pro
vid
ed
ab
ou
t th
e
pro
ce
du
res
co
nd
uc
ted
by e
ac
h
gro
up
.
�
Me
asu
res
of
inju
ry s
eve
rity
use
d w
ere
diffe
ren
t fr
om
th
e n
orm
al a
pp
roa
ch
.
No
use
of
the
ISS s
o it
wa
s n
ot
po
ssib
le
to a
sse
ss p
rob
ab
ility
of
surv
iva
l w
ith
refe
ren
ce
to
a s
uita
ble
po
pu
latio
n
suc
h a
s M
TOS.
�
Imp
erf
ec
t va
lidity o
f A
PA
CH
E,
TISS a
nd
ISS m
ay h
ave
imp
lica
tio
ns
reg
ard
ing
ba
lan
ce
of
gro
up
s a
t b
ase
line
.
�
Un
cle
ar
wh
eth
er
the
re w
as
an
y
va
riatio
n in
crite
ria
fo
r th
e d
isp
atc
h o
f
the
he
lico
pte
rs w
ith
diffe
ren
t c
rew
s.
�
Ob
serv
atio
n s
tud
y is
su
sce
ptib
le t
o
co
nfo
un
din
g.
�
Un
cle
ar
ho
w m
an
y r
ec
eiv
ing
ho
spita
ls
we
re in
clu
de
d –
if t
he
re w
as
mo
re
tha
n o
ne
it m
ay h
ave
re
sulte
d in
va
riatio
n in
qu
alit
y o
f c
are
at
diffe
ren
t
ho
spita
ls, re
sultin
g in
diffe
ren
t
ou
tco
me
s.
TRANSPORTATION OF EMERGENCY PATIENTS
30
Ta
ble
7
Ev
iden
ce t
ab
les
of
stu
die
s co
mp
arin
g t
he
ou
tco
me
or
pa
tien
ts t
ran
spo
rted
by
hel
ico
pte
r w
ith
an
d w
ith
ou
t a
med
ica
l d
oct
or
on
boa
rd (
con
tin
ued
)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Bu
rne
y e
t a
l. 19
92)
USA
co
ntin
ue
d
M
ea
n a
ge
(ye
ars
)
Ph
ysi
cia
n g
rou
p:
45.7
Nu
rse
gro
up
: 5
0.9
P=
0.0
01
Ma
le (
%)
Ph
ysi
cia
n g
rou
p:
66
Nu
rse
gro
up
: 6
1
Pa
tie
nt
orig
in (
%)
ED
Ph
ysi
cia
n g
rou
p:
68
Nu
rse
gro
up
: 5
1
Inp
atie
nt
Ph
ysi
cia
n g
rou
p:
25
Nu
rse
gro
up
: 4
7
Sc
en
e
Ph
ysi
cia
n g
rou
p:
7
Nu
rse
gro
up
: 2
P=
0.0
01
Clin
ica
l ca
teg
ory
Ca
rdia
c
Ph
ysi
cia
n g
rou
p: 4
0
Nu
rse
gro
up
: 3
6
Tra
um
a
Ph
ysi
cia
n g
rou
p: 3
8
Nu
rse
gro
up
: 3
0
Oth
er
Ph
ysi
cia
n g
rou
p:
22
Nu
rse
gro
up
: 3
4
P=
0.0
03
�
Pa
tie
nt
orig
in m
ay b
e c
on
sist
en
t w
ith
the
nu
rse
gro
up
tra
nsp
ort
ing
a m
ore
sta
ble
gro
up
of
pa
tie
nts
.
�
Als
o v
aria
tio
n in
clin
ica
l ca
teg
ory
gro
up
tra
nsp
ort
ed
be
twe
en
th
e t
wo
gro
up
s.
�
Nu
rse
gro
up
tra
nsp
ort
ed
a
sig
nific
an
tly o
lde
r g
rou
p o
f p
atie
nts
–
oth
er
seve
rity
ind
ica
tors
be
ing
eq
ua
l
this
wo
uld
su
gg
est
a g
rou
p w
ith
a
po
ore
r p
rog
no
sis.
�
Str
atifie
d a
na
lysi
s b
y c
linic
al s
ub
gro
up
an
d p
atie
nt
orig
in s
ub
gro
up
ha
d lo
w
stu
dy p
ow
er.
�
No
su
bg
rou
p a
na
lyse
s p
rese
nte
d b
y
diffe
ren
t m
ark
ers
of
inju
ry s
eve
rity
.
Co
mm
en
ts
�
Ove
rall
sam
ple
siz
e o
f 659
is la
rge
en
ou
gh
to
ide
ntify
a 1
0%
diffe
ren
ce
in
surv
iva
l with
a p
ow
er
of
0.8
0.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
No
ob
jec
tive
diffe
ren
ce
s in
ou
tco
me
of
pa
tie
nts
we
re f
ou
nd
be
twe
en
ph
ysi
cia
n/n
urs
e a
nd
nu
rse
/nu
rse
te
am
s.
Alth
ou
gh
sm
all
diffe
ren
ce
s w
ere
fo
un
d in
typ
es
of
flig
hts
ta
ke
n b
y P
/N a
nd
N/N
te
am
s,
the
re w
ere
no
diffe
ren
ce
s in
ob
jec
tive
me
asu
res
of
seve
rity
be
twe
en
th
e t
wo
tea
ms.
We
fin
d n
o o
bje
ctive
ev
ide
nc
e t
o
pre
fer
on
e c
rew
co
mp
osi
tio
n o
ve
r a
no
the
r.
TRANSPORTATION OF EMERGENCY PATIENTS
31
Ta
ble
7
Ev
iden
ce t
ab
les
of
stu
die
s co
mp
arin
g t
he
ou
tco
me
or
pa
tien
ts t
ran
spo
rted
by
hel
ico
pte
r w
ith
an
d w
ith
ou
t a
med
ica
l d
oct
or
on
boa
rd (
con
tin
ued
)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Bu
rne
y e
t a
l. 19
95)
USA
Pro
spe
ctive
co
ho
rt s
tud
y
Leve
l III-
2.
Stu
dy s
ett
ing
.
Follo
w o
n t
o p
rev
iou
s re
tro
spe
ctive
stu
dy b
y B
urn
ey e
t a
l. (1
992
). A
ll a
du
lt a
ir
me
dic
al p
atie
nts
be
twe
en
Ju
ly 1
, 19
90
an
d J
un
e 3
0, 19
92.
Pa
rtic
ipa
nts
: (n
=1,1
69)
Inte
rve
ntio
n (
n=
25
5)
Ph
ysi
cia
n a
nd
nu
rse
te
am
Co
mp
ara
tor
(n=
91
4)
Two
nu
rse
te
am
.
An
aly
ses
co
mp
arin
g g
rou
ps
at
ba
selin
e.
Me
an
Ag
e (
ye
ars
):
Ph
ysi
cia
n g
rou
p:
48.5
Nu
rse
gro
up
: 4
5.6
Ma
le (
%)
Ph
ysi
cia
n g
rou
p:
62
Nu
rse
gro
up
: 6
3
Pa
tie
nt
orig
in (
%)
ED
Ph
ysi
cia
n g
rou
p:
49
Nu
rse
gro
up
: 6
1
Ho
spita
l
Ph
ysi
cia
n g
rou
p:
38
Nu
rse
gro
up
: 3
2
Sc
en
e
Ph
ysi
cia
n g
rou
p:
12
Nu
rse
gro
up
: 6
AP
AC
HE1 s
co
re
Ph
ysi
cia
n g
rou
p:
10.5
Nu
rse
gro
up
: 1
0.4
Inc
lu/e
xcl c
rite
ria
.
Inc
lud
ed
all
pa
tie
nts
tra
nsf
err
ed
du
rin
g t
he
stu
dy p
erio
d.
Exc
lud
ed
pa
tie
nts
un
de
r 1
6 y
ea
rs
an
d p
atie
nts
tra
nsf
err
ed
to
oth
er
ho
spita
ls
Da
ta c
olle
ctio
n
Da
ta c
olle
cte
d p
rosp
ec
tive
ly b
y
flig
ht
nu
rse
s.
Se
ve
rity
of
illn
ess
me
asu
red
usi
ng
RTS
, A
PA
CH
E-I
I a
nd
th
e T
he
rap
eu
tic
.
Inte
rve
ntio
n S
co
rin
g S
yst
em
(TI
SS).
Two
AP
AC
HE s
co
res
we
re o
bta
ine
d:
the
first
(A
PA
CH
E1)
at
tim
e o
f
ho
spita
l arr
iva
l an
d t
he
se
co
nd
(AP
AC
HE2
) o
n t
he
ba
sis
of
the
first
24 h
ou
rs o
f h
osp
ita
lisa
tio
n a
fte
r
tra
nsf
er
Fou
r TI
SS s
co
res
we
re o
bta
ine
d:
TISS1=
inte
rve
ntio
ns
ca
rrie
d o
ut
in
the
24 h
ou
rs b
efo
re t
he
arr
iva
l of
the
flig
ht
tea
m
TISS2=
inte
rve
ntio
ns
co
ntin
ue
d o
r
initia
ted
by t
he
flig
ht
tea
m
TISS3=
inte
rve
ntio
ns
in t
he
first
24
ho
urs
aft
er
tra
nsf
er
TISS4=
co
mb
ine
d in
terv
en
tio
ns
du
rin
g f
ligh
t a
nd
th
e f
irst
24 h
ou
rs
aft
erw
ard
.
Thre
e R
TS s
co
res
we
re o
bta
ine
d:
RTS
1=
co
nd
itio
n b
efo
re t
ran
sfe
r
RTS
2=
co
nd
itio
n o
bta
ine
d d
urin
g
tra
nsf
er
RTS
3=
co
nd
itio
n a
fte
r tr
an
sfe
r.
Pro
po
rtio
n d
isc
ha
rge
d a
live
, a
ll
pa
tie
nts
(%
)
Ph
ysi
cia
n g
rou
p:
75
Nu
rse
gro
up
: 7
9
P=
0.1
2
Pro
po
rtio
n d
isc
ha
rge
d a
live
, o
rig
in
of
flig
ht
fro
m t
he
sc
en
e (
%)
Ph
ysi
cia
n g
rou
p:
84
Nu
rse
gro
up
: 8
4
Nu
mb
er
of
ho
spita
l da
ys
Pe
rio
d 1
990
-19
91
Ph
ysi
cia
n g
rou
p:
17.6
Nu
rse
gro
up
: 2
2.2
P=
0.0
9
Pe
rio
d 1
991
-19
92
Ph
ysi
cia
n g
rou
p:
33.4
Nu
rse
gro
up
: 2
2.5
P=
0.0
05
Lim
ita
tio
ns
�
On
ly 7
.6%
of
tra
nsp
ort
s o
rig
ina
ted
at
the
sc
en
e.
�
No
de
tails
pro
vid
ed
ab
ou
t th
e
pro
ce
du
res
co
nd
uc
ted
by e
ac
h
gro
up
.
�
Me
asu
res
of
inju
ry s
eve
rity
use
d w
ere
diffe
ren
t fr
om
th
e n
orm
al a
pp
roa
ch
.
No
use
of
the
ISS s
o it
wa
s n
ot
po
ssib
le
to a
sse
ss p
rob
ab
ility
of
surv
iva
l w
ith
refe
ren
ce
to
a s
uita
ble
po
pu
latio
n
suc
h a
s M
TOS.
�
Imp
erf
ec
t va
lidity o
f A
PA
CH
E,
TISS a
nd
ISS m
ay h
ave
imp
lica
tio
ns
reg
ard
ing
ba
lan
ce
of
gro
up
s a
t b
ase
line
.
�
Au
tho
rs d
oc
um
en
ted
, in
re
latio
n t
o
ye
ar
2 o
f th
e s
tud
y, th
at
ph
ysi
cia
ns
we
re in
vo
lve
d in
tra
nsf
err
ing
a s
ma
ller
nu
mb
er
of
pa
tie
nts
with
ve
ry
co
mp
lica
ted
inju
rie
s, t
he
refo
re t
he
y
exp
ec
ted
mo
rta
lity t
o b
e h
igh
er
in t
his
gro
up
. Th
ere
wa
s n
o a
na
lysi
s a
dju
stin
g
for
the
va
ria
tio
n in
se
ve
rity
.
�
Ob
serv
atio
n s
tud
y is
su
sce
ptib
le t
o
co
nfo
un
din
g.
�
Un
cle
ar
ho
w m
an
y r
ec
eiv
ing
ho
spita
ls
we
re in
clu
de
d –
if t
he
re w
as
mo
re
tha
n o
ne
it m
ay h
ave
re
sulte
d in
va
riatio
n in
qu
alit
y o
f c
are
at
diffe
ren
t
ho
spita
ls, re
sultin
g in
diffe
ren
t
ou
tco
me
s.
�
Str
atifie
d a
na
lysi
s b
y c
linic
al s
ub
gro
up
an
d p
atie
nt
orig
in s
ub
gro
up
like
ly h
ad
low
stu
dy p
ow
er.
TRANSPORTATION OF EMERGENCY PATIENTS
32
Ta
ble
7
Ev
iden
ce t
ab
les
of
stu
die
s co
mp
arin
g t
he
ou
tco
me
or
pa
tien
ts t
ran
spo
rted
by
hel
ico
pte
r w
ith
an
d w
ith
ou
t a
med
ica
l d
oct
or
on
boa
rd (
con
tin
ued
)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Bu
rne
y e
t a
l. 19
95)
USA
co
ntin
ue
d
A
PA
CH
E2 s
co
re
Ph
ysi
cia
n g
rou
p:
12.0
Nu
rse
gro
up
: 1
1.9
Clin
ica
l ca
teg
ory
(%
)
Ca
rdia
c
Ph
ysi
cia
n g
rou
p:
20
Nu
rse
gro
up
: 1
6
Tra
um
a
Ph
ysi
cia
n g
rou
p:
41
Nu
rse
gro
up
: 4
5
Oth
er
Ph
ysi
cia
n g
rou
p:
39
Nu
rse
gro
up
: 3
9
RTS
1
Ph
ysi
cia
n g
rou
p:
10.9
Nu
rse
gro
up
: 1
0.5
RTS
2
Ph
ysi
cia
n g
rou
p:
10.8
Nu
rse
gro
up
: 1
0.5
RTS
3
Ph
ysi
cia
n g
rou
p:
11.5
Nu
rse
gro
up
: 1
1.0
TISS1
Ph
ysi
cia
n g
rou
p:
19.5
Nu
rse
gro
up
: 1
9.0
TISS2
Ph
ysi
cia
n g
rou
p:
17.4
Nu
rse
gro
up
: 1
6.5
Ou
tco
me
me
asu
res
Ho
spita
l mo
rta
lity
ICU
len
gth
of
sta
y
Ho
spita
l le
ng
th o
f st
ay
An
aly
sis
Pa
tie
nts
str
atifie
d in
to t
hre
e g
rou
ps:
ca
rdia
c, tr
au
ma
an
d o
the
r. O
rig
ins
of
the
tra
nsp
ort
an
d t
ran
sfe
r tim
es
we
re in
clu
de
d in
th
e a
na
lysi
s.
Da
ta a
na
lyse
d u
sin
g S
YSTA
T.
Co
ntin
uo
us
va
ria
ble
s w
ere
an
aly
sed
usi
ng
Stu
de
nt’
s t
test
an
d
ca
teg
oric
al d
ata
usi
ng
th
e χ
2 t
est
.
�
No
su
bg
rou
p a
na
lyse
s p
rese
nte
d b
y
diffe
ren
t m
ark
ers
of
inju
ry s
eve
rity
.
�
Sig
nific
an
t d
iffe
ren
ce
s in
ba
selin
e
me
asu
res
in t
he
tim
e p
erio
d 1
990
-
1991:
Ph
ysi
cia
n g
rou
p o
f p
atie
nts
we
re
old
er,
mo
re li
ke
ly t
o b
e f
rom
ho
spita
l
or
sce
ne
, a
nd
ha
d h
igh
er
RTS
3 s
co
re.
Du
rin
g s
ec
on
d p
erio
d (
1991
-19
92
),
ph
ysi
cia
n g
rou
p h
ad
hig
he
r TI
SS1 a
nd
TISS2 s
co
res.
�
No
ove
rall
resu
lts
pre
sen
ted
fo
r
du
ratio
n o
f st
ay (
all
resu
lts
stra
tifie
d b
y
the
tw
o s
tud
y y
ea
rs).
�
If t
he
stu
dy w
as
to h
ave
80%
po
we
r to
de
tec
t a
5%
diffe
ren
ce
in m
ort
alit
y a
t
the
5%
sig
nific
an
ce
leve
l,
ap
pro
xim
ate
ly 2
,00
0 p
atie
nts
wo
uld
ha
ve
be
en
re
qu
ired
.
Co
mm
en
ts
�
Co
mp
lete
ou
tco
me
da
ta o
bta
ine
d
on
1,1
69
of
1,1
70 e
ligib
le p
atie
nts
.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
Two
ye
ars
of
de
taile
d p
rosp
ec
tive
me
asu
rem
en
t o
f a
ir m
ed
ica
l pa
tie
nt
ch
ara
cte
ristic
s a
nd
ou
tco
me
s c
on
firm
ed
the
in
itia
l fin
din
g t
ha
t n
o s
ign
ific
an
t
diffe
ren
ce
s in
clin
ica
l ou
tco
me
s c
ou
ld b
e
ide
ntifie
d b
etw
ee
n p
atie
nts
ma
na
ge
d b
y
P/N
ve
rsu
s N
/N c
rew
s.
TRANSPORTATION OF EMERGENCY PATIENTS
33
Ta
ble
7
Ev
iden
ce t
ab
les
of
stu
die
s co
mp
arin
g t
he
ou
tco
me
or
pa
tien
ts t
ran
spo
rted
by
hel
ico
pte
r w
ith
an
d w
ith
ou
t a
med
ica
l d
oct
or
on
boa
rd (
con
tin
ued
)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Bu
rne
y e
t a
l. 19
95)
USA
co
ntin
ue
d
TI
SS3
Ph
ysi
cia
n g
rou
p:
29.7
Nu
rse
gro
up
: 2
8.5
TISS4
Ph
ysi
cia
n g
rou
p:
32.7
Nu
rse
gro
up
: 3
2.0
TRANSPORTATION OF EMERGENCY PATIENTS
34
Summary and Conclusions
Results were conflicting among the seven studies eligible for the review examining the effectiveness of including a doctor on board helicopter transportation. Some studies suggested there was some benefit to including doctors on board helicopters (Baxt and Moody 1987; Garner et al. 1999; Schmidt et al. 1992) while others found no difference in outcomes of interest between study groups (Burney et al. 1992; Cameron et al. 2005; Hamman et al. 1991). One study found no difference in mortality but found a significantly shorter hospital stay among the non-doctor group (Burney et al. 1995). It should be noted that the two papers by Burney et al are of marginal relevance to the use of air ambulances in New Zealand as the great preponderance of patients in these studies were inter-hospital transfers rather than transports directly from the scene. Each study had limitations that might help to explain the discrepant results.
There was variation in study design among the three studies that suggested some benefit from the inclusion of doctors on the helicopter. One made use of registry data (Schmidt et al. 1992), one used a pseudorandomised controlled trial design (Baxt and Moody 1987), and the other made use of a retrospective design (Garner et al. 1999). In relation to the pseudorandomised controlled trial, a particular consideration was the use of limiting the mortality outcome to deaths that were thought to be directly due to the trauma or complications of the trauma. This may have produced outcome misclassification with the potential for underestimating mortality in either group. The use of all-cause mortality as an outcome would have avoided this limitation. Nevertheless this was the strongest study in this section of the review. There were also limitations to the registry based study but the effect of these limitations on the study estimates was not clear. Firstly, a significant proportion of eligible patients were excluded from the doctor group due to missing charts. There were no deaths among these patients, thus the level of reduced mortality in the doctor group may have been underestimated. However, time to arrival on the scene was shorter in the doctor group. This may have resulted in an improved prognosis in the doctor group and may not be replicated in other settings where time to arrival of the doctor group may be delayed. Perhaps most significantly, the two groups (doctor and no doctor) were located in two different countries so there may have been other reasons that explain differences in outcomes other that the personnel supplying pre-hospital care. For example, level of hospital care may vary between the two settings. In the retrospective study (Garner et al. 1999), seven deaths in the non-doctor group were omitted due to missing case sheets, potentially underestimating the effectiveness of care provided by doctor crewed helicopters. Patients were also directed to different hospitals in this study depending on the helicopter crew mix. Based on the above limitations there is uncertainty about the robustness of the findings in these three studies.
There were similar limitations in the three studies that did not find any difference in outcome between the doctor and no doctor groups. Hamman et al. (1991) used a before and after design which is associated with low level evidence (level III-3). The study was underpowered to compare mortality across study groups, potentially explaining the lack of difference between groups. Burney et al. (1992) published a retrospective study that examined patient transfers to a base hospital. Unfortunately only 5.5% of these transfers were directly from the scene thus severely limiting the relevance of the study to this review. It should also be noted that the non-doctor group appeared to carry a more stable group of patients potentially underestimating any benefit from doctor involvement in helicopter transportation. Cameron et al. (2005) also published a retrospective chart review. This study was limited by the inclusion of limited injury severity data and low study power to detect a difference in mortality. Burney et al. also published a prospective study following on from their retrospective study and found no difference in mortality between doctor and no doctor groups but did find a reduced period of hospitalisation in the no doctor group. However, the authors noted that this wasn’t surprising given the less severe case mix in the no doctor group. Again this study was of limited applicability given the high proportion of inter-hospital transfers.
While overall there was more support for the inclusion of doctors on board helicopters there is a significant level of uncertainty across the literature examining this question. There certainly was not sufficient evidence to suggest that doctors should not be included on board helicopters. Other issues should also be noted:
1. The literature examined in this section does not answer the question whether wider training in procedures currently accessible to doctors would have an impact on patient outcome. For example, others have suggested that task specific crewing should be
TRANSPORTATION OF EMERGENCY PATIENTS
35
adhered to and noted that the “utilisation of experienced critical care physicians, nurses or paramedics with enhanced skills, including rapid sequence intubation, must be entertained” (Rashford and Myers 2004). Others have documented the use of rapid sequence intubation by non-doctor personnel (Bernard et al. 2002; Bernard 2006; Sloane et al. 2000). However, such an approach does not consider the role of assessment in determining outcome. Hamman et al. (1991) commented in their conclusions in their study included in this review that “it appears that experienced nurses and paramedics, operating with well established protocols, can provide aggressive care that yields equal outcome results compared with those of a flight team that includes a physician. However, their study appeared to be underpowered to establish such equivalence.
2. Whether there may be variation in outcome across crew mixes for different clinical scenarios. For example, the inclusion of doctors on the helicopters tended to be associated with longer at scene times. This longer period of stabilization could be associated with improved outcome in some circumstances but not others. Cameron commented that advanced life support skills are more likely to be beneficial in the blunt trauma patient (Cameron 1999). Two of the three studies with reduced mortality among the doctor treated group were restricted to patients with blunt trauma.
3. The literature identified related to trauma only. There was no literature identified that was eligible for inclusion and examined the effect of different crew configurations in medical emergencies.
4. There was insufficient information to compare outcomes in paediatric and adult age groups or to stratify results by ISS score.
5. There was variation in the level of experience across both study teams in the selected studies.
Further research would be useful. Firstly, a well designed prospective study that follows clear and well documented dispatch criteria and provides for carriage to the same hospital (that is equipped to manage all patients). The study would need to have an adequate sample size to ensure meaningful results could be obtained. Appropriate control for injury severity and other factors associated with mortality would be required (a randomised controlled trial would be the ideal method of doing this). The study would need to encompass the study population for which any proposed helicopter services would provide coverage. Secondly, a study evaluating the role of training non-doctor crews to perform certain procedures such as rapid sequence intubation should be conducted. The specific comparison of interest would be doctors versus fully trained non-doctor personnel. The study should be adequately powered to detect equivalence in outcome.
Doctor versus no doctor on board road ambulances
From the search strategy for question two (outcome by time from ambulance callout to emergency department delivery) we identified, 516 potentially relevant articles/abstracts of which 34 were retrieved. Of these retrieved articles, 30 were excluded. These excluded papers are presented in Appendix 4. Reasons for exclusion of studies before retrieval in full text are outlined in Table 8. Reasons for exclusion of studies retrieved in full text are detailed in Table 9.
TRANSPORTATION OF EMERGENCY PATIENTS
36
Table 8 Reasons for exclusion of studies before retrieval in full text: doctor versus no doctor
on board road ambulances
Reason for exclusion Number
Not relevant to review question aim 413
Methods were not clearly described 0
Wrong publication type 51
Incorrect population 0
Sample size less than 50 11
Incorrect comparator 1
Incorrect outcomes 3
Publication superseded 0
Non-English language 0
Neonatal study 2
Duplicate reference 1
Total 482
Table 9 Reasons for exclusion of studies retrieved in full text: doctor versus no doctor on
board road ambulances
Reason for exclusion Number
Not relevant to review question aim 24
Methods were not clearly described 1
Wrong publication type 2
Incorrect population 2
Sample size less than 50 0
Incorrect comparator 0
Incorrect outcomes 0
Publication superseded 0
Non-English language 1
Neonatal study 0
Total 30
Four retrieved articles were appraised and are listed in the references and Appendix 7. Included papers are presented in the evidence table below. Three studies were level III-3 (before and after studies) and the other was level III-2 (cohort study) according to NHMRC’s hierarchy of evidence.
Frandsen et al. 1991
This study (level III-3 evidence) compared three different emergency medical service configurations over three different time periods in the city of Odense, Denmark. The three configurations were:
1. Advanced EMS (n=85): included a tiered response service incorporating specifically trained doctors.
2. Intermediate EMS (n=160): included a tiered response service without doctors.
3. Basic EMS (n=148): a service without doctors.
The focus was on out of hospital cardiac arrest. The study measured mortality and cerebral status (amongst the survivors). Non-adjusted statistical analyses were conducted.
Survival between the three groups was:
• Advanced EMS (with doctors): 13% (95% CI 7-22)
• Intermediate EMS (without doctors): 1% (95% CI 0-6)
• Basic EMS (without doctors): 5% (95% CI 2-10)
• P<0.001.
However, there were significant limitations to this study:
TRANSPORTATION OF EMERGENCY PATIENTS
37
� it was not possible to be certain that any difference in outcome was due to the different crew configurations
� the study was highly susceptible to confounding and the analyses have not adjusted for potential confounding factors
� the advanced EMS group treated a younger group of patients, which could explain the improved outcome in this group
� there was missing data.
These factors make it difficult to interpret the results of this study.
Koefoed-Nielsen et al. 2002
This before and after study (level III-3 evidence) compared 28 day mortality in acute myocardial infarction (MI) patients over two time periods:
1. A period preceding introduction of a mobile emergency care unit (MECU), (September to November 1996).
2. A period with a MECU (plus standard ambulances) that included anaesthetist staffing (September to November 1997).
There were 54 patients in each period.
The crude mortality rate was higher in the pre-MECU period (20.6% versus 11.1%). Multivariate regression (controlling for age, gender, pulse and systolic blood pressure) found a significantly lower odds of 28 day mortality in the time period that included a MECU (OR 0.3, P < 0.025). Forty-four percent of patients in the second time period were treated by the MECU. Another multivariate model also estimated lower odds of 28 day mortality in the group treated by MECU than the non-MECU group (OR 0.2, P < 0.05).
As with all before and after studies, there were limitations:
� it was not possible to be certain that any difference in outcome was due to the different crew configurations. The authors noted the increased proportion of patients undergoing angioplasty may explain the results.
� potential selection bias, with 25 people being excluded on the basis of insufficient information about the diagnosis.
� the multivariate models controlled for a limited range of potential confounders. Most importantly, the estimated odds ratio comparing MECU with non-MECU patients may underestimate the effectiveness of MECU due to the selection of more severely unwell patients for the MECU service.
� it was unclear if the differences in outcome would be maintained if non-anaesthetist groups were trained in further procedures.
Lee et al. 2003
A retrospective cohort study (level III-2 evidence) was conducted in Australia (Lee et al. 2003). This study compared the outcome across different levels of ambulance officer and physicians. There were three levels of ambulance officer (two classified as providing basic life support and the third providing advanced life support). Details of the procedures available to these groups are provided in Table 10. Logistic regression was used to control for confounding with the following predictor variables being included in initial models: level of pre-hospital care, time from injury to arrival in hospital, type of injury, mechanism of injury, age, sex, ISS, GCS and systolic blood pressure.
The effect of pre-hospital care on mortality was dependent on level of ICU care. Key results in the group that did not receive ICU care were (using basic life support as the reference group):
� level 5 ambulance: OR 2.18 (95% CI, 1.05-4.55)
� physician: OR 4.27 (95% CI 1.46-12.45).
TRANSPORTATION OF EMERGENCY PATIENTS
38
The majority of these deaths occurred within 24 hours of admission, which the authors suggested was on the basis of not surviving initial resuscitation.
Key results in the group that did receive ICU care were (using basic life support as the reference group):
� level 5 ambulance: OR 0.70 (95% CI 0.53-1.18)
� physician: OR 0.63 (95% CI 0.28-1.39)
There were significant limitations to this study:
� the study used a retrospective design
� a selective dispatch strategy was used which probably explains the increased mortality rates in the level 5 ambulance group and the physician group in the non-ICU population
� paramedics may have involved the physician group when patient death was imminent
� the observational study design is susceptible to residual confounding.
Christenszen et al. 2003
Christenszen et al. (2003) examined the effect of introducing a mobile emergency care unit (MECU) in a before and after study (level III-3 evidence) set in Denmark. Two time periods were studied: in the first a consecutive sample of ambulance users was studied and in the second a consecutive sample of ambulance or MECU users was sampled. Twenty-eight percent of the second period sample used the MECU. There were 5,819 users overall. There was no significant difference in 180 day mortality between the two time periods although the mortality rate was significantly higher in the MECU group than the non-MECU group in the second study period. However, this was an unadjusted analysis and most notably did not control for injury severity.
There were significant unanswered questions in this study due to the nature of the study design. Most notably, due to the lack of control over injury severity it was not possible to form any conclusions about the effectiveness of MECU in reducing mortality. Other limitations included:
� poor control over confounding
� lack of statistical detail in some analyses
� a difference in outcome may have been noted if a higher proportion of users had been attended by a MECU in the second study period.
More detail is provided in Table 10.
TRANSPORTATION OF EMERGENCY PATIENTS
39
Ta
ble
10
E
vid
ence
ta
ble
s o
f st
ud
ies
com
pa
rin
g t
he
ou
tco
me
of
pa
tien
ts t
ran
spo
rted
by
ro
ad
am
bu
lan
ce w
ith
an
d w
ith
ou
t a
med
ica
l d
oct
or
on
bo
ard
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Fra
nd
sen
et
al.
19
91
)
De
nm
ark
Be
fore
an
d
aft
er
Leve
l III-
3.
Stu
dy s
ett
ing
.
Se
t in
Od
en
se (
a c
ity w
ith
a p
op
ula
tio
n
of
23
8,0
00 in
De
nm
ark
). T
hre
e d
iffe
ren
t
tim
e p
erio
ds
we
re s
tud
ied
. O
ut
of
ho
spita
l ca
rdia
c a
rre
sts
we
re t
he
fo
cu
s
of
the
stu
dy.
Pa
rtic
ipa
nts
:
Inte
rve
ntio
n (
n=
85
).
Six
mo
nth
pe
rio
d o
f a
dva
nc
ed
EM
S w
ith
spe
cific
ally
tra
ine
d d
oc
tors
pro
vid
ing
ad
va
nc
ed
life
su
pp
ort
at
arr
iva
l in
a
tie
red
re
spo
nse
syst
em
.
Co
mp
ara
tor.
Two
tim
e p
erio
ds:
on
e p
rovid
ed
ba
sic
EM
S (
n=
16
0)
an
d a
n “
inte
rme
dia
te E
MS
pe
riod
” (n
=1
48)
wh
ich
inv
olv
ed
a t
iere
d
resp
on
se. N
eith
er
of
the
se p
erio
ds
use
d
do
cto
rs in
th
e p
re-h
osp
ita
l ca
re.
Ba
selin
e a
na
lyse
s
Me
an
ag
e: 65 y
ea
rs
Ma
les:
64%
Byst
an
de
r C
PR
: 1
4%
Co
llap
se t
ime
> 6
min
ute
s: 66
%
Inc
lu/e
xcl c
rite
ria
.
Ass
um
ed
to
be
all
tra
nsp
ort
s in
th
e
thre
e r
ele
va
nt
tim
e p
erio
ds
wh
o
suff
ere
d a
n o
ut
of
ho
spita
l ca
rdia
c
arr
est
.
Ou
tco
me
me
asu
res
Me
asu
red
mo
rta
lity a
nd
ce
reb
ral
sta
tus
An
aly
sis
χ2 t
est
, M
an
n-W
hitn
ey U
te
st a
nd
Kru
ska
l-W
alli
s a
na
lysi
s o
f va
rian
ce
.
Sig
nific
an
ce
leve
l se
t a
t 0
.05.
Su
rviv
al ra
te (
95%
CI)
Ba
sic
EM
S (
no
n-d
oc
tor)
: 5%
(2-1
0)
Inte
rme
dia
te E
MS (
no
n-d
oc
tor)
: 1%
(0-6
)
Ad
va
nc
ed
EM
S (
Do
cto
r): 1
3%
(7-2
2)
P<
0.0
01
Lim
ita
tio
ns
�
Low
stu
dy p
ow
er.
�
No
co
ntr
ol o
f c
on
fou
nd
ing
in t
he
an
aly
sis
wh
ich
is p
art
icu
larly
pro
ble
ma
tic
in t
his
be
fore
an
d a
fte
r
de
sig
n.
�
The
me
an
ag
e w
as
yo
un
ge
r in
th
e
ad
va
nc
ed
EM
S p
ha
se –
wh
ich
ma
y
exp
lain
th
e im
pro
ve
d s
urv
iva
l in
th
is
gro
up
.
�
Ce
ntr
al c
om
mu
nic
atio
n w
as
no
t
do
cu
me
nte
d f
or
eith
er
gro
up
.
�
Da
ta m
issi
ng
fo
r so
me
ba
ckg
rou
nd
va
riab
les.
Fo
r e
xam
ple
, c
olla
pse
tim
e
do
cu
me
nte
d in
85
%. R
esp
on
se t
ime
an
d V
F ra
tio
at
arr
iva
l of
am
bu
lan
ce
sta
ff w
as
no
t d
oc
um
en
ted
in
th
e
ba
sic
EM
S g
rou
p (
41%
of
the
sa
mp
le).
�
Un
cle
ar
wh
at
the
P v
alu
e r
efe
rre
d t
o
in c
om
pa
rin
g s
urv
iva
l – w
as
it a
te
st f
or
tre
nd
or
a c
om
pa
riso
n o
f c
ert
ain
EM
S
ca
teg
orie
s.
Co
mm
en
ts
�
Aim
wa
s to
eva
lua
te (
1)
if m
ore
inte
nsi
ve
EM
S c
an
inc
rea
se s
urv
iva
l
aft
er
ou
t o
f h
osp
ita
l ca
rdia
c a
rre
st
an
d (
2)
if m
ore
inte
nsi
ve
EM
S c
an
dim
inis
h c
ere
bra
l da
ma
ge
aft
er
ou
t o
f
ho
spita
l ca
rdia
c a
rre
st.
�
Cle
ar
do
cu
me
nta
tio
n o
f d
efin
itio
ns
ap
plie
d in
th
e s
tud
y a
nd
th
e u
se o
f
the
se d
efin
itio
ns
me
an
s
mis
cla
ssific
atio
n o
f e
xpo
sure
is h
igh
ly
un
like
ly.
TRANSPORTATION OF EMERGENCY PATIENTS
40
Ta
ble
10
E
vid
ence
ta
ble
s o
f st
ud
ies
com
pa
rin
g t
he
ou
tco
me
of
pa
tien
ts t
ran
spo
rted
by
ro
ad
am
bu
lan
ce w
ith
an
d w
ith
ou
t a
med
ica
l d
oct
or
on
bo
ard
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Fra
nd
sen
et
al.
19
91
)
De
nm
ark
co
ntin
ue
d
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
The
re
sults
of
the
in
ve
stig
atio
n d
em
on
stra
te
tha
t th
e m
ore
inte
nsi
ve
th
e p
re-h
osp
ita
l
tre
atm
en
t o
f o
ut-
of-
ho
spita
l ca
rdia
c a
rre
st,
the
mo
re p
atie
nts
su
rviv
e a
nd
th
e m
ore
pa
tie
nts
su
rviv
e w
ith
go
od
ce
reb
ral
fun
ctio
n.
TRANSPORTATION OF EMERGENCY PATIENTS
41
Ta
ble
10
E
vid
ence
ta
ble
s o
f st
ud
ies
com
pa
rin
g t
he
ou
tco
me
of
pa
tien
ts t
ran
spo
rted
by
ro
ad
am
bu
lan
ce w
ith
an
d w
ith
ou
t a
med
ica
l d
oct
or
on
bo
ard
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Ko
efo
ed
-Nie
lse
n e
t a
l.
2002
)
De
nm
ark
Be
fore
an
d
aft
er
Leve
l III-
3.
Stu
dy s
ett
ing
.
A m
ob
ile e
me
rge
nc
y c
are
un
it (
MEC
U),
wh
ich
inc
lud
ed
an
an
ae
sth
etist
, w
as
set
up
in a
re
gio
n o
f D
en
ma
rk.
Co
nse
cu
tive
pa
tie
nts
with
ac
ute
MI w
ere
stu
die
d in
two
tim
e p
erio
ds
:
1. Se
pt
to N
ov 1
99
6 (
be
fore
MEC
U)
2. Se
pt
to N
ov 1
99
7 (
with
MEC
U).
The
are
a c
ove
red
ap
pro
xim
ate
d
800km
2. M
ed
ian
re
spo
nse
tim
e f
or
MEC
U
wa
s 8.9
min
ute
s a
nd
6.5
min
ute
s fo
r
sta
nd
ard
am
bu
lan
ce
s.
Pa
rtic
ipa
nts
:
Inte
rve
ntio
n (
n=
54
)
An
ae
sth
etist
pre
sen
t (w
ith
MEC
U)
MEC
U w
as
als
o c
rew
ed
with
a s
pe
cia
lly
tra
ine
d e
me
rge
nc
y t
ec
hn
icia
n.
Ad
ditio
na
l tre
atm
en
t p
rovid
ed
by
an
ae
sth
etist
: tr
ac
he
al i
ntu
ba
tio
n,
tra
nsc
uta
ne
ou
s p
ac
ing
, a
na
est
he
tic
s
(hyp
no
tic
s a
nd
mu
scle
re
laxa
nts
),
op
ioid
s, h
ea
rt s
tim
ula
tin
g d
rug
s a
nd
an
tia
rrh
yth
mic
s.
Pre
-ho
spita
l
thro
mb
oly
sis
wa
s n
ot
pro
vid
ed
.
Co
mp
ara
tor
(n=
54
)
No
n p
hysi
cia
n c
rew
(b
efo
re M
EC
U)
Inc
lu/e
xcl c
rite
ria
.
Use
rs o
f e
me
rge
nc
y s
erv
ice
s (b
ase
d
on
am
bu
lan
ce
co
mp
an
y’s
pa
tie
nt
rolls
) w
ho
we
re c
lass
ifie
d a
s a
dia
gn
osi
s o
f M
I (I
CD
-10 c
od
es
I21-
I22)
on
ad
mis
sio
n t
o a
n e
me
rge
nc
y
de
pa
rtm
en
t o
r c
oro
na
ry c
are
un
it in
on
e o
f th
ree
ho
spita
ls in
Aa
rhu
s,
De
nm
ark
.
The
pa
tie
nt
wa
s a
live
wh
en
rea
ch
ing
ho
spita
l.
The
ho
spita
l re
co
rd c
on
firm
ed
MI
dia
gn
osi
s, b
ase
d o
n e
nzy
me
te
sts
an
d E
CG
.
The
ho
spita
l re
co
rd p
rovid
ed
suff
icie
nt
info
rma
tio
n o
n d
iag
no
sis
an
d t
rea
tme
nt.
Ou
tco
me
me
asu
res
28 d
ay m
ort
alit
y
An
aly
sis
Pe
ars
on
’s χ
2, Fis
he
r’s
exa
ct
test
,
Sp
ea
rma
n’s
no
n-p
ara
me
tric
ra
nk
co
rre
latio
n, K
ap
lan
-Me
ier
surv
iva
l
an
aly
sis
an
d m
ultip
le lo
gis
tic
reg
ress
ion
we
re c
on
du
cte
d.
Cru
de
mo
rta
lity r
ate
at
28 d
ays,
by
stu
dy p
erio
d.
Pre
-MEC
U:
20.6
%
MEC
U: 11
.1%
Ad
just
ed
od
ds
ratio
by s
tud
y p
erio
d
(28 d
ay m
ort
alit
y),
(p
re-M
EC
U a
s
the
re
fere
nc
e)
OR
0.3
(P
<0.0
25
)
Ad
just
ed
fo
r a
ge
, g
en
de
r, p
uls
e
an
d s
yst
olic
blo
od
pre
ssu
re.
Ad
just
ed
od
ds
ratio
by u
se o
f M
EC
U
(28 d
ay m
ort
alit
y),
(p
re-M
EC
U a
s
the
re
fere
nc
e)
OR
0.2
(P
<0.0
5)
Ad
just
ed
fo
r a
ge
, g
en
de
r, p
uls
e
an
d s
yst
olic
blo
od
pre
ssu
re.
Lim
ita
tio
ns
�
Re
tro
spe
ctive
stu
dy.
�
Exc
lusi
on
s: s
ix w
ere
eith
er
de
ad
on
arr
iva
l or
die
d im
me
dia
tely
aft
er
arr
iva
l (fo
ur
pre
MEC
U a
nd
tw
o w
ith
MEC
U),
sp
ec
ific
MI d
iag
no
sis
co
uld
no
t b
e c
on
firm
ed
in
25
. U
nc
lea
r if a
ny
we
re e
xclu
de
d d
ue
to
in
suff
icie
nt
info
rma
tio
n o
n t
rea
tme
nt.
�
Lim
ite
d d
ata
pro
vid
ed
at
tim
e o
f firs
t
att
en
da
nc
e o
f p
re-h
osp
ita
l ca
re.
�
Be
fore
an
d a
fte
r st
ud
y is
a lo
w q
ua
lity
de
sig
n –
fe
atu
res
oth
er
tha
n t
he
inte
rve
ntio
n o
f in
tere
st m
ay h
ave
ch
an
ge
d s
o it
is u
nc
lea
r to
wh
at
ext
en
t a
ny c
ha
ng
e in
ou
tco
me
is a
resu
lt o
f th
e in
tro
du
ctio
n o
f M
EC
U. In
this
stu
dy, th
e im
pro
ve
d p
rog
no
sis
ma
y h
ave
be
en
du
e t
o a
ng
iop
last
y
rath
er
tha
n M
EC
U.
�
Ba
sis
of
dia
gn
osi
s o
f M
I n
ot
pre
cis
ely
de
fin
ed
: p
ote
ntia
l fo
r in
ap
pro
pria
te
sele
ctio
n.
�
Po
ten
tia
l fo
r m
isc
lass
ific
atio
n o
f
ou
tco
me
, th
ou
gh
th
e s
ize
an
d
dire
ctio
n o
f su
ch
mis
cla
ssific
atio
n is
diffic
ult t
o d
ete
rmin
e.
�
Du
rin
g t
he
MEC
U p
erio
d,
som
e
pa
tie
nts
we
re n
ot
att
en
de
d b
y M
EC
U
(56%
). H
ow
eve
r, a
lth
ou
gh
MEC
U
pa
tie
nts
we
re m
ore
like
ly t
o b
e
co
nsi
de
red
as
seve
re,
MEC
U p
atie
nts
ha
d h
igh
er
ad
just
ed
od
ds
of
surv
iva
l
co
mp
are
d w
ith
no
n-M
EC
U p
atie
nts
.
TRANSPORTATION OF EMERGENCY PATIENTS
42
Ta
ble
10
E
vid
ence
ta
ble
s o
f st
ud
ies
com
pa
rin
g t
he
ou
tco
me
of
pa
tien
ts t
ran
spo
rted
by
ro
ad
am
bu
lan
ce w
ith
an
d w
ith
ou
t a
med
ica
l d
oct
or
on
bo
ard
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Ko
efo
ed
-Nie
lse
n e
t a
l.
2002
)
De
nm
ark
co
ntin
ue
d
A
na
lyse
s c
om
pa
ring
gro
up
s a
t b
ase
line
Ag
e ≤
69 y
ea
rs (
%)
Pre
MEC
U: 4
1
MEC
U: 41
Ma
le s
ex
(%)
Pre
MEC
U: 6
3
MEC
U: 72
PTC
A p
erf
orm
ed
(%
)
Pre
MEC
U: 1
9
MEC
U: 26
Thro
mb
oly
sis
giv
en
(%
)
Pre
MEC
U: 2
8
MEC
U: 33
Co
mm
en
ts
�
Aim
ed
to
ass
ess
th
e im
pa
ct
of
a
MEC
U o
n s
urv
iva
l am
on
g p
atie
nts
with
ac
ute
MI.
�
MEC
U p
atie
nts
we
re m
ore
lik
ely
to
rec
eiv
e t
hro
mb
oly
sis.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
In t
he
pre
sen
t st
ud
y, M
I p
atie
nts
tre
ate
d in
a
MEC
U s
taff
ed
by a
n a
na
est
he
tist
an
d/o
r
ha
vin
g a
ng
iop
last
y w
as
fou
nd
to
be
ass
oc
iate
d w
ith
a r
ed
uc
ed
mo
rta
lity. Th
ese
ob
serv
atio
ns
ha
ve
be
en
ba
sed
on
qu
asi
-
exp
erim
en
tal r
ath
er
tha
n r
an
do
mis
ed
exp
erim
en
tal d
ata
, a
nd
ra
nd
om
ise
d d
ata
wo
uld
be
hig
hly
de
sira
ble
.
TRANSPORTATION OF EMERGENCY PATIENTS
43
Ta
ble
10
E
vid
ence
ta
ble
s o
f st
ud
ies
com
pa
rin
g t
he
ou
tco
me
of
pa
tien
ts t
ran
spo
rted
by
ro
ad
am
bu
lan
ce w
ith
an
d w
ith
ou
t a
med
ica
l d
oct
or
on
bo
ard
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Le
e e
t a
l. 2
003
)
Au
stra
lia
Re
tro
spe
ctive
co
ho
rt s
tud
y
Leve
l III-
2.
Stu
dy s
ett
ing
.
Se
ve
re b
lun
t tr
au
ma
pa
tie
nts
ad
mitte
d
to W
est
me
ad
Ho
spita
l, Syd
ne
y b
etw
ee
n
July
1986 a
nd
De
ce
mb
er
20
00.
Am
bu
lan
ce
off
ice
rs t
rain
ed
to
th
ree
diffe
ren
t le
ve
ls: tw
o le
ve
ls o
f b
asi
c li
fe
sup
po
rt a
nd
on
e le
ve
l of
ad
va
nc
ed
life
sup
po
rt.
Als
o h
ad
tw
o p
hysi
cia
n-s
taff
ed
em
erg
en
cy m
ed
ica
l se
rvic
es
wh
ich
resp
on
d t
o a
cc
ide
nt
sce
ne
s e
ith
er
by
roa
d o
r h
elic
op
ter.
Leve
l 3 a
mb
ula
nc
e o
ffic
er:
ba
sic
life
sup
po
rt w
ith
ou
t e
xte
rna
l co
ntr
ol o
f
ha
em
orr
ha
ge
, sp
lintin
g,
no
n-in
va
siv
e
airw
ay m
an
oe
uvre
s a
nd
ba
g-v
alv
e-
ma
sk v
en
tila
tio
n.
Leve
l 4 a
mb
ula
nc
e o
ffic
er:
ba
sic
life
sup
po
rt p
lus
intr
ave
no
us
ca
nn
ula
tio
n
an
d a
dm
inis
tra
tio
n o
f IV
flu
ids,
in
ad
ditio
n t
o a
lim
ite
d r
an
ge
of
IV
me
dic
atio
ns
an
d n
ee
dle
th
ora
ce
nte
sis.
Leve
l 5 a
mb
ula
nc
e o
ffic
er:
Ad
va
nc
ed
life
su
pp
ort
. A
ble
to
pe
rfo
rm a
ll th
e
ab
ove
pro
ce
du
res
plu
s o
ral
en
do
tra
ch
ea
l in
tub
atio
n.
Ac
ce
ss t
o a
wid
er
ran
ge
of
IV m
ed
ica
tio
ns
(bu
t n
ot
ne
uro
mu
scu
lar
blo
cka
de
, a
na
est
he
tic
ag
en
ts o
r se
da
tive
ag
en
ts t
o f
ac
ilita
te
intu
ba
tio
n).
Ph
ysi
cia
ns
are
fre
e t
o e
xerc
ise
th
eir
clin
ica
l ju
dg
em
en
t in
ea
ch
ca
se.
Inc
lu/e
xcl c
rite
ria
.
Blu
nt
tra
um
a p
atie
nts
with
ISS >
15.
Ou
tco
me
me
asu
res
Mo
rta
lity d
urin
g h
osp
ita
l ad
mis
sio
n
An
aly
sis
Log
istic
re
gre
ssio
n u
sed
with
th
e
follo
win
g p
red
icto
r va
ria
ble
s: le
ve
l
of
pre
-ho
spita
l ca
re,
tim
e f
rom
inju
ry
to a
rriv
al i
n h
osp
ita
l, ty
pe
of
inju
ry,
me
ch
an
ism
of
inju
ry, a
ge
, se
x, ISS,
GC
S a
nd
syst
olic
blo
od
pre
ssu
re.
Mo
de
l ca
libra
tio
n a
sse
sse
d b
y t
he
Ho
sme
r-Le
me
sho
w g
oo
dn
ess
-of-
fit
χ2 t
est
an
d p
red
ictive
ac
cu
rac
y
ass
ess
ed
by t
he
are
a u
nd
er
the
rec
eiv
er
op
era
tin
g c
ha
rac
terist
ic
cu
rve
.
Ris
k in
od
ds
ratio
of
mo
rta
lity b
y
leve
l of
pre
-ho
spita
l ca
re a
nd
IC
U
tre
atm
en
t (b
asi
c li
fe s
up
po
rt a
s th
e
refe
ren
ce
), (
95
% C
I)
No
IC
U a
dm
issi
on
:
Leve
l 5 a
mb
ula
nc
e:
2.1
8 (
1.0
5-4
.55)
Ph
ysi
cia
n: 4.2
7 (
1.4
6-1
2.4
5)
ICU
ad
mis
sio
n:
Leve
l 5 a
mb
ula
nc
e:
0.7
0 (
0.5
3-1
.18)
Ph
ysi
cia
n: 0.6
3 (
0.2
8-1
.39
)
Lim
ita
tio
ns
�
Re
tro
spe
ctive
stu
dy.
�
A s
ele
ctive
dis
pa
tch
str
ate
gy w
as
use
d w
hic
h p
rob
ab
ly e
xpla
ins
the
inc
rea
sed
mo
rta
lity r
ate
s in
th
e le
ve
l 5
am
bu
lan
ce
gro
up
an
d t
he
ph
ysi
cia
n
gro
up
in
th
e n
on
-IC
U p
op
ula
tio
n.
�
Pa
ram
ed
ics
ma
y h
ave
in
vo
lve
d t
he
ph
ysi
cia
n g
rou
p w
he
n p
atie
nt
de
ath
wa
s im
min
en
t.
�
Un
cle
ar
if s
om
e p
hysi
cia
n g
rou
p
pa
tie
nts
ma
y h
ave
be
en
tra
nsp
ort
ed
by h
elic
op
ter.
�
Diffe
ren
t le
ve
ls o
f a
cc
ess
to
pro
ce
du
res
in t
he
no
n-d
oc
tor
gro
up
s
ma
y n
ot
be
ge
ne
ralis
ab
le t
o o
the
r
sett
ing
s, m
ay g
uid
e d
isp
atc
h d
ec
isio
ns
an
d m
ay r
esu
lt in
bia
s in
co
mp
ara
tiv
e
est
ima
tes.
�
Ob
serv
atio
n s
tud
y is
su
sce
ptib
le t
o
co
nfo
un
din
g.
Co
mm
en
ts
�
Aim
ed
to
de
term
ine
th
e a
sso
cia
tio
n
be
twe
en
mo
rta
lity a
nd
leve
l of
pre
-
ho
spita
l ca
re in
se
ve
rely
inju
red
blu
nt
tra
um
a p
atie
nts
with
or
with
ou
t se
ve
re
he
ad
tra
um
a.
�
No
on
line
me
dic
al c
on
tro
l pro
vid
ed
.
�
We
ll d
esc
ribe
d a
nd
co
nd
uc
ted
sta
tist
ica
l me
tho
do
log
y.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
The
leve
l of
pre
-ho
spita
l ca
re w
as
ass
oc
iate
d w
ith
th
e r
isk o
f m
ort
alit
y. Th
is w
as
mo
difie
d b
y w
he
the
r th
e p
atie
nt
surv
ive
d
lon
g e
no
ug
h t
o b
e a
dm
itte
d t
o t
he
IC
U.
TRANSPORTATION OF EMERGENCY PATIENTS
44
Ta
ble
10
E
vid
ence
ta
ble
s o
f st
ud
ies
com
pa
rin
g t
he
ou
tco
me
of
pa
tien
ts t
ran
spo
rted
by
ro
ad
am
bu
lan
ce w
ith
an
d w
ith
ou
t a
med
ica
l d
oct
or
on
bo
ard
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Le
e e
t a
l. 2
003
)
Au
stra
lia
co
ntin
ue
d
P
art
icip
an
ts (
n=
2010
):
Inte
rve
ntio
n.
Leve
l of
pre
-ho
spita
l ca
re w
as
cla
ssifie
d
into
th
ree
gro
up
s: b
asi
c li
fe s
up
po
rt,
ad
va
nc
ed
life
su
pp
ort
an
d p
hysi
cia
n
ca
re.
An
aly
ses
co
mp
arin
g g
rou
ps
at
ba
selin
e.
Me
an
ISS b
y le
ve
l of
pre
-ho
spita
l ca
re:
No
n-E
MS t
ran
spo
rt:
20
Leve
l 3 a
mb
ula
nc
e:
24
Leve
l 4 a
mb
ula
nc
e:
25
Leve
l 5 a
mb
ula
nc
e:
31
Ph
ysi
cia
n: 3
1
Me
dia
n a
ge
30 y
ea
rs (
inte
rqu
art
ile
ran
ge
21-4
9 y
ea
rs)
Ma
les:
76%
Ca
use
s:
Ro
ad
tra
ffic
ac
cid
en
t 6
7%
Falls
: 13%
Ass
au
lt 5
%.
No
he
ad
inju
rie
s: 3
6%
Iso
late
d h
ea
d in
jury
: 52%
He
ad
inju
ry w
ith
ab
do
min
al/
ch
est
inju
rie
s: 1
2%
Pre
-ho
spita
l ca
re:
No
n-E
MS t
ran
spo
rt 5
%
Leve
l 3 a
mb
ula
nc
e 2
3%
Leve
l 4 a
mb
ula
nc
e 2
%
Leve
l 5 a
mb
ula
nc
e 5
9%
Ph
ysi
cia
n E
MS 1
1%
TRANSPORTATION OF EMERGENCY PATIENTS
45
Ta
ble
10
E
vid
ence
ta
ble
s o
f st
ud
ies
com
pa
rin
g t
he
ou
tco
me
of
pa
tien
ts t
ran
spo
rted
by
ro
ad
am
bu
lan
ce w
ith
an
d w
ith
ou
t a
med
ica
l d
oct
or
on
bo
ard
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Ch
rist
en
sze
n e
t a
l.
2003
)
De
nm
ark
Be
fore
an
d
aft
er
stu
dy
Leve
l III-
3.
Stu
dy s
ett
ing
.
Co
ve
rs a
n a
rea
of
~8
00km
2 a
nd
a
po
pu
latio
n o
f ~
330,0
00.
Mo
st o
f th
e
po
pu
latio
n is
an
urb
an
ce
ntr
e
(~2
50,0
00
). A
mo
bile
em
erg
en
cy c
are
un
it (
sta
ffe
d w
ith
an
an
ae
sth
etist
) is
dis
pa
tch
ed
fo
r th
e m
ost
se
rio
us
ca
ses.
The
mo
bile
em
erg
en
cy c
are
un
it
(MEC
U)
wa
s se
t u
p in
1997
.
Am
bu
lan
ce
cre
w in
clu
de
s b
asi
c li
fe
sup
po
rt s
kill
s, s
em
iau
tom
atic
de
fib
rilla
tio
n,
ad
min
istr
atio
n o
f n
itro
-g
lyc
erin
e s
pra
ys,
inh
ala
tio
n o
f β
-2-
an
tag
on
ists
an
d t
he
ap
plic
atio
n o
f
dia
zep
am
re
cta
lly a
nd
nitro
us
oxi
de
/oxy
ge
n.
Pa
rtic
ipa
nts
(n
=5
819
):
Co
nse
cu
tive
am
bu
lan
ce
use
rs d
urin
g 1
Se
pte
me
br-
30
No
ve
mb
er
199
6 (
be
fore
MEC
U)
an
d 1
Se
pte
mb
er-
30 N
ove
mb
er
1997 (
aft
er
MEC
U in
tro
du
ctio
n).
Inte
rve
ntio
n.
MEC
U
Co
mp
ara
tor.
No
MEC
U
An
aly
ses
co
mp
arin
g g
rou
ps
at
ba
selin
e.
Ma
les
52%
Me
an
ag
e: Fe
ma
le 5
0.7
ye
ars
, m
ale
45.0
Co
nse
cu
tive
use
rs in
pe
rio
d 1
: 295
0
Co
nse
cu
tive
use
rs in
pe
rio
d 2
: 286
9
(in
clu
de
d 2
7.6
% a
tte
nd
ed
by
am
bu
lan
ce
an
d M
EC
U)
Inc
lu/e
xcl c
rite
ria
.
Co
nse
cu
tive
am
bu
lan
ce
use
rs in
the
pe
rio
ds
of
inte
rest
.
Wh
en
th
ere
wa
s m
ore
th
an
on
e
am
bu
lan
ce
ca
ll d
urin
g t
he
stu
dy
pe
riod
th
e u
ser
wa
s in
clu
de
d o
nly
on
th
e d
ay o
f th
e in
itia
l ca
ll.
Ou
tco
me
me
asu
res
Ho
spita
lisa
tio
n
Dia
gn
ost
ic p
att
ern
Su
rviv
al a
t 1,
7, 2
8 a
nd
180
da
ys
An
aly
sis
Mu
ltip
le lo
gis
tic
re
gre
ssio
n w
as
use
d
for
da
ta a
na
lysi
s.
180 d
ay m
ort
alit
y: c
om
pa
riso
n
be
twe
en
pe
rio
d b
efo
re a
nd
aft
er
intr
od
uc
tio
n o
f M
EC
U (
pe
rio
d
be
fore
intr
od
uc
tio
n a
s th
e
refe
ren
ce
):
OR
1.0
6 (
no
t st
atist
ica
lly s
ign
ific
an
t)
Ad
just
ed
fo
r a
ge
an
d g
en
de
r
180 d
ay m
ort
alit
y: c
om
pa
riso
n
be
twe
en
MEC
U u
se a
nd
no
n-u
se in
the
pe
rio
d a
fte
r in
tro
du
ctio
n o
f
MEC
U.
MEC
U u
sers
: 14.7
% m
ort
alit
y
No
n-M
EC
U u
sers
8.9
% m
ort
alit
y
P<
0.0
01
Lim
ita
tio
ns
�
Be
fore
an
d a
fte
r st
ud
y is
a lo
w q
ua
lity
de
sig
n –
fe
atu
res
oth
er
tha
n t
he
inte
rve
ntio
n o
f in
tere
st m
ay h
ave
ch
an
ge
d s
o it
is u
nc
lea
r to
wh
at
ext
en
t a
ny c
ha
ng
e in
ou
tco
me
is a
resu
lt o
f th
e in
tro
du
ctio
n o
f M
EC
U.
�
The
se
co
nd
pe
rio
d in
clu
de
s a
mix
of
MEC
U a
nd
am
bu
lan
ce
re
trie
va
ls.
�
No
co
ntr
ol f
or
me
asu
res
of
inju
ry
seve
rity
in c
om
pa
rin
g t
he
pe
rio
d p
re
an
d p
ost
intr
od
uc
tio
n o
f M
EC
U o
r in
a
co
mp
ariso
n o
f M
EC
U w
ith
no
n-M
EC
U
use
rs in
th
e p
erio
d a
fte
r in
tro
du
ctio
n
of
MEC
U.
�
Co
nfid
en
ce
inte
rva
ls w
ere
no
t
pre
sen
ted
fo
r th
e a
dju
ste
d
co
mp
ariso
ns
of
mo
rta
lity.
Co
mm
en
ts
�
The
stu
dy a
im w
as
(1)
to d
esc
ribe
mo
rta
lity, h
osp
ita
lisa
tio
n, a
nd
th
e
dia
gn
ost
ic p
att
ern
am
on
g
em
erg
en
cy a
mb
ula
nc
e u
sers
an
d (
2)
to e
va
lua
te t
he
im
pa
ct
of
on
e M
EC
U
sta
ffe
d b
y a
n a
na
est
he
tist
.
�
Me
dia
n r
esp
on
se t
ime
fo
r M
EC
U 8
.9
min
ute
s a
nd
6.5
min
ute
s fo
r
am
bu
lan
ce
.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
Aft
er
the
MEC
U f
ew
er
we
re b
rou
gh
t to
ho
spita
l. Th
e o
ve
rall
mo
rta
lity f
or
all
am
bu
lan
ce
use
rs w
as
no
t in
flu
en
ce
d b
y t
he
MEC
U. Fo
r th
e s
ub
gro
up
s, e
spe
cia
lly A
MI,
mo
rta
lity w
as
low
er
aft
er
the
intr
od
uc
tio
n o
f
the
MEC
U.
TRANSPORTATION OF EMERGENCY PATIENTS
46
Summary and Conclusions
Results were conflicting among the four studies eligible for the review examining the effectiveness of including a doctor on board ambulance transportation. Two studies estimated an increased level of effectiveness in services with a doctor on board (Frandsen et al. 1991; Koefoed-Nielsen et al. 2002), one had variable results depending on the comparator group and the use of ICU (Lee et al. 2003) and one found a significantly worse outcome associated with incorporation of a doctor (Christenszen et al. 2003). However, it is useful to consider the results more critically. Three of the four studies used a before and after design. This is a weak study design since it is not possible to be certain that the intervention of interest has resulted in any change in outcome or if some other factor has changed over time that has resulted in the change in outcome.
Three studies were set in Denmark. Two of these studies evaluated MECUs. Both these studies used before and after designs with the later period having access to MECUs. However, only 56% and 28% of patients in this later period were actually attended by a MECU. One of these studies reported on a population of patients with acute MI (Koefoed-Nielsen et al. 2002) and the other had no such restriction (Christenszen et al. 2003). In the study reporting on MI patients there were significantly lower odds of 28 day mortality both in the period with MECU available and in the direct comparison between MECU and non-MECU patients. The latter result is pertinent since the MECU was directed towards more severe patients. However, the results in the other evaluation of MECU were different. Specifically, there was no difference in 180 day mortality between the time periods with and without MECU and the 180 day mortality was significantly higher in MECU users compared with non-users. The latter may represent the casemix with more severe cases being attended by MECU. The other Danish study compared three different approaches for the pre-hospital care of out of hospital cardiac arrest (Frandsen et al. 1991). The survival rate was higher in the group that included a doctor on board compared with two non-doctor arrangements (survival rate 13% versus 5% and 1%). However, this study did not control for potential confounders. This lack of control of confounders was problematic because, amongst other potential issues, the mean age was lower in the doctor group compared with the other groups. This difference in age could explain the difference in outcome between groups. The fourth study was set in Australia (Lee et al. 2003). The study population consisted of patients with severe blunt trauma. Three types of pre-hospital care were studied. The most basic level of life support was used as the reference category and was compared with another non-medical configuration and a configuration with a doctor on board. The results varied by whether the patients were subsequently admitted to ICU. The odds of mortality were significantly higher in the two more advanced pre-hospital configurations when the patient was not admitted to ICU. However, when the patient was admitted to ICU there were no statistically significant differences between pre-hospital care groups. It should be noted that a selective dispatch strategy was used so the more severely injured patients were seen by the more advanced ambulance group and the doctor group. The authors also commented that paramedics may have involved the physician group when patient death was imminent. These factors may explain the poorer prognosis in the two more advance pre-hospital care groups among the patients who did not proceed on to ICU care.
Similar considerations applied in the comparison of effectiveness of doctors versus non-doctor configurations on road ambulances as they did on helicopters. Specifically, the literature identified had limitations as identified above. These limitations are such that no clear conclusions can be drawn on the question of benefit from having a doctor on board road ambulances. Further considerations also apply:
1. The literature examined in this section does not answer the question whether wider training in procedures accessible to doctors would have an impact on patient outcome.
2. Whether there may be variation in outcome across crew mixes for different clinical scenarios. For example, the inclusion of doctors on road ambulances may be associated with longer at scene times. This longer period of stabilization could be associated with improved outcome in some circumstances but not others.
3. There was insufficient information to compare outcomes in paediatric and adult age groups or to stratify results by ISS score. Note the one study limited to trauma patients was restricted to patients with an ISS>15.
Like the section above examining doctors versus no doctors on board helicopters further research is required to adequately answer the question about the effectiveness of doctors versus no doctors on
TRANSPORTATION OF EMERGENCY PATIENTS
47
board road ambulances. A similar approach would be useful to that proposed in the helicopter section to further elucidate this issue.
Comparison of outcomes amongst crews that do and do not perform rapid sequence
intubation and/or thoracostomy
The identification of studies for inclusion in review question three (comparison of outcomes in patients transported by crews that do and do not have the ability to perform rapid sequence intubation and/or thoracostomy) were identified from three searches. The first two searches were the same as those used in questions 1 and 2. An additional search was conducted that identified 253 additional potentially relevant articles/abstracts. Therefore, there were 1837 potentially relevant articles/abstracts. One hundred of these were retrieved. Of these retrieved articles, 95 were excluded. These excluded papers are presented in Appendix 5. Two additional articles were identified from reference lists. Both these studies were excluded: one was not relevant to the review question and the other used an incorrect comparator. Reasons for exclusion of studies before retrieval in full text are outlined in Table 11. Reasons for exclusion of studies retrieved in full text are detailed in Table 12.
Table 11 Reasons for exclusion of studies before retrieval in full text (from additional search):
patients transported by crews that do and do not have the ability to perform rapid
sequence intubation and/or thoracostomy
Reason for exclusion Number
Not relevant to review question aim 1473
Methods were not clearly described 0
Wrong publication type 220
Incorrect population 1
Sample size less than 50 21
Incorrect comparator 10
Incorrect outcomes 7
Publication superseded 0
Non-English language 0
Neonatal study 5
Total 1737
Table 12 Reasons for exclusion of studies retrieved in full text: patients transported by crews
that do and do not have the ability to perform rapid sequence intubation and/or
thoracostomy
Reason for exclusion Number
Not relevant to review question aim 26
Methods were not clearly described 3
Wrong publication type 23
Incorrect population 1
Sample size less than 50 0
Incorrect comparator 10
Incorrect outcomes 5
Publication superseded 0
Non-English language 1
Neonatal study 0
No documentation of procedures by different crews 25
Patient transfer 1
Total 95
Five retrieved articles were appraised and are listed in the references and Appendix 7. Included papers are presented in the evidence table below. Included studies were all level III-3 and above according to NHMRC’s hierarchy of evidence, including a pseudorandomised controlled trial, two cohort studies and two before and after studies.
TRANSPORTATION OF EMERGENCY PATIENTS
48
Baxt et al. 1987
Baxt et al. (1987) conducted a pseudorandomised controlled trial (Level III-1 evidence) comparing mortality in a group of consecutive patients with blunt trauma transported by helicopter with physician and nurse on board with another group with paramedic and nurse on board. In relation to the procedures of interest, the physician group was able to perform both needle and tube thoracostomies whereas the paramedic group was not. There were also other differences in procedures performed and these are noted in Table 13. There were 574 participants (316 in the physician group and 258 in the comparator group). Actual mortality was compared with predicted mortality using TRISS methodology. The trauma score scale rather than the revised trauma score scale was included in this calculation. Actual mortality was not statistically significantly different from predicted mortality in the paramedic group while, in the physician group, actual mortality was significantly lower than predicted (P<0.05). There was a statistically significant difference in the Z statistic between the two groups, supporting reduced mortality in the physician group compared with the paramedic group. This reduction in mortality may have been related to the difference in procedures available to the physician group.
There were potential sources of confounding and bias that should be considered when interpreting this study. Key issues included:
� the study was not truly randomised so is susceptible to confounding. However, significant baseline differences were not observed for transport time, trauma score, ISS, GCS, predicted survival or patient age
� the key difference between the groups related to the category of patients who survived but were expected to die. There were only 22 patients who were expected to die in the physician group (five survived) and 16 who were expected to die in the paramedic group (none survived)
� the TRISS methodology used in this review did not assess the degree of match in injury severity between the two groups, or adjust for different casemix in the study groups
� the study did not use all-cause mortality, resulting in the potential for misclassification of outcome.
It should also be noted that although the results supported reduced mortality in the physician group and that this was the only group that was able to perform thoracostomies it does not necessarily mean that the difference in outcome is due to the ability to perform this procedure. It is possible that if the paramedic group had also been able to perform thoracostomies there may not have been support for reducing mortality in the physician group compared with the paramedic group but again this was not the focus of the study so no conclusion can be formed on this point. For such a conclusion to be made, a study with three arms would be required: the two arms included in the present study plus another arm for a paramedic group that was able to perform thoracostomy.
Garner et al. 1999
Garner et al. (1999) reported on a retrospective study set in Australia (level III-2 evidence). They compared the outcome (mortality) between groups transported via helicopter with a physician on board versus patients transported with a paramedic on board. The physician group performed a number of rapid sequence intubations (28 of the 34 intubations in this group were conducted after muscle relaxant drugs were provided). The use of muscle relaxant drugs was beyond the paramedic protocol. In general, the physician group was treated more aggressively. All patients were transported directly from the scene to the relevant hospital (hospitals varied by the crew mix on the helicopter). There were 67 patients in the physician group and 140 in the paramedic group. The patients were restricted to those with blunt trauma and an ISS score greater than 10. Actual mortality was compared with predicted mortality using TRISS methodology (MTOS as the reference population) and the adjusted W statistic was also used to directly compare the physician and paramedic groups. The degree of match on injury severity between the MTOS population and the physician and paramedic groups was poor, therefore the adjusted W statistic was appropriately presented. When comparing the physician group with the MTOS population it was estimated that 9.48 (95% CI 3.84-15.12) extra lives per 100 population were saved in the physician group. There was no significant difference in mortality between the MTOS population and the paramedic group. Direct comparison between the paramedic and physician groups suggested 13.44 (95% CI 7.80-19.08) extra lives per 100 population were saved in the physician group.
TRANSPORTATION OF EMERGENCY PATIENTS
49
There were differences in the procedures performed between the two groups so these differences may have contributed to the difference in outcome. These are detailed in Table 13.
The study had limitations:
� it was a retrospective study
� there were sources of selection bias – with differences in baseline measures between the two study groups (the physician group appeared to manage a more severely injured group) and seven patients who died were excluded from the paramedic group due to missing case sheets
� confounding was a potential problem between the two groups although use of the W statistic should have partially controlled confounding (based on injury severity)
� the degree of match in injury severity with the MTOS study was poor and there were variations in methods adopted in the MTOS study and this study (most notably related to the timing of RTS measurement) which limits the usefulness of the MTOS cohort as a reference population.
It should also be noted that although the results supported reduced mortality in the physician group and that this was the only group that performed rapid sequence intubations it does not necessarily mean that the difference in outcome is due to the ability to perform this procedure. It is possible that if the paramedic group had performed rapid sequence intubations there may not have been support for reducing mortality in the physician group compared with the paramedic group but again this was not the focus of the study so no conclusion can be formed on this point. For such a conclusion to be made, a study with three arms would be required: the two arms included in the present study plus another arm for a paramedic group that performed rapid sequence intubation.
Koefoed-Nielsen et al. 2002
This before and after study (level III-3 evidence) compared 28 day mortality in acute MI patients over two time periods:
1. A period preceding introduction of a mobile emergency care unit (MECU), (September to November 1996).
2. A period with a MECU (plus standard ambulances) that included anaesthetist staffing (September to November 1997).
There were 54 patients in each period. The anaesthetist was able to perform the following additional procedures: tracheal intubation, transcutaneous pacing, anaesthetics (hypnotics and muscle relaxants), opioids, heart stimulating drugs and antiarrhythmics. On the basis of this description, it was interpreted that the anaesthetist was able to perform rapid sequence intubation in the field.
The crude mortality rate was higher in the pre-MECU period (20.6% versus 11.1%). Multivariate regression (controlling for age, gender, pulse and systolic blood pressure) found a significantly lower odds of 28 day mortality in the time period that included a MECU (OR 0.3, P < 0.025). Forty-four percent of patients in the second time period were treated by the MECU. Another multivariate model also estimated lower odds of 28 day mortality in the group treated by MECU than the non-MECU group (OR 0.2, P < 0.05).
As with all before and after studies, there were limitations:
� it is not possible to be certain that any difference in outcome is due to the different crew configurations. The authors noted the increased proportion of patients undergoing angioplasty may explain the results.
� potential selection bias, with 25 people being excluded on the basis of insufficient information about the diagnosis.
� the multivariate models controlled for a limited range of potential confounders. Most importantly, the estimated odds ratio comparing MECU with non-MECU patients may underestimate the effectiveness of MECU due to the selection of more severely unwell patients for this service.
� it was unclear if the differences in outcome would be maintained if non-anaesthetist groups were trained in further procedures.
TRANSPORTATION OF EMERGENCY PATIENTS
50
It should also be noted that although the results supported reduced mortality in the anaesthetist group (MECU) and that this was the only group that performed rapid sequence intubations it does not necessarily mean that the difference in outcome is due to the ability to perform this procedure. It is possible that if the non-anaesthetist group had performed rapid sequence intubations there may not have been support for reducing mortality in the anaesthetist group compared with the non-anaesthetist group but again this was not the focus of the study so no conclusion can be formed on this point. For such a conclusion to be made, a study with three arms would be required: the two arms included in the present study plus another arm for a non-anaesthetist group that performed rapid sequence intubation.
Lee et al. 2003
A retrospective cohort study (level III-2 evidence) was conducted in Australia (Lee et al. 2003). This study compared the outcome across different levels of ambulance officer and physicians. There were three levels of ambulance officer (two classified as providing basic life support and the third providing advanced life support). Details of the procedures available to these groups are provided in Table 10. Most notably, physicians were able to perform any procedure they considered warranted, whereas other groups were not able to perform rapid sequence intubation or tube thoracocentesis. Logistic regression was used to control for confounding with the following predictor variables being included in initial models: level of pre-hospital care, time from injury to arrival in hospital, type of injury, mechanism of injury, age, sex, ISS, GCS and systolic blood pressure.
The effect of pre-hospital care on mortality was dependent on level of ICU care. Key results in the group that did not receive ICU care were (using basic life support as the reference group):
� level 5 ambulance: OR 2.18 (95% CI, 1.05-4.55)
� physician: OR 4.27 (95% CI 1.46-12.45).
The majority of these deaths occurred within 24 hours of admission, which the authors suggested was on the basis of not surviving initial resuscitation. Thus it is not clear if the logistic regression model adequately controlled for injury severity.
Key results in the group that did receive ICU care were (using basic life support as the reference group):
� level 5 ambulance: OR 0.70 (95% CI 0.53-1.18)
� physician: OR 0.63 (95% CI 0.28-1.39).
There were significant limitations to this study:
� the study used a retrospective design
� a selective dispatch strategy was used which probably explains the increased mortality rates in the level 5 ambulance group and the physician group in the non-ICU population
� paramedics may have involved the physician group when patient death was imminent
� the observational study is susceptible to residual confounding.
Cameron et al. 2005
A retrospective chart review was conducted in Australia (Cameron et al. 2005). This study used a before and after design (Level III-3 evidence) to compare outcome in a period where helicopters included emergency physicians with a subsequent period where the helicopter did not include an emergency physician (intensive care paramedics were used). The physicians were able to perform all the usual treatment and monitoring facilities that they could normally provide in the emergency department. In contrast, the non-physician team was unable to do rapid sequence intubations. Given the nature of the data recorded measures of injury severity were restricted to the RTS. Chart abstraction was primarily performed by one person but a 10% sample was validated by another abstractor. There was an excellent level of agreement between the two abstractors. There were 163 patients in the physician group and 211 in the paramedic group. Mortality was measured at 30 days. There were 10 deaths in total and no significant difference was detected between the study groups. There was also no
TRANSPORTATION OF EMERGENCY PATIENTS
51
significant difference in the length of stay, although the length of stay was only two days and one day respectively in the physician and paramedic groups.
There were significant limitations to this study:
� the effects of a retrospective design were apparent. As the authors documented, they were unable to extract data that would have provided a better indication of injury/illness severity.
� there was no control over potential confounders. Given baseline differences suggestive of a more severe casemix in the physician group this may have led to bias in the comparison.
� the outcome of the group discharged from ED was not obtained.
� the study power was low, particularly for mortality, so the lack of a significant difference in outcome was not surprising.
Wirtz et al. 2002
There was one other study of interest identified, although it did not meet the eligibility criteria for the review. It is included here for completeness. Wirtz et al. (2002) noted that both paramedics and flight nurses performed rapid sequence intubation. There was therefore no comparison group in this study involving a crew that did not perform rapid sequence intubation. Therefore, the study could not be included. Mortality was similar in both groups. However, it leaves the question whether there truly would be a difference in outcome between:
1. Doctors and other crew configurations that are both able to conduct rapid sequence intubation.
2. Non-doctor crews able to perform rapid sequence intubation and non-doctor crews that are not able to perform rapid sequence intubation.
TRANSPORTATION OF EMERGENCY PATIENTS
52
Ta
ble
13
E
vid
ence
ta
ble
s o
f st
ud
ies
com
pa
rin
g c
rew
s th
at
do
an
d d
o n
ot
per
form
ra
pid
seq
uen
ce i
ntu
ba
tio
n a
nd
/or
tho
raco
sto
my
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Ba
xt
an
d M
oo
dy 1
987
)
USA
Pse
ud
o-
ran
do
mis
ed
co
ntr
olle
d t
rial
Leve
l III-
1
Stu
dy s
ett
ing
.
Co
nse
cu
tive
pa
tie
nts
with
blu
nt
tra
um
a
ove
r a
24 m
on
th p
erio
d.
All
pa
tie
nts
we
re t
ran
spo
rte
d t
o t
he
Un
ive
rsity o
f
Ca
lifo
rnia
, Sa
n D
ieg
o,
Me
dic
al T
rau
ma
Ce
nte
r w
he
re t
he
y w
ere
ca
red
fo
r u
ntil
dis
ch
arg
e.
Pa
rtic
ipa
nts
:
Tota
l sa
mp
le 5
74
Inte
rve
ntio
n.
He
lico
pte
r st
aff
ed
by f
ligh
t n
urs
e a
nd
ph
ysi
cia
n (
n=
316
)
Pro
ce
du
res:
ora
l/n
asa
l* e
nd
otr
ac
he
al
intu
ba
tio
n
Ne
ed
le/t
ub
e t
ho
rac
ost
om
y p
lac
em
en
t*
Pe
rip
he
ral/
ce
ntr
al I
V li
ne
pla
ce
me
nt
Pe
ric
ard
ioc
en
tesi
s*
Cric
oth
yre
oto
my p
lac
em
en
t*
Exp
an
de
d m
ed
ica
tio
ns*
Co
mp
ara
tor.
He
lico
pte
r st
aff
ed
by f
ligh
t n
urs
e a
nd
pa
ram
ed
ic (
n=
25
8)
Pro
ce
du
res:
ora
l en
do
tra
ch
ea
l
intu
ba
tio
n
IV li
ne
pla
ce
me
nt
Lim
ite
d m
ed
ica
tio
ns
Pn
eu
ma
tic
an
tish
oc
k g
arm
en
t
pla
ce
me
nt*
Inc
lu/e
xcl c
rite
ria
.
Pa
tie
nts
with
blu
nt
tra
um
a
Exc
lud
ed
pa
tie
nts
wh
o d
id n
ot
ha
ve
an
y r
esu
scita
tive
pro
ce
du
res
in t
he
fie
ld
Da
ta c
olle
ctio
n
Tra
um
a s
co
re c
alc
ula
ted
on
pa
tie
nt
co
nta
ct
by t
he
cre
w.
Inju
ry s
eve
rity
sc
ore
ca
lcu
late
d f
rom
pa
tie
nt
rec
ord
s a
nd
au
top
sy
rep
ort
s.
Ou
tco
me
me
asu
res
Mo
rta
lity: d
efin
ed
as
de
ath
du
e t
o
the
in
itia
l in
jurie
s o
r c
om
plic
atio
ns
of
the
in
jurie
s
Follo
w-u
p in
terv
al
Min
imu
m o
f si
x m
on
ths
An
aly
sis
Pre
dic
ted
mo
rta
lity e
stim
ate
d u
sin
g
the
TR
ISS m
eth
od
olo
gy, u
tilis
ing
th
e
mo
st r
ec
en
t c
oe
ffic
ien
ts a
va
ilab
le
at
the
tim
e.
An
aly
tic
me
tho
ds
inc
lud
ed
usi
ng
χ2,
two
ta
iled
Stu
de
nt
t te
st,
Ma
nte
l-
He
an
sze
l te
st a
nd
th
e Z
sta
tist
ic o
f
co
mp
ariso
n b
etw
ee
n p
red
icte
d
an
d a
ctu
al s
urv
iva
l.
Nu
mb
er
of
ac
tua
l de
ath
s b
y t
he
nu
mb
er
pre
dic
ted
to
die
(b
ase
d o
n
Ps
≤ 0
.50)
Pa
ram
ed
ic g
rou
p:
Pre
dic
ted
= 1
9.5
Ac
tua
l=1
9
Z s
tatist
ic 0
.208 (
P>
0.0
5)
Ph
ysi
cia
n g
rou
p:
Pre
dic
ted
16.9
Ac
tua
l 11
Z s
tatist
ic 2
.284 (
P<
0.0
5)
Diffe
ren
ce
in Z
sta
tist
ic b
etw
ee
n t
he
two
gro
up
s: 2
.076 (
P<
0.0
5)
Ind
ica
tin
g a
sta
tist
ica
lly s
ign
ific
an
t
imp
rove
d o
utc
om
e in
th
e p
hysi
cia
n
gro
up
.
Dis
trib
utio
n o
f p
atie
nts
by
pro
ba
bili
ty o
f su
rviv
al
Exp
ec
ted
to
die
bu
t liv
ed
:
Pa
ram
ed
ic: 0
Ph
ysi
cia
n 5
Exp
ec
ted
to
live
bu
t d
ied
:
Pa
ram
ed
ic: 5
Ph
ysi
cia
n: 3
Exp
ec
ted
to
die
an
d d
ied
:
Pa
ram
ed
ic: 1
4
Ph
ysi
cia
n: 8
Lim
ita
tio
ns
�
No
t tr
uly
ra
nd
om
ise
d: d
isp
atc
h
de
pe
nd
ed
on
ro
tatio
n o
f c
alls
or
wh
ich
he
lico
pte
r w
as
clo
ser
to t
he
sce
ne
at
tim
e o
f d
isp
atc
h.
�
Ce
ntr
al c
om
mu
nic
atio
n d
id n
ot
ap
pe
ar
to b
e a
va
ilab
le f
or
eith
er
sta
ff
gro
up
.
�
The
leve
l of
exp
erie
nc
e o
f b
oth
sta
ff
gro
up
s w
as
un
cle
ar.
�
TRIS
S m
eth
od
olo
gy in
clu
de
d t
he
tra
um
a s
co
re (
TS)
rath
er
tha
n t
he
revis
ed
tra
um
a s
co
re (
RTS
). In
late
r
ye
ars
th
e R
TS s
co
re w
as
co
nsi
de
red
to
be
mo
re a
cc
ura
te t
ha
n t
he
TS s
co
re.
Su
bse
qu
en
t d
eve
lop
me
nts
in T
RIS
S
me
tho
do
log
y m
ad
e u
se o
f th
e M
sta
tist
ic w
hic
h a
llow
s a
n a
sse
ssm
en
t o
f
the
in
jury
se
ve
rity
mix
be
twe
en
stu
dy
gro
up
s a
nd
, if a
pp
rop
ria
te,
the
W
sta
tist
ic, w
hic
h d
ea
ls w
ith
diffe
ren
t
ca
se m
ixe
s a
cro
ss s
am
ple
s.
�
All-
ca
use
mo
rta
lity n
ot
use
d. M
ay
ha
ve
lea
d t
o o
utc
om
e
mis
cla
ssific
atio
n.
�
No
do
cu
me
nta
tio
n o
f b
lind
ing
in t
he
ass
ess
me
nt
of
ca
use
of
de
ath
.
�
Un
cle
ar
if t
he
re w
ere
diffe
ren
ce
s in
the
du
ratio
n o
f fo
llow
-up
be
twe
en
stu
dy g
rou
ps
(alth
ou
gh
all
rec
ord
ed
de
ath
s o
cc
urr
ed
with
in 4
8 h
ou
rs o
f
ad
mis
sio
n).
TRANSPORTATION OF EMERGENCY PATIENTS
53
Ta
ble
13
E
vid
ence
ta
ble
s o
f st
ud
ies
com
pa
rin
g c
rew
s th
at
do
an
d d
o n
ot
per
form
ra
pid
seq
uen
ce i
ntu
ba
tio
n a
nd
/or
tho
raco
sto
my
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Ba
xt
an
d M
oo
dy 1
987
)
USA
co
ntin
ue
d
A
na
lyse
s c
om
pa
ring
gro
up
s a
t b
ase
line
.
Me
dia
n p
rob
ab
ility
of
surv
iva
l:
Pa
ram
ed
ic c
rew
: 0.9
5-1
.0
Ph
ysi
cia
n c
rew
: 0.9
5-1
.0
Me
dia
n G
lasg
ow
Co
ma
Sc
ore
of
seve
re
bra
in in
jure
d p
atie
nts
(G
CS≤8
)
Pa
ram
ed
ic c
rew
(n
=44,
17%
of
tota
l): 4
Ph
ysi
cia
n c
rew
(n
=5
4, 1
7%
of
tota
l):
5
Me
an
Tra
um
a S
co
re:
Pa
ram
ed
ic g
rou
p:
14.2
Ph
ysi
cia
n g
rou
p:
14.3
Me
an
In
jury
se
ve
rity
sc
ore
:
Pa
ram
ed
ic g
rou
p:
13.6
Ph
ysi
cia
n g
rou
p:1
3.9
Me
an
pre
dic
ted
su
rviv
al
Pa
ram
ed
ic g
rou
p:
0.9
24
Ph
ysi
cia
n g
rou
p:
0.9
47
Me
an
ag
e
Pa
ram
ed
ic g
rou
p:
27.6
ye
ars
Ph
ysi
cia
n g
rou
p:
27.8
ye
ars
Tra
nsp
ort
tim
es:
Me
an
re
spo
nse
tim
e:
Pa
ram
ed
ic g
rou
p 1
5.5
min
ute
s
Ph
ysi
cia
n g
rou
p:
14.9
min
ute
s
Me
an
sc
en
e t
ime
:
Pa
ram
ed
ic g
rou
p:
18.6
min
ute
s
Ph
ysi
cia
n g
rou
p:
19.1
min
ute
s
Me
an
de
live
ry t
ime
:
Pa
ram
ed
ic g
rou
p:
16.9
min
ute
s
Ph
ysi
cia
n g
rou
p:
16.1
min
ute
s.
B
lind
ed
ch
art
an
aly
sis
ass
ess
ing
ad
he
ren
ce
to
writt
en
me
dic
al
tre
atm
en
t p
roto
co
ls.
1.
pa
tie
nts
wh
o s
urv
ive
d
Pa
ram
ed
ic g
rou
p18 o
f 23
9 p
atie
nts
with
inc
on
sist
en
cie
s fr
om
th
e
rec
om
me
nd
ed
pro
toc
ols
Ph
ysi
cia
n g
rou
p:
2 o
f 305
pa
tie
nts
with
inc
on
sist
en
cie
s fr
om
th
e
rec
om
me
nd
ed
pro
toc
ols
2.
pa
tie
nts
wh
o d
ied
Pa
ram
ed
ic g
rou
p:
9 o
f 19 p
atie
nts
with
inc
on
sist
en
cie
s fr
om
th
e
rec
om
me
nd
ed
pro
toc
ols
Ph
ysi
cia
n g
rou
p:
0 o
f 11 p
atie
nts
with
inc
on
sist
en
cie
s fr
om
th
e
rec
om
me
nd
ed
pro
toc
ols
.
No
te in
co
nsi
ste
nc
ies
inc
lud
ed
failu
re t
o c
on
du
ct
the
ind
ica
ted
pro
ce
du
re o
r m
ed
ica
l pro
ce
du
re
no
t fo
llow
ed
.
�
Po
ten
tia
l fo
r c
on
fou
nd
ing
, a
lth
ou
gh
ba
selin
e a
na
lyse
s in
dic
ate
litt
le
diffe
ren
ce
in t
ran
spo
rt t
ime
, tr
au
ma
sco
re, in
jury
se
ve
rity
sc
ore
, G
CS,
pre
dic
ted
su
rviv
al a
nd
pa
tie
nt
ag
e
be
twe
en
gro
up
s.
�
Ke
y r
esu
lts
are
ba
sed
on
a s
ma
ll
nu
mb
er
of
pa
tie
nts
wh
o s
urv
ive
d b
ut
we
re e
xpe
cte
d t
o d
ie (
5 o
f 22 in
th
e
ph
ysi
cia
n g
rou
p a
nd
0 o
f 1
6 in
th
e
pa
ram
ed
ic g
rou
p).
Co
mm
en
ts
�
All
pa
tie
nts
att
en
de
d a
sin
gle
tra
um
a
ce
ntr
e.
�
The
TR
ISS m
eth
od
olo
gy w
as
ap
plie
d t
o
the
tw
o s
tud
y g
rou
ps
usi
ng
da
ta t
ha
t
we
re c
olle
cte
d a
t th
e s
am
e t
ime
be
twe
en
th
e t
wo
gro
up
s.
�
Use
d a
pp
rop
ria
te m
eth
od
olo
gy t
o
est
ima
te in
jury
se
ve
rity
.
�
Thre
e p
atie
nts
we
re e
xclu
de
d in
ea
ch
gro
up
du
e t
o t
he
lac
k o
f re
susc
ita
tiv
e
me
asu
res
in t
he
fie
ld.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
A s
tatist
ica
lly s
ign
ific
an
t re
du
ctio
n in
th
e
mo
rta
lity o
f p
atie
nts
with
blu
nt
tra
um
a
tre
ate
d b
y a
me
dic
al h
elic
op
ter
em
erg
en
cy
ca
re s
erv
ice
sta
ffe
d b
y a
nu
rse
/ph
ysi
cia
n
co
mb
ina
tio
n c
ou
ld b
e d
em
on
stra
ted
co
mp
are
d w
ith
th
at
sta
ffe
d b
y a
nu
rse
/pa
ram
ed
ic c
om
bin
atio
n.
* D
iffer
ence
in p
roce
dure
s av
aila
ble
to th
e tw
o st
affin
g gr
oups
TRANSPORTATION OF EMERGENCY PATIENTS
54
Ta
ble
13
E
vid
ence
ta
ble
s o
f st
ud
ies
com
pa
rin
g c
rew
s th
at
do
an
d d
o n
ot
per
form
ra
pid
seq
uen
ce i
ntu
ba
tio
n a
nd
/or
tho
raco
sto
my
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Ga
rne
r e
t a
l. 19
99
)
Au
stra
lia
Re
tro
spe
ctive
co
ho
rt s
tud
y
Leve
l III-
2.
Stu
dy s
ett
ing
.
He
lico
pte
r tr
an
spo
rta
tio
n o
f p
atie
nts
fro
m t
he
sc
en
e o
ve
r a
28 m
on
th p
erio
d.
Pa
rtic
ipa
nts
(n
=2
07
):
Inte
rve
ntio
n (
n=
67
).
Ph
ysi
cia
n s
taff
ed
NR
MA
Ca
reFl
igh
t
he
lico
pte
r
Co
mp
ara
tor
(n=
14
0).
Pa
ram
ed
ic s
taff
ed
We
stp
ac
Hu
nte
r
reg
ion
he
lico
pte
r.
An
aly
ses
co
mp
arin
g g
rou
ps
at
ba
selin
e.
Me
dia
n a
ge
(ye
ars
)
Ph
ysi
cia
n g
rou
p:
31 (
13
-70
)
Pa
ram
ed
ic g
rou
p:
33 (
2-8
9)
Me
ch
an
ism
of
inju
ry
Mo
tor
ve
hic
le o
cc
up
an
t
Ph
ysi
cia
n g
rou
p:
63%
Pa
ram
ed
ic g
rou
p:
63
%
Mo
tor
bik
e r
ide
r
Ph
ysi
cia
n g
rou
p:
9%
Pa
ram
ed
ic g
rou
p:
11
%
Pe
da
l cyc
list
or
pe
de
stria
n
Ph
ysi
cia
n g
rou
p:
3%
Pa
ram
ed
ic g
rou
p:
5%
Inc
lu/e
xcl c
rite
ria
.
Blu
nt
tra
um
a
ISS ≥
10
Tra
nsp
ort
ed
dire
ctly f
rom
th
e
inc
ide
nt
sce
ne
Inc
ide
nt
oc
cu
rre
d b
etw
ee
n
Jan
ua
ry 1
996 a
nd
Ap
ril 1
998.
Da
ta c
olle
ctio
n
Pa
ram
ed
ic g
rou
p r
etr
osp
ec
tive
ly
ide
ntifie
d f
rom
th
e t
rau
ma
re
gis
try
of
Joh
n H
un
ter
Ho
spita
l, N
ew
ca
stle
.
Ph
ysi
cia
n g
rou
p id
en
tifie
d f
rom
th
e
me
dic
al d
ata
ba
se o
f N
RM
A
Ca
reFl
igh
t/N
SW
Me
dic
al r
etr
ieva
l
Se
rvic
e w
ho
we
re t
ran
spo
rte
d t
o
We
stm
ea
d o
r N
ep
ea
n h
osp
ita
ls in
Syd
ne
y.
Pre
-ho
spita
l ca
se s
he
ets
we
re
exa
min
ed
to
allo
w t
he
ca
lcu
latio
n
of
the
RTS
(firs
t re
co
rde
d d
ata
use
d).
Oth
er
da
ta c
olle
cte
d
inc
lud
ed
de
mo
gra
ph
ics,
me
ch
an
ism
of
inju
ry, re
spo
nse
,
sce
ne
an
d t
ran
spo
rt t
ime
s,
en
tra
pm
en
t a
t th
e s
ce
ne
,
req
uire
me
nt
for
win
ch
extr
ac
tio
n,
flu
ids
ad
min
iste
red
an
d p
roc
ed
ure
s
pe
rfo
rme
d a
t th
e s
ce
ne
or
in t
ran
sit.
Ou
tco
me
me
asu
res
Mo
rta
lity. C
om
pa
red
with
TR
ISS
me
tho
do
log
y u
sin
g c
oe
ffic
ien
ts
de
rive
d f
rom
th
e M
TOS u
sin
g t
he
1990 a
bb
revia
ted
inju
ry s
ca
le.
Co
mp
aris
on
be
twe
en
ob
serv
ed
an
d p
red
icte
d m
ort
alit
y m
ad
e a
t
ho
spita
l dis
ch
arg
e.
Nu
mb
er
of
ac
tua
l de
ath
s b
y t
he
nu
mb
er
pre
dic
ted
to
die
(b
ase
d o
n
Ps
≤ 0
.50)
Ph
ysi
cia
n g
rou
p
Z s
tatist
ic +
2.7
2
P<
0.0
1
M s
tatist
ic 0
.62
Ad
just
ed
W s
tatist
ic 9
.48 (
95%
CI
3.8
4-1
5.1
2)
co
mp
are
d w
ith
th
e
MTO
S p
op
ula
tio
n.
Pa
ram
ed
ic g
rou
p
Z s
tatist
ic -
1.1
6
P=
0.2
5
M s
tatist
ic 0
.68
Ad
just
ed
W s
tatist
ic -
2.3
7 (
95%
CI -
6.8
1 t
o 2
.07-1
5.1
2)
co
mp
are
d w
ith
the
MTO
S p
op
ula
tio
n.
Dire
ct
co
mp
ariso
n b
etw
ee
n
ph
ysi
cia
n a
nd
pa
ram
ed
ic g
rou
p
Ad
just
ed
W s
tatist
ic 1
3.4
4 (
95%
CI
7.8
0-1
9.0
8)
sug
ge
stin
g a
n a
dd
itio
na
l
13 s
urv
ivo
rs p
er
10
0 p
atie
nts
tre
ate
d
in t
he
ph
ysi
cia
n g
rou
p c
om
pa
red
with
th
e p
ara
me
dic
gro
up
.
Ro
ad
tra
nsp
ort
ed
pa
tie
nts
: D
irec
t
co
mp
ariso
n b
etw
ee
n p
hysi
cia
n
an
d p
ara
me
dic
gro
up
Ad
just
ed
W s
tatist
ic 2
.11 (
95%
CI -
0.3
4 t
o 4
.56)
Lim
ita
tio
ns
�
Re
tro
spe
ctive
stu
dy.
�
Gro
up
s tr
ea
ted
in d
iffe
ren
t h
osp
ita
ls –
pa
ram
ed
ic g
rou
p t
rea
ted
in a
leve
l 6
ho
spita
l, p
hysi
cia
n g
rou
p in
a le
ve
l 5
or
leve
l 6 h
osp
ita
l.
�
Sta
tist
ica
lly s
ign
ific
an
t d
iffe
ren
ce
in
ba
selin
e G
CS a
nd
ISS s
co
res
co
nsi
ste
nt
with
in
cre
ase
d s
eve
rity
in
the
ph
ysi
cia
n g
rou
p.
�
Un
cle
ar
if t
he
re w
ere
diffe
ren
ce
s in
the
du
ratio
n o
f fo
llow
-up
be
twe
en
stu
dy g
rou
ps.
�
Ob
serv
atio
n s
tud
y is
su
sce
ptib
le t
o
co
nfo
un
din
g a
lth
ou
gh
use
of
the
W
sta
tist
ic h
elp
s a
dju
st f
or
TRIS
S v
aria
ble
s
be
twe
en
th
e s
tud
y p
op
ula
tio
ns.
�
Ce
ntr
al c
om
mu
nic
atio
n w
as
no
t
do
cu
me
nte
d f
or
eith
er
gro
up
.
�
RTS
sc
ore
in t
he
MTO
S s
tud
y w
as
ca
lcu
late
d a
t a
dm
issi
on
ra
the
r th
an
at
the
sc
en
e a
s p
erf
orm
ed
in t
his
stu
dy. Th
e a
pp
roa
ch
use
d in
th
is s
tud
y
ha
s th
e a
dva
nta
ge
of
co
llec
tin
g R
TS
da
ta b
efo
re in
tub
atio
n a
nd
co
mp
arin
g R
TS in
bo
th g
rou
ps
at
ap
pro
xim
ate
ly t
he
sa
me
tim
e.
Ho
we
ve
r, c
om
pa
riso
n w
ith
MTO
S is
no
t so
va
lid g
ive
n t
he
diffe
ren
ce
in
tim
ing
.
�
Se
ve
n p
atie
nts
we
re e
xclu
de
d d
ue
to
mis
sin
g c
ase
sh
ee
ts.
All
7 w
ere
in t
he
pa
ram
ed
ic g
rou
p p
rod
uc
ing
a
sele
ctio
n b
ias.
TRANSPORTATION OF EMERGENCY PATIENTS
55
Ta
ble
13
E
vid
ence
ta
ble
s o
f st
ud
ies
com
pa
rin
g c
rew
s th
at
do
an
d d
o n
ot
per
form
ra
pid
seq
uen
ce i
ntu
ba
tio
n a
nd
/or
tho
raco
sto
my
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Ga
rne
r e
t a
l. 19
99
)
Au
stra
lia
co
ntin
ue
d
Fa
lls
Ph
ysi
cia
n g
rou
p:
10%
Pa
ram
ed
ic g
rou
p:
6%
Me
dia
n t
ime
inte
rva
ls (
min
ute
s)
Ca
ll to
sc
en
e a
rriv
al
Ph
ysi
cia
n g
rou
p:
29
Pa
ram
ed
ic g
rou
p:
26
Sc
en
e t
ime
(e
xclu
din
g t
rap
pe
d a
nd
win
ch
ed
pa
tie
nts
)
Ph
ysi
cia
n g
rou
p:
33
Pa
ram
ed
ic g
rou
p:
34
Tra
nsp
ort
tim
e t
o h
osp
ita
l
Ph
ysi
cia
n g
rou
p:
15
Pa
ram
ed
ic g
rou
p:
12
Tota
l pre
-ho
spita
l tim
e
Ph
ysi
cia
n g
rou
p:
86
Pa
ram
ed
ic g
rou
p:
82
Me
dia
n R
TS
Ph
ysi
cia
n g
rou
p:
6.9
0
Pa
ram
ed
ic g
rou
p:
7.5
5
Me
dia
n G
CS
Ph
ysi
cia
n g
rou
p: 1
3
Pa
ram
ed
ic g
rou
p:
14
P=
0.0
5
Me
dia
n ISS
Ph
ysi
cia
n g
rou
p:
25
Pa
ram
ed
ic g
rou
p:
18
P=
0.0
5
Follo
w-u
p in
terv
al
No
t st
ate
d
An
aly
sis
Ca
teg
oric
al v
aria
ble
s: χ
2 o
r Fi
she
r’s
exa
ct
test
, a
s a
pp
rop
ria
te.
Co
ntin
uo
us
va
ria
ble
s: M
an
n-
Wh
itn
ey U
te
st.
Co
mp
aris
on
be
twe
en
pre
dic
ted
an
d o
bse
rve
d m
ort
alit
y u
sin
g Z
, W
an
d M
sta
tist
ics.
An
ad
just
ed
W
sta
tist
ic w
as
ca
lcu
late
d b
y t
he
me
tho
d o
f Y
ou
ng
e w
he
n t
he
M
sta
tist
ic in
dic
ate
d a
po
or
ma
tch
with
th
e M
TOS c
oh
ort
an
d t
o
dire
ctly c
om
pa
re t
he
pa
ram
ed
ic
an
d p
hysi
cia
n t
rea
ted
gro
up
s.
Pro
ce
du
res
at
sce
ne
Me
dia
n v
olu
me
of
flu
id in
fuse
d in
pa
tie
nts
wh
o r
ec
eiv
ed
> 5
0m
L
Ph
ysi
cia
n g
rou
p:
250
0
Pa
ram
ed
ic g
rou
p:
825
P<
0.0
01
Me
dia
n v
olu
me
of
flu
id (
mL)
infu
sed
in p
atie
nts
with
initia
l hyp
ote
nsi
on
(syst
olic
BP
<90
mm
Hg
)
Ph
ysi
cia
n g
rou
p:
503
5
Pa
ram
ed
ic g
rou
p:
147
5
P<
0.0
01
Nu
mb
er
of
pa
tie
nts
intu
ba
ted
Ph
ysi
cia
n g
rou
p:
34/6
7 (
1
cric
oth
yro
ido
tom
y, m
usc
le r
ela
xan
t
dru
gs
use
d in
28 o
f th
e 3
4
intu
ba
tio
ns)
Pa
ram
ed
ic g
rou
p:
14
/14
0
P<
0.0
01
Pro
po
rtio
n o
f p
atie
nts
with
GC
S<
9
intu
ba
ted
Ph
ysi
cia
n g
rou
p:
23/2
3
Pa
ram
ed
ic g
rou
p:
14
/36
P<
0.0
01
Tho
rac
ic d
ec
om
pre
ssio
ns
Ph
ysi
cia
n g
rou
p:
8/6
7 (
6 t
ub
e, 2
ne
ed
le)
Pa
ram
ed
ic g
rou
p:
2/1
40 (
bo
th
ne
ed
le)
P<
0.0
1
Co
mm
en
ts
�
All
pa
tie
nts
att
en
de
d a
sin
gle
tra
um
a
ce
ntr
e in
ea
ch
co
un
try.
�
TRIS
S m
eth
od
olo
gy a
pp
rop
ria
tely
use
d
RTS
sc
ore
.
�
TRIS
S a
na
lysi
s a
pp
rop
riate
ly in
clu
de
d
est
ima
tio
n o
f th
e M
an
d W
sta
tist
ics.
�
Use
d a
pp
rop
ria
te m
eth
od
olo
gy t
o
est
ima
te in
jury
se
ve
rity
.
�
Diffe
ren
ce
s in
pro
ce
du
res
pe
rfo
rme
d
be
twe
en
stu
dy g
rou
ps.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
Ph
ysi
cia
ns
pe
rfo
rm a
gre
ate
r n
um
be
r o
f
pro
ce
du
res
at
ac
cid
en
t sc
en
es
with
ou
t
inc
rea
sin
g s
ce
ne
tim
e.
This
re
sults
in
sig
nific
an
tly lo
we
r m
ort
alit
y. C
ritic
al c
are
ph
ysi
cia
ns
sho
uld
be
ad
de
d t
o p
ara
me
dic
he
lico
pte
r se
rvic
es
for
sce
ne
re
spo
nse
to
blu
nt
tra
um
a.
TRANSPORTATION OF EMERGENCY PATIENTS
56
Ta
ble
13
E
vid
ence
ta
ble
s o
f st
ud
ies
com
pa
rin
g c
rew
s th
at
do
an
d d
o n
ot
per
form
ra
pid
seq
uen
ce i
ntu
ba
tio
n a
nd
/or
tho
raco
sto
my
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Ko
efo
ed
-Nie
lse
n e
t a
l.
2002
)
De
nm
ark
Be
fore
an
d
aft
er
Leve
l III-
3.
Stu
dy s
ett
ing
.
A m
ob
ile e
me
rge
nc
y c
are
un
it (
MEC
U),
wh
ich
inc
lud
ed
an
an
ae
sth
etist
, w
as
set
up
in a
re
gio
n o
f D
en
ma
rk.
Co
nse
cu
tive
pa
tie
nts
with
ac
ute
MI w
ere
stu
die
d in
two
tim
e p
erio
ds
:
1. Se
pt
to N
ov 1
99
6 (
be
fore
MEC
U)
2. Se
pt
to N
ov 1
99
7 (
with
MEC
U).
The
are
a c
ove
red
ap
pro
xim
ate
ly
800km
2. M
ed
ian
re
spo
nse
tim
e f
or
MEC
U
wa
s 8.9
min
ute
s a
nd
6.5
min
ute
s fo
r
sta
nd
ard
am
bu
lan
ce
s.
Pa
rtic
ipa
nts
:
Inte
rve
ntio
n (
n=
54
)
An
ae
sth
etist
pre
sen
t (w
ith
MEC
U)
MEC
U w
as
als
o c
rew
ed
with
a s
pe
cia
lly
tra
ine
d e
me
rge
nc
y t
ec
hn
icia
n.
Ad
ditio
na
l tre
atm
en
t p
rovid
ed
by
an
ae
sth
etist
: tr
ac
he
al i
ntu
ba
tio
n,
tra
nsc
uta
ne
ou
s p
ac
ing
, a
na
est
he
tic
s
(hyp
no
tic
s a
nd
mu
scle
re
laxa
nts
),
op
ioid
s, h
ea
rt s
tim
ula
tin
g d
rug
s a
nd
an
tia
rrh
yth
mic
s.
Pre
-ho
spita
l
thro
mb
oly
sis
wa
s n
ot
pro
vid
ed
.
Co
mp
ara
tor
(n=
54
)
No
n p
hysi
cia
n c
rew
(b
efo
re M
EC
U)
Inc
lu/e
xcl c
rite
ria
.
Use
rs o
f e
me
rge
nc
y s
erv
ice
s (b
ase
d
on
am
bu
lan
ce
co
mp
an
y’s
pa
tie
nt
rolls
) w
ho
we
re c
lass
ifie
d a
s a
dia
gn
osi
s o
f M
I (I
CD
-10 c
od
es
I21-
I22)
on
ad
mis
sio
n t
o a
n e
me
rge
nc
y
de
pa
rtm
en
t o
r c
oro
na
ry c
are
un
it in
on
e o
f th
ree
ho
spita
ls in
Aa
rhu
s,
De
nm
ark
.
The
pa
tie
nt
wa
s a
live
wh
en
rea
ch
ing
ho
spita
l.
The
ho
spita
l re
co
rd c
on
firm
ed
MI
dia
gn
osi
s, b
ase
d o
n e
nzy
me
te
sts
an
d E
CG
.
The
ho
spita
l re
co
rd p
rovid
ed
suff
icie
nt
info
rma
tio
n o
n d
iag
no
sis
an
d t
rea
tme
nt.
Ou
tco
me
me
asu
res
28 d
ay m
ort
alit
y
An
aly
sis
Pe
ars
on
’s χ
2, Fis
he
r’s
exa
ct
test
,
Sp
ea
rma
n’s
no
n-p
ara
me
tric
ra
nk
co
rre
latio
n, K
ap
lan
-Me
ier
surv
iva
l
an
aly
sis
an
d m
ultip
le lo
gis
tic
reg
ress
ion
we
re c
on
du
cte
d.
Cru
de
mo
rta
lity r
ate
at
28 d
ays,
by
stu
dy p
erio
d.
Pre
-MEC
U:
20.6
%
MEC
U: 11
.1%
Ad
just
ed
od
ds
ratio
by s
tud
y p
erio
d
(28 d
ay m
ort
alit
y),
(p
re-M
EC
U a
s
the
re
fere
nc
e)
OR
0.3
(P
<0.0
25
)
Ad
just
ed
fo
r a
ge
, g
en
de
r, p
uls
e
an
d s
yst
olic
blo
od
pre
ssu
re.
Ad
just
ed
od
ds
ratio
by u
se o
f M
EC
U
(28 d
ay m
ort
alit
y),
(p
re-M
EC
U a
s
the
re
fere
nc
e)
OR
0.2
(P
<0.0
5)
Ad
just
ed
fo
r a
ge
, g
en
de
r, p
uls
e
an
d s
yst
olic
blo
od
pre
ssu
re.
Lim
ita
tio
ns
�
Re
tro
spe
ctive
stu
dy.
�
Exc
lusi
on
s: s
ix w
ere
eith
er
de
ad
on
arr
iva
l or
die
d im
me
dia
tely
aft
er
arr
iva
l (fo
ur
pre
MEC
U a
nd
tw
o w
ith
MEC
U),
sp
ec
ific
MI d
iag
no
sis
co
uld
no
t b
e c
on
firm
ed
in
25
. U
nc
lea
r if a
ny
we
re e
xclu
de
d d
ue
to
in
suff
icie
nt
info
rma
tio
n o
n t
rea
tme
nt.
�
Lim
ite
d d
ata
pro
vid
ed
at
tim
e o
f firs
t
att
en
da
nc
e o
f p
re-h
osp
ita
l ca
re.
�
Be
fore
an
d a
fte
r st
ud
y is
a lo
w q
ua
lity
de
sig
n –
fe
atu
res
oth
er
tha
n t
he
inte
rve
ntio
n o
f in
tere
st m
ay h
ave
ch
an
ge
d s
o it
is u
nc
lea
r to
wh
at
ext
en
t a
ny c
ha
ng
e in
ou
tco
me
is a
resu
lt o
f th
e in
tro
du
ctio
n o
f M
EC
U. In
this
stu
dy, th
e im
pro
ve
d p
rog
no
sis
ma
y h
ave
be
en
du
e t
o a
ng
iop
last
y
rath
er
tha
n M
EC
U.
�
Ba
sis
of
dia
gn
osi
s o
f M
I n
ot
pre
cis
ely
de
fin
ed
: p
ote
ntia
l fo
r in
ap
pro
pria
te
sele
ctio
n.
�
Po
ten
tia
l fo
r m
isc
lass
ific
atio
n o
f
ou
tco
me
, th
ou
gh
th
e s
ize
an
d
dire
ctio
n o
f su
ch
mis
cla
ssific
atio
n is
diffic
ult t
o d
ete
rmin
e.
�
Du
rin
g t
he
MEC
U p
erio
d,
som
e
pa
tie
nts
we
re n
ot
att
en
de
d b
y M
EC
U
(56%
). H
ow
eve
r, a
lth
ou
gh
MEC
U
pa
tie
nts
we
re m
ore
like
ly t
o b
e
co
nsi
de
red
as
seve
re,
MEC
U p
atie
nts
ha
d h
igh
er
ad
just
ed
od
ds
of
surv
iva
l
co
mp
are
d w
ith
no
n-M
EC
U p
atie
nts
.
�
Un
cle
ar
if r
esu
lts
co
uld
be
re
plic
ate
d if
oth
er
cre
ws
we
re s
taff
ed
with
pe
op
le
ca
pa
ble
of
pe
rfo
rmin
g r
ap
id
seq
ue
nc
e in
tub
atio
n.
TRANSPORTATION OF EMERGENCY PATIENTS
57
Ta
ble
13
E
vid
ence
ta
ble
s o
f st
ud
ies
com
pa
rin
g c
rew
s th
at
do
an
d d
o n
ot
per
form
ra
pid
seq
uen
ce i
ntu
ba
tio
n a
nd
/or
tho
raco
sto
my
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Ko
efo
ed
-Nie
lse
n e
t a
l.
2002
)
De
nm
ark
co
ntin
ue
d
A
na
lyse
s c
om
pa
ring
gro
up
s a
t b
ase
line
Ag
e ≤
69 y
ea
rs (
%)
Pre
MEC
U: 4
1
MEC
U: 41
Ma
le s
ex
(%)
Pre
MEC
U: 6
3
MEC
U: 72
PTC
A p
erf
orm
ed
(%
)
Pre
MEC
U: 1
9
MEC
U: 26
Thro
mb
oly
sis
giv
en
(%
)
Pre
MEC
U: 2
8
MEC
U: 33
Co
mm
en
ts
�
aim
ed
to
ass
ess
th
e im
pa
ct
of
a
MEC
U o
n s
urv
iva
l am
on
g p
atie
nts
with
ac
ute
MI.
�
MEC
U p
atie
nts
we
re m
ore
lik
ely
to
rec
eiv
e t
hro
mb
oly
sis.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
In t
he
pre
sen
t st
ud
y, M
I p
atie
nts
tre
ate
d in
a
MEC
U s
taff
ed
by a
n a
na
est
he
tist
an
d/o
r
ha
vin
g a
ng
iop
last
y w
as
fou
nd
to
be
ass
oc
iate
d w
ith
a r
ed
uc
ed
mo
rta
lity. Th
ese
ob
serv
atio
ns
ha
ve
be
en
ba
sed
on
qu
asi
-
exp
erim
en
tal r
ath
er
tha
n r
an
do
mis
ed
exp
erim
en
tal d
ata
, a
nd
ra
nd
om
ise
da
ta
wo
uld
be
hig
hly
de
sira
ble
.
TRANSPORTATION OF EMERGENCY PATIENTS
58
Ta
ble
13
E
vid
ence
ta
ble
s o
f st
ud
ies
com
pa
rin
g c
rew
s th
at
do
an
d d
o n
ot
per
form
ra
pid
seq
uen
ce i
ntu
ba
tio
n a
nd
/or
tho
raco
sto
my
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Le
e e
t a
l. 2
003
)
Au
stra
lia
Re
tro
spe
ctive
co
ho
rt s
tud
y
Leve
l III-
2.
Stu
dy s
ett
ing
.
Se
ve
re b
lun
t tr
au
ma
pa
tie
nts
ad
mitte
d
to W
est
me
ad
Ho
spita
l, Syd
ne
y b
etw
ee
n
July
1986 a
nd
De
ce
mb
er
20
00.
Am
bu
lan
ce
off
ice
rs t
rain
ed
to
th
ree
diffe
ren
t le
ve
ls: tw
o le
ve
ls o
f b
asi
c li
fe
sup
po
rt a
nd
on
e le
ve
l of
ad
va
nc
ed
life
sup
po
rt.
Als
o h
ad
tw
o p
hysi
cia
n-s
taff
ed
em
erg
en
cy m
ed
ica
l se
rvic
es
wh
ich
resp
on
d t
o a
cc
ide
nt
sce
ne
s e
ith
er
by
roa
d o
r h
elic
op
ter.
Leve
l 3 a
mb
ula
nc
e o
ffic
er:
ba
sic
life
sup
po
rt w
ith
ou
t e
xte
rna
l co
ntr
ol o
f
ha
em
orr
ha
ge
, sp
lintin
g,
no
n-in
va
siv
e
airw
ay m
an
oe
uvre
s a
nd
ba
g-v
alv
e-
ma
sk v
en
tila
tio
n.
Leve
l 4 a
mb
ula
nc
e o
ffic
er:
ba
sic
life
sup
po
rt p
lus
intr
ave
no
us
ca
nn
ula
tio
n
an
d a
dm
inis
tra
tio
n o
f IV
flu
ids,
in
ad
ditio
n t
o a
lim
ite
d r
an
ge
of
IV
me
dic
atio
ns
an
d n
ee
dle
th
ora
ce
nte
sis.
Leve
l 5 a
mb
ula
nc
e o
ffic
er:
Ad
va
nc
ed
life
su
pp
ort
. A
ble
to
pe
rfo
rm a
ll th
e
ab
ove
pro
ce
du
res
plu
s o
ral
en
do
tra
ch
ea
l in
tub
atio
n.
Ac
ce
ss t
o a
wid
er
ran
ge
of
IV m
ed
ica
tio
ns
(bu
t n
ot
ne
uro
mu
scu
lar
blo
cka
de
, a
na
est
he
tic
ag
en
ts o
r se
da
tive
ag
en
ts t
o f
ac
ilita
te
intu
ba
tio
n).
Ph
ysi
cia
ns
are
fre
e t
o e
xerc
ise
th
eir
clin
ica
l ju
dg
em
en
t in
ea
ch
ca
se.
Inc
lu/e
xcl c
rite
ria
.
Blu
nt
tra
um
a p
atie
nts
with
ISS >
15.
Ou
tco
me
me
asu
res
Mo
rta
lity d
urin
g h
osp
ita
l ad
mis
sio
n
An
aly
sis
Log
istic
re
gre
ssio
n u
sed
with
th
e
follo
win
g p
red
icto
r va
ria
ble
s: le
ve
l
of
pre
-ho
spita
l ca
re,
tim
e f
rom
inju
ry
to a
rriv
al i
n h
osp
ita
l, ty
pe
of
inju
ry,
me
ch
an
ism
of
inju
ry, a
ge
, se
x, ISS,
GC
S a
nd
syst
olic
blo
od
pre
ssu
re.
Mo
de
l ca
libra
tio
n a
sse
sse
d b
y t
he
Ho
sme
r-Le
me
sho
w g
oo
dn
ess
-of-
fit
χ2 t
est
an
d p
red
ictive
ac
cu
rac
y
ass
ess
ed
by t
he
are
a u
nd
er
the
rec
eiv
er
op
era
tin
g c
ha
rac
terist
ic
cu
rve
.
Ris
k in
od
ds
ratio
of
mo
rta
lity b
y
leve
l of
pre
-ho
spita
l ca
re a
nd
IC
U
tre
atm
en
t (b
asi
c li
fe s
up
po
rt a
s th
e
refe
ren
ce
), (
95
% C
I)
No
IC
U a
dm
issi
on
:
Leve
l 5 a
mb
ula
nc
e:
2.1
8 (
1.0
5-4
.55)
Ph
ysi
cia
n: 4.2
7 (
1.4
6-1
2.4
5)
ICU
ad
mis
sio
n:
Leve
l 5 a
mb
ula
nc
e:
0.7
0 (
0.5
3-1
.18)
Ph
ysi
cia
n: 0.6
3 (
0.2
8-1
.39
)
Lim
ita
tio
ns
�
Re
tro
spe
ctive
stu
dy.
�
A s
ele
ctive
dis
pa
tch
str
ate
gy w
as
use
d w
hic
h p
rob
ab
ly e
xpla
ins
the
inc
rea
sed
mo
rta
lity r
ate
s in
th
e le
ve
l 5
am
bu
lan
ce
gro
up
an
d t
he
ph
ysi
cia
n
gro
up
in
th
e n
on
-IC
U p
op
ula
tio
n.
�
Pa
ram
ed
ics
ma
y h
ave
in
vo
lve
d t
he
ph
ysi
cia
n g
rou
p w
he
n p
atie
nt
de
ath
wa
s im
min
en
t.
�
Un
cle
ar
if s
om
e p
hysi
cia
n g
rou
p
pa
tie
nts
ma
y h
ave
be
en
tra
nsp
ort
ed
by h
elic
op
ter.
�
Diffe
ren
t le
ve
ls o
f a
cc
ess
to
pro
ce
du
res
in t
he
no
n-d
oc
tor
gro
up
s
ma
y n
ot
be
ge
ne
ralis
ab
le t
o o
the
r
sett
ing
s, m
ay g
uid
e d
isp
atc
h d
ec
isio
ns
an
d m
ay r
esu
lt in
bia
s in
co
mp
ara
tiv
e
est
ima
tes.
�
Ob
serv
atio
n s
tud
y is
su
sce
ptib
le t
o
co
nfo
un
din
g.
Co
mm
en
ts
�
Aim
ed
to
de
term
ine
th
e a
sso
cia
tio
n
be
twe
en
mo
rta
lity a
nd
leve
l of
pre
-
ho
spita
l ca
re in
se
ve
rely
inju
red
blu
nt
tra
um
a p
atie
nts
with
or
with
ou
t se
ve
re
he
ad
tra
um
a.
�
No
on
line
me
dic
al c
on
tro
l pro
vid
ed
.
�
We
ll d
esc
ribe
d a
nd
co
nd
uc
ted
sta
tist
ica
l me
tho
do
log
y.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
The
leve
l of
pre
-ho
spita
l ca
re w
as
ass
oc
iate
d w
ith
th
e r
isk o
f m
ort
alit
y. Th
is w
as
mo
difie
d b
y w
he
the
r th
e p
atie
nt
surv
ive
d
lon
g e
no
ug
h t
o b
e a
dm
itte
d t
o t
he
IC
U.
TRANSPORTATION OF EMERGENCY PATIENTS
59
Ta
ble
13
E
vid
ence
ta
ble
s o
f st
ud
ies
com
pa
rin
g c
rew
s th
at
do
an
d d
o n
ot
per
form
ra
pid
seq
uen
ce i
ntu
ba
tio
n a
nd
/or
tho
raco
sto
my
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Le
e e
t a
l. 2
003
)
Au
stra
lia
co
ntin
ue
d
P
art
icip
an
ts (
n=
2010
):
Inte
rve
ntio
n.
Leve
l of
pre
-ho
spita
l ca
re w
as
cla
ssifie
d
into
th
ree
gro
up
s: b
asi
c li
fe s
up
po
rt,
ad
va
nc
ed
life
su
pp
ort
an
d p
hysi
cia
n
ca
re.
An
aly
ses
co
mp
arin
g g
rou
ps
at
ba
selin
e.
Me
an
ISS b
y le
ve
l of
pre
-ho
spita
l ca
re:
No
n-E
MS t
ran
spo
rt:
20
Leve
l 3 a
mb
ula
nc
e:
24
Leve
l 4 a
mb
ula
nc
e:
25
Leve
l 5 a
mb
ula
nc
e:
31
Ph
ysi
cia
n: 3
1
Me
dia
n a
ge
30 y
ea
rs (
inte
rqu
art
ile
ran
ge
21-4
9 y
ea
rs)
Ma
les:
76%
Ca
use
s:
Ro
ad
tra
ffic
ac
cid
en
t 6
7%
Falls
: 13%
Ass
au
lt 5
%.
No
he
ad
inju
rie
s: 3
6%
Iso
late
d h
ea
d in
jury
: 52%
He
ad
inju
ry w
ith
ab
do
min
al/
ch
est
inju
rie
s: 1
2%
Pre
-ho
spita
l ca
re:
No
n-E
MS t
ran
spo
rt 5
%
Leve
l 3 a
mb
ula
nc
e 2
3%
Leve
l 4 a
mb
ula
nc
e 2
%
Leve
l 5 a
mb
ula
nc
e 5
9%
Ph
ysi
cia
n E
MS 1
1%
TRANSPORTATION OF EMERGENCY PATIENTS
60
Ta
ble
13
E
vid
ence
ta
ble
s o
f st
ud
ies
com
pa
rin
g c
rew
s th
at
do
an
d d
o n
ot
per
form
ra
pid
seq
uen
ce i
ntu
ba
tio
n a
nd
/or
tho
raco
sto
my
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Ca
me
ron
et
al.
20
05)
Au
stra
lia
Be
fore
an
d
aft
er
stu
dy.
Re
tro
spe
ctive
ch
art
re
vie
w.
Leve
l III-
3.
Stu
dy s
ett
ing
.
Ca
irn
s B
ase
ho
spita
l. U
ntil 2
00
1
he
lico
pte
rs in
clu
de
d e
me
rge
nc
y
ph
ysi
cia
ns.
Sin
ce
2001 t
he
y h
ave
be
en
sta
ffe
d b
y in
ten
sive
ca
re p
ara
me
dic
s.
Pa
rtic
ipa
nts
(n
=3
74
):
Inte
rve
ntio
n (
n=
16
3)
Sto
pp
ed
th
e p
rese
nc
e o
f a
n
em
erg
en
cy p
hysi
cia
n o
n a
n
em
erg
en
cy h
elic
op
ter.
C
rew
mix
wa
s
un
ab
le t
o p
erf
orm
ra
pid
se
qu
en
ce
intu
ba
tio
n o
r tu
be
th
ora
co
sto
my.
Co
mp
ara
tor
(n=
21
1)
Em
erg
en
cy p
hysi
cia
n (
EP
) o
n b
oa
rd.
The
EP
wa
s a
ble
to
pe
rfo
rm a
ny
pro
ce
du
re t
ha
t th
ey c
an
pe
rfo
rm in
th
e
em
erg
en
cy d
ep
art
me
nt.
An
aly
ses
co
mp
arin
g g
rou
ps
at
ba
selin
e
Me
dia
n a
ge
(ye
ars
)
Ph
ysi
cia
n g
rou
p:
34
Pa
ram
ed
ic g
rou
p:
33
Ma
les
(%)
Ph
ysi
cia
n g
rou
p:
64.0
Pa
ram
ed
ic g
rou
p:
65.6
Me
an
RTS
Ph
ysi
cia
n g
rou
p:
7.7
22
Pa
ram
ed
ic g
rou
p:
7.7
30
Inc
lu/e
xcl c
rite
ria
.
An
y p
rim
ary
ta
skin
g o
f th
e
he
lico
pte
r. C
ase
s w
ere
ide
ntifie
d b
y
the
‘m
od
e o
f a
rriv
al’
fie
ld re
co
rde
d
on
th
e E
D in
form
atio
n s
yst
em
Da
ta c
olle
ctio
n
The
RTS
wa
s c
alc
ula
ted
usi
ng
th
e
initia
l clin
ica
l ob
serv
atio
ns
in t
he
me
dic
al r
ec
ord
s a
nd
am
bu
lan
ce
form
s.
Ou
tco
me
me
asu
res
30 d
ay m
ort
alit
y
Len
gth
of
in-h
osp
ita
l sta
y
Tra
nsf
er
rate
s
Ra
tes
of
dis
ch
arg
e d
ire
ctly f
rom
ho
spita
l
An
aly
sis
An
aly
ses
co
mp
arin
g g
rou
ps
at
ba
selin
e.
On
e w
ay a
na
lysi
s o
f va
ria
nc
e w
as
un
de
rta
ke
n a
nd
P v
alu
es
an
d a
χ2
test
with
Ya
tes
co
rre
ctio
n w
ere
ca
lcu
late
d w
he
re a
pp
rop
ria
te
Ka
pp
a s
tatist
ic w
as
use
d t
o a
sse
ss
inte
r-ra
ter
relia
bili
ty in
th
e c
ha
rt
ext
rac
tio
n.
30 d
ay m
ort
alit
y p
rop
ort
ion
, b
y
stu
dy g
rou
p (
%)
Ph
ysi
cia
n g
rou
p:
2.8
%
Pa
ram
ed
ic g
rou
p:
2.5
%
P=
0.8
Me
an
ho
spita
l le
ng
th o
f st
ay, b
y
stu
dy g
rou
p (
da
ys)
Ph
ysi
cia
n g
rou
p:
2
Pa
ram
ed
ic g
rou
p:
1
P=
0.3
Lim
ita
tio
ns
�
Re
tro
spe
ctive
stu
dy.
�
The
ac
cu
rac
y o
f c
od
ing
th
e m
od
e o
f
arr
iva
l (u
sed
to
ide
ntify
re
leva
nt
pa
tie
nts
) w
as
no
t d
oc
um
en
ted
.
Ho
we
ve
r, t
his
is n
ot
like
ly t
o b
e a
ma
jor
sou
rce
of
bia
s.
�
Un
cle
ar
if t
he
tim
ing
of
the
me
asu
rem
en
ts u
sed
to
ass
ess
RTS
wa
s
the
sa
me
in b
oth
gro
up
s.
�
Me
asu
res
of
inju
ry s
eve
rity
use
d w
ere
diffe
ren
t fr
om
th
e n
orm
al a
pp
roa
ch
.
No
use
of
the
ISS s
o it
wa
s n
ot
po
ssib
le
to a
sse
ss p
rob
ab
ility
of
surv
iva
l w
ith
refe
ren
ce
to
a s
uita
ble
po
pu
latio
n
suc
h a
s M
TOS.
�
Ob
serv
atio
n s
tud
y is
su
sce
ptib
le t
o
co
nfo
un
din
g.
�
Ce
ntr
al c
om
mu
nic
atio
n w
as
no
t
do
cu
me
nte
d f
or
eith
er
gro
up
.
�
Ba
selin
e d
iffe
ren
ce
s in
pa
tie
nts
ad
mitte
d w
ith
hig
he
r p
rop
ort
ion
of
the
ph
ysi
cia
n g
rou
p b
ein
g a
dm
itte
d.
�
Ve
ry lo
w n
um
be
r o
f d
ea
ths
co
nsi
ste
nt
with
low
stu
dy p
ow
er
(10 d
ea
ths
in
tota
l).
�
Au
tho
rs s
ug
ge
ste
d R
TS w
as
a p
oo
r
pre
dic
tor
of
ne
ed
fo
r a
dm
issi
on
an
d
po
stu
late
d t
ha
t A
PA
CH
E m
ay h
ave
be
en
a b
ett
er
me
asu
re.
�
No
fo
llow
-up
of
pa
tie
nts
dis
ch
arg
ed
dire
ctly f
rom
ED
.
TRANSPORTATION OF EMERGENCY PATIENTS
61
Ta
ble
13
E
vid
ence
ta
ble
s o
f st
ud
ies
com
pa
rin
g c
rew
s th
at
do
an
d d
o n
ot
per
form
ra
pid
seq
uen
ce i
ntu
ba
tio
n a
nd
/or
tho
raco
sto
my
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Ca
me
ron
et
al.
20
05)
Au
stra
lia
co
ntin
ue
d
P
rop
ort
ion
dis
ch
arg
ed
fro
m E
D
Ph
ysi
cia
n g
rou
p:
14.7
%
Pa
ram
ed
ic g
rou
p:
33.1
%
P=
0.0
00
1
Pro
po
rtio
n o
f tr
au
ma
pa
tie
nts
ad
mitte
d
Ph
ysi
cia
n g
rou
p:
86.7
%
Pa
ram
ed
ic g
rou
p:
68.9
%
P=
0.0
02
Pro
po
rtio
n o
f n
on
-tra
um
a p
atie
nts
ad
mitte
d
Ph
ysi
cia
n g
rou
p:
83.7
Pa
ram
ed
ic g
rou
p:
64.4
P=
0.0
04
Pro
po
rtio
n o
f tr
au
ma
pa
tie
nts
with
ma
xim
um
RTS
Ph
ysi
cia
n g
rou
p:
89.4
Pa
ram
ed
ic g
rou
p:
90.0
Co
mm
en
ts
�
Two
co
nse
cu
tive
ye
ars
fo
r e
ac
h g
rou
p
we
re e
xam
ine
d in
th
e c
ha
rt r
ev
iew
.
�
A s
ec
on
d r
ev
iew
er
va
lida
ted
th
e
ch
art
ext
rac
tio
n in
40 r
an
do
mly
sele
cte
d c
ha
rts
(10.7
% o
f th
e t
ota
l).
Exc
elle
nt
leve
l of
ag
ree
me
nt
ac
hie
ve
d (
Ka
pp
a 0
.937
).
�
All
pa
tie
nts
tra
nsp
ort
ed
to
th
e s
am
e
ba
se h
osp
ita
l.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
The
sim
ilaritie
s in
ou
tco
me
s fo
r a
dm
itte
d
pa
tie
nts
su
pp
ort
th
e v
iew
th
at
bo
th g
rou
ps
ha
ve
sim
ilar
task
ing
crite
ria
fo
r h
igh
ac
uity
pa
tie
nts
an
d s
ug
ge
st t
ha
t p
ara
me
dic
s a
re
as
eff
ica
cio
us
as
ph
ysi
cia
ns
in d
eliv
erin
g
pre
-ho
spita
l ca
re in
th
is g
rou
p o
f p
atie
nts
.
Ho
we
ve
r, f
or
low
er
ac
uity p
atie
nts
, th
ere
is a
sta
tist
ica
lly s
ign
ific
an
t h
igh
er
rate
of
clin
ica
lly
un
ne
ce
ssa
ry t
ask
ing
s b
y t
he
am
bu
lan
ce
gro
up
. G
ive
n t
he
re
ce
nt
fata
l ae
rom
ed
ica
l
ac
cid
en
ts in
Qu
ee
nsl
an
d it
wo
uld
se
em
pru
de
nt
to r
ed
uc
e c
linic
ally
un
ne
ce
ssa
ry
retr
ieva
ls t
hro
ug
h c
linic
al c
oo
rdin
atio
n w
ith
ap
pro
pria
tely
qu
alif
ied
em
erg
en
cy
ph
ysi
cia
ns.
TRANSPORTATION OF EMERGENCY PATIENTS
62
Summary and Conclusions
Five studies were identified that were eligible for examining the question “In adults and children with a medical or trauma related emergency, does the presence of a medical crew able to perform rapid sequence intubation and/or thoracostomy improve health outcome when compared with a medical crew unable to perform rapid sequence intubation and/or tube thoracostomy and/or thoracotomy?” In three studies the mortality rate was lower in the group receiving care from crews able to provide at least one of the stipulated procedures (Baxt and Moody 1987; Garner et al. 1999; Koefoed-Nielsen et al. 2002). One other study demonstrated mixed results when stratified by admission to ICU (Lee et al. 2003) and the final study found no significant difference in mortality or hospital length of stay between the two groups (Cameron et al. 2005).
The included studies were only partially helpful in answering this review question as the additional procedures (rapid sequence intubation, tube thoracostomy or thoracotomy) were performed by crews with a doctor present. That is, there were no studies that compared one non doctor crew that was able to perform any of these procedures with another non doctor crew that were not able to perform those procedures. Therefore, although the overall results suggest an improved outcome when being attended by crews that were able to perform at least one of rapid sequence intubation, tube thoracostomy or thoracotomy, there could be other reasons for any such improved outcome. For example, if the assessment process differed between crews and subsequent management decisions differed based on the assessments made by the different groups then this may explain any difference in outcome (rather than a difference in procedures).
There were other inherent limitations in the five studies selected. There was variation in study design among the three studies that suggested some benefit from being attended by crews with the additional procedural capabilities. One used a pseudorandomised controlled trial design (Baxt and Moody 1987), one used a retrospective design (Garner et al. 1999) and the other used a before and after design (Koefoed-Nielsen et al. 2002). In relation to the pseudorandomised controlled trial, a particular consideration was the use of limiting the mortality outcome to deaths that were thought to be directly due to the trauma or complications of the trauma. This may have produced outcome misclassification with the potential for underestimating mortality in either group. The use of all-cause mortality as an outcome would have avoided this limitation. There were also limitations to the registry based study but the effect of these limitations on the study estimates was not clear. Firstly, a significant proportion of eligible patients were excluded from the doctor group due to missing charts. There were no deaths among these patients, thus the level of reduced mortality in the doctor group may have been underestimated. However, time to arrival on the scene was shorter in the doctor group. This may have resulted in an improved prognosis in the doctor group and may not be replicated in other settings where time to arrival of the doctor group may be delayed. Perhaps most significantly, the two groups (doctor and no doctor) were located in two different countries so there may have been other reasons that explain differences in outcomes other than the personnel supplying pre-hospital care. For example, level of hospital care may vary between the two settings. In the retrospective study (Garner et al. 1999), seven deaths in the non-doctor group were omitted due to missing case sheets, potentially underestimating the effectiveness of care provided by doctor crewed helicopters. Patients were also directed to different hospitals in this study depending on the helicopter crew mix. The before and after study was restricted to patients with acute MI. The before and after design (Koefoed-Nielsen et al. 2002) is the biggest limitation since it is not possible to be certain the improved outcome was a result of the different crewing mix or other factors that had changed over time. Based on the above limitations there is uncertainty about the robustness of the findings in these three studies.
Cameron et al. (2005) published a retrospective chart review. This study found no significant difference in outcome between study groups. However, it was limited by the inclusion of limited injury severity data and low study power to detect a difference in mortality.
The other study was set in Australia (Lee et al. 2003). The study population consisted of patients with severe blunt trauma. Three types of pre-hospital care were studied. The most basic level of life support was used as the reference category and was compared with another non-medical configuration and a configuration with a doctor on board. It was only the latter group that was able to perform rapid sequence intubation or tube thoracentesis. The results varied by whether the patients were subsequently admitted to ICU. The odds of mortality were significantly higher in the two more advanced pre-hospital configurations when the patient was not admitted to ICU. However, when the patient was admitted to
TRANSPORTATION OF EMERGENCY PATIENTS
63
ICU there were no statistically significant differences between pre-hospital care groups. It should be noted that a selective dispatch strategy was used so the more severely injured patients were seen by the more advanced ambulance group and the doctor group. The authors also commented that paramedics may have involved the physician group when patient death was imminent. These factors may explain the poorer prognosis in the two more advance pre-hospital care groups among the patients who did not proceed on to ICU care.
As in previous sections, more research is required to answer this question. A useful study would be to compare doctors versus fully trained non-doctor personnel. The study should be adequately powered to detect equivalence in outcome. Other considerations include
1. Whether there may be variation in outcome across crew mixes for different clinical scenarios. For example, the inclusion of doctors on road ambulances may be associated with longer at scene times. This longer period of stabilisation could be associated with improved outcome in some circumstances but not others.
2. Comparing outcomes in paediatric and adult age groups and stratifying results by ISS score.
Outcomes by time from ambulance call out to emergency department delivery
From the search strategy for question four (outcome by time from ambulance callout to emergency department delivery) we identified, 1863 potentially relevant articles/abstracts of which 152 were retrieved. Of these retrieved articles, 132 were excluded. These papers, annotated with the reason for exclusion, are presented in Appendix 6. One study was identified from reference lists and was included in the papers for appraisal. Reasons for exclusion of studies before retrieval in full text are outlined in Table 14. Reasons for exclusion of studies retrieved in full text are detailed in Table 15.
Table 14 Reasons for exclusion of studies before retrieval in full text: time from callout to
emergency department delivery
Reason for exclusion Number
Not relevant to review question aim 1424
Methods were not clearly described 0
Wrong publication type 184
Incorrect population 4
Sample size less than 50 71
Incorrect comparator 5
Incorrect outcomes 11
Publication superseded 0
Non-English language 0
Neonatal study 1
Duplicate abstract 1
Wrong or uncertain time component presented 10
Total 1711
Table 15 Reasons for exclusion of studies retrieved in full text: time from callout to emergency
department delivery
Reason for exclusion Number
Not relevant to review question aim 49
Methods were not clearly described 0
Wrong publication type 2
Incorrect population 3
Sample size less than 50 1
Incorrect comparator 16
Incorrect outcomes 4
Publication superseded 0
Non-English language 1
Neonatal study 0
Wrong or uncertain time component presented 55
Duplicate study 1
Total 132
TRANSPORTATION OF EMERGENCY PATIENTS
64
Twenty-one retrieved articles were appraised and are listed in the references and Appendix 7. Included papers are presented in the evidence table below. Included studies were all level III-2 according to NHMRC’s hierarchy of evidence, including 21 cohort studies and one case control study.
Pepe et al. 1987
Pepe et al. (1987) investigated the outcome of patients following penetrating trauma. The 498 consecutive patients were stratified into four groups based on trauma scores and survival was assessed by total pre-hospital time across these four trauma group categories. Chi square analysis was used to compare survival by four groups of total pre-hospital time. The sample size varied across the four categories of trauma score (35-317). The study was set in Texas, average age was 31 years and the mean total pre-hospital time was 32.6 minutes. There was no significant difference in survival across the four categories of total pre-hospital time within each trauma score stratum.
There were limitations to this study:
� stratifying by trauma score reduced study power. The trauma score category with the largest number of participants consisted of patients with >90% probability of surviving (based on TRISS methodology).
� the observational design is susceptible to confounding. Although the authors have stratified by trauma score, this measure provides a physiological assessment (rather than anatomical assessment) and can change rapidly over time. Therefore, injury severity may vary within the trauma score strata. Although some reassurance is provided by the relative uniformity of predicted survival (based on TRISS methodology) within trauma score strata, small sample sizes in some categories mean residual confounding could remain as an issue.
� the results of this study can only be applied to patients with penetrating trauma given the selection criteria for the study population.
Schiller et al. 1988
Schiller et al. (1988) compared helicopter with ground transportation in a group of patients with blunt trauma and ISS of 20-39. This was a retrospective chart review and total pre-hospital time had to be estimated in 15% of patients due to lack of recording. There were 259 patients transported by ground ambulance and 347 by helicopter. Statistical analysis was restricted to univariate analyses by Student’s t test and chi square test. The mean mission time for ambulances was 39 minutes and 50 minutes for the helicopters. Mortality was significantly higher in the helicopter group (18% versus 13%, P<0.05). There was no difference in length of stay between the two groups (26 days in both groups). There was no comparison between pre-hospital time and the outcome of interest.
Potential sources of bias in this study included:
� the arbitrary estimation of pre-hospital time in 15% of participants.
� the ecological nature of comparing two different transportation groups and basing any association with pre-hospital time on the mean pre-hospital times of the two groups.
� the lack of control over potential confounders.
� uncertainty whether consecutive patients were used in the study.
� uncertainty whether any difference in mortality between the two groups is due to a difference in pre-hospital time or other factors such as the dispatch strategy. The skill mix may also result in bias in the comparative outcome estimates if the crews in the two different modes of transport have different levels of skill.
Sloan et al. 1989
A study set in Chicago investigated the effects of taking trauma patients directly to a level 1 trauma centre whether or not they bypassed other hospitals (Sloan et al. 1989). Thus two groups were formed: a direct group and a bypass group with the latter group bypassing other hospitals en route to the level 1 trauma centre. On that basis the total run time (time from dispatch to trauma centre arrival) varied by patient. Data comparing the mortality and survival groups were presented including total run time in the two groups. Eligibility criteria included one of the following three categories:
TRANSPORTATION OF EMERGENCY PATIENTS
65
1. Life threatening injury, including traumatic arrest, penetrating neck trauma, and/or blunt or penetrating chest or abdominal trauma with systolic BP < 100mmHg
2. Field trauma score ≤ 12
3. Limb threatening injury.
Patients were excluded if they arrived at the trauma centre without vital signs and were unable to be resuscitated or if outcome data were missing.
There was no significant difference in total run time between the mortality and survival groups (32 minutes versus 35 minutes respectively) although the study had 90% power to detect a 6% difference in survival.
However, there were limitations:
� the observational design was susceptible to confounding and the method of analysis did not help to control confounding (multivariate or stratified analyses were not presented)
� the method of deriving time data was unclear therefore the accuracy of the total run time was uncertain
� fifty five (21%) patients were excluded, including 48 who presented to the trauma centre without vital signs.
Schwartz et al. 1990
Schwartz et al. (1990) compared air and ground ambulance programmes to determine whether pre-hospital time or pre-hospital care was the major contributor towards survival in a group of patients following blunt trauma. All patients were transported directly from the scene to definitive care. There were 126 patients, 93 transported by air and 33 by ground. The authors extracted data from three registries and chart review.
The average pre-hospital time was longer in the air group (65 minutes versus 34 minutes). However, Z scores (based on TRISS methodology via comparison with the MTOS cohort) found a significantly improved survival in the air group (Z=2.23) and significantly poorer outcome in the ground group (Z=-2.69).
There were a number of limitations to this study:
� confounding was a potential problem in this observational study. In this study it is likely that the crew mix was a more important determinant of outcome than the pre-hospital time. On this basis the study results are difficult to interpret.
� the basis for dispatching a helicopter rather than a ground crew was not clear. There may have been a potential selection bias as a result, although it is noted that if there is a bias other studies have tended to dispatch helicopters to the more severely unwell patients.
� the degree of match between the study data and the MTOS cohort data was unclear as the M statistic was not documented.
� the ecological nature of comparing two different transportation groups and basing any association with pre-hospital time on the mean pre-hospital times of the two groups.
Sampalis et al. 1992
Sampalis et al. (1992) conducted a study that aimed to compare observed and expected mortality (using TRISS methodology and based on the MTOS cohort) overall and by subgroups (including pre-hospital time, level of pre-hospital care and level of in hospital care). The investigators used a complicated three stage sampling process. The aim of this sampling process was to select patients with severe but survivable injuries. It was unclear if the approach was set prior to selecting the sample. The final sample consisted of 355 patients with a mean ISS of 13.7. However, there was a wide range of ISS scores (1-59) so some patients did not fulfil the severe injury aim of the sampling strategy. There were three broad data analyses:
TRANSPORTATION OF EMERGENCY PATIENTS
66
1. Comparison of the overall data (using the Z score and the SMR)
2. A subanalysis of different strata defined on pre-hospital time, pre-hospital care and in-hospital care (using the Z score and the SMR)
3. An adjusted comparison of the above strata using logistic regression.
Overall there were more deaths than expected as reflected in the Z score (6.77, P<0.0001) and SMR (1.81, 95% CI 1.42-2.21). Within strata defined by pre-hospital time (>60 minutes compared with reference of 0-60 minutes) there were greater excess deaths in the > 60 minute group with an SMR ratio (> 60 minutes versus 0-60 minutes) of 6.41 (95% CI 1.69-17.37). Logistic regression also found an association between prolonged pre-hospital time and poor survival (OR 29.9, 95% CI 2.7-33.3).
There were strong aspects to this study, not the least of which was to incorporate a multivariate analysis within the methodology. However, limitations also existed:
� it was unclear from the selection process whether the criteria were preset and just how representative the selected sample was of the group the investigators were aiming to explore. The reviewers are unclear why an approach such as stratified random selection based on ISS score were not used.
� there were further sources of selection bias due to missing data. In particular, 30 of 385 potential patients from the final sample were excluded due to missing charts and pre-hospital time data was only available on 270 of 355 eligible participants (76%).
� there were only 13 patients with a pre-hospital time > 60 minutes.
� the accuracy of the pre-hospital time was not clear.
� although a multivariate analysis was conducted this study is still susceptible to confounding by other unknown and uncontrolled factors. However, it is important to recognize that these findings suggest in this study population that prolonged pre-hospital time (> 60 minutes) was associated with poorer outcome even after controlling for different mixes of pre-hospital crews (including the presence of a physician). Furthermore, the level of care provided by the hospital (based on the American College of Surgeons criteria for trauma centre categorisation) was also controlled.
Sampalis et al. 1993
Sampalis et al. (1993) also published a case control study where cases died within 6 days of injury and controls survived more than 6 days after injury. There were similarities to their 1992 study and it is assumed the study populations overlapped. Specifically, the first two stages of the three stage sampling process were the same with the same number of patients selected at the end of sampling stage 2. The difference was at stage 3 of the sampling process where the selection was based on specific criteria to fulfil either a case or a control. More detail is provided in Table 16. There were 72 cases and 288 controls. Again the study focused on three factors, total pre-hospital time, the crew mix at the pre-hospital phase and the level of care provided in-hospital. Both univariate and multivariate analyses were conducted. A wide range of variables were considered in the stepwise selection of the logistic regression model before finishing with a relatively simple model.
There were increased odds of survival of more than six days in association with a pre-hospital time under 60 minutes (OR 3.01, 95% CI 1.27-5.06).
Similar quality considerations apply to this study as they did with the 1992 study. There were strong aspects to this study, not the least of which was to incorporate a multivariate analysis within the methodology. However, limitations also existed:
� it was unclear from the selection process whether the criteria were preset and just how representative the selected sample was of the group the investigators were aiming to explore. The reviewers are unclear why an approach such as stratified random selection based on ISS score was not used.
� there were further sources of selection bias due to missing data. In particular, 34 of 337 potential patients with a PHI>3 were excluded from the final sample due to missing charts.
� the accuracy of the pre-hospital time was not clear.
TRANSPORTATION OF EMERGENCY PATIENTS
67
� although a multivariate analysis was conducted this study is still susceptible to confounding by other unknown factors. However, it is important to recognize that these findings suggest in this study population that prolonged pre-hospital time (> 60 minutes) was associated with poorer outcome even after controlling for different mixes of pre-hospital crews (including the presence of a physician). Furthermore, the level of care provided by the hospital (based on the American College of Surgeons criteria for trauma centre categorisation) was also controlled. It is interesting to note the odds ratio in this study was much smaller than in the previous study, although still indicating that pre-hospital time more than 60 minutes appears to have an adverse outcome on survival.
Bonatti et al. 1995
Bonatti et al. (1995) aimed to identify predictors of short-term survival in their Austrian setting. The study was based on a HEMS unit that included physician staffing. There were no specific eligibility criteria listed but it is presumed that all missions between 1989 and 1991 were included. There were 2139 participants with a preponderance of sporting injuries (53.7%). Data were extracted from medical records, flight logs and discharge summaries. Univariate and multivariate analyses were conducted.
The univariate analyses showed decreasing survival with increasing total mission time (P=0.0001):
� 0-20 minutes: 95.5% survival
� 21-40 minutes: 91.7% survival
� 41-60 minutes: 87.6% survival
� 61-80 minutes: 86.8% survival
� > 80 minutes: 78.8% survival.
However, on multivariate analysis, there was no association between total mission time and survival after adjusting for cause of injury/emergency, flight time to scene, scene time, patient age, patient gender, NACA score, state of consciousness, respiratory status, circulatory status, emergency physician.
There was relatively little methodological data given. It is difficult to assess the probability of selection bias given the lack of details about the process although it should be recognised that there were a high proportion of sporting injuries in this population. The accuracy of data recording in the sources used for data extraction was not documented. Adjusting for components of the total mission time in the multivariate model may have contributed to the lack of association observed. Finally, despite the use of a multivariate model, the possibility of residual confounding cannot be discounted.
Feero et al. 1995
This group used a different study design where they compared unexpected survivors with unexpected deaths (based on TRISS methodology), (Feero et al. 1995). While there were 848 eligible trauma victims in the study time period, there were only 13 unexpected survivors and 20 unexpected deaths. The study relied on identifying patients from a local registry. Entry on this registry consisted of a set of mandatory criteria and a set of optional criteria. The mandatory criteria were divided into physiological, anatomical and mechanism of injury characteristics. The key result was a prolonged total EMS time interval in the unexpected death group when compared with the unexpected survivor group (29.3 minutes compared with 20.8 minutes, P=0.02). However, the unexpected death group was also significantly older than the unexpected survivor group (50.8 years versus 29.5 years, P=0.01).
Study limitations included:
� while the TRISS methodology was useful for identifying the two unexpected outcome groups (and there was a high degree of concordance between the reference population and the actual population), the lack of control for potential confounders in this study was problematic
� there were small numbers in the two study groups of interest (total of 33 patients)
� probability of selection bias due to the lack of consistent use of objective criteria for study inclusion (a reflection of the retrospective design that made use of registry data).
TRANSPORTATION OF EMERGENCY PATIENTS
68
Young et al. 1998
Young et al. (1998) presented a study comparing mortality and length of hospital stay across two groups: trauma patients transported directly to a level 1 trauma centre versus trauma patients transferred via another hospital en route to the level 1 trauma centre. The study was restricted to patients over 18 years with an ISS greater than 15. The study used a retrospective design and relied on registry plus hospital note data. The time from injury to arrival at the trauma centre averaged 480 minutes in the transfer group and 92 minutes in the direct group. There was no significant difference in length of hospital stay or overall mortality between the two groups. The authors studied two mortality subgroups (deaths within 24 hours and deaths more than 24 hours after injury). Unexpected deaths (based on TRISS methods) were analysed further in the group of deaths in the first 24 hours and found a higher proportion of unexpected deaths in the transfer patients (75% versus 28%, P<0.05).
The study had significant limitations
� there were discrepancies in the number of deaths within the paper (three deaths were not accounted for when categorizing to the first 24 hours and more than 24 hours after injury)
� M statistic indicated a poor match between the reference data and the actual data casting doubt on the validity of the probability of survival data
� no direct comparison between pre-hospital time and outcome
� observational study design that is susceptible to confounding.
Frezza et al. 1999
A study set in the USA examined the effect of pre-hospital time on outcome in patients undergoing emergency room thoracotomy (ERT), (Frezza and Mezghebe 1999). There were 58 adult patients with penetrating chest trauma, although the analysis was restricted to 33 of these patients who actually received ERT. Twenty-four hour survival was higher in the group with a pre-hospital time <30 minutes compared with the group with a pre-hospital time >30 minutes (20/27 (63%) versus 0/6 (0%)).
This study had significant limitations making it difficult to interpret the above results. In particular:
� scant details were presented in the methods
� there were apparent deaths > 24 hours post injury thus incorporation of those deaths in the analysis of pre-hospital time would have reduced the difference in survival between the two groups
� the components of the pre-hospital time recorded were not documented so it is unclear if this time refers to time from dispatch of emergency services to time of arrival at hospital
� data were missing on nine patients and a further 16 were excluded due to lack of vital signs being recorded from the field.
Phillips et al. 1999
Phillips et al. (1999) compared the outcome in patients transported by road and air ambulance. The aim of this study was to assess outcome against national standards. Patients retrieved by air ambulance had, on average, a longer period of pre-hospital time than the road ambulance group (77 minutes versus 54 minutes). The air ambulance crew was permitted to conduct more advanced procedures than the road ambulance crew so therefore were preferentially given the more severely injured patients to transport.
As background, based on TRISS methodology, the mean predicted survival rate was 93.9% in the road ambulance group and 83.1% in the air ambulance group. There was a significantly longer hospital stay in the air ambulance group than the road ambulance group (4.21 days versus 8.97 days, P<0.001). Estimation of Z scores (based on comparison with the MTOS cohort using TRISS methodology) showed no significant difference in actual versus predicted mortality either within the road ambulance group or the air ambulance group. The M statistic was not estimated so the degree of fit between the MTOS cohort and the study cohort was not clear.
Other limitations also existed. The most significant was that this study was not designed to compare pre-hospital time against outcome thus the differences in outcome (especially hospital length of stay) could be fully explained by the increased severity of injury in the air transport group. It is not possible
TRANSPORTATION OF EMERGENCY PATIENTS
69
to determine whether the prolonged hospital stay in the air ambulance group was partially due to the longer pre-hospital period in this group. There were other limitations that are outlined in Table 16. These limitations are such that it would be inadvisable to form any conclusions regarding the effect of different pre-hospital times on patient outcome based on this study.
Sampalis et al. 1999
Following the two earlier studies by Sampalis et al. (1992; 1993) a programme of regionalization of the trauma services occurred. This cohort study aimed to assess the impact of regionalization on mortality. It also investigated the association between pre-hospital time and mortality. There were 12,208 patients included in the study. Selection criteria were
� treated for injuries at acute care hospitals in Montreal and Quebec
� one of:
• Death as a result of injury
• ISS>12
• At least two injuries with AIS ≥3
• Hospital stays > 3 days.
Patients who died at the scene were excluded.
The analytic method varied by hypothesis tested. In relation to the association between pre-hospital time and mortality, logistic regression was used. The mean age of the sample was 48 years. This decreased over the six study years. Mean ISS was 26.1. The majority were discharged alive (72%).
During the six years of the study 3,453 (28%) of the patients died. The adjusted odds ratio for the association between each additional minute of pre-hospital time and mortality was 1.046 (95% CI 1.044-1.050). This was adjusted for time to admission, trauma centre designation, transfer versus direct transport, patient age and ISS. This result indicates a 5% increase in risk of mortality for every minute’s pre-hospital delay.
This was a well conducted study and it had the advantage of a large sample size. Any biases present are likely to be small and could arise for inaccurate pre-hospital times, confounding (given the observational design) and potential selection biases resulting from the selection methods.
Grzybowski et al. 2000
This study compared patients surviving at least seven days with deaths within that time period after presenting with chest pain or shortness of breath (Grzybowski et al. 2000). Ninety-six percent of patients had an acute MI. The study population was restricted to patients 18 years and over and nine patients were excluded due to missing outcome data. There were 244 patients in the final study population. Bivariate comparison found a significantly longer total pre-hospital time in the deaths than
the survivors (50.6 minutes versus 42.8 minutes, P≤0.01).
Limitations of this study included:
� while multivariate regression was used, indices of pre-hospital time were not included in this model, so there was no control over potential confounders in the pre-hospital time to outcome relationship
� it is unclear if the prolonged time in the non-survivors may have been due to more severe disease requiring immediate management on the scene.
Berns et al. 2001
Berns et al. (2001) compared outcome amongst a group of cardiac patients transported by helicopter with another group transported by road ambulance. There were 266 helicopter patients and 28 road ambulance patients. Most patients were transferred from referring emergency departments rather than the site of onset of cardiac symptoms and the pre-hospital time reflected time from the request for
TRANSPORTATION OF EMERGENCY PATIENTS
70
transfer to arrival at the definitive treatment hospital. Data on hospital length of stay and mortality were presented.
The pre-hospital times were a mean of 104 minutes in the helicopter group and 142 minutes in the ground ambulance group. Hospital length of stay was significantly shorter in the helicopter group (6.4 versus 8 days, P=0.04) but there was no significant difference in mortality between the two groups (7% in helicopter group and 4% in ground group).
In regards to the review question of interest, this study was difficult to interpret as the difference in hospital length of stay may have reflected differences in staffing mixes by the two different forms of transport. The study was underpowered to detect a difference in mortality. There were no comparisons with individual pre-hospital time data further limiting this study.
Clarke et al. 2002
This study focused on patients with severe abdominal trauma who had systolic BP < 90mmHg on ED arrival and either died in ED or were transferred to the operating room for laparotomy. There were 243 patients included in the study. Interval risk ratios for death were estimated based on pre-hospital time. All risk ratios included one indicating no increased risk of death for any pre-hospital time interval. However, the time interval 31-60 minutes neared significance (RR 1.268, 95% CI 0.980-1.641). There were 117 patients in this time category (including 63 who survived and 54 who died).
There were potential sources of selection bias (omission of patients who did not have appropriate time intervals recorded in the registry and exclusion of patients who had extreme time intervals), misclassification (due to reliance on registry data that the authors may have been frequently rounded to the nearest five minutes) and confounding based on the observational design and lack of analyses that could control for known confounding factors. In general, the study was well conducted but the main focus was on ED time rather than pre-hospital time.
Lim et al. 2002
A study set in Singapore investigated survival following out of hospital cardiac arrest (OHCA), (Lim and Seow 2002). This study divided the 93 patients into two groups: patients who survived post ED resuscitation and patients who did not survive beyond this time. There were 15 survivors using this classification although only one survived to hospital discharge. All patients with non-traumatic OHCA presenting during a three month period from November 2001 were included. Data were extracted from various records, including ambulance case records, ED resuscitation charts and in-patient records. Univariate analyses were conducted using the t test and the chi square test. There was no significant difference in total pre-hospital time between the survivors and non-survivors (38.3 minutes versus 35.4 minutes respectively).
There were significant limitations to this study:
� the sample size was low so the power to detect a significant difference in pre-hospital time across the two groups was low
� there is likely to be misclassification of the total pre-hospital time since the recordings were only documented once the ambulance arrived at the hospital
� the combination of the observational design and the lack of multivariate analysis mean the results are highly susceptible to confounding.
Osterwalder et al. 2002
Osterwalder et al. (2002), in their Swiss based study, aimed to test the hypothesis that exceeding the 60 minute limit for the entire pre-hospital time increases mortality of blunt trauma patients. There were 254 participants including 107 with a rescue time up to 60 minutes and 147 with a rescue time over 60 minutes. All the blunt trauma patients were treated at a single hospital (St Gallen Cantonal Hospital) and had an AIS of at least two for at least two of six defined body regions. The actual 30 day mortality was compared with predicted mortality (based on ASCOT score). Flora’s z statistic was used to compare actual with expected mortality. Univariate and multivariate analyses (logistic regression) were also conducted. The adjusted odds ratio found increased odds of dying in the group with a transport
TRANSPORTATION OF EMERGENCY PATIENTS
71
time up to 60 minutes compared with the group with a transport time more than 60 minutes (OR 8, 95% CI 1.7-38.5).
There were limitations to this study:
� the observational design is susceptible to confounding and while a multivariate analysis was conducted, the variables included in the model were not documented. There were differences between the two groups at baseline
� while consecutive patients were included in the study, 9% were omitted due to missing time data.
Lerner et al. 2003
Lerner et al. (2003) conducted a chart review examining the association between total pre-hospital time and mortality. Charts were selected for patients who were transported directly to the study hospital and were either admitted to hospital or died in ED. Patients were excluded if there was incomplete data, more than one day between the time of injury and time of admission, CPR was initiated in the field, or the patient was transported from a correctional facility. Most of the data were extracted from the trauma registry. Univariate and multivariate analyses (logistic regression) were conducted. There were 1877 participants.
On univariate analysis the total pre-hospital time was longer in the survivors than the non-survivors (35.26 minutes versus 31.58 minutes, difference 3.69 minutes, 95% CI -.52-6.85 minutes). There was no association between total out of hospital time and mortality on multivariate analysis (OR 0.987, 0.97-1.00).
Limitations of the study included:
� the limitations associated with chart reviews including missing data and inconsistent recording of data
� the authors commented they expected the pre-hospital time to be randomly misclassified, thus diluting any association
� approximately 20% of the study population had to be omitted due to missing data, resulting in selection bias
� the design is susceptible to confounding although the use of logistic regression helps to control this.
Biewener et al. 2004
Biewener et al. (2004) studied four pathways for the transportation of polytrauma patients:
1. Helicopter transportation to a level 1 trauma centre (HEMS-UNI group).
2. Ambulance transportation to a level 1 trauma centre (AMB-UNI group).
3. Ambulance transportation to a level 2 or 3 trauma centre (AMB-REG group).
4. Ambulance transportation to a level 2 or 3 trauma centre followed by transfer to a level 1 trauma centre (INTER group).
In the context of this review, the first two categories were of interest. The AMB-REG group did not fulfil the criteria for definitive care and the pre-hospital times were not stated for the INTER group.
There were 403 patients in total, including 140 in the HEMS-UNI group and 70 in the AMB-UNI group. Inclusion was limited to patients with an ISS at least 16, alive at time of hospital arrival and had complete documentation of all patent data. Patients over 75 years were excluded as were patients with an ISS score over 67. There were no differences in age, gender or ISS across the groups.
The mean pre-hospital time in the HEMS-UNI and AMB-UNI groups were 90 minutes and 68 minutes respectively. There was no significant difference in mortality between the two groups on logistic regression (controlling for study group, age and ISS).
TRANSPORTATION OF EMERGENCY PATIENTS
72
Limitations of this study included:
� in relation to the review question of interest our primary interest is with pre-hospital time whereas the authors’ primary interest was with comparing different transport pathways. As a consequence there was no comparison between different pre-hospital times at an individual level. This also had the consequence of lack of control over other differences between study groups, such as aggressiveness of management during the pre-hospital phase.
� the study made use of registry collected data but there was no indication of the accuracy of data recording.
� it is noted that there were no cases of penetrating trauma within the study population.
Gao et al. 2006
A retrospective review of polytrauma patients was conducted in China (Gao et al. 2006). There were 15,340 eligible patients during the ten year study period (1993-2003). To be included there needed to be injuries to more than two ISS regions and at least one region needed to include an AIS of at least three. Data were extracted on sex, age, causes of injury, duration of preadmission and injured regions, shock state on admission, amount of blood transfusion, severity of injuries, method of diagnosis, therapeutic procedures. The chi square test was used in data analysis. Mortality was significantly higher in the group with a preadmission time of at least one hour (7.7% versus 3.9%, P<0.01).
Limitations of this study included:
� potential limitations of this type of retrospective review, including inconsistent recording of data (e.g. some may round pre-hospital time and others may not) and uncertainty about the accuracy of data
� no control of potential confounders (absence of multivariate analysis in this observational design)
� potential lack of applicability to other populations.
Hartl et al. 2006
Hartl et al. (2006) explored the effect of pre-hospital management decisions on early mortality following severe traumatic brain injury (TBI). A major focus was on the decision to indirectly transport patients to definitive care via an intermediate hospital. Nevertheless the investigators also examined the pre-hospital time and its influence on two week mortality. Patients were restricted to those with head injury with GCS<9 for at least six hours after injury and arrival at a level 1 or level 2 trauma centre within 24 hours of injury. More detail is provided in Table 16. Data were extracted from the TBI-trac registry. There was no significant association between pre-hospital time and two week mortality (OR for each minute increase in transport time 1.00, 95% CI 1.00, 1.00).
There were potential sources of bias:
� there were patient exclusions, some of which fulfilled the a priori eligibility criteria and some did not. Specifically from 1449 patients entered in the TBI-trac data base, 1123 were included in the study. From the list of exclusion criteria documented in the study methods, 210 of the 326 exclusions appeared to fulfil those pre-set criteria. There was also incomplete participation of the trauma centres throughout New York State with 54% of all trauma centres participating in the New York State quality improvement program (which was used as the source of trauma centres) being included in the study. These limitations indicate potential selection biases.
� while a multivariate model was developed that included some potential confounders other potential confounders may have been present in this observational study that were overlooked.
� there was no information presented on the accuracy of the registry data. Misclassification may have occurred due to for example coding errors. Misclassification of pre-hospital time may also have occurred if, for example there was a tendency to round times.
TRANSPORTATION OF EMERGENCY PATIENTS
73
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Pe
pe
et
al.
198
7)
USA
Co
ho
rt s
tud
y
Leve
l III-
2.
Stu
dy s
ett
ing
.
Su
bje
cts
with
pe
ne
tra
tin
g in
jurie
s
de
live
red
to
a s
ing
le r
eg
ion
al tr
au
ma
ce
ntr
e in
Ho
ust
on
, Te
xas.
Re
spo
nse
are
a
co
ve
rs c
lose
to
700 s
qu
are
mile
s a
nd
tra
nsp
ort
tim
es
to t
he
tra
um
a c
en
tre
ca
n e
xce
ed
30 m
inu
tes.
Pa
rtic
ipa
nts
:
498 c
on
sec
utive
pa
rtic
ipa
nts
Ba
selin
e m
ea
sure
me
nts
Ave
rag
e a
ge
31.3
ye
ars
Me
an
tra
um
a s
co
re 1
1.1
Me
an
ISS 2
0.2
Me
an
re
spo
nse
tim
e 5
.3 m
inu
tes
Me
an
sc
en
e t
ime
15.8
min
ute
s
Me
an
tra
nsp
ort
tim
e 1
1.7
min
ute
s
Me
an
to
tal p
re-h
osp
ita
l tim
e 3
2.6
min
ute
s
Inc
lu/e
xcl c
rite
ria
.
Pe
ne
tra
tin
g t
rau
ma
Syst
olic
BP
≤ 9
0m
mH
g
Tra
nsp
ort
ed
dire
ctly t
o B
en
Ta
ub
Ge
ne
ral H
osp
ita
l
Da
ta c
olle
ctio
n
Fire
De
pa
rtm
en
t re
co
rds
tim
es
of
rec
eip
t o
f c
all,
dis
pa
tch
of
pa
ram
ed
ics,
pa
ram
ed
ics’
arr
iva
l at
inc
ide
nt
loc
atio
n, le
av
ing
in
cid
en
t
loc
atio
n, a
nd
ho
spita
l arr
iva
l. Th
e
tota
l pre
-ho
spita
l tim
e (
TPT)
wa
s
de
fin
ed
as
the
tim
e f
rom
re
ce
ipt
of
the
ca
ll u
ntil th
e t
ime
of
arr
iva
l at
the
tra
um
a c
en
tre
.
Ou
tco
me
me
asu
res
Dis
ch
arg
ed
aliv
e f
orm
ho
spita
l
An
aly
sis
Pa
tie
nts
str
atifie
d in
to f
ou
r g
rou
ps
ba
sed
on
th
eir in
itia
l pre
-ho
spita
l
tra
um
a s
co
re (
1, 2-6
, 7
-11
, 12
-15
).
Ea
ch
of
the
se g
rou
ps
wa
s st
ud
ied
ind
ep
en
de
ntly in
re
latio
n t
o T
PT.
Fou
r g
rou
ps
of
TPT
we
re f
orm
ed
: 0
-
20 m
inu
tes,
21-3
0 m
inu
tes,
31
-40
min
ute
s a
nd
> 4
0 m
inu
tes.
All
pa
tie
nts
we
re a
lso
ass
ess
ed
in
term
s o
f th
eir p
rob
ab
ility
of
surv
iva
l
usi
ng
TR
ISS m
eth
od
olo
gy.
Su
rviv
al ra
tes
we
re c
om
pa
red
usi
ng
ch
i-sq
ua
re a
na
lysi
s (o
r Fi
she
r’s
exa
ct
test
wh
en
n<
75).
Co
ntin
uo
us
va
riab
les
we
re a
sse
sse
d u
sin
g
an
aly
sis
of
va
rian
ce
.
With
in t
he
fo
ur
tra
um
a s
co
re
gro
up
ing
s, t
he
re w
as
no
sig
nific
an
t
diffe
ren
ce
in s
urv
iva
l by T
PT
Tra
um
a s
co
re=
1
TPT
(Min
s)
Ob
serv
ed
(%)
Pre
dic
te
d (
%)
≤20
0
2
21-3
0
0
2
31-4
0
0
2
>40
0
2
Tra
um
a s
co
re=
2-6
TPT
(Min
s)
Ob
serv
ed
(%)
Pre
dic
te
d (
%)
≤20
14
14
21-3
0
31
24
31-4
0
24
28
>40
0
3
Tra
um
a s
co
re=
7-1
1
TPT
(Min
s)
Ob
serv
ed
(%)
Pre
dic
te
d (
%)
≤20
50
71
21-3
0
52
64
31-4
0
52
69
>40
69
70
Tra
um
a s
co
re=
12
-15
TPT
(Min
s)
Ob
serv
ed
(%)
Pre
dic
te
d (
%)
≤20
90
96
21-3
0
91
90
31-4
0
91
92
>40
91
91
Lim
ita
tio
ns
�
Ob
serv
atio
n s
tud
y is
su
sce
ptib
le t
o
co
nfo
un
din
g. Li
mite
d c
on
tro
l of
po
ten
tia
l co
nfo
un
din
g (
stra
tific
atio
n
by p
re-h
osp
ita
l tra
um
a s
co
re).
�
Tim
ing
of
BP
me
asu
rem
en
t u
nc
lea
r
an
d m
ay h
ave
re
sulte
d in
va
riab
le
ap
plic
atio
n o
f se
lec
tio
n c
rite
ria
.
�
Tra
um
a s
co
re is
a p
hysi
olo
gic
al
me
asu
re t
ha
t c
an
ch
an
ge
ove
r tim
e,
thu
s tim
e o
f m
ea
sure
me
nt
is c
ritic
al t
o
en
surin
g c
on
sist
en
cy in
gro
up
ing
�
Sm
all
sam
ple
s in
so
me
ce
lls li
mitin
g
po
we
r to
de
tec
t si
gn
ific
an
t
diffe
ren
ce
s a
cro
ss t
he
tim
e
ca
teg
orie
s.
�
Stu
dy li
mite
d t
o p
en
etr
atin
g in
jurie
s so
lac
ks
ge
ne
ralis
ab
ility
to
blu
nt
tra
um
a
an
d m
ed
ica
l em
erg
en
cie
s.
TRANSPORTATION OF EMERGENCY PATIENTS
74
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Pe
pe
et
al.
198
7)
USA
co
ntin
ue
d
Co
mm
en
ts
�
Aim
ed
to
exa
min
e t
he
re
latio
nsh
ip
be
twe
en
th
e s
urv
iva
l ra
tes
of
pa
tie
nts
with
pre
sum
ed
ha
em
orr
ha
gic
sh
oc
k
du
e t
o p
en
etr
atin
g in
jurie
s a
nd
th
e
tota
l pre
-ho
spita
l tim
e r
eq
uire
d t
o
ma
na
ge
an
d d
eliv
er
tho
se p
atie
nts
to
a s
ing
le r
eg
ion
al tr
au
ma
ce
ntr
e in
a
larg
e u
rba
n a
rea
.
�
Pa
ram
ed
ics
op
era
te u
nd
er
a
ma
na
ge
me
nt
pla
n.
Ke
y p
oin
ts f
or
pe
ne
tra
tin
g in
jurie
s in
clu
de
co
ntr
ol o
f
an
y s
ign
ific
an
t e
xte
rna
l ha
em
orr
ha
ge
,
ag
gre
ssiv
e a
irw
ay m
an
ag
em
en
t
(pre
fera
bly
by in
tub
atio
n),
larg
e b
ore
IV c
an
nu
latio
n e
n r
ou
te, p
atie
nts
pla
ce
d o
n b
ac
kb
oa
rds
an
d c
erv
ica
l
spin
e is
im
mo
bili
sed
. P
rim
ary
go
al i
s
rap
id e
va
cu
atio
n. P
atie
nt’
s c
on
ditio
n
is r
ad
ioe
d e
n r
ou
te.
�
Co
nse
cu
tive
pa
rtic
ipa
nts
se
lec
ted
.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
The
tim
e f
ac
tor
invo
lve
d in
ma
na
gin
g a
nd
tra
nsp
ort
ing
hyp
ote
nsi
ve
pe
ne
tra
tin
g in
jury
vic
tim
s d
ire
ctly t
o a
re
gio
na
l tra
um
a c
en
tre
do
es
no
t a
pp
ea
r to
be
re
late
d t
o a
n
ad
ve
rse
ou
tco
me
, a
t le
ast
du
rin
g t
he
first
ho
ur
of
inju
ry.
TRANSPORTATION OF EMERGENCY PATIENTS
75
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Sc
hill
er
et
al.
198
8)
USA
Re
tro
spe
ctive
co
ho
rt s
tud
y
Leve
l III-
2.
Stu
dy s
ett
ing
.
Pa
tie
nts
ad
mitte
d t
o t
he
tra
um
a c
en
tre
at
St
Jose
ph
’s H
osp
ita
l, P
ho
en
ix,
Arizo
na
du
rin
g 1
983-1
98
6.
Ap
pro
xim
ate
ly 8
00
Ca
teg
ory
1 t
rau
ma
pa
tie
nts
ad
mitte
d
an
nu
ally
.
Pa
rtic
ipa
nts
:
606 p
art
icip
an
ts w
ith
25
9 t
ran
spo
rte
d b
y
gro
un
d a
mb
ula
nc
e a
nd
347
by
he
lico
pte
r.
An
aly
ses
co
mp
arin
g g
rou
ps
at
ba
selin
e.
Me
an
ag
e (
ye
ars
):
Am
bu
lan
ce
31
He
lico
pte
r 3
0
Ma
le (
%)
Am
bu
lan
ce
74
He
lico
pte
r 7
8
Me
an
tra
um
a s
co
re
Am
bu
lan
ce
12.7
He
lico
pte
r 1
2.1
Me
an
GC
S
Am
bu
lan
ce
10.4
He
lico
pte
r 9
.6
Inc
lu/e
xcl c
rite
ria
.
ISS 2
0-3
9
Blu
nt
tra
um
a
Da
ta c
olle
ctio
n
Mo
de
of
tra
nsp
ort
atio
n,
site
of
orig
in, e
lap
sed
tim
e o
f th
e r
esc
ue
mis
sio
n, G
CS, a
ge
, g
en
de
r a
nd
inju
rie
s.
Ou
tco
me
me
asu
res
Ho
spita
l da
ys
Mo
rta
lity
An
aly
sis
Stu
de
nt’
s u
np
aire
d t
te
st, c
hi s
qu
are
test
Me
an
mis
sio
n t
ime
s (m
inu
tes)
Am
bu
lan
ce
39
He
lico
pte
r 5
0
Mo
rta
lity (
%)
Am
bu
lan
ce
13
He
lico
pte
r 1
8
P<
0.0
5
Ho
spita
l le
ng
th o
f st
ay (
da
ys)
Am
bu
lan
ce
26
He
lico
pte
r 2
6
Lim
ita
tio
ns
�
Tota
l pre
-ho
spita
l tim
e f
req
ue
ntly
mis
sin
g.
Wh
en
ne
ce
ssa
ry (
~1
5%
), t
his
wa
s e
stim
ate
d b
y d
ou
blin
g t
he
tim
e
fro
m t
he
sc
en
e a
nd
ad
din
g 1
0
min
ute
s. T
hu
s p
re-h
osp
ita
l tim
e is
sub
jec
t to
mis
cla
ssific
atio
n a
nd
th
e
dire
ctio
n o
f a
ny b
ias
is u
nc
lea
r
alth
ou
gh
th
e a
uth
ors
fe
lt t
his
wo
uld
un
de
rest
ima
te m
issi
on
tim
e in
th
e
he
lico
pte
r g
rou
p.
�
Ob
serv
atio
n s
tud
y is
su
sce
ptib
le t
o
co
nfo
un
din
g.
�
Ele
me
nts
of
ec
olo
gic
al a
na
lysi
s fo
r th
e
resu
lts
of
inte
rest
to
th
is r
ev
iew
.
Sp
ec
ific
ally
, th
ere
wa
s n
o c
om
pa
riso
n
be
twe
en
ind
ivid
ua
l tim
e d
ata
an
d
ou
tco
me
, ra
the
r th
e c
om
pa
riso
n w
as
be
twe
en
he
lico
pte
r a
nd
gro
un
d
tra
nsp
ort
atio
n.
�
Re
tro
spe
ctive
an
aly
sis.
�
Un
cle
ar
if c
on
sec
utive
pa
tie
nts
we
re
use
d.
�
No
do
cu
me
nta
tio
n a
bo
ut
the
exp
erie
nc
e a
nd
skill
s o
f th
e c
rew
s in
the
air v
ers
us
gro
un
d c
om
pa
riso
n.
�
No
do
cu
me
nta
tio
n o
f th
e b
asi
s fo
r
de
cid
ing
wh
eth
er
a h
elic
op
ter
or
gro
un
d a
mb
ula
nc
e s
ho
uld
be
dis
pa
tch
ed
.
TRANSPORTATION OF EMERGENCY PATIENTS
76
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Sc
hill
er
et
al.
198
8)
USA
co
ntin
ue
d
Co
mm
en
ts
�
Prim
ary
aim
wa
s to
ass
ess
wh
eth
er
tra
nsp
ort
atio
n o
f p
atie
nts
with
ISS 2
0-
39 b
y h
elic
op
ter
resu
lte
d in
im
pro
ve
d
surv
iva
l wh
en
co
mp
are
d w
ith
gro
un
d
tra
nsp
ort
atio
n.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
The
re is
no
su
rviv
al a
dva
nta
ge
in t
he
he
lico
pte
r tr
an
spo
rte
d g
rou
p in
an
urb
an
are
a w
ith
a s
op
his
tic
ate
d p
re-h
osp
ita
l ca
re
syst
em
. P
atie
nts
of
rura
l orig
in d
ese
rve
furt
he
r st
ud
y.
TRANSPORTATION OF EMERGENCY PATIENTS
77
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Slo
an
et
al.
19
89
)
USA
Co
ho
rt s
tud
y
Leve
l III-
2.
Stu
dy s
ett
ing
.
Stu
dy in
Ch
ica
go
th
at
co
mp
are
d
tra
um
a p
atie
nts
tra
nsp
ort
ed
dire
ctly t
o
the
ne
are
st le
ve
l 1 t
rau
ma
ce
ntr
e w
ith
pa
tie
nts
wh
o h
ad
to
byp
ass
oth
er
em
erg
en
cy d
ep
art
me
nts
to
ge
t to
th
e
ne
are
st le
ve
l 1 t
rau
ma
ce
ntr
e S
tud
y
pe
riod
: M
arc
h t
o N
ove
mb
er
19
87.
Pa
rtic
ipa
nts
(n
=2
03
):
Inte
rve
ntio
n (
n=
66
).
Dire
ct
tra
nsp
ort
gro
up
. Ta
ke
n d
irec
tly t
o
Co
ok C
ou
nty
Ho
spita
l with
ou
t
byp
ass
ing
an
y o
the
r h
osp
ita
ls.
Co
mp
ara
tor
(n=
13
7).
Re
qu
ire
d h
osp
ita
l byp
ass
. P
atie
nts
byp
ass
ed
oth
er
ho
spita
ls o
n r
ou
te t
o
Co
ok C
ou
nty
Ho
spita
l.
Ba
selin
e a
na
lysi
s
Ave
rag
e a
ge
26 y
ea
rs
Ma
le 8
3%
Blu
nt
tra
um
a 5
7%
Op
era
tive
tra
um
a 6
3%
Ave
rag
e ISS 1
7
Ho
spita
l tra
um
a s
co
re 1
3
Ave
rag
e t
ota
l ru
n t
ime
35 m
inu
tes
Ave
rag
e h
osp
ita
l sta
y 1
2 d
ays
Inc
lu/e
xcl c
rite
ria
.
Fell
into
on
e o
f th
e f
ollo
win
g t
hre
e
ca
teg
orie
s:
1.
Life
th
rea
ten
ing
inju
ry,
inc
lud
ing
tra
um
atic
arr
est
,
pe
ne
tra
tin
g n
ec
k t
rau
ma
,
an
d/o
r b
lun
t o
r p
en
etr
atin
g
ch
est
or
ab
do
min
al tr
au
ma
with
syst
olic
BP
< 1
00
mm
Hg
.
2.
Fie
ld t
rau
ma
sc
ore
≤ 1
2.
3.
Lim
b t
hre
ate
nin
g in
jury
.
Exc
lud
ed
: 1. p
atie
nts
wh
o a
rriv
ed
at
Co
ok C
ou
nty
Ho
spita
l in
tra
um
atic
arr
est
wh
o w
ere
un
ab
le t
o b
e
resu
scita
ted
. 2. p
atie
nts
with
mis
sin
g
ou
tco
me
da
ta.
Da
ta c
olle
ctio
n
Tota
l ru
n t
ime
wa
s th
e t
ime
fro
m
Ch
ica
go
Fire
De
pa
rtm
en
t (C
FD
)
dis
pa
tch
to
arr
iva
l at
tra
um
a
ce
ntr
e. O
ve
rall
pre
-ho
spita
l tim
e
als
o in
clu
de
d d
ela
y t
ime
fro
m t
ime
of
inju
ry t
o C
FD d
isp
atc
h.
Re
gis
try d
ata
use
d t
o e
xtr
ac
t
me
ch
an
ism
of
inju
ry,
initia
l h
osp
ita
l
tra
um
a s
co
re, e
stim
ate
d
ab
bre
via
ted
inju
ry s
ca
le a
nd
inju
ry
seve
rity
sc
ore
.
Ou
tco
me
me
asu
res
Su
rviv
al
An
aly
sis
Pro
po
rtio
ns
co
mp
are
d b
y c
hi
squ
are
te
st. Stu
de
nt’
s t
test
use
d t
o
co
mp
are
diffe
ren
ce
be
twe
en
me
an
s.
Co
mp
aris
on
of
mo
rta
lity a
nd
surv
iva
l gro
up
s
Tota
l ru
n t
ime
(m
inu
tes)
:
Mo
rta
lity g
rou
p 3
2
Su
rviv
al g
rou
p 3
5
no
sig
nific
an
t d
iffe
ren
ce
Lim
ita
tio
ns
�
Ob
serv
atio
n s
tud
y is
su
sce
ptib
le t
o
co
nfo
un
din
g. M
ultiv
aria
te a
na
lysi
s
wa
s n
ot
co
nd
uc
ted
th
us
furt
he
r
limitin
g c
on
tro
l ove
r p
ote
ntia
l
co
nfo
un
de
rs (
alth
ou
gh
th
ere
we
re n
o
sig
nific
an
t d
iffe
ren
ce
s in
ba
selin
e
da
ta b
etw
ee
n d
irec
t a
nd
byp
ass
pa
tie
nts
).
�
Sm
all
nu
mb
er
of
de
ath
s (n
=29
)
red
uc
ing
po
we
r o
f th
e s
tud
y.
�
Ac
cu
rac
y o
f tim
e d
ata
un
ce
rta
in.
�
Inju
ry s
eve
rity
sc
ore
on
ly k
no
wn
fo
r 1
90
of
the
203 p
atie
nts
.
�
Me
asu
rem
en
t o
f tr
au
ma
sc
ore
co
nd
uc
ted
on
ho
spita
l arr
iva
l ra
the
r
tha
n o
n s
ce
ne
.
�
Me
ch
an
ism
of
tra
um
a d
oc
um
en
ted
in
196 o
f 20
3 p
atie
nts
.
�
Un
suc
ce
ssfu
lly r
esu
scita
ted
tra
um
atic
arr
est
wa
s th
e r
ea
son
fo
r e
xclu
sio
n in
48 (
19%
) w
ith
hig
he
r p
rop
ort
ion
exc
lud
ed
fo
r th
is r
ea
son
in d
irec
t
tra
nsp
ort
gro
up
(28
% v
ers
us
14%
,
P<
0.0
5).
Se
ve
n p
atie
nts
exc
lud
ed
du
e
to in
ad
eq
ua
te o
utc
om
e d
ata
.
Co
mm
en
ts
�
Stu
die
d t
he
in
flu
en
ce
of
ho
spita
l
byp
ass
on
pre
-ho
spita
l tim
es
an
d le
ve
l
1 t
rau
ma
pa
tie
nt
surv
iva
l.
�
Stu
dy h
ad
90%
po
we
r to
de
tec
t a
diffe
ren
ce
in s
urv
iva
l of
6%
or
mo
re.
TRANSPORTATION OF EMERGENCY PATIENTS
78
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Slo
an
et
al.
19
89
)
USA
co
ntin
ue
d
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
The
urb
an
use
of
ho
spita
l byp
ass
do
es
no
t
de
cre
ase
tra
um
a p
atie
nt
surv
iva
l in
th
ose
wh
o a
rriv
e a
t th
e t
rau
ma
ce
ntr
e w
ith
vita
l
sig
ns.
We
als
o c
on
clu
de
th
at
att
em
pts
sho
uld
be
ma
de
to
sh
ort
en
de
lay in
CFD
co
nta
ct
to r
ed
uc
e o
ve
rall
pre
-ho
spita
l tim
e
an
d m
axim
ise
pa
tie
nt
surv
iva
l. Fu
rth
er
stu
dy
in b
oth
urb
an
an
d r
ura
l se
ttin
gs
sho
uld
de
term
ine
wh
eth
er
byp
ass
allo
ws
de
ath
to
oc
cu
r d
urin
g t
ran
spo
rt a
nd
wh
eth
er
lon
ge
r
byp
ass
tim
es
influ
en
ce
ove
rall
pre
-ho
spita
l
tim
e a
nd
mo
rta
lity.
TRANSPORTATION OF EMERGENCY PATIENTS
79
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Sc
hw
art
z e
t a
l. 1
990
)
USA
Re
tro
spe
ctive
co
ho
rt s
tud
y
Leve
l III-
2.
Stu
dy s
ett
ing
.
EM
S s
yst
em
in C
on
ne
ctic
ut:
60
% o
f
po
pu
latio
n c
ove
red
by g
rou
nd
am
bu
lan
ce
an
d e
ntire
po
pu
latio
n c
an
be
re
ac
he
d b
y a
ir a
mb
ula
nc
e.
Pa
rtic
ipa
nts
:
126 p
atie
nts
, 93 t
ran
spo
rte
d b
y a
ir a
nd
33 b
y g
rou
nd
.
An
aly
ses
co
mp
arin
g g
rou
ps
at
ba
selin
e.
Ave
rag
e r
esp
on
se t
ime
(tim
e t
o s
ce
ne
)
Air 3
4 m
inu
tes
Gro
un
d 6
min
ute
s
Ave
rag
e s
ce
ne
tim
e
Air 2
2 m
inu
tes
Gro
un
d 1
8 m
inu
tes
Ave
rag
e t
ime
to
ho
spita
l
Air 10 m
inu
tes
Gro
un
d 1
1 m
inu
tes
Ave
rag
e t
ota
l pre
-ho
spita
l tim
e
Air 6
5 m
inu
tes
Gro
un
d 3
4 m
inu
tes
Inc
lu/e
xcl c
rite
ria
.
Mu
ltis
yst
em
inju
red
pa
tie
nts
Blu
nt
tra
um
a
Tra
nsp
ort
ed
dire
ctly f
rom
sc
en
e t
o
Ha
rtfo
rd H
osp
ita
l
Tre
ate
d b
y g
rou
nd
pa
ram
ed
ics
or
LIFE
STA
R.
Da
ta c
olle
ctio
n
Da
ta o
bta
ine
d f
rom
th
ree
se
pa
rate
co
mp
ute
rise
d d
ata
ma
na
ge
me
nt
reg
istr
ies
an
d m
ed
ica
l re
co
rds.
Pa
ram
ed
ic a
nd
LIF
E S
TAR
re
gis
trie
s
co
nta
in d
ata
on
pre
-ho
spita
l tim
es,
inte
rve
ntio
ns
an
d in
div
idu
als
wh
o
pe
rfo
rme
d t
he
pro
ce
du
res.
Tra
um
a
reg
istr
y c
on
tain
s in
pa
tie
nt
da
ta
inc
lud
ing
len
gth
of
sta
y. P
atie
nt
ch
art
s w
ere
exa
min
ed
fo
r o
utc
om
e
an
d c
on
firm
atio
n o
f re
gis
try d
ata
.
Da
ta c
olle
cte
d in
clu
de
d a
ge
, se
x,
mo
de
of
tra
nsp
ort
, m
ec
ha
nis
m o
f
inju
ry, p
re-h
osp
ita
l tim
es,
me
dic
al
inte
rve
ntio
ns,
tra
um
a s
co
re, IS
S a
nd
ou
tco
me
. Ti
me
of
dis
pa
tch
wa
s
use
d t
o a
pp
roxim
ate
th
e t
ime
of
inju
ry.
An
aly
sis
An
aly
sis
of
pre
-ho
spita
l tim
es
wa
s
ma
de
by t
he
t t
est
. TR
ISS m
eth
od
s
we
re u
sed
to
co
mp
are
su
rviv
al
be
twe
en
th
e t
wo
gro
up
s.
Su
rviv
al (Z
sc
ore
co
mp
are
d w
ith
MTO
S d
ata
set)
Air a
mb
ula
nc
e
Z=2.2
3
Sig
nific
an
tly im
pro
ve
d c
om
pa
red
with
MTO
S c
oh
ort
Gro
un
d a
mb
ula
nc
e
Z=
-2.6
9
Sig
nific
an
tly w
ors
e t
ha
n M
TOS
co
ho
rt
Lim
ita
tio
ns
�
Diffe
ren
ce
s in
cre
win
g b
etw
ee
n t
he
air
an
d g
rou
nd
se
rvic
es.
Th
ere
fore
,
diffic
ult t
o e
sta
blis
h if
diffe
ren
ce
in
ou
tco
me
wa
s d
ue
to
th
e d
iffe
ren
ce
in
pre
-ho
spita
l tim
e,
the
cre
w m
ix o
r
som
eth
ing
els
e.
The
re w
ere
diffe
ren
ce
s in
pro
ce
du
res
pe
rfo
rme
d
be
twe
en
th
e t
wo
gro
up
s (t
he
air
gro
up
wa
s m
ore
inte
rve
ntio
na
l).
On
the
ba
sis
tha
t th
e p
oo
rer
ou
tco
me
wa
s a
sso
cia
ted
with
th
e g
rou
p w
ith
sho
rte
r p
re-h
osp
ita
l tim
es
it s
ee
ms
like
ly t
ha
t sk
ill m
ix w
as
a b
igg
er
co
ntr
ibu
tor
tha
n t
he
pre
-ho
spita
l tim
e.
�
Ob
serv
atio
n s
tud
y is
su
sce
ptib
le t
o
co
nfo
un
din
g. M
ultiv
aria
te a
na
lysi
s
wa
s n
ot
co
nd
uc
ted
th
us
furt
he
r
limitin
g c
on
tro
l ove
r p
ote
ntia
l
co
nfo
un
de
rs
�
No
do
cu
me
nta
tio
n o
f th
e b
asi
s fo
r
de
cid
ing
wh
eth
er
a h
elic
op
ter
or
gro
un
d a
mb
ula
nc
e s
ho
uld
be
dis
pa
tch
ed
, th
ere
fore
po
ten
tia
l
sele
ctio
n b
ias
in b
etw
ee
n g
rou
p
co
mp
ariso
ns.
�
M s
tatist
ic c
om
pa
rin
g m
atc
h b
etw
ee
n
the
ac
tua
l da
ta a
nd
th
e r
efe
ren
ce
da
ta w
as
no
t p
rese
nte
d s
o t
he
re m
ay
ha
ve
be
en
a p
oo
r m
atc
h b
etw
ee
n
da
ta.
The
refo
re z
sta
tist
ic d
ata
ma
y
be
un
relia
ble
. W
sta
tist
ic a
lso
no
t
pre
sen
ted
.
�
Ac
cu
rac
y o
f d
ata
extr
ac
ted
fro
m
reg
istr
ies
wa
s n
ot
do
cu
me
nte
d
Ele
me
nts
of
ec
olo
gic
al a
na
lysi
s fo
r th
e
resu
lts
of
inte
rest
to
th
is r
ev
iew
. Sp
ec
ific
ally
,
the
re w
as
no
co
mp
aris
on
be
twe
en
ind
ivid
ua
l tim
e d
ata
an
d o
utc
om
e,
rath
er
the
co
mp
ariso
n w
as
be
twe
en
air
an
d
gro
un
d t
ran
spo
rta
tio
n
TRANSPORTATION OF EMERGENCY PATIENTS
80
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Sc
hw
art
z e
t a
l. 1
990
)
USA
co
ntin
ue
d
Co
mm
en
ts
�
Co
mp
are
d a
ho
spita
l ba
sed
ae
rom
ed
ica
l pro
gra
mm
e t
o a
gro
un
d
pa
ram
ed
ic s
erv
ice
in o
rde
r to
de
term
ine
wh
eth
er
pre
-ho
spita
l tim
e
or
pre
-ho
spita
l ca
re is
th
e m
ajo
r
co
ntr
ibu
tor
tow
ard
s su
rviv
al.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
Sin
ce
th
e s
ce
ne
tim
e o
f b
oth
ae
rom
ed
ica
l
an
d g
rou
nd
se
rvic
es
we
re s
imila
r, t
he
imp
rove
d s
urv
iva
l of
the
air
pa
tie
nts
ma
y b
e
du
e t
o t
he
te
ch
nic
al i
nte
rve
ntio
n
pro
ce
du
res
pe
rfo
rme
d.
TRANSPORTATION OF EMERGENCY PATIENTS
81
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Sa
mp
alis
et
al.
19
92)
Ca
na
da
Re
tro
spe
ctive
co
ho
rt s
tud
y
Leve
l III-
2.
Stu
dy s
ett
ing
.
All
EM
S in
Mo
ntr
ea
l is
co
ntr
olle
d b
y
Urg
en
ce
s-sa
nte
. U
rge
nc
es-
san
te
co
ord
ina
tes
pre
-ho
spita
l em
erg
en
cy
serv
ice
s, c
oo
rdin
ate
s a
mb
ula
nc
e
tra
nsp
ort
, p
lan
s e
me
rge
nc
y r
oo
m u
se in
co
llab
ora
tio
n w
ith
ho
spita
ls a
nd
co
ntr
ols
ad
mittin
g p
olic
ies
an
d d
ata
ac
cu
mu
latio
n o
n t
he
re
gio
na
l
ava
ilab
ility
of
ho
spita
l be
ds.
Cre
ws
att
en
din
g a
re d
ep
en
de
nt
on
th
e
seve
rity
of
inju
ry. Fo
r c
ritic
ally
ill,
a
ph
ysi
cia
n is
inc
lud
ed
wh
ere
as
in le
ss
seve
re c
ase
s a
n a
mb
ula
nc
e a
nd
em
erg
en
cy m
ed
ica
l te
ch
nic
ian
will
be
dis
pa
tch
ed
.
Pa
rtic
ipa
nts
:
Sa
mp
le 1
: 32
93 (
29
56 w
ith
min
or
tra
um
a
an
d 3
37 w
ith
ma
jor
tra
um
a)
Sa
mp
le 2
: 92
8
Sa
mp
le 3
: 35
5.
Ba
selin
e a
na
lyse
s
Me
an
ag
e 3
3 y
ea
rs (
ran
ge
0-8
4)
Inju
ry s
ust
ain
ed
at
ho
me
26%
Mo
tor
ve
hic
le c
rash
37%
He
ad
inju
ry 3
7%
Ch
est
in
jury
29%
Ab
do
min
al i
nju
ry 2
5%
Pe
ne
tra
tin
g in
jury
22%
Me
an
ISS 1
3.7
(ra
ng
e 1
-59
)
Me
an
to
tal p
re-h
osp
ita
l tim
e 3
6 m
inu
tes
Me
an
tim
e o
n s
ce
ne
20 m
inu
tes
De
ath
s 70/3
55
Inc
lu/e
xcl c
rite
ria
.
Thre
e s
tud
y s
am
ple
s.
Sa
mp
le 1
. R
etr
ieve
d r
ec
ord
s o
f 47
22
of
55
53 p
atie
nts
tre
ate
d b
y a
ph
ysi
cia
n a
t th
e s
ce
ne
, 147
7
pa
tie
nts
fo
r w
hic
h a
nu
rse
req
ue
ste
d a
ph
ysi
cia
n b
ut
no
ne
we
re a
va
ilab
le a
nd
of
977 p
atie
nts
for
wh
ich
on
ly a
n E
MT
wa
s
req
ue
ste
d a
nd
dis
pa
tch
ed
. Th
e
latt
er
gro
up
wa
s se
lec
ted
by
ran
do
mly
sa
mp
ling
on
e o
f e
igh
t
da
ys
for
the
last
se
ve
n m
on
ths
of
the
stu
dy. Exc
lusi
on
s: d
ec
lare
d
de
ad
at
sce
ne
or
no
t ta
ke
n t
o
ho
spita
l.
Sa
mp
le 2
. A
ra
nd
om
10%
sub
sam
ple
of
pa
tie
nts
with
min
or
tra
um
a (
Pre
-ho
spita
l in
de
x ≤3
) a
nd
tre
ate
d b
y a
ph
ysi
cia
n, a
ll p
atie
nts
with
ma
jor
tra
um
a a
nd
on
e 1
3%
ran
do
m s
am
ple
of
pa
tie
nts
tre
ate
d
by E
MT
on
ly.
Sa
mp
le 3
(fin
al s
am
ple
). D
erive
d
fro
m s
am
ple
2. Se
lec
ted
pa
tie
nts
aliv
e a
t th
e t
ime
th
e a
mb
ula
nc
e
arr
ive
d a
t th
e s
ce
ne
, tr
an
spo
rte
d t
o
a h
osp
ita
l by a
n U
rge
nc
es-
san
te
am
bu
lan
ce
an
d o
ne
of:
ad
mitte
d
to h
osp
ita
l, h
ad
su
rge
ry, tr
ea
ted
in
ICU
or
on
site
pre
-ho
spita
l in
de
x>3.
Ou
tco
me
me
asu
res
Mo
rta
lity
Ove
rall
resu
lts
(ob
serv
ed
co
mp
are
d
with
exp
ec
ted
ba
sed
on
MTO
S
po
pu
latio
n a
s re
fere
nc
e)
Z=
6.7
7
P=
0.0
00
1
SM
R 1
.81 (
95%
CI 1.4
2-2
.21
)
Bo
th in
dic
ate
hig
he
r o
bse
rve
d t
ha
n
exp
ec
ted
de
ath
s.
Re
sults
by t
ota
l pre
-ho
spita
l tim
e
Pre
-ho
spita
l tim
e 0
-60 m
inu
tes
SM
R (
ob
serv
ed
co
mp
are
d w
ith
exp
ec
ted
): 1
.56 (
95
% C
I 1.1
3-1
.97
)
Z=
3.9
2
Pre
-ho
spita
l tim
e >
60
min
ute
s
SM
R (
ob
serv
ed
co
mp
are
d w
ith
exp
ec
ted
): 1
0.0
(95
% C
I 2.9
6-1
9.9
6)
Z=
5.0
0
SM
R r
atio
(p
re-h
osp
ita
l tim
e 0
-60
min
ute
s ve
rsu
s >
60 m
inu
tes)
(95%
CI 1.6
9-1
7.3
7)
Ind
ica
tin
g in
cre
ase
d e
xce
ss
mo
rta
lity in
th
e lo
ng
er
pre
-ho
spita
l
tim
e g
rou
p.
Ad
just
ed
od
ds
ratio
(95%
CI)
fo
r p
re-
ho
spita
l tim
e >
60 m
inu
tes
co
mp
are
d w
ith
0-6
0 m
inu
tes:
OR
29.9
(2
.7-3
3.3
)
Co
ntr
olle
d f
or
pre
-ho
spita
l cre
w
mix
, in
-ho
spita
l ca
re le
ve
l an
d ISS.
Lim
ita
tio
ns
�
Co
nfu
sin
g s
am
plin
g a
pp
roa
ch
. It
wa
s
un
cle
ar
if c
om
po
ne
nts
of
sam
ple
1
we
re r
an
do
mly
se
lec
ted
– s
pe
cific
ally
the
re w
as
no
do
cu
me
nta
tio
n a
bo
ut
ho
w t
he
pa
tie
nts
tre
ate
d a
t th
e s
ce
ne
by a
ph
ysi
cia
n w
ere
se
lec
ted
o
r
wh
eth
er
the
147
7 c
ase
s w
he
re a
nu
rse
req
ue
ste
d a
ph
ysi
cia
n t
o a
tte
nd
th
e
sce
ne
bu
t n
on
e w
ere
ava
ilab
le
rep
rese
nte
d t
he
en
tire
co
ho
rt o
r
wh
eth
er
som
e u
nd
esc
ribe
d s
ele
ctio
n
pro
ce
ss a
pp
lied
. O
n t
his
ba
sis
sele
ctio
n b
ias
ca
nn
ot
be
exc
lud
ed
. It
wa
s u
nc
lea
r if s
am
plin
g r
ule
s w
ere
se
t
be
fore
se
lec
tin
g t
he
sa
mp
le.
�
Furt
he
r so
urc
es
of
sele
ctio
n b
ias
am
on
gst
so
me
exc
lusi
on
s. F
or
exa
mp
le, 30 o
f 38
5 p
atie
nts
we
re
exc
lud
ed
fro
m s
am
ple
3 d
ue
to
ho
spita
l ch
art
s b
ein
g n
ot
ava
ilab
le.
�
M s
tatist
ic c
om
pa
rin
g m
atc
h b
etw
ee
n
the
ac
tua
l da
ta a
nd
th
e r
efe
ren
ce
da
ta w
as
no
t p
rese
nte
d (
alth
ou
gh
in
the
qu
est
ion
an
d a
nsw
er
sec
tio
n
Sa
mp
alis
sta
ted
it
wa
s n
ot
sig
nific
an
tly
low
er
tha
n 0
.9)
so t
he
re m
ay h
ave
be
en
a p
oo
r m
atc
h b
etw
ee
n d
ata
.
The
refo
re z
sta
tist
ic d
ata
ma
y b
e
un
relia
ble
.
TRANSPORTATION OF EMERGENCY PATIENTS
82
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Sa
mp
alis
et
al.
19
92)
Ca
na
da
co
ntin
ue
d
An
aly
sis
Two
me
tho
ds
use
d t
o c
om
pa
re t
he
ob
serv
ed
mo
rta
lity w
ith
th
e
exp
ec
ted
mo
rta
lity (
ba
sed
on
th
e
MTO
S p
op
ula
tio
n).
First
wa
s
est
ima
tin
g t
he
Z s
co
re a
nd
th
e
sec
on
d b
y e
stim
atin
g t
he
sta
nd
ard
ise
d m
ort
alit
y r
atio
(SM
R).
Thre
e s
tep
s to
th
e d
ata
an
aly
sis:
1.
The
Z s
co
re a
nd
th
e S
MR
we
re
est
ima
ted
in
sa
mp
le 3
.
2.
Aim
ed
to
eva
lua
te t
he
diffe
ren
ce
be
twe
en
exp
ec
ted
an
d o
bse
rve
d d
ea
ths
in
diffe
ren
t st
rata
de
fin
ed
to
rep
rese
nt
pre
-ho
spita
l ca
re,
in-
ho
spita
l ca
re a
nd
to
tal p
re-
ho
spita
l tim
e. Z s
co
res
an
d
SM
Rs
we
re e
stim
ate
d f
or
ea
ch
of
the
se s
tra
ta.
3.
Aim
ed
to
pe
rfo
rm a
dju
ste
d
co
mp
ariso
ns
of
the
SM
Rs
in
diffe
ren
t le
ve
ls o
f th
e v
aria
ble
s
de
scrib
ed
ab
ove
. Lo
gis
tic
reg
ress
ion
wa
s u
sed
in t
his
an
aly
sis.
Th
e m
od
el c
om
pa
red
the
ou
tco
me
ra
te in
on
e le
ve
l
of
an
in
de
pe
nd
en
t va
riab
le
with
th
e r
ate
exp
ec
ted
ac
co
rdin
g t
o in
dire
ct
sta
nd
ard
isa
tio
n w
hile
co
ntr
olli
ng
fo
r th
e e
ffe
ct
of
oth
er
co
va
ria
tes.
�
Ob
serv
atio
n s
tud
y is
su
sce
ptib
le t
o
co
nfo
un
din
g t
ho
ug
h m
ultiv
aria
te
an
aly
sis
wa
s c
on
du
cte
d w
hic
h is
an
imp
rove
me
nt
on
oth
er
stu
die
s.
�
Pre
-ho
spita
l tim
e d
ata
re
stric
ted
to
270 o
f 35
5 (
76%
) w
ith
co
mp
lete
da
ta.
�
On
ly 1
3 p
atie
nts
with
a p
re-h
osp
ita
l
tim
e >
60
min
ute
s so
de
alin
g w
ith
sma
ll p
atie
nt
nu
mb
ers
in t
his
gro
up
.
Co
mm
en
ts
�
Prim
ary
aim
wa
s to
ap
ply
Flo
ra’s
Z
sta
tist
ic a
nd
in
dire
ct
sta
nd
ard
isa
tio
n
to t
he
MTO
S in
a s
am
ple
of
seve
rely
inju
red
pa
tie
nts
. A
se
co
nd
aim
wa
s to
ass
ess
th
e a
sso
cia
tio
n b
etw
ee
n p
re-
ho
spita
l an
d in
-ho
spita
l co
mp
on
en
ts
of
the
Mo
ntr
ea
l EM
S w
ith
th
e S
MR
in
this
sa
mp
le o
f tr
au
ma
vic
tim
s.
�
Sa
mp
ling
ha
d t
he
aim
of
sele
ctin
g
pa
tie
nts
with
se
ve
re b
ut
surv
iva
ble
inju
rie
s.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
Sta
nd
ard
isa
tio
n t
o t
he
MTO
S p
op
ula
tio
n
ind
ica
ted
a s
ign
ific
an
tly h
igh
ove
rall
exc
ess
mo
rta
lity in
th
e M
on
tre
al s
am
ple
. B
ein
g
tre
ate
d in
a le
ve
l I o
r le
ve
l II c
om
pa
tib
le
ho
spita
l wa
s a
sso
cia
ted
with
low
er
exc
ess
mo
rta
lity.
Tota
l pre
-ho
spita
l tim
e o
ve
r 60
min
ute
s w
as
ass
oc
iate
d w
ith
a s
ign
ific
an
t
inc
rea
se in
exc
ess
mo
rta
lity.
TRANSPORTATION OF EMERGENCY PATIENTS
83
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Sa
mp
alis
et
al.
19
93)
Ca
na
da
Ca
se c
on
tro
l
stu
dy
Leve
l III-
2
Stu
dy s
ett
ing
.
All
EM
S in
Mo
ntr
ea
l is
co
ntr
olle
d b
y
Urg
en
ce
s-sa
nte
. U
rge
nc
es-
san
te
co
ord
ina
tes
pre
-ho
spita
l em
erg
en
cy
serv
ice
s, c
oo
rdin
ate
s a
mb
ula
nc
e
tra
nsp
ort
, p
lan
s e
me
rge
nc
y r
oo
m u
se in
co
llab
ora
tio
n w
ith
ho
spita
ls a
nd
co
ntr
ols
ad
mittin
g p
olic
ies
an
d d
ata
ac
cu
mu
latio
n o
n t
he
re
gio
na
l
ava
ilab
ility
of
ho
spita
l be
ds.
Cre
ws
att
en
din
g a
re d
ep
en
de
nt
on
th
e
seve
rity
of
inju
ry. Fo
r c
ritic
ally
ill,
a
ph
ysi
cia
n is
inc
lud
ed
wh
ere
as
in le
ss
seve
re c
ase
s a
n a
mb
ula
nc
e a
nd
em
erg
en
cy m
ed
ica
l te
ch
nic
ian
will
be
dis
pa
tch
ed
.
Pa
rtic
ipa
nts
:
Ca
ses
72
Co
ntr
ols
288
Ba
selin
e a
na
lyse
s.
Me
an
ag
e 3
3.9
ye
ars
Ma
les
71%
At
lea
st o
ne
co
mo
rbid
co
nd
itio
n 1
2%
Mo
tor
ve
hic
le c
rash
32%
Tota
l pre
-ho
spita
l tim
e 3
5.6
min
ute
s
Inc
lu/e
xcl c
rite
ria
.
Thre
e s
tud
y s
am
ple
s.
Sa
mp
le 1
. R
etr
ieve
d r
ec
ord
s o
f 47
22
of
55
53 p
atie
nts
tre
ate
d b
y a
ph
ysi
cia
n a
t th
e s
ce
ne
, 147
7
pa
tie
nts
fo
r w
hic
h a
nu
rse
req
ue
ste
d a
ph
ysi
cia
n b
ut
no
ne
we
re a
va
ilab
le a
nd
of
977 p
atie
nts
for
wh
ich
on
ly a
n E
MT
wa
s
req
ue
ste
d a
nd
dis
pa
tch
ed
. Th
e
latt
er
gro
up
wa
s se
lec
ted
by
ran
do
mly
sa
mp
ling
on
e o
f e
igh
t
da
ys
for
the
last
se
ve
n m
on
ths
of
the
stu
dy. Exc
lusi
on
s: d
ec
lare
d
de
ad
at
sce
ne
or
no
t ta
ke
n t
o
ho
spita
l.
Sa
mp
le 2
. A
ra
nd
om
10%
sub
sam
ple
of
pa
tie
nts
with
min
or
tra
um
a (
Pre
-ho
spita
l in
de
x ≤3
) a
nd
tre
ate
d b
y a
ph
ysi
cia
n, a
ll p
atie
nts
with
ma
jor
tra
um
a a
nd
on
e 1
3%
ran
do
m s
am
ple
of
pa
tie
nts
tre
ate
d
by E
MT
on
ly.
Od
ds
of
6 d
ay s
urv
iva
l (p
re-h
osp
ita
l
tim
e ≤
60 m
inu
tes
ve
rsu
s >
60
min
ute
s)
OR
2.0
9 (
95%
CI 0.6
7-6
.29)
Ad
just
ed
od
ds
of
6 d
ay s
urv
iva
l (p
re-h
osp
ita
l tim
e ≤
60
min
ute
s
ve
rsu
s >
60 m
inu
tes)
OR
3.0
1 (
95%
CI 1.2
7-5
.06)
Ad
just
ed
fo
r a
ge
, IS
S, M
VC
, fire
arm
,
leve
l of
pre
-ho
spita
l an
d in
ho
spita
l
ca
re.
Re
sults
ind
ica
te in
cre
ase
d o
dd
s o
f
surv
iva
l be
yo
nd
6 d
ays
with
a p
re-
ho
spita
l tim
e <
60 m
inu
tes.
Lim
ita
tio
ns
�
Co
nfu
sin
g s
am
plin
g a
pp
roa
ch
. It
wa
s
un
cle
ar
if c
om
po
ne
nts
of
sam
ple
1
we
re r
an
do
mly
se
lec
ted
– s
pe
cific
ally
the
re w
as
no
do
cu
me
nta
tio
n a
bo
ut
ho
w t
he
pa
tie
nts
tre
ate
d a
t th
e s
ce
ne
by a
ph
ysi
cia
n w
ere
se
lec
ted
or
wh
eth
er
the
147
7 c
ase
s w
he
re “
a
nu
rse
re
qu
est
ed
a p
hysi
cia
n t
o a
tte
nd
the
sc
en
e b
ut
no
ne
we
re a
va
ilab
le”
rep
rese
nte
d t
he
en
tire
co
ho
rt o
r
wh
eth
er
som
e u
nd
esc
ribe
d s
ele
ctio
n
pro
ce
ss a
pp
lied
. O
n t
his
ba
sis
sele
ctio
n b
ias
ca
nn
ot
be
exc
lud
ed
. It
wa
s u
nc
lea
r if s
am
plin
g r
ule
s w
ere
se
t
be
fore
se
lec
tin
g t
he
sa
mp
le.
�
Furt
he
r so
urc
es
of
sele
ctio
n b
ias
am
on
gst
so
me
exc
lusi
on
s. F
or
exa
mp
le, 34 o
f 33
7 w
ith
a P
HI>
3 w
ere
exc
lud
ed
fro
m s
am
ple
3 d
ue
to
ho
spita
l ch
art
s b
ein
g n
ot
ava
ilab
le.
�
Ob
serv
atio
n s
tud
y is
su
sce
ptib
le t
o
co
nfo
un
din
g t
ho
ug
h m
ultiv
aria
te
an
aly
sis
wa
s c
on
du
cte
d w
hic
h is
an
imp
rove
me
nt
on
oth
er
stu
die
s.
.
TRANSPORTATION OF EMERGENCY PATIENTS
84
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Sa
mp
alis
et
al.
19
93)
Ca
na
da
co
ntin
ue
d
Sa
mp
le 3
(fin
al s
am
ple
). C
ase
s fr
om
sam
ple
2 w
ho
fu
lfill
ed
th
e c
rite
ria
fo
r
be
ing
a c
ase
or
a c
on
tro
l we
re
inc
lud
ed
. C
ase
s: a
live
at
tim
e o
f
am
bu
lan
ce
arr
iva
l at
sce
ne
,
tra
nsp
ort
ed
to
a h
osp
ita
l by a
n
Urg
en
ce
s-sa
nte
am
bu
lan
ce
, d
ied
≤6 d
ays
of
tim
e o
f in
jury
. C
on
tro
ls:
aliv
e a
t tim
e o
f a
mb
ula
nc
e a
rriv
al
at
sce
ne
, tr
an
spo
rte
d t
o a
ho
spita
l
by a
n U
rge
nc
es-
san
te a
mb
ula
nc
e,
surv
ive
d >
6 d
ays
of
tim
e o
f in
jury
,
fulfill
ed
an
y o
f: a
dm
itte
d t
o
ho
spita
l, h
ad
su
rge
ry,
tre
ate
d in
IC
U
or
on
site
pre
-ho
spita
l in
de
x>3.
Ou
tco
me
me
asu
res
Six
da
y s
urv
iva
l
An
aly
sis
Un
iva
ria
te m
eth
od
s u
sed
to
co
mp
are
ca
ses
an
d c
on
tro
ls.
Mu
ltip
le lo
gis
tic
re
gre
ssio
n u
sed
to
co
ntr
ol f
or
po
ten
tia
lly c
on
fou
nd
ing
fac
tors
. P
re-s
et
va
ria
ble
s a
dd
ed
to
the
mo
de
l an
d f
ina
l m
od
el w
as
de
rive
d f
rom
th
e s
tep
wis
e s
ele
ctio
n
me
tho
d.
C
om
me
nts
�
Aim
ed
to
ass
ess
th
e a
sso
cia
tio
n
be
twe
en
use
of
on
-site
ad
va
nc
ed
life
sup
po
rt,
tota
l pre
-ho
spita
l tim
e a
nd
leve
l of
in-h
osp
ita
l ca
re w
ith
six
da
y
surv
iva
l in
se
ve
rely
inju
red
pa
tie
nts
.
�
Sim
ilar
sam
plin
g s
tra
teg
y t
o t
ha
t u
sed
in S
am
pa
lis e
t a
l. 200
2 w
ith
th
e f
irst
two
sta
ge
s a
pp
ea
rin
g t
o id
en
tify
th
e
sam
e p
atie
nts
. U
nd
ou
bte
dly
co
nsi
de
rab
le o
ve
rla
p in
pa
tie
nts
.
�
Hig
he
r p
rop
ort
ion
of
ca
ses
ha
d a
t
lea
st o
ne
co
mo
rbid
ity (
22%
v 1
0%
).
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
No
be
ne
fit
is a
sso
cia
ted
with
th
e u
se o
f
ph
ysi
cia
n-p
rov
ide
d o
n-s
ite
ad
va
nc
e li
fe
sup
po
rt in
re
du
cin
g t
he
ris
k o
f d
ea
th in
seve
rely
inju
red
pa
tie
nts
. Th
e d
ata
str
on
gly
sup
po
rts
the
sig
nific
an
ce
of
red
uc
ed
pre
-
ho
spita
l tim
e a
nd
hig
h le
ve
l in
-ho
spita
l ca
re
for
the
co
ntr
ol o
f tr
au
ma
re
late
d m
ort
alit
y
TRANSPORTATION OF EMERGENCY PATIENTS
85
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Bo
na
tti e
t a
l. 19
95
)
Au
stria
Re
tro
spe
ctive
co
ho
rt s
tud
y
Leve
l III-
2
Stu
dy s
ett
ing
.
Co
nd
uc
ted
at
the
HEM
S u
nit
Ch
risto
ph
oru
s I b
ase
d a
t In
nsb
ruc
k,
Au
stria
du
rin
g a
th
ree
ye
ar
pe
rio
d f
rom
1989 t
o 1
991 in
clu
sive
.
Pa
rtic
ipa
nts
:
2139 p
art
icip
an
ts
Ba
selin
e a
na
lyse
s.
Sp
ort
ing
ac
cid
en
ts 5
3.7
%
Mo
tor
ve
hic
le a
cc
ide
nts
11.1
%
Oc
cu
pa
tio
na
l in
jurie
s 5.6
%
Me
dic
al e
me
rge
nc
ies
16.1
%
Ne
uro
log
ica
l em
erg
en
cie
s 2.8
%
Oth
er
mis
sio
ns
10.7
%
30 d
ay s
urv
iva
l 87
.9%
Inc
lu/e
xcl c
rite
ria
.
No
t st
ate
d
Da
ta c
olle
ctio
n
Ob
tain
ed
fro
m H
EM
S o
pe
ratio
n
pro
toc
ols
an
d b
y w
ritt
en
, p
ers
on
al
or
tele
ph
on
e r
eq
ue
st f
rom
me
dic
al
rec
ord
s o
f th
e a
dm
ittin
g h
osp
ita
ls.
Flig
ht
log
s w
ere
re
co
rde
d in
ele
ctr
on
ic f
orm
an
d f
ollo
w-u
p d
ata
ad
de
d a
s h
osp
ita
l dis
ch
arg
e
sum
ma
rie
s w
ere
re
ce
ive
d.
Initia
l vita
l sig
ns
(sta
te o
f
co
nsc
iou
sne
ss,
resp
irato
ry s
tatu
s,
circ
ula
tory
sta
tus)
we
re a
sse
sse
d o
n
a f
ou
r p
oin
t sc
ale
An
aly
sis
Un
iva
ria
te s
urv
iva
l an
aly
sis
by t
he
life
ta
ble
me
tho
d a
nd
Wilc
oxo
n
test
. C
ox
pro
po
rtio
na
l h
aza
rds
mo
de
l fo
r m
ultiv
aria
te a
na
lysi
s.
30 d
ay s
urv
iva
l by t
ota
l mis
sio
n t
ime
0-2
0 m
inu
tes:
95.5
% s
urv
iva
l
21-4
0 m
inu
tes:
91.7
% s
urv
iva
l
41-6
0 m
inu
tes:
87.6
% s
urv
iva
l
61-8
0 m
inu
tes:
86.8
% s
urv
iva
l
> 8
0 m
inu
tes:
78.8
% s
urv
iva
l
Un
iva
ria
te a
na
lysi
s, P
=0.0
00
1
Mu
ltiv
aria
te a
na
lysi
s, n
o s
ign
ific
an
t
ass
oc
iatio
n, a
dju
ste
d f
or
ca
use
of
inju
ry/e
me
rge
nc
y, flig
ht
tim
e t
o
sce
ne
, sc
en
e t
ime
, p
atie
nt
ag
e,
pa
tie
nt
ge
nd
er,
NA
CA
sc
ore
, st
ate
of
co
nsc
iou
sne
ss, re
spira
tory
sta
tus,
circ
ula
tory
sta
tus,
em
erg
en
cy
ph
ysi
cia
n.
Lim
ita
tio
ns
�
No
do
cu
me
nta
tio
n o
f se
lec
tio
n
crite
ria
. It
is a
ssu
me
d a
ll p
atie
nts
we
re
inc
lud
ed
.
�
Ob
serv
atio
n s
tud
y is
su
sce
ptib
le t
o
co
nfo
un
din
g t
ho
ug
h m
ultiv
aria
te
an
aly
sis
wa
s c
on
du
cte
d w
hic
h is
an
imp
rove
me
nt
on
oth
er
stu
die
s.
�
Ac
cu
rac
y o
f d
ata
re
co
rdin
g in
th
e
da
ta b
ase
s u
sed
wa
s n
ot
rec
ord
ed
.
�
Pa
tie
nts
ap
pe
are
d t
o b
e t
ake
n t
o
mu
ltip
le h
osp
ita
ls –
crite
ria
fo
r ta
kin
g
pa
tie
nts
to
sp
ec
ific
ho
spita
ls w
ere
no
t
sta
ted
an
d m
ay h
ave
in
flu
en
ce
d
ou
tco
me
.
�
Ad
just
ing
fo
r flig
ht
tim
e t
o t
he
sc
en
e
an
d s
ce
ne
tim
e m
ay h
ave
dim
inis
he
d
the
ass
oc
iatio
n b
etw
ee
n t
ota
l mis
sio
n
tim
e a
nd
su
rviv
al s
inc
e t
he
se
me
asu
res
are
su
bse
ts o
f to
tal m
issi
on
tim
e.
Co
mm
en
ts
�
Aim
ed
to
ide
ntify
ea
sily
ob
tain
ab
le
pre
dic
tors
of
sho
rt-t
erm
ou
tco
me
fo
r
em
erg
en
cy v
ictim
s tr
ea
ted
by a
ph
ysi
cia
n s
taff
ed
he
lico
pte
r
em
erg
en
cy m
ed
ica
l syst
em
.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
The
fo
llow
ing
pa
ram
ete
rs c
an
be
use
d in
an
initia
l pre
dic
tive
ass
ess
me
nt
by t
he
flig
ht
ph
ysi
cia
n a
nd
th
e a
dm
ittin
g in
stitu
tio
n:
seve
rity
of
em
erg
en
cy, in
itia
l re
spira
tory
sta
tus,
tim
e a
t sc
en
e,
pa
tie
nt
ag
e a
nd
pa
tie
nt
ge
nd
er.
TRANSPORTATION OF EMERGENCY PATIENTS
86
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Fe
ero
et
al.
199
5)
USA
Re
tro
spe
ctive
co
ho
rt s
tud
y
Leve
l III-
2.
Stu
dy s
ett
ing
.
Stu
dy s
et
in P
ort
lan
d O
reg
on
(po
pu
latio
n 5
00,0
00 2
00 s
qu
are
mile
s).
Em
erg
en
cy s
erv
ice
s w
ork
un
de
r a
tw
o
tie
r sy
ste
m: b
asi
c a
nd
ad
va
nc
ed
life
sup
po
rt)
Pa
rtic
ipa
nts
:
The
re w
ere
848 m
ajo
r tr
au
ma
ca
ses
bu
t
the
stu
dy c
on
ce
ntr
ate
d o
n t
he
un
exp
ec
ted
su
rviv
ors
an
d t
he
un
exp
ec
ted
de
ath
s (b
ase
d o
n T
RIS
S
me
tho
do
log
y)
Un
exp
ec
ted
su
rviv
ors
(n
=1
3)
Un
exp
ec
ted
de
ath
s (n
=20).
An
aly
ses
co
mp
arin
g g
rou
ps
at
ba
selin
e.
Me
ch
an
ism
of
inju
ry:
Mo
tor
ve
hic
le c
olli
sio
n 3
7%
Sta
bb
ing
17%
Fall
12%
Au
to v
pe
de
stria
n 1
2%
Gu
nsh
ot
wo
un
d 9
%
Au
to v
bic
yc
le 2
%
Bic
yc
le c
olli
sio
n 1
%
Oth
er
8%
Un
kn
ow
n 2
%
Me
an
ag
e (
ye
ars
)
Un
exp
ec
ted
su
rviv
or
29
.5
Un
exp
ec
ted
de
ath
50.8
P=
0.0
1
Ma
le
Un
exp
ec
ted
su
rviv
or
67
%
Un
exp
ec
ted
de
ath
61%
NS
Inc
lu/e
xcl c
rite
ria
.
All
ma
jor
tra
um
a c
ase
s fo
r 199
0
we
re o
bta
ine
d f
rom
th
e S
tate
of
Ore
go
n In
jury
Re
gis
try a
nd
th
e
Me
dic
al R
eso
urc
e H
osp
ita
l. M
ajo
r
tra
um
a d
efin
ed
as
tho
se c
ase
s
en
tere
d b
y E
MS p
rovid
ers
into
th
e
loc
al t
rau
ma
syst
em
. M
an
da
tory
crite
ria
inc
lud
ed
:
Syst
olic
BP
< 9
0 m
mH
g
Re
spira
tory
ra
te <
10 o
r >
29
bre
ath
s/m
in
GC
S<
13
Pe
ne
tra
tin
g in
jury
of
he
ad
, n
ec
k,
tors
o, g
roin
<20%
to
tal s
urf
ac
e a
rea
bu
rns
Am
pu
tatio
n a
bo
ve
th
e w
rist
or
an
kle
Sp
ina
l co
rd in
jury
with
lim
b p
ara
lysi
s
Fla
il c
he
st
Two
or
mo
re o
bv
iou
s p
roxim
al l
on
g
bo
ne
fra
ctu
res
De
ath
of
sam
e c
ar
oc
cu
pa
nt
Eje
ctio
n f
rom
en
clo
sed
ve
hic
le
Ext
rica
tio
n t
ime
lon
ge
r th
an
20
min
ute
s.
Pa
tie
nts
co
uld
be
en
tere
d if
:
Hig
h e
ne
rgy t
ran
sfe
r
Ba
sed
on
co
mo
rbid
co
nd
itio
ns
Da
ta c
olle
ctio
n
Ag
e,
sex,
me
ch
an
ism
of
inju
ry, EM
S
resp
on
se t
ime
inte
rva
ls, e
me
rge
nc
y
de
pa
rtm
en
t a
nd
inp
atie
nt
dis
po
sitio
n,
rev
ise
d t
rau
ma
sc
ore
, IS
S
Ou
tco
me
me
asu
res
Su
rviv
al to
lea
ve
ho
spita
l
Tota
l EM
S t
ime
inte
rva
l (m
inu
tes)
un
exp
ec
ted
su
rviv
ors
an
d
un
exp
ec
ted
de
ath
s
Un
exp
ec
ted
su
rviv
ors
: 20.8
min
ute
s
Un
exp
ec
ted
de
ath
s: 2
9.3
min
ute
s
P=
0.0
2
Lim
ita
tio
ns
�
Sm
all
nu
mb
ers
of
pa
tie
nts
in t
he
un
exp
ec
ted
su
rviv
or
an
d u
ne
xpe
cte
d
de
ath
gro
up
s.
�
Po
ssib
le m
isc
lass
ific
atio
n o
f th
e
un
exp
ec
ted
su
rviv
or
an
d u
ne
xpe
cte
d
de
ath
gro
up
s (a
lth
ou
gh
M s
tatist
ic
wa
s 0.9
8 s
ug
ge
stin
g a
go
od
fit
be
twe
en
th
e r
efe
ren
ce
da
ta a
nd
th
e
ac
tua
l da
ta).
�
Po
ten
tia
l fo
r in
co
nsi
ste
nc
y in
th
e
sele
ctio
n p
roc
ess
giv
en
a c
ate
go
ry o
f
no
n-m
an
da
tory
re
po
rtin
g.
�
Po
ten
tia
l fo
r c
on
fou
nd
ing
in t
his
ob
serv
atio
na
l stu
dy.
�
Mix
ture
of
RTS
da
ta u
sed
– s
om
e f
rom
sce
ne
an
d s
om
e f
rom
ho
spita
l,
alth
ou
gh
sim
ilar
pro
po
rtio
ns
use
d
ho
spita
l da
ta in
th
e u
ne
xpe
cte
d
surv
ivo
rs a
nd
th
e u
ne
xpe
cte
d d
ea
ths
(42%
v 3
9%
).
Co
mm
en
ts
�
Aim
ed
to
de
term
ine
if o
ut
of
ho
spita
l
em
erg
en
cy m
ed
ica
l se
rvic
es
tim
e
inte
rva
ls a
re a
sso
cia
ted
with
un
exp
ec
ted
de
ath
an
d s
urv
iva
l in
urb
an
ma
jor
tra
um
a.
�
All
tra
um
a c
ase
s ta
ke
n t
o a
sin
gle
ho
spita
l.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
Sh
ort
ou
t o
f h
osp
ita
l tim
e in
terv
al m
ay
po
sitive
ly a
ffe
ct
pa
tie
nt
su
rviv
al i
n s
ele
cte
d
urb
an
ma
jor
tra
um
a p
atie
nts
TRANSPORTATION OF EMERGENCY PATIENTS
87
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Fe
ero
et
al.
199
5)
USA
co
ntin
ue
d
An
aly
sis
TRIS
S m
eth
od
olo
gy u
sed
to
ca
lcu
late
pro
ba
bili
ty o
f su
rviv
al,
Flo
ra’s
Z s
tatist
ic u
sed
to
co
mp
are
exp
ec
ted
an
d o
bse
rve
d d
ea
ths.
Un
pa
ire
d t
te
st u
sed
to
co
mp
are
me
an
tim
e in
terv
als
fo
r th
e
un
exp
ec
ted
su
rviv
or
an
d d
ea
th
gro
up
s.
TRANSPORTATION OF EMERGENCY PATIENTS
88
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Yo
un
g e
t a
l. 199
8)
USA
Re
tro
spe
ctive
co
ho
rt s
tud
y
Leve
l III-
2
Stu
dy s
ett
ing
.
Se
t in
th
e U
niv
ers
ity o
f V
irg
inia
He
alth
Sc
ien
ce
s C
en
ter
wh
ich
is a
leve
l 1
tra
um
a c
en
tre
se
rvin
g c
en
tra
l an
d
we
ste
rn V
irgin
ia.
An
ae
rom
ed
ica
l
pro
gra
mm
e e
xist
s th
at
tra
nsf
ers
pa
tie
nts
fro
m t
he
sc
en
e a
nd
fro
m o
utlyin
g
ho
spita
ls. Stu
dy c
on
du
cte
d d
urin
g 1
994-
1995.
Pa
rtic
ipa
nts
:
316 p
art
icip
an
ts d
ivid
ed
into
dire
ct
pa
tie
nts
(n
=16
5)
an
d t
ran
sfe
r p
atie
nts
(n=
151
)
An
aly
ses
co
mp
arin
g g
rou
ps
at
ba
selin
e.
Ag
e (
ye
ars
)
Tra
nsf
er
gro
up
46
Dire
ct
gro
up
44
ISS
Tra
nsf
er
gro
up
23
.1
Dire
ct
gro
up
24.8
GC
S in
ED
Tra
nsf
er
gro
up
11
.4
Dire
ct
gro
up
11.4
Exp
ec
ted
nu
mb
er
of
de
ath
s
Tra
nsf
er
gro
up
23
Dire
ct
gro
up
34
Inc
lu/e
xcl c
rite
ria
.
Ag
e >
18 y
ea
rs
ISS >
15
Da
ta c
olle
ctio
n
Da
ta e
xtr
ac
ted
fro
m t
rau
ma
re
gis
try
an
d p
atie
nt
rec
ord
s.
ISS, d
ela
y a
t o
uts
ide
ho
spita
l,
pa
tie
nt
de
mo
gra
ph
ics
co
llec
ted
.
Ou
tco
me
me
asu
res
Ho
spita
l le
ng
th o
f st
ay a
nd
mo
rta
lity.
An
aly
sis
TRIS
S c
alc
ula
ted
with
re
fere
nc
e t
o
MTO
S c
oe
ffic
ien
ts.
Ch
i sq
ua
re t
est
use
d f
or
ca
teg
oric
al d
ata
an
d
Stu
de
nt’
s t
test
fo
r c
on
tin
uo
us
da
ta.
Tim
e f
rom
inju
ry t
o a
rriv
al a
t tr
au
ma
ce
ntr
e
Tra
nsf
er
gro
up
48
0 m
inu
tes
Dire
ct
gro
up
92 m
inu
tes
Len
gth
of
ho
spita
l sta
y
Tra
nsf
er
gro
up
19
.1 d
ays
Dire
ct
gro
up
15.4
da
ys
No
sig
nific
an
t d
iffe
ren
ce
Mo
rta
lity >
24 h
ou
rs a
fte
r in
jury
Tra
nsf
er
gro
up
12
de
ath
s
Dire
ct
gro
up
10 d
ea
ths
No
sig
nific
an
t d
iffe
ren
ce
Mo
rta
lity <
24 h
ou
rs a
fte
r in
jury
Tra
nsf
er
gro
up
16
de
ath
s
Dire
ct
gro
up
25 d
ea
ths
No
sig
nific
an
t d
iffe
ren
ce
De
ath
s w
ith
pro
ba
bili
ty o
f su
rviv
al >
50%
in f
irst
24 h
ou
rs
Tra
nsf
er
gro
up
12
of
16
Dire
ct
gro
up
7 o
f 25
P<
0.0
5
Lim
ita
tio
ns
�
Ele
me
nts
of
ec
olo
gic
al a
na
lysi
s fo
r th
e
resu
lts
of
inte
rest
to
th
is r
ev
iew
.
Sp
ec
ific
ally
, th
ere
wa
s n
o c
om
pa
riso
n
be
twe
en
ind
ivid
ua
l tim
e d
ata
an
d
ou
tco
me
, ra
the
r th
e c
om
pa
riso
n w
as
be
twe
en
ou
tco
me
tra
nsf
er
an
d d
ire
ct
da
ta (
an
d t
hu
s u
sed
a s
a p
roxy
fo
r
tim
e,
giv
en
th
e lo
ng
er
tra
nsp
ort
atio
n
tim
e in
th
e t
ran
sfe
r g
rou
p t
ha
n t
he
dire
ct
gro
up
, 480 m
inu
tes
ve
rsu
s 9
2
min
ute
s).
�
Ac
cu
rac
y o
f tr
au
ma
re
gis
try n
ot
sta
ted
.
�
Ob
serv
atio
n s
tud
y is
su
sce
ptib
le t
o
co
nfo
un
din
g. M
ultiv
aria
te a
na
lysi
s
wa
s n
ot
co
nd
uc
ted
th
us
furt
he
r
limitin
g c
on
tro
l ove
r p
ote
ntia
l
co
nfo
un
de
rs (
alth
ou
gh
th
ere
we
re n
o
sig
nific
an
t d
iffe
ren
ce
s in
ba
selin
e
da
ta b
etw
ee
n d
irec
t a
nd
byp
ass
pa
tie
nts
).
�
Dis
cre
pa
nt
resu
lts
pre
sen
ted
in t
ha
t
the
to
tal d
ea
ths
pre
sen
ted
in t
he
dire
ct
gro
up
(n
=38
) is
no
t c
on
sist
en
t
with
to
tal d
ea
ths
in f
irst
24 h
ou
rs in
dire
ct
gro
up
(n
=10
) p
lus
tota
l de
ath
s
aft
er
24 h
ou
rs in
th
e d
ire
ct
gro
up
(n=
25
).
TRANSPORTATION OF EMERGENCY PATIENTS
89
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Yo
un
g e
t a
l. 199
8)
USA
co
ntin
ue
d
�
Did
no
t p
rese
nt
un
exp
ec
ted
de
ath
s
mo
re t
ha
n 2
4 h
ou
rs a
fte
r in
jury
an
d
did
no
t p
rese
nt
un
exp
ec
ted
su
rviv
ors
.
�
M s
co
re w
as
< 0
.88 in
dic
atin
g a
po
or
ma
tch
with
th
e M
TOS d
ata
set.
Co
mm
en
ts
�
Exa
min
ed
th
e h
yp
oth
esi
s th
at
de
lay a
t
the
re
ferr
ing
ho
spita
l is
de
trim
en
tal t
o
pa
tie
nt
ou
tco
me
.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
Pa
tie
nts
with
ma
jor
tra
um
a t
ake
n d
ire
ctly t
o
the
tra
um
a c
en
tre
ha
d s
ho
rte
r h
osp
ita
l sta
y
an
d lo
we
r m
ort
alit
y. Th
e s
tud
y s
up
po
rts
tra
nsf
err
ing
ma
jor
tra
um
a p
atie
nts
dire
ctly t
o
tra
um
a c
en
tre
s fr
om
th
e in
jury
sc
en
e.
TRANSPORTATION OF EMERGENCY PATIENTS
90
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Fre
zza
an
d M
ezg
he
be
1999
)
USA
Re
tro
spe
ctive
co
ho
rt s
tud
y
Leve
l III-
2
Stu
dy s
ett
ing
.
Tra
um
a p
atie
nts
att
en
din
g t
he
Ho
wa
rd
Un
ive
rsity H
osp
ita
l Em
erg
en
cy
De
pa
rtm
en
t b
etw
ee
n 1
992 a
nd
199
5.
Pa
rtic
ipa
nts
:
58 a
du
lt p
atie
nts
with
pe
ne
tra
tin
g c
he
st
tra
um
a
Ba
selin
e a
na
lyse
s
Gu
nsh
ot
wo
un
ds
70
%
Sta
b w
ou
nd
s 1
2%
Syst
olic
BP
< 7
0m
mH
g 2
4%
Tra
nsf
er
to IC
U 6
3%
Ave
rag
e p
re-h
osp
ita
l tim
e:
At
the
sc
en
e 1
1 m
inu
tes
Tra
nsi
t 8
min
ute
s
ED
10 m
inu
tes
Inc
lu/e
xcl c
rite
ria
.
Pa
tie
nts
wh
o u
nd
erw
en
t
em
erg
en
cy r
oo
m t
ho
rac
oto
my
(ER
T) a
nd
ha
d v
ita
l sig
ns
in t
he
fie
ld
Pe
ne
tra
tin
g c
he
st t
rau
ma
.
Da
ta c
olle
ctio
n
Pre
-ad
mis
sio
n d
ata
extr
ac
ted
fro
m
EM
S r
ep
ort
s.
Ou
tco
me
me
asu
res
Mo
rta
lity
An
aly
sis
Fish
er
co
rre
cte
d c
hi s
qu
are
te
st
Su
rviv
al w
ith
in 2
4 h
ou
rs b
y p
re-
ho
spita
l tim
e
Pre
-ho
spita
l tim
e <
30 m
inu
tes:
63%
surv
iva
l (20/2
7)
Pre
-ho
spita
l tim
e >
30 m
inu
tes:
0%
surv
iva
l (0/6
)
Lim
ita
tio
ns
�
Sc
an
t d
eta
ils p
rese
nte
d in
me
tho
ds.
�
Re
vie
we
r is
no
t a
wa
re o
f Fis
he
r
co
rre
cte
d c
hi s
qu
are
te
st –
oth
er
co
rre
ctio
ns
are
ava
ilab
le –
th
e
me
tho
d is
no
t re
fere
nc
ed
.
�
Ac
cu
rac
y o
f p
re-h
osp
ita
l tim
e
un
cle
ar.
�
Ob
serv
atio
n s
tud
y is
su
sce
ptib
le t
o
co
nfo
un
din
g. M
ultiv
aria
te a
na
lysi
s
wa
s n
ot
co
nd
uc
ted
th
us
furt
he
r
limitin
g c
on
tro
l ove
r p
ote
ntia
l
co
nfo
un
de
rs.
�
Da
ta o
nly
pre
sen
ted
on
33 o
f th
e 5
8
pa
tie
nts
(d
ata
we
re m
issi
ng
on
nin
e
pa
tie
nts
an
d 1
6 w
ere
exc
lud
ed
fro
m
furt
he
r a
na
lysi
s d
ue
to
lac
k o
f v
ita
l
sig
ns
in t
he
fie
ld.
�
Pre
-ho
spita
l tim
e n
ot
cle
arly d
efin
ed
.
In p
art
icu
lar
it w
as
un
cle
ar
if it
inc
lud
ed
tim
e f
rom
dis
pa
tch
to
tim
e o
f
arr
iva
l at
sce
ne
.
�
Ap
pe
are
d t
o b
e d
ea
ths
aft
er
24 h
ou
rs
bu
t it w
as
no
t p
oss
ible
to
est
ab
lish
ho
w m
an
y d
ea
ths
the
re w
ere
in t
his
tim
e p
erio
d.
The
refo
re, if t
he
nu
mb
er
of
de
ath
s p
rese
nte
d b
y p
re-h
osp
ita
l
tim
e h
ad
be
en
exte
nd
ed
be
yo
nd
24
ho
urs
, th
e d
iffe
ren
ce
in s
urv
iva
l
be
twe
en
th
e t
wo
tim
e g
rou
ps
wo
uld
ha
ve
be
en
less
.
TRANSPORTATION OF EMERGENCY PATIENTS
91
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Fre
zza
an
d M
ezg
he
be
1999
)
USA
co
ntin
ue
d
Co
mm
en
ts
�
Aim
ed
to
ass
ess
if p
re-h
osp
ita
l tim
e
co
uld
be
use
d a
s th
e p
rin
cip
le
pa
ram
ete
r to
pre
dic
t w
he
the
r
em
erg
en
cy r
oo
m t
ho
rac
oto
my in
pe
ne
tra
tin
g c
he
st t
rau
ma
is u
sefu
l.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
The
on
ly r
ole
of
ER
T in
ou
r o
pin
ion
is in
pa
tie
nts
wh
o a
rriv
e w
ith
in 3
0 m
inu
tes
of
pre
-
ho
spita
l tim
e.
TRANSPORTATION OF EMERGENCY PATIENTS
92
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Ph
illip
s e
t a
l. 19
99)
USA
Re
tro
spe
ctive
co
ho
rt s
tud
y
Leve
l III-
2
Stu
dy s
ett
ing
.
Pa
tie
nts
tra
nsp
ort
ed
to
Bro
oke
Arm
y
Me
dic
al C
en
tre
leve
l 1 t
rau
ma
ce
ntr
e
by e
ith
er
air o
r ro
ad
am
bu
lan
ce
du
rin
g
1995
-6.
Pa
rtic
ipa
nts
:
792 c
on
sec
utive
pa
tie
nts
(6
87 d
eliv
ere
d
by r
oa
d a
mb
ula
nc
e a
nd
105 b
y a
ir
am
bu
lan
ce
).
An
aly
ses
co
mp
arin
g g
rou
ps
at
ba
selin
e.
Me
an
ag
e (
ye
ars
)
Gro
un
d: 3
2.2
3
Air 3
2.1
4
Ma
le
Gro
un
d 7
1.8
%
Air 6
7.6
%
Blu
nt
tra
um
a
Gro
un
d 7
1.3
%
Air 8
4.7
%
Tim
e f
rom
inju
ry t
o h
osp
ita
l arr
iva
l
Gro
un
d 5
4 m
inu
tes
Air 7
7 m
inu
tes
Inc
lu/e
xcl c
rite
ria
.
Co
nse
cu
tive
am
bu
lan
ce
tra
nsp
ort
ed
tra
um
a p
atie
nts
.
Exc
lud
ed
pa
tie
nts
wh
o d
id n
ot
ha
ve
TR
ISS v
alu
es.
Da
ta c
olle
ctio
n
Ext
rac
ted
da
ta r
eq
uire
d f
or
TRIS
S
ca
lcu
latio
ns
Ou
tco
me
me
asu
res
Su
rviv
al
An
aly
sis
Z st
atist
ic c
alc
ula
ted
ba
sed
on
co
mp
ariso
n w
ith
th
e M
TOS
po
pu
latio
n.
Co
mp
aris
on
of
ac
tua
l an
d
exp
ec
ted
mo
rta
lity b
y t
ran
spo
rt
gro
up
Gro
un
d t
ran
spo
rt (
sho
rte
r tim
e)
Exp
ec
ted
de
ath
s 39.1
Ac
tua
l de
ath
s 41
Z=
0.0
4
Air t
ran
spo
rt (
lon
ge
r a
ve
rag
e
tra
nsp
ort
tim
e)
Exp
ec
ted
de
ath
s 16.3
Ac
tua
l de
ath
s 15
Z=
-0.1
51
Me
an
len
gth
of
sta
y
Gro
un
d t
ran
spo
rt 4
.21 d
ays
Air a
mb
ula
nc
e 8
.97
da
ys
P<
0.0
01
Lim
ita
tio
ns
�
Mis
sin
g in
form
atio
n o
n 3
8 p
atie
nts
led
to t
he
ir e
xclu
sio
n (
4.8
%).
�
Diffe
ren
t st
aff
ing
on
th
e t
wo
mo
de
s o
f
de
live
ry: ro
ad
am
bu
lan
ce
ha
d t
wo
pa
ram
ed
ics,
air
am
bu
lan
ce
ha
d a
pa
ram
ed
ic a
nd
a f
ligh
t n
urs
e.
�
Mo
re s
eve
rely
inju
red
pa
tie
nts
we
re
pre
fere
ntia
lly t
rea
ted
by a
ir
am
bu
lan
ce
- t
his
co
uld
exp
lain
th
e
pro
lon
ge
d s
tay in
th
is g
rou
p.
TRIS
S
va
lue
s in
dic
ate
d a
diffe
ren
ce
in
seve
rity
be
twe
en
th
e t
wo
gro
up
s w
ith
pro
ba
bili
ty o
f su
rviv
al b
ein
g lo
we
r in
the
air g
rou
p (
93.9
% v
ers
us
83
.1%
).
�
Air a
mb
ula
nc
e p
atie
nts
re
ce
ive
d a
hig
he
r le
ve
l of
ca
re e
n r
ou
te.
�
M s
tatist
ic n
ot
pre
sen
ted
so
de
gre
e o
f
fit
with
MTO
S d
ata
wa
s u
nc
lea
r.
�
Ob
serv
atio
n s
tud
y is
su
sce
ptib
le t
o
co
nfo
un
din
g. M
ultiv
aria
te a
na
lysi
s
wa
s n
ot
co
nd
uc
ted
th
us
furt
he
r
limitin
g c
on
tro
l ove
r p
ote
ntia
l
co
nfo
un
de
rs.
�
Ele
me
nts
of
ec
olo
gic
al a
na
lysi
s fo
r th
e
resu
lts
of
inte
rest
to
th
is r
ev
iew
.
Sp
ec
ific
ally
, th
ere
wa
s n
o c
om
pa
riso
n
be
twe
en
ind
ivid
ua
l tim
e d
ata
an
d
ou
tco
me
, ra
the
r th
e c
om
pa
riso
n w
as
be
twe
en
air a
nd
ro
ad
am
bu
lan
ce
(an
d t
hu
s u
sed
as
a p
roxy
fo
r tim
e,
giv
en
th
e lo
ng
er
tra
nsp
ort
atio
n t
ime
in
the
air g
rou
p.
TRANSPORTATION OF EMERGENCY PATIENTS
93
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Ph
illip
s e
t a
l. 19
99)
USA
co
ntin
ue
d
Co
mm
en
ts
�
Aim
ed
to
re
vie
w w
he
the
r a
ir
am
bu
lan
ce
tra
nsp
ort
atio
n o
f tr
au
ma
pa
tie
nts
to
a le
ve
l 1 t
rau
ma
ce
ntr
e
co
ntr
ibu
ted
to
ma
inta
inin
g n
atio
na
l
mo
rta
lity s
tan
da
rds
in t
he
tra
um
a c
are
of
the
se p
atie
nts
.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
Re
sults
sug
ge
st t
ha
t a
ero
me
dic
al
eva
cu
atio
n o
f th
e m
ore
se
ve
rely
inju
red
pa
tie
nts
fa
rth
est
fro
m t
he
tra
um
a c
en
tre
resu
lte
d in
mo
rta
lity r
ate
s th
at
me
t n
atio
na
l
sta
nd
ard
s.
TRANSPORTATION OF EMERGENCY PATIENTS
94
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Sa
mp
alis
et
al.
19
99)
Ca
na
da
Pro
spe
ctive
co
ho
rt s
tud
y
Leve
l III-
2
Stu
dy s
ett
ing
.
Stu
dy s
et
in M
on
tre
al a
nd
Qu
eb
ec
du
rin
g a
nd
aft
er
a t
ime
of
reg
ion
alis
atio
n o
f tr
au
ma
ca
re s
erv
ice
s
Pa
rtic
ipa
nts
(n
=1
2,2
08):
Ba
selin
e a
na
lyse
s
Me
an
ag
e 4
8 y
ea
rs
Ma
le 6
7.6
%
Me
an
ISS 2
6.1
Dis
ch
arg
ed
aliv
e 7
1.6
%
Inc
lu/e
xcl c
rite
ria
.
Tre
ate
d f
or
inju
rie
s a
t a
cu
te c
are
ho
spita
ls in
Mo
ntr
ea
l an
d Q
ue
be
c.
On
e o
f:
De
ath
as
a r
esu
lt o
f in
jury
ISS>
12
PH
I>3
≥2 in
jurie
s w
ith
AIS
≥3
Ho
spita
l sta
y >
3 d
ays
Exc
lusi
on
s: d
ied
at
sce
ne
Da
ta c
olle
ctio
n
Da
ta e
xtr
ac
ted
fro
m r
ec
ord
s u
sin
g
a s
tan
da
rdis
ed
da
ta e
xtr
ac
tio
n
form
an
d t
he
n e
nte
red
into
a
cu
sto
mis
ed
da
ta m
an
ag
em
en
t
soft
wa
re p
rog
ram
. Fin
al a
na
lysi
s
wa
s c
on
du
cte
d in
SP
SS.
Ou
tco
me
me
asu
res
De
ath
du
rin
g h
osp
ita
l ad
mis
sio
n
An
aly
sis
The
an
aly
tic
al m
eth
od
s w
ere
div
ide
d b
y h
yp
oth
esi
s.
Hyp
oth
esi
s 1 t
est
ed
th
at
tra
um
a
ca
re r
eg
ion
alis
atio
n is
ass
oc
iate
d
with
a r
ed
uc
tio
n in
tra
um
a r
ela
ted
mo
rta
lity.
An
aly
sis
co
nsi
ste
d o
f
co
mp
ariso
n o
f m
ort
alit
y r
ate
s d
urin
g
ea
ch
fis
ca
l ye
ar
be
fore
an
d a
fte
r
reg
ion
alis
atio
n, c
om
pa
riso
n o
f
mo
rta
lity r
ate
s d
urin
g e
ac
h p
ha
se
of
imp
lem
en
tatio
n o
f th
e
reg
ion
alis
ed
Qu
eb
ec
syst
em
.
Log
istic
re
gre
ssio
n w
as
use
d.
Ove
rall
mo
rta
lity r
ate
28
% t
hro
ug
h
the
six
ye
ars
.
Ad
just
ed
od
ds
of
de
ath
by p
re-
ho
spita
l tim
e (
OR
fo
r e
ac
h
ad
ditio
na
l min
ute
of
pre
-ho
spita
l
tim
e)
OR
1.0
46 (
95%
CI 1.0
44-1
.05
0)
Ad
just
ed
fo
r tim
e t
o a
dm
issi
on
,
tra
um
a c
en
tre
de
sig
na
tio
n,
tra
nsf
er
ve
rsu
s d
ire
ct
tra
nsp
ort
, p
atie
nt
ag
e
an
d ISS.
Lim
ita
tio
ns
�
Ac
cu
rac
y o
f p
re-h
osp
ita
l tim
e
un
cle
ar.
�
Ob
serv
atio
n s
tud
y is
su
sce
ptib
le t
o
co
nfo
un
din
g a
lth
ou
gh
with
th
e
mu
ltiv
aria
te m
od
elli
ng
th
e r
isk o
f
co
nfo
un
din
g b
y k
no
wn
co
nfo
un
de
rs is
red
uc
ed
.
�
Po
ten
tia
l fo
r in
ap
pro
pria
te s
ele
ctio
n
as
the
fin
al p
roc
ess
re
lied
on
ch
art
revie
w.
Co
mm
en
ts
�
This
stu
dy a
ime
d t
o a
sse
ss t
he
imp
ac
t
of
reg
ion
alis
atio
n o
f tr
au
ma
ca
re
serv
ice
s o
n m
ort
alit
y. R
eg
ion
alis
atio
n
wa
s in
itia
ted
in 1
993. N
ote
th
e t
wo
ea
rlie
r Sa
mp
alis
stu
die
s (1
99
2 a
nd
1993
) su
pp
ort
ed
su
ch
re
gio
na
lisa
tio
n.
�
No
ris
k o
f lo
ss t
o f
ollo
w-u
p d
ue
to
th
e
na
ture
of
the
stu
dy d
esi
gn
.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
This
stu
dy p
rod
uc
ed
em
piric
al e
vid
en
ce
tha
t th
e in
teg
ratio
n o
f tr
au
ma
ca
re s
erv
ice
s
into
a r
eg
ion
alis
ed
syst
em
re
du
ce
s m
ort
alit
y.
The
re
sults
sho
w t
ha
t te
rtia
ry t
rau
ma
ce
ntr
es
an
d r
ed
uc
ed
pre
-ho
spita
l tim
es
are
th
e
ess
en
tia
l co
mp
on
en
ts o
f a
n e
ffic
ien
t tr
au
ma
ca
re s
yst
em
.
TRANSPORTATION OF EMERGENCY PATIENTS
95
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Sa
mp
alis
et
al.
19
99)
Ca
na
da
co
ntin
ue
d
Hyp
oth
esi
s 2a
. te
ste
d m
ort
alit
y r
ate
s
of
pa
tie
nts
tre
ate
d a
t te
rtia
ry c
are
ce
ntr
es
co
mp
are
d w
ith
pa
tie
nts
at
less
sp
ec
ialis
ed
ho
spita
ls.
Als
o
test
ed
mo
rta
lity r
ate
s in
th
ose
wh
o
we
re t
ran
spo
rte
d d
ire
ctly f
rom
th
e
sce
ne
to
th
e t
ert
iary
ce
ntr
e a
nd
tho
se w
ho
we
re t
ran
spo
rte
d
ind
irec
tly.
Hyp
oth
esi
s 2b
(te
ste
d t
he
ass
oc
iatio
n b
etw
ee
n p
roc
ess
of
tra
um
a c
are
re
gio
na
lisa
tio
n a
nd
mo
rta
lity a
s it r
ela
ted
to
th
e
Qu
eb
ec
tra
um
a s
yst
em
- w
he
re t
he
rate
of
ap
pro
pria
te p
atie
nt
tria
ge
will
inc
rea
se a
nd
pre
-ho
spita
l tim
e
will
de
cre
ase
ove
r tim
e).
Th
is
co
mp
on
en
t w
as
no
t re
leva
nt
to t
his
revie
w.
Hyp
oth
esi
s 2c
(re
du
ce
d p
re-h
osp
ita
l
tim
e is
ass
oc
iate
d w
ith
re
du
ce
d
mo
rta
lity).
Lo
gis
tic
re
gre
ssio
n u
sed
.
TRANSPORTATION OF EMERGENCY PATIENTS
96
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Grz
yb
ow
ski e
t a
l. 2
000
)
USA
Re
tro
spe
ctive
co
ho
rt s
tud
y
Leve
l II-
2
Stu
dy s
ett
ing
.
Stu
dy c
on
du
cte
d in
19
96 a
nd
19
97
co
nsi
stin
g o
f p
atie
nts
ha
vin
g a
n A
MI
wh
o w
ere
tra
nsp
ort
ed
by a
mb
ula
nc
e t
o
on
e o
f th
ree
ho
spita
ls in
th
e s
ub
urb
s o
f
De
tro
it.
Pa
rtic
ipa
nts
:
253 e
ligib
le b
ut
244 s
ele
cte
d d
ue
to
mis
sin
g o
utc
om
e d
ata
in t
he
oth
er
nin
e
pa
tie
nts
Ba
selin
e a
na
lysi
s
Me
an
ag
e 6
6.6
ye
ars
Ma
le 6
0.2
%
Ca
rdia
c d
ea
th w
ith
in s
eve
n d
ays
14.8
%
Ac
ute
MI 96%
Ca
rdia
c a
rre
st 7
%
Me
an
to
tal E
MS t
ime
44 m
inu
tes
EM
S v
ita
l sig
ns:
He
art
ra
te 7
8.9
Re
spira
tory
ra
te 2
3.1
Syst
olic
BP
128
.1
Dia
sto
lic B
P 8
0
Inc
lu/e
xcl c
rite
ria
.
≥18 y
ea
rs
Ch
ief
co
mp
lain
t o
f c
he
st p
ain
or
sho
rtn
ess
of
bre
ath
Pa
tie
nts
with
su
ita
ble
ou
tco
me
da
ta
Da
ta c
olle
ctio
n
Am
bu
lan
ce
ru
n s
he
ets
: a
ge
,
ge
nd
er,
ra
ce
, EM
S v
ita
l sig
ns,
am
bu
lan
ce
ru
n t
ime
s, t
yp
e o
f
ho
spita
l.
Ou
tco
me
me
asu
res
De
ath
with
in s
eve
n d
ays
of
ED
arr
iva
l
An
aly
sis
Pre
dic
tor
va
riab
les
we
re c
om
pa
red
by s
urv
iva
l sta
tus.
Od
ds
ratio
s a
nd
95%
co
nfid
en
ce
inte
rva
ls w
ere
est
ima
ted
fo
r e
ac
h p
red
icto
r
va
riab
le.
A f
orw
ard
ste
pw
ise
log
istic
reg
ress
ion
mo
de
l wa
s fitt
ed
.
Me
an
to
tal E
MS t
ime
, su
rviv
ors
v
de
ath
s (m
inu
tes)
Su
rviv
ors
42.8
De
ath
s 50.6
P
≤0.0
1
Lim
ita
tio
ns
�
Initia
l po
pu
latio
n o
f 291
se
lec
ted
fo
r
stu
dy. Exc
lusi
on
s: in
elig
ible
ch
ief
co
mp
lain
t (n
=37
), m
issi
ng
ED
ch
ief
co
mp
lain
t (n
=1),
mis
sin
g o
utc
om
e
da
ta (
n=
9).
�
Ob
serv
atio
na
l stu
dy is
su
sce
ptib
le t
o
co
nfo
un
din
g.
Wh
ile m
ultiv
aria
te
mo
de
llin
g w
as
co
nd
uc
ted
, p
re-
ho
spita
l tim
e w
as
no
t in
clu
de
d in
th
e
mo
de
l, th
us
co
mp
ariso
n o
f p
re-
ho
spita
l tim
es
wa
s b
ase
d o
n
un
iva
ria
te a
na
lysi
s o
nly
.
Co
mm
en
ts
�
Ass
ess
ed
wh
ich
ind
ep
en
de
nt
va
riab
les
pre
dic
t d
ea
th w
ith
in s
eve
n
da
ys
in –
pa
tie
nts
with
su
spe
cte
d A
MI
tra
nsp
ort
ed
by E
MS.
�
Ro
bu
stn
ess
of
the
da
ta f
or
est
ima
tin
g
tota
l pre
-ho
spita
l tim
e w
as
no
t c
lea
r
bu
t a
ny e
rro
r se
em
s lik
ely
to
be
sm
all.
�
Low
ris
k o
f o
utc
om
e m
isc
lass
ific
atio
n.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
A t
riag
e r
ule
ba
sed
on
a m
ultiv
aria
te m
od
el
ca
n id
en
tify
th
e g
rou
p a
t h
igh
ris
k o
f e
arly
ca
rdia
c d
ea
th.
This
de
cis
ion
ru
le n
ee
ds
to
be
pro
spe
ctive
ly v
alid
ate
d.
TRANSPORTATION OF EMERGENCY PATIENTS
97
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Be
rns
et
al.
20
01)
USA
Re
tro
spe
ctive
co
ho
rt s
tud
y
Leve
l III-
2
Stu
dy s
ett
ing
.
A h
osp
ita
l ba
sed
he
lico
pte
r p
rog
ram
me
in M
inn
eso
ta.
Co
nd
uc
ted
ove
r Ja
nu
ary
1998 t
o J
un
e 1
999.
Pa
rtic
ipa
nts
:
266 h
elic
op
ter
pa
tie
nts
an
d 2
8 r
oa
d
am
bu
lan
ce
pa
tie
nts
An
aly
ses
co
mp
arin
g g
rou
ps
at
ba
selin
e.
Me
an
ag
e (
ye
ars
)
He
lico
pte
r 65
Gro
un
d 6
7
Ma
le:
He
lico
pte
r 67%
Gro
un
d 6
1%
Tim
e f
rom
ca
ll to
ho
spita
l arr
iva
l
(min
ute
s)
He
lico
pte
r 104
Gro
un
d 1
42
Inc
lu/e
xcl c
rite
ria
.
All
ca
rdia
c p
atie
nts
tra
nsp
ort
ed
by
the
Ma
yo
On
e R
oc
he
ste
r
he
lico
pte
r, in
clu
din
g p
atie
nts
with
ch
est
pa
in, a
ng
ina
, M
I a
nd
arr
hyth
mia
s. E
xclu
sio
n c
rite
ria
inc
lud
ed
pa
tie
nts
tra
nsp
ort
ed
to
a
diffe
ren
t h
osp
ita
l, b
y t
he
Ma
yo
fix
ed
win
g s
erv
ice
, b
y g
rou
nd
with
a f
ligh
t
nu
rse
on
bo
ard
, b
y t
he
Ma
yo
On
e
Ea
u C
laire
he
lico
pte
r a
nd
by
an
oth
er
he
lico
pte
r se
rvic
e.
Da
ta c
olle
ctio
n
Ch
art
re
vie
w
Ou
tco
me
me
asu
re
Ho
spita
l le
ng
th o
f st
ay (
LOS)
Mo
rta
lity
An
aly
sis
t te
st p
erf
orm
ed
on
tra
nsp
ort
tim
e,
tim
e f
rom
ca
ll u
ntil h
osp
ita
l arr
iva
l,
CC
U L
OS a
nd
ho
spita
l LO
S
Ho
spita
l le
ng
th o
f st
ay (
da
ys)
He
lico
pte
r 6.4
Gro
un
d 8
P=
0.0
4
Mo
rta
lity d
ata
He
lico
pte
r 7%
Gro
un
d 4
%
Au
tho
rs d
id n
ot
pre
sen
t a
sta
tist
ica
l
an
aly
sis
of
this
re
sult.
Re
vie
we
rs s
elf
an
aly
sis,
usi
ng
Fis
he
r’s
exa
ct
test
fou
nd
no
sig
nific
an
t d
iffe
ren
ce
be
twe
en
th
e t
wo
gro
up
s
Lim
ita
tio
ns
�
Wh
ile t
he
re w
ere
50 e
ligib
le g
rou
nd
am
bu
lan
ce
pa
tie
nts
re
co
rds
we
re
on
ly r
ec
eiv
ed
in 2
8 o
f th
ese
re
sult
ing
in
a s
ign
ific
an
t se
lec
tio
n b
ias.
�
Diffe
ren
t st
aff
ing
mix
es
be
twe
en
he
lico
pte
r a
nd
ro
ad
am
bu
lan
ce
s
me
an
s it is
no
t p
oss
ible
to
asc
rib
e a
ny
diffe
ren
ce
in o
utc
om
e t
o d
iffe
ren
ce
in
pre
-ho
spita
l tim
e.
�
Ob
serv
atio
na
l stu
dy is
su
sce
ptib
le t
o
co
nfo
un
din
g.
�
Ele
me
nts
of
ec
olo
gic
al a
na
lysi
s fo
r th
e
resu
lts
of
inte
rest
to
th
is r
ev
iew
.
Sp
ec
ific
ally
, th
ere
wa
s n
o c
om
pa
riso
n
be
twe
en
ind
ivid
ua
l tim
e d
ata
an
d
ou
tco
me
, ra
the
r th
e c
om
pa
riso
n w
as
be
twe
en
air a
nd
ro
ad
am
bu
lan
ce
(an
d t
hu
s u
sed
as
a p
roxy
fo
r tim
e,
giv
en
th
e lo
ng
er
tra
nsp
ort
atio
n t
ime
in
the
gro
un
d g
rou
p).
Co
mm
en
ts
�
Aim
ed
to
inve
stig
ate
th
e o
utc
om
e in
ca
rdia
c p
atie
nts
tra
nsp
ort
ed
by
he
lico
pte
r ve
rsu
s g
rou
nd
am
bu
lan
ce
.
�
Gro
un
d t
ran
spo
rta
tio
n w
as
use
d
un
de
r c
on
ditio
ns
tha
t d
id n
ot
allo
w f
or
he
lico
pte
r flig
ht
(eg
we
ath
er,
ma
inte
na
nc
e, a
nd
airc
raft
in
use
or
dis
tan
ce
in
vo
lve
d).
�
Mo
st p
atie
nts
tra
nsf
err
ed
fro
m t
he
refe
rrin
g f
ac
ility
’s E
D.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
He
lico
pte
r tr
an
spo
rt b
en
efits
th
e c
ard
iac
pa
tie
nt
with
de
cre
ase
d c
he
st p
ain
as
a
resu
lt o
f m
ore
tre
atm
en
ts e
n r
ou
te;
de
cre
ase
d t
ime
fro
m c
all
to a
rriv
al,
resu
ltin
g
in d
ec
rea
sed
tim
e t
o in
terv
en
tio
n; a
nd
sho
rte
r p
re-h
osp
ita
l tim
e a
nd
ho
spita
l sta
ys.
TRANSPORTATION OF EMERGENCY PATIENTS
98
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Cla
rke
et
al.
2002
)
USA
Re
tro
spe
ctive
co
ho
rt s
tud
y
Leve
l III-
2
Stu
dy s
ett
ing
.
Inju
red
pa
tie
nts
wh
o w
ere
ca
red
fo
r a
t
a P
en
nsy
lva
nia
tra
um
a c
en
tre
Pa
rtic
ipa
nts
:
250 p
atie
nts
me
t a
prio
ri e
ligib
ility
crite
ria
bu
t se
ve
n w
ere
exc
lud
ed
du
e t
o
ext
rem
e p
re-h
osp
ita
l or
ED
tim
es.
Ba
selin
e a
na
lyse
s
Syst
olic
BP
ra
ng
e 3
0-9
0m
mH
g
Ela
pse
d t
ime
to
ED
ra
ng
e 7
-185
min
ute
s
Tim
e in
ED
ra
ng
e 7
-91
5 m
inu
tes
Inc
lu/e
xcl c
rite
ria
.
Ma
de
use
of
tra
um
a r
eg
istr
y d
ata
wh
ich
om
its
info
rma
tio
n o
n p
atie
nts
wh
o d
ied
, w
ere
tra
nsf
err
ed
to
oth
er
tra
um
a c
en
tre
s o
r h
ad
a h
osp
ita
l
sta
y o
f m
ore
th
an
tw
o d
ays.
Pa
tie
nts
with
iso
late
d h
ip f
rac
ture
s
we
re e
xclu
de
d.
Pa
tie
nts
we
re r
est
ric
ted
to
th
ose
bro
ug
ht
dire
ctly t
o t
he
tra
um
a
ce
ntr
e f
rom
th
e s
ce
ne
, w
ere
no
t
tra
nsf
err
ed
fro
m t
he
ED
to
an
oth
er
ho
spita
l, d
id n
ot
ha
ve
co
nfo
un
din
g
bu
rns
or
pre
-exi
stin
g c
on
ditio
ns.
Pa
tie
nts
we
re t
he
n s
ele
cte
d b
ase
d
on
:
Syst
olic
BP
< 9
0m
mH
g o
n a
rriv
al a
t
ED
Pa
tie
nt
eith
er
die
d in
ED
or
wa
s
tra
nsf
err
ed
to
th
e o
pe
ratin
g r
oo
m
for
lap
aro
tom
y
Ab
do
min
al v
asc
ula
r, s
olid
org
an
or
wa
ll in
jury
with
an
ab
bre
via
ted
inju
ry s
ca
le s
co
re (
AIS
) o
f 3
-6
No
oth
er
inju
ries
with
an
AIS
>2
exc
ep
t fo
r a
lac
era
ted
dia
ph
rag
m
or
op
en
, d
isp
lac
ed
, c
om
min
ute
d
pe
lvic
fra
ctu
re
Eith
er
the
tim
e o
f in
jury
or
am
bu
lan
ce
dis
pa
tch
an
d t
he
tim
e
of
arr
iva
l in
ED
an
d t
ime
of
de
pa
rtu
re f
rom
ED
or
de
ath
in E
D o
r
arr
iva
l at
OR
.
Ris
k r
atio
s fo
r d
ea
th b
y m
inu
tes
to
ED
(95%
CI)
1-3
0 m
inu
tes
RR
0.7
73 (
0.5
01-1
.194)
31-6
0 m
inu
tes
RR
1.2
68 (
0.9
80
-1.6
41
)
61-9
0 m
inu
tes
RR
0.8
32 (
0.4
96
-1.3
96
)
91-1
85 m
ins
RR
0.7
40
(0
.18
9-2
.888
)
Lim
ita
tio
ns
�
Re
lied
on
ac
cu
rac
y o
f re
gis
try d
ata
.
No
da
ta p
rese
nte
d o
n t
he
ac
cu
rac
y
of
tha
t so
urc
e.
�
Ge
ne
ralis
ab
ility
re
stric
ted
to
a n
arr
ow
ran
ge
of
inju
rie
s re
sultin
g f
rom
tra
um
a
du
e t
o t
he
na
rro
w s
ele
ctio
n c
rite
ria
.
�
Ob
serv
atio
na
l stu
dy is
su
sce
ptib
le t
o
co
nfo
un
din
g.
�
Foc
us
of
the
stu
dy w
as
mo
re o
n E
D
tim
e t
ha
n t
he
pre
-ho
spita
l pe
rio
d.
�
Se
ve
n o
f th
e 2
50 e
ligib
le p
atie
nts
we
re e
xclu
de
d d
ue
to
extr
em
e p
re-
ho
spita
l tim
ing
s (8
ho
urs
fo
r o
ne
an
d 7
da
ys
20h
ou
rs f
or
an
oth
er)
an
d
pro
lon
ge
d E
D t
ime
(>
24 h
ou
rs).
�
Po
ten
tia
l bia
ses
ide
ntifie
d b
y t
he
au
tho
rs in
clu
de
d m
isc
lass
ific
atio
n o
f
tim
ing
inte
rva
ls d
ue
to
a t
en
de
nc
y t
o
rou
nd
to
th
e n
ea
rest
5 m
inu
tes,
fa
ilure
to id
en
tify
pre
-exis
tin
g c
on
ditio
ns
in
ind
ivid
ua
ls w
ho
die
d s
ho
rtly
aft
er
arr
iva
l, se
lec
tio
n b
ias
du
e t
o m
issi
ng
tim
e d
ata
.
TRANSPORTATION OF EMERGENCY PATIENTS
99
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Cla
rke
et
al.
2002
)
USA
co
ntin
ue
d
Da
ta c
olle
ctio
n
Use
d d
ata
fro
m t
he
Pe
nn
sylv
an
ia
Tra
um
a S
yst
em
s Fo
un
da
tio
n t
rau
ma
reg
istr
y. D
ata
extr
ac
ted
inc
lud
ed
:
Tim
e o
f in
jury
, tim
e o
f a
mb
ula
nc
e
dis
pa
tch
, tim
e p
atie
nt
arr
ive
d a
t ED
,
syst
olic
BP
, d
iag
no
ses,
pre
-exi
stin
g
co
nd
itio
ns,
tim
e p
atie
nt
left
ED
, tim
e
pa
tie
nt
arr
ive
d in
op
era
tin
g r
oo
m,
op
era
tive
pro
ce
du
res,
pa
tie
nts
ou
tco
me
.
Ou
tco
me
me
asu
res
Mo
rta
lity
An
aly
sis
Ris
k r
atio
s fo
r d
ea
th w
ere
ca
lcu
late
d f
or
the
tim
e t
o t
he
ED
,
tim
e in
th
e E
D a
nd
to
tal tim
e (
tim
e
to E
D a
nd
tim
e in
ED
) a
nd
th
e S
BP
on
arr
iva
l in
th
e E
D. Lo
gis
tic
reg
ress
ion
wa
s u
sed
to
mo
de
l
pre
dic
tio
ns
of
ou
tco
me
usi
ng
co
ntin
uo
us
va
ria
ble
s o
f tim
e a
nd
SB
P w
ith
in t
he
tim
e in
terv
als
th
at
we
re f
ou
nd
to
ha
ve
sig
nific
an
t risk
ratio
s.
C
om
me
nts
�
Exa
min
ed
th
e r
ela
tio
nsh
ip b
etw
ee
n
surv
iva
l an
d t
ime
in
th
e e
me
rge
nc
y
de
pa
rtm
en
t b
efo
re la
pa
roto
my f
or
hyp
ote
nsi
ve
pa
tie
nts
ble
ed
ing
fro
m
ab
do
min
al i
nju
ries.
�
Pre
-ho
spita
l tim
e p
refe
ren
tia
lly u
sed
tim
e f
rom
dis
pa
tch
ra
the
r th
an
tim
e o
f
inju
ry a
s th
e s
tart
of
the
pre
-ho
spita
l
pe
riod
.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
Am
on
g p
atie
nts
in a
tra
um
a r
eg
istr
y w
ho
we
re h
yp
ote
nsi
ve
on
arr
iva
l in
ED
an
d h
ad
ma
jor
inju
rie
s is
ola
ted
to
th
e a
bd
om
en
req
uirin
g e
me
rge
nc
y la
pa
roto
my,
the
pro
ba
bili
ty o
f d
ea
th s
ho
we
d a
re
latio
nsh
ip
to b
oth
th
e e
xte
nt
of
hyp
ote
nsi
on
an
d t
he
len
gth
of
tim
e in
th
e E
D f
or
pa
tie
nts
wh
o
we
re in
th
e E
D f
or
90 m
inu
tes
or
less
.
TRANSPORTATION OF EMERGENCY PATIENTS
10
0
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Lim
an
d S
eo
w 2
00
2)
Sin
ga
po
re
Re
tro
spe
ctive
co
ho
rt s
tud
y
Leve
l III-
2
Stu
dy s
ett
ing
.
Am
bu
lan
ce
se
rvic
e in
Sin
ga
po
re u
ses
a
sin
gle
tie
r sy
ste
m. Stu
dy s
et
in E
D o
f Y
an
Toc
k S
en
g H
osp
ita
l, w
hic
h s
ee
s a
bo
ut
350 p
atie
nts
pe
r d
ay.
Pa
rtic
ipa
nts
:
n=
93 (
15 s
urv
ivo
rs, 78
no
n-s
urv
ivo
rs)
An
aly
ses
co
mp
arin
g g
rou
ps
at
ba
selin
e.
Me
an
ag
e (
ye
ars
)
Su
rviv
ors
63.1
No
n-s
urv
ivo
rs 6
5.5
Ma
le (
%)
Su
rviv
ors
53.3
No
n-s
urv
ivo
rs 6
2.8
Initia
l ca
rdia
c r
hyth
m: a
syst
ole
(%
)
Su
rviv
ors
53.3
No
n-s
urv
ivo
rs 7
1.3
Byst
an
de
r C
PR
(%
)
Su
rviv
ors
6.6
No
n-s
urv
ivo
rs 1
8.0
Pre
-ho
spita
l de
fib
rilla
tio
n (
%)
Su
rviv
ors
6.6
No
n-s
urv
ivo
rs 1
8.0
RO
SC
(%
)
Su
rviv
ors
46.7
No
n-s
urv
ivo
rs 0
.0
P<
0.0
01
Inc
lu/e
xcl c
rite
ria
.
All
ou
t-o
f-h
osp
ita
l ca
rdia
c a
rre
st
(OH
CA
) p
atie
nts
pre
sen
tin
g f
rom
No
v 2
001 t
hro
ug
h J
an
20
02 w
ith
no
n-t
rau
ma
tic
OH
CA
.
Da
ta c
olle
ctio
n
Da
ta c
olle
cte
d f
rom
am
bu
lan
ce
ca
se r
ec
ord
s, E
D r
esu
scita
tio
n
ch
art
s a
nd
ED
VH
F C
ase
Lo
g S
he
ets
,
in-p
atie
nt
ho
spita
l re
co
rds.
Co
llec
ted
de
mo
gra
ph
ic
info
rma
tio
n,
tim
e r
ela
ted
da
ta,
initia
l ca
rdia
c r
hyth
m,
use
of
au
tom
atic
exte
rna
l de
fib
rilla
tor,
resu
lt o
f re
susc
ita
tio
n o
n s
ce
ne
or
en
-ro
ute
to
ho
spita
l, p
atie
nt’
s
pre
mo
rbid
co
nd
itio
n.
Ou
tco
me
me
asu
res
Su
rviv
al p
ost
ED
re
susc
ita
tio
n
An
aly
sis
Da
ta a
na
lyse
d u
sin
g t
wo
ta
iled
t
test
fo
r a
ll c
on
tin
uo
us
va
ria
ble
s a
nd
ch
i-sq
ua
re t
est
fo
r a
ll d
isc
rete
va
riab
les.
Co
mp
aris
on
of
surv
ivo
rs (
po
st E
D
resu
scita
tio
n)
an
d n
on
-su
rviv
ors
,
tota
l pre
-ho
spita
l tim
e (
min
ute
s)
Su
rviv
ors
: 3
8.3
No
n-s
urv
ivo
rs: 3
5.4
P=
0.9
2
No
te o
nly
on
e p
atie
nt
surv
ive
d t
o
ho
spita
l dis
ch
arg
e.
Lim
ita
tio
ns
�
Re
lied
on
ac
cu
rac
y o
f re
co
rde
d d
ata
.
The
pa
ram
ed
ics
are
on
ly a
ble
to
co
mp
lete
th
e r
ele
va
nt
form
co
nta
inin
g t
he
tim
e d
ata
on
arr
iva
l a
t
ED
so
th
e t
ime
re
co
rde
d is
like
ly t
o b
e
susc
ep
tib
le t
o m
isc
lass
ific
atio
n.
�
Ob
serv
atio
na
l stu
dy is
su
sce
ptib
le t
o
co
nfo
un
din
g a
nd
me
tho
d o
f a
na
lysi
s
wa
s n
ot
use
ful f
or
co
ntr
olli
ng
po
ten
tia
l
co
nfo
un
de
rs.
�
Sm
all
pa
tie
nt
nu
mb
ers
, p
art
icu
larly
am
on
gst
th
e s
urv
ivo
rs (
n=
15
), r
ed
uc
ed
stu
dy p
ow
er.
�
No
t th
e m
ost
use
ful o
utc
om
e m
ea
sure
(su
rviv
al p
ost
ED
re
susc
ita
tio
n).
It
is
no
tew
ort
hy t
ha
t o
nly
1 o
f th
e 1
5
pa
tie
nts
su
rviv
ing
ED
re
susc
ita
tio
n
ac
tua
lly s
urv
ive
d t
o h
osp
ita
l
dis
ch
arg
e.
�
So
me
inc
on
sist
en
cie
s in
th
e p
ap
er
eg
.
On
e s
tate
me
nt
sug
ge
ste
d 1
5 s
urv
ive
d
ED
re
susc
ita
tio
n a
nd
an
oth
er
sug
ge
ste
d s
eve
n s
urv
ive
d E
D
resu
scita
tio
n.
TRANSPORTATION OF EMERGENCY PATIENTS
10
1
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Lim
an
d S
eo
w 2
00
2)
Sin
ga
po
re
co
ntin
ue
d
Co
mm
en
ts
�
Aim
ed
to
eva
lua
te c
ha
rac
terist
ics
an
d o
utc
om
e o
f o
ut-
of-
ho
spita
l
ca
rdia
c a
rre
st p
atie
nts
pre
sen
tin
g t
o
the
ED
, a
nd
to
exa
min
e f
ac
tors
th
at
co
uld
be
use
d t
o d
ete
rmin
e w
he
the
r
to p
rolo
ng
or
ab
ort
re
susc
ita
tio
n f
or
the
se p
atie
nts
.
�
Inc
lud
ed
co
nse
cu
tive
pa
tie
nts
.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
The
su
rviv
al ra
te f
or
pa
tie
nts
with
OH
CA
aft
er
ED
re
susc
ita
tio
n is
sim
ilar
to t
he
re
sults
fro
m o
the
r st
ud
ies.
Pro
lon
ge
d r
esu
scita
tio
n
eff
ort
s a
pp
ea
r to
be
fu
tile
fo
r O
HC
A p
atie
nts
if t
he
tim
e f
rom
ca
rdia
c a
rre
st u
ntil a
rriv
al i
n
the
ED
is a
t le
ast
30 m
inu
tes
co
up
led
with
RO
SC
, a
nd
if c
on
tin
uo
us
asy
sto
le h
as
be
en
do
cu
me
nte
d f
or
mo
re t
ha
n 1
0 m
inu
tes.
TRANSPORTATION OF EMERGENCY PATIENTS
10
2
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Ost
erw
ald
er
20
02
)
Sw
itze
rla
nd
Pro
spe
ctive
co
ho
rt s
tud
y
Leve
l III-
2
Stu
dy s
ett
ing
.
Stu
dy h
osp
ita
l (S
t G
alle
n C
an
ton
al
Ho
spita
l) s
erv
es
Ea
ste
rn S
witze
rla
nd
, h
as
an
imm
ed
iate
ca
tch
me
nt
po
pu
latio
n o
f
ab
ou
t 100,0
00
an
d h
as
ab
ou
t 80
0 b
ed
s
(in
clu
din
g t
wo
IC
Us)
.
EM
S in
clu
de
d h
elic
op
ters
(o
fte
n w
ith
a
ph
ysi
cia
n o
n b
oa
rd)
an
d g
rou
nd
am
bu
lan
ce
s
Pa
rtic
ipa
nts
:
N=
254
inc
lud
ing
107
with
a r
esc
ue
p
erio
d ≤
60 m
inu
tes
an
d 1
47 w
ith
a
resc
ue
pe
rio
d >
60 m
inu
tes.
An
aly
ses
co
mp
arin
g g
rou
ps
at
ba
selin
e.
Me
an
ag
e (
ye
ars
)
≤60 m
inu
tes
gro
up
: 30
>60 m
inu
tes
gro
up
: 29
Ma
le (
%)
≤60 m
inu
tes
gro
up
: 66
>60 m
inu
tes
gro
up
: 78
Me
dia
n ISS
≤60 m
inu
tes
gro
up
: 24
>60 m
inu
tes
gro
up
: 24
Inc
lu/e
xcl c
rite
ria
.
Blu
nt
tra
um
a
Tre
atm
en
t in
th
e s
ho
ck r
oo
m,
ED
, St
Ga
llen
Ca
nto
na
l Ho
spita
l
Pre
sen
ce
of
inju
ries
with
a m
inim
um
AIS
of
≥2 in
at
lea
st t
wo
of
six
de
fin
ed
bo
dy r
eg
ion
s
Eith
er
tra
nsf
er
to IC
U o
r a
sta
y o
f a
t
lea
st t
hre
e d
ays
in h
osp
ita
l or
de
ath
follo
win
g a
dm
issi
on
.
Ou
tco
me
me
asu
res
30 d
ay m
ort
alit
y
Pre
dic
ted
mo
rta
lity b
ase
d o
n
ASC
OT
sco
re
Re
sultin
g e
xce
ss m
ort
alit
y r
ate
(ac
tua
l – e
xpe
cte
d d
ea
ths)
An
aly
sis
Flo
ra’s
Z s
tatist
ic u
sed
to
co
mp
are
ac
tua
l with
exp
ec
ted
mo
rta
lity.
Po
ssib
le c
on
fou
nd
ing
va
riab
les
an
d
furt
he
r c
om
pa
riso
ns
we
re t
est
ed
usi
ng
th
e in
de
pe
nd
en
t Stu
de
nt’
s t
test
, M
an
n W
hitn
ey U
te
st, c
hi
squ
are
te
st a
nd
log
istic
re
gre
ssio
n
Ac
tua
l ve
rsu
s p
red
icte
d m
ort
alit
y
(30 d
ays)
Tr
an
spo
rt t
ime
≤60 m
inu
tes
Ac
tua
l: 1
4%
Pre
dic
ted
: 9.5
%
P=
0.0
6
Tra
nsp
ort
tim
e >
60 m
inu
tes
Ac
tua
l: 1
0.2
%
Pre
dic
ted
: 13.1
%
P=
0.1
9
Ad
just
ed
co
mp
aris
on
be
twe
en
tra
nsp
ort
tim
e ≤
60 m
inu
tes
an
d >
60
min
ute
s, a
nd
mo
rta
lity
OR
(>
60 m
inu
tes
as
refe
ren
ce
) 8
(95%
CI 1.7
-38.5
)
Lim
ita
tio
ns
�
M s
tatist
ic n
ot
pre
sen
ted
so
de
gre
e o
f
fit
with
MTO
S d
ata
wa
s u
nc
lea
r.
�
Ob
serv
atio
na
l stu
dy is
su
sce
ptib
le t
o
co
nfo
un
din
g a
lth
ou
gh
mu
ltiv
aria
te
an
aly
sis
is a
use
ful m
eth
od
to
co
ntr
ol
for
kn
ow
n c
on
fou
nd
ers
. H
ow
eve
r, t
he
va
riab
les
inc
lud
ed
in t
he
mu
ltiv
aria
te
mo
de
l we
re n
ot
do
cu
me
nte
d.
�
Stu
dy r
est
ric
ted
to
blu
nt
tra
um
a
pa
tie
nts
wh
ich
ne
ed
s to
be
rec
og
nis
ed
wh
en
co
nsi
de
rin
g
ge
ne
ralis
ab
ility
.
�
Re
lied
on
ac
cu
rac
y o
f re
gis
try d
ata
.
No
da
ta p
rese
nte
d o
n t
he
ac
cu
rac
y
of
tha
t so
urc
e.
TRANSPORTATION OF EMERGENCY PATIENTS
10
3
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Ost
erw
ald
er
20
02
)
Sw
itze
rla
nd
co
ntin
ue
d
C
au
se o
f tr
au
ma
:
roa
d t
raff
ic a
cc
ide
nt
(%)
≤60 m
inu
tes
gro
up
: 77
>60 m
inu
tes
gro
up
: 69
Wo
rk (
%)
≤60 m
inu
tes
gro
up
: 11
>60 m
inu
tes
gro
up
: 12
Sp
ort
(%
):
≤60 m
inu
tes
gro
up
: 1
>60 m
inu
tes
gro
up
: 13
P=
0.0
05
Su
icid
e/v
iole
nc
e (
%)
≤60 m
inu
tes
gro
up
: 9
>60 m
inu
tes
gro
up
: 1
P=
0.0
04
�
Sig
nific
an
t d
iffe
ren
ce
s in
ba
selin
e
me
asu
res
in r
ela
tio
n t
o c
au
se o
f
tra
um
a:
spo
rt w
as
ass
oc
iate
d w
ith
lon
ge
r tr
an
spo
rt t
ime
an
d
suic
ide
/vio
len
ce
with
sh
ort
er
tra
nsp
ort
tim
e.
Als
o f
ew
er
pa
tie
nts
we
re t
rea
ted
w
ith
a p
hysi
cia
n in
th
e ≤
60 m
inu
tes
gro
up
.
�
26 p
atie
nts
we
re o
mitte
d d
ue
to
mis
sin
g t
ime
da
ta (
ove
rall
the
re w
as
mis
sin
g d
ata
in 9
% o
f th
e s
tud
y
po
pu
latio
n).
Co
mm
en
ts
�
Aim
ed
to
eva
lua
te t
he
hyp
oth
esi
s th
at
exc
ee
din
g t
he
60 m
inu
te li
mit f
or
the
en
tire
pre
-ho
spita
l tim
e in
cre
ase
s
mo
rta
lity o
f b
lun
t p
oly
tra
um
a p
atie
nts
.
�
All
pa
tie
nts
tre
ate
d a
t th
e s
am
e L
ev
el
1 t
rau
ma
ho
spita
l.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
It a
pp
ea
rs in
th
is t
rau
ma
syst
em
, in
wh
ich
em
erg
en
cy p
hysi
cia
ns
oft
en
are
de
plo
ye
d,
tha
t th
e g
old
en
ho
ur
of
sho
ck c
an
be
ext
en
de
d s
afe
ly in
ma
ny b
lun
t p
oly
tra
um
a
pa
tie
nts
, si
nc
e t
his
wa
s a
sso
cia
ted
with
be
tte
r su
rviv
al f
igu
res
tha
n in
th
ose
pa
tie
nts
for
wh
om
th
e t
ime
wa
s <
1 h
ou
r.
TRANSPORTATION OF EMERGENCY PATIENTS
10
4
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Le
rne
r e
t a
l. 20
03
)
USA
Re
tro
spe
ctive
co
ho
rt s
tud
y
Leve
l III-
2
Stu
dy s
ett
ing
.
Da
ta o
bta
ine
d f
rom
re
co
rds
ma
inta
ine
d
by t
he
on
ly a
du
lt r
eg
ion
al t
rau
ma
ce
ntr
e in
we
ste
rn N
ew
Yo
rk.
The
ce
ntr
e
wa
s a
389 b
ed
te
rtia
ry c
are
te
ac
hin
g
fac
ility
with
ab
ou
t 1
3,5
00 a
nn
ua
l
ad
mis
sio
ns
(ap
pro
xim
ate
ly 1
,600 o
f
wh
ich
re
sulte
d f
rom
tra
um
a).
Pa
rtic
ipa
nts
:
N=
187
7
Ba
selin
e a
na
lyse
s (p
atie
nts
with
co
mp
lete
da
ta)
Tra
nsp
ort
ed
by h
elic
op
ter
8%
Pe
ne
tra
tin
g in
jury
23%
Ma
le 7
2%
Me
an
ag
e 3
8 y
ea
rs
Me
an
re
vis
ed
tra
um
a s
co
re 7
.5
Me
an
ISS 1
0
Me
an
to
tal o
ut-
of-
ho
spita
l tim
e 3
5
min
ute
s
Inc
lu/e
xcl c
rite
ria
.
All
pa
tie
nts
fro
m J
an
199
3 t
o O
ct
1996 if
th
e p
atie
nt
ha
d b
ee
n
tra
nsp
ort
ed
dire
ctly f
rom
th
e s
ce
ne
by a
mb
ula
nc
e o
r h
elic
op
ter.
Pa
tie
nts
we
re a
dm
itte
d f
rom
ED
or
die
d in
th
e E
D.
Exc
lud
ed
pa
tie
nts
with
inc
om
ple
te
da
ta, w
ith
mo
re t
ha
n o
ne
da
y
diffe
ren
ce
be
twe
en
th
e d
ate
of
inju
ry a
nd
th
e d
ate
of
ad
mis
sio
n,
CP
R in
itia
ted
in t
he
fie
ld o
r
tra
nsp
ort
ed
fro
m a
co
rre
ctio
na
l
fac
ility
.
Da
ta c
olle
ctio
n
Mo
st d
ata
we
re e
xtr
ac
ted
fro
m t
he
tra
um
a r
eg
istr
y. O
ut-
of-
ho
spita
l
pa
tie
nt
ca
re r
ep
ort
an
d d
isp
atc
h
ag
en
cy r
ec
ord
s u
sed
to
sup
ple
me
nt
the
re
gis
try t
ime
da
ta
as
it w
as
oft
en
in
co
mp
lete
.
Ou
t o
f h
osp
ita
l va
ria
ble
s: t
ran
spo
rt
mo
de
, to
tal o
ut-
of-
ho
spita
l tim
e,
pa
tie
nt’
s C
UP
S s
tatu
s.
Ho
spita
l va
ria
ble
s in
clu
de
d r
ev
ise
d
tra
um
a s
ca
le, IS
S, E c
od
e, a
dm
issi
on
da
te, a
ge
, se
x, t
yp
e o
f in
jury
.
Ou
tco
me
me
asu
res
Mo
rta
lity
Diffe
ren
ce
in m
ea
n t
ota
l ou
t-o
f-
ho
spita
l tim
e b
etw
ee
n s
urv
ivo
rs a
nd
no
n-s
urv
ivo
rs
Su
rviv
ors
: 3
5.2
6 m
inu
tes
No
n-s
urv
ivo
rs: 3
1.5
8 m
inu
tes
Diffe
ren
ce
3.6
9 m
inu
tes
(95%
CI
0.5
2-6
.85 m
inu
tes)
Ad
just
ed
OR
, to
tal o
ut
of
ho
spita
l
tim
e,
inc
rea
sin
g p
re-h
osp
ita
l tim
e
an
d o
dd
s o
f m
ort
alit
y
OR
0.9
87 (
95%
CI 0.9
7-1
.00).
Lim
ita
tio
ns
�
Me
dic
al r
ec
ord
s re
vie
w w
ith
inh
ere
nt
limita
tio
ns
of
this
so
urc
e. P
oss
ible
limita
tio
ns
inc
lud
e m
issi
ng
da
ta a
nd
inc
on
sist
en
t m
eth
od
s o
f re
co
rdin
g.
�
Po
ten
tia
l fo
r m
isc
lass
ific
atio
n o
f to
tal
pre
-ho
spita
l tim
e o
r p
ote
ntia
l
co
nfo
un
din
g v
aria
ble
s. M
ost
like
ly t
o
be
ra
nd
om
, re
sultin
g in
dilu
tio
n o
f th
e
eff
ec
t.
�
Like
ly s
ele
ctio
n b
ias
du
e t
o t
he
om
issi
on
of
pa
tie
nts
with
mis
sin
g d
ata
(48
2 o
f 235
9 w
ere
om
itte
d d
ue
to
mis
sin
g d
ata
, 2
0%
).
�
Ob
serv
atio
na
l stu
dy is
su
sce
ptib
le t
o
co
nfo
un
din
g a
lth
ou
gh
mu
ltiv
aria
te
an
aly
sis
is a
use
ful m
eth
od
to
co
ntr
ol
for
kn
ow
n c
on
fou
nd
ers
.
�
It is
po
ssib
le t
ha
t p
rov
ide
rs t
ran
spo
rt
the
pa
tie
nts
th
ey b
elie
ve
d t
o b
e m
ost
seve
rely
inju
red
qu
icke
r, t
hu
s b
iasi
ng
the
re
sults.
TRANSPORTATION OF EMERGENCY PATIENTS
10
5
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Le
rne
r e
t a
l. 20
03
)
USA
co
ntin
ue
d
An
aly
sis
Biv
aria
te a
na
lyse
s c
on
du
cte
d t
o
de
term
ine
wh
ich
va
ria
ble
s w
ere
ass
oc
iate
d w
ith
mo
rta
lity. Stu
de
nt’
s
t te
st u
sed
fo
r c
on
tin
uo
us
va
riab
les
an
d c
hi s
qu
are
or
Fis
he
r’s
exa
ct
test
use
d f
or
ca
teg
oric
al v
aria
ble
s.
Str
atific
atio
n b
y in
jury
se
ve
rity
an
d
typ
e a
lso
co
nd
uc
ted
. M
ultip
le
pre
dic
tors
log
istic
re
gre
ssio
n u
sed
to
de
term
ine
if t
ota
l ou
t o
f h
osp
ita
l
tim
e w
as
a s
ign
ific
an
t p
red
icto
r o
f
tra
um
a m
ort
alit
y. V
aria
ble
s
ass
oc
iate
d w
ith
mo
rta
lity o
n
un
iva
ria
te a
na
lysi
s w
ere
inc
lud
ed
in
the
mo
de
l.
C
om
me
nts
�
Aim
wa
s to
de
term
ine
if t
he
re is
an
ass
oc
iatio
n b
etw
ee
n t
ota
l ou
t o
f
ho
spita
l tim
e a
nd
tra
um
a m
ort
alit
y.
�
We
ll c
on
du
cte
d s
tatist
ica
l an
aly
sis.
�
All
pa
tie
nts
tra
nsp
ort
ed
to
a s
ing
le
ho
spita
l.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
Pro
vid
er
ass
ign
ed
CU
PS s
tatu
s, p
atie
nt
ag
e,
Inju
ry S
eve
rity
Sc
ore
, a
nd
Re
vis
ed
Tra
um
a
Sc
ore
all
we
re s
ign
ific
an
t p
red
icto
rs o
f
tra
um
a p
atie
nt
mo
rta
lity. To
tal o
ut
of
ho
spita
l tim
e w
as
no
t a
sso
cia
ted
with
mo
rta
lity.
TRANSPORTATION OF EMERGENCY PATIENTS
10
6
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Bie
we
ne
r e
t a
l. 2
004
)
Ge
rma
ny
Re
tro
spe
ctive
co
ho
rt s
tud
y
Leve
l III-
2
Stu
dy s
ett
ing
.
Stu
die
d f
ou
r p
oss
ible
pa
thw
ays
of
po
lytr
au
ma
pa
tie
nts
in D
resd
en
,
Ge
rma
ny: 1
. H
elic
op
ter
tra
nsp
ort
atio
n
to L
eve
l 1 t
rau
ma
ce
ntr
e (
HEM
S-U
NI)
, 2.
Am
bu
lan
ce
tra
nsp
ort
atio
n t
o L
eve
l 1
tra
um
a c
en
tre
(A
MB
-UN
I),
3.
Am
bu
lan
ce
tra
nsp
ort
atio
n t
o L
eve
l 2 o
r
3 t
rau
ma
ce
ntr
e (
AM
B-R
EG
), 4
.
Am
bu
lan
ce
tra
nsp
ort
atio
n t
o L
eve
l 2 o
r
3 tr
au
ma
ce
ntr
e w
ith
su
bse
qu
en
t
tra
nsf
er
to le
ve
l 1 t
rau
ma
ce
ntr
e (
INTE
R).
Pa
rtic
ipa
nts
:
403 p
art
icip
an
ts, H
EM
S-U
NI 140,
AM
B-
REG
10
2,
AM
B-U
NI 70, IN
TER
92.
An
aly
ses
co
mp
arin
g g
rou
ps
at
ba
selin
e.
No
diffe
ren
ce
s b
etw
ee
n t
he
fo
ur
gro
up
s
by a
ge
, g
en
de
r o
r IS
S.
Me
an
ag
e 3
6.8
ye
ars
Ma
le 7
3.3
%
Inc
lu/e
xcl c
rite
ria
.
ISS ≥
16
Arr
iva
l of
pa
tie
nt
aliv
e a
t th
e
ho
spita
l
Co
mp
lete
do
cu
me
nta
tio
n o
f a
ll
pa
tie
nt
da
ta.
Exc
lusi
on
crite
ria: a
ge
> 7
5 y
ea
rs,
ISS>
67.
Da
ta c
olle
ctio
n
Da
ta e
xtr
ac
tio
n f
or
all
bu
t th
e A
MB
-
REG
gro
up
fro
m p
oly
tra
um
a
da
tab
ase
of
a s
ing
le L
eve
l 1 t
rau
ma
ce
ntr
e (
co
mp
iled
pro
spe
ctive
ly).
Da
ta c
olle
ctio
n p
erf
orm
ed
retr
osp
ec
tive
ly in
th
e A
MB
-REG
gro
up
.
Do
cu
me
nte
d ISS, a
ge
, g
en
de
r,
resc
ue
tim
e.
Ou
tco
me
me
asu
res
Mo
rta
lity a
t 30 d
ays
An
aly
sis
Sta
tist
ica
l an
aly
sis
of
the
diffe
ren
ce
s
be
twe
en
gro
up
s w
as
co
nd
uc
ted
usi
ng
ch
i-sq
ua
re a
nd
Fis
he
r’s
exa
ct
test
s.
Log
istic
re
gre
ssio
n u
sed
to
ad
just
mo
rta
lity r
isk d
iffe
ren
ce
fo
r a
ge
, IS
S
an
d g
rou
p.
Pre
-ho
spita
l tim
es
(min
ute
s)
HEM
S-U
NI g
rou
p:
90
AM
B-U
NI 68
Un
iva
ria
te c
om
pa
riso
n o
f 30 d
ay
mo
rta
lity:
HEM
S-U
NI 22.1
%
AM
B-U
NI: 1
5.7
%
Mu
ltiv
aria
te c
om
pa
riso
n o
f m
ort
alit
y
(HEM
S-U
NI a
s re
fere
nc
e)
AM
B-U
NI: O
R 1
.06 (
95%
CI 0.4
27-
2.6
35
)
Inte
rpre
tatio
n:
no
sig
nific
an
t
diffe
ren
ce
in m
ort
alit
y b
etw
ee
n t
he
two
tra
nsp
ort
atio
n m
eth
od
s
invo
lvin
g d
ire
ct
tra
nsp
ort
atio
n t
o
leve
l 1 t
rau
ma
ce
ntr
e d
esp
ite
pro
lon
ge
d t
ran
spo
rta
tio
n t
ime
in
the
he
lico
pte
r g
rou
p.
Lim
ita
tio
ns
�
Re
gis
try b
ase
d s
tud
y w
ith
so
me
retr
osp
ec
tive
da
ta c
olle
ctio
n a
nd
inc
om
ple
te T
RIS
S d
ata
ava
ilab
le
(la
ckin
g in
th
e A
MB
-REG
gro
up
).
�
Ac
cu
rac
y o
f d
ata
un
cle
ar.
�
Ob
serv
atio
na
l stu
dy is
su
sce
ptib
le t
o
co
nfo
un
din
g.
�
Ele
me
nts
of
ec
olo
gic
al a
na
lysi
s fo
r th
e
resu
lts
of
inte
rest
to
th
is r
ev
iew
.
Sp
ec
ific
ally
, th
ere
wa
s n
o c
om
pa
riso
n
be
twe
en
ind
ivid
ua
l tim
e d
ata
an
d
ou
tco
me
, ra
the
r th
e c
om
pa
riso
n w
as
be
twe
en
diffe
ren
t g
rou
ps
(an
d t
hu
s
use
d a
s a
pro
xy f
or
tim
e).
�
Diffe
ren
t st
aff
ing
mix
es
be
twe
en
tra
nsp
ort
atio
n m
eth
od
s (m
ore
pro
ce
du
res
ten
d t
o b
e p
erf
orm
ed
in
the
he
lico
pte
r p
atie
nts
) a
nd
diffe
ren
ce
s in
ma
na
ge
me
nt
ac
ross
the
diffe
ren
t h
osp
ita
ls m
ea
ns
it is
no
t
po
ssib
le t
o a
scrib
e a
ny d
iffe
ren
ce
in
ou
tco
me
to
diffe
ren
ce
in p
re-h
osp
ita
l
tim
e.
�
Pre
-ho
spita
l tim
e t
o le
ve
l 1 t
rau
ma
ca
re n
ot
giv
en
in IN
TER
gro
up
.
TRANSPORTATION OF EMERGENCY PATIENTS
10
7
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Bie
we
ne
r e
t a
l. 2
004
)
Ge
rma
ny
co
ntin
ue
d
Co
mm
en
ts
�
Aim
ed
to
co
mp
are
th
e m
ort
alit
y o
f
fou
r ty
pic
al a
nd
co
mp
lete
pa
thw
ays
of
po
lytr
au
ma
pa
tie
nts
: a
ir o
r g
rou
nd
tra
nsp
ort
to
a le
ve
l 1 t
rau
ma
ce
ntr
e,
gro
un
d t
ran
spo
rt in
to le
ve
l II o
r III
co
mm
un
ity h
osp
ita
ls o
r in
terh
osp
ita
l
tra
nsf
er.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
Prim
ary
tra
nsf
er
into
a L
eve
l 1 t
rau
ma
ce
ntr
e
red
uc
es
mo
rta
lity m
ark
ed
ly. In
prin
cip
le, th
is
be
ne
fit
ca
n b
e a
ttrib
ute
d t
o s
up
erio
r
pre
clin
ica
l th
era
py, p
rim
ary
ad
mis
sio
n t
o a
Leve
l 1 t
rau
ma
ce
ntr
e o
r b
oth
. H
ow
eve
r, t
he
ide
ntic
al p
rob
ab
ility
of
surv
iva
l of
the
AM
B-
UN
I a
nd
HEM
S-U
NI g
rou
ps
in t
his
an
d
co
mp
ara
ble
stu
die
s d
oe
s n
ot
co
nfirm
ge
ne
rally
be
tte
r su
rviv
al r
ate
s o
n a
cc
ou
nt
of
a m
ore
ag
gre
ssiv
e o
n-s
ite
ap
pro
ac
h.
TRANSPORTATION OF EMERGENCY PATIENTS
10
8
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Ga
o e
t a
l. 200
6)
Ch
ina
Re
tro
spe
ctive
co
ho
rt s
tud
y
Leve
l III-
2
Stu
dy s
ett
ing
.
Po
lytr
au
ma
pa
tie
nts
with
th
ora
cic
an
d/o
r a
bd
om
ina
l in
jurie
s tr
ea
ted
at
Ch
on
gq
ing
Em
erg
en
cy M
ed
ica
l Ce
nte
r,
Ch
ina
fro
m O
ct
19
93 t
o S
ep
t 2
003.
Pa
rtic
ipa
nts
:
n=
1540
Ba
selin
e a
na
lyse
s.
Me
an
ag
e 2
8.8
ye
ars
Ma
les
79%
Du
ratio
n o
f p
rea
dm
issi
on
(%
)
< 1
ho
ur:
38.4
%
1-6
ho
urs
: 4
0.6
%
>6 h
ou
rs: 21.0
%
Blu
nt
tra
um
a:
61
.7%
Inc
lu/e
xcl c
rite
ria
.
Inju
ries
to m
ore
th
an
tw
o ISS b
od
y
reg
ion
s a
nd
at
lea
st o
ne
re
gio
n h
ad
AIS
≥3.
Da
ta c
olle
ctio
n
Ext
rac
ted
da
ta o
n s
ex,
ag
e, c
au
ses
of
inju
ry, d
ura
tio
n o
f p
rea
dm
issi
on
an
d in
jure
d r
eg
ion
s, s
ho
ck s
tate
on
ad
mis
sio
n, a
mo
un
t o
f b
loo
d
tra
nsf
usi
on
, se
ve
rity
of
inju
ries,
me
tho
d o
f d
iag
no
sis,
th
era
pe
utic
pro
ce
du
res.
Ou
tco
me
me
asu
res
Mo
rta
lity
An
aly
sis
Ch
i sq
ua
re t
est
.
Re
latio
nsh
ip b
etw
ee
n p
rea
dm
issi
on
tim
e a
nd
mo
rta
lity
Pre
ad
mis
sio
n <
1 h
ou
r: 3
.9%
mo
rta
lity
Pre
ad
mis
sio
n ≥
1 h
ou
r: 7
.7%
mo
rta
lity
P<
0.0
1
Lim
ita
tio
ns
�
Re
tro
spe
ctive
re
vie
w. P
ote
ntia
l
limita
tio
ns
of
this
ap
pro
ac
h in
clu
de
mis
sin
g d
ata
, a
nd
inc
on
sist
en
t
rec
ord
ing
of
da
ta.
�
Ac
cu
rac
y o
f d
ata
un
cle
ar.
�
Ob
serv
atio
na
l stu
dy is
su
sce
ptib
le t
o
co
nfo
un
din
g. N
o m
ultiv
aria
te a
na
lysi
s
to c
on
tro
l fo
r c
on
fou
nd
ing
.
Co
mm
en
ts
�
Aim
ed
to
inve
stig
ate
th
e e
arly
dia
gn
osi
s a
nd
tre
atm
en
t o
f
po
lytr
au
ma
pa
tie
nts
with
th
ora
cic
an
d/o
r a
bd
om
ina
l in
jurie
s.
�
All
pa
tie
nts
ta
ke
n t
o t
he
sa
me
ho
spita
l.
Re
po
rte
d c
on
clu
sio
ns
(by a
uth
ors
).
The
first
go
lde
n h
ou
r a
fte
r tr
au
ma
sh
ou
ld b
e
gra
spe
d, si
nc
e t
he
tre
atm
en
t in
th
is h
ou
r
ca
n d
ete
rmin
e g
rea
tly w
he
the
r th
e c
ritic
ally
inju
red
vic
tim
co
uld
su
rviv
e.
Pro
mp
t
dia
gn
osi
s a
nd
pro
pe
r tr
ea
tme
nt
co
ntr
ibu
te
mo
re g
rea
tly t
o t
he
su
rviv
al o
f th
e v
ictim
tha
n t
he
se
ve
rity
of
inju
ry.
TRANSPORTATION OF EMERGENCY PATIENTS
10
9
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Ha
rtl e
t a
l. 2
006
)
USA
Re
tro
spe
ctive
co
ho
rt s
tud
y
Leve
l III-
2
Stu
dy s
ett
ing
.
Pa
tie
nts
tre
ate
d a
t 22 t
rau
ma
ce
ntr
es
in
a N
ew
Yo
rk S
tate
qu
alit
y im
pro
ve
me
nt
pro
gra
m b
etw
ee
n 2
000 a
nd
20
04.
Pa
rtic
ipa
nts
:
1123 p
atie
nts
Ba
selin
e a
na
lyse
s
Me
an
ag
e 3
6 y
ea
rs
Ma
le 7
5%
GC
S: 2-5
54%
6-8
33%
≥9 1
3%
Pu
pill
ary
ab
no
rma
litie
s 21
%
Tra
um
a lo
ca
tio
n u
rba
n 2
8%
Air t
ran
spo
rt m
od
e 3
6%
Dire
ct
tra
nsp
ort
tim
e m
ea
n 1
.1 h
ou
rs
Ind
irec
t tr
an
spo
rt t
ime
me
an
4.5
ho
urs
Am
bu
lan
ce
intu
ba
tio
n 4
2%
Inc
lu/e
xcl c
rite
ria
.
Da
ta e
xtr
ac
ted
fro
m T
BI-
tra
c.
TBI-
tra
c in
clu
de
s:
Arr
iva
l at
leve
l 1 o
r le
ve
l 2 t
rau
ma
ce
ntr
e w
ith
in 2
4 h
ou
rs o
f in
jury
GC
S<
9 f
or
at
lea
st 6
ho
urs
aft
er
inju
ry a
nd
aft
er
resu
scita
tio
n e
ffo
rts
inc
lud
ing
airw
ay m
an
ag
em
en
t,
ve
ntila
tory
su
pp
ort
, a
nd
circ
ula
tory
sup
po
rt.
Me
ch
an
ism
of
inju
ry m
ust
be
co
nsi
ste
nt
with
tra
um
a. Exc
lud
es
sub
ara
ch
no
id h
ae
mo
rrh
ag
e
sec
on
da
ry t
o a
ne
ury
sm o
r st
roke
,
pa
tie
nts
wh
o e
xpire
d in
th
e E
D,
or
ad
mitte
d w
ith
a d
iag
no
sis
of
bra
in
de
ath
, o
r w
ere
tra
nsf
err
ed
to
th
e
stu
dy h
osp
ita
l > 2
4 h
ou
rs a
fte
r in
jury
.
No
np
ara
lyse
d p
atie
nts
with
a G
CS
of
3 o
r 4
an
d f
ixe
d a
nd
dila
ted
pu
pils
we
re e
xclu
de
d f
rom
an
aly
sis.
Da
ta c
olle
ctio
n
Da
ta e
xtr
ac
ted
fro
m T
BI-
tra
c:
Tim
e o
f in
jury
, tim
e o
f a
rriv
al a
t
tra
um
a c
en
tre
, m
od
e o
f tr
an
spo
rt,
typ
e o
f EM
S p
rovid
er,
dire
ct
or
ind
irec
t tr
an
spo
rt, b
loo
d p
ress
ure
an
d p
uls
e o
xim
etr
y v
alu
es,
GC
S,
pu
pill
ary
ass
ess
me
nt
an
d a
irw
ay
ma
na
ge
me
nt
pro
ce
du
res.
Ou
tco
me
me
asu
res
Two
we
ek m
ort
alit
y
Ass
oc
iatio
n b
etw
ee
n t
ime
to
tra
um
a c
en
tre
a
nd
tw
o w
ee
k
mo
rta
lity, a
dju
ste
d o
dd
s ra
tio
(9
5%
CI)
OR
1.0
0 (
1.0
0,
1.0
0)
for
ea
ch
on
e
min
ute
in
cre
ase
in t
ran
spo
rt t
ime
.
Ad
just
ed
fo
r h
yp
ote
nsi
on
sta
tus
on
da
y 1
, <
or
> 6
0 y
ea
rs o
f a
ge
,
pu
pill
ary
sta
tus
on
da
y 1
an
d in
itia
l
GC
S.
Lim
ita
tio
ns
�
Stu
dy c
on
du
cte
d in
54%
of
the
to
tal
tra
um
a c
en
tre
s in
th
e s
tate
.
�
Un
cle
ar
if c
on
sec
utive
pa
tie
nts
we
re
sele
cte
d in
th
e p
art
icip
atin
g t
rau
ma
ce
ntr
es.
�
Re
gis
try b
ase
d d
ata
with
inh
ere
nt
limita
tio
ns
ab
ou
t re
lian
ce
on
da
ta
co
llec
ted
.
�
Ac
cu
rac
y o
f d
ata
co
llec
ted
no
t
sta
ted
.
�
Ob
serv
atio
na
l stu
dy is
su
sce
ptib
le t
o
co
nfo
un
din
g.
A lim
ite
d r
an
ge
of
po
ten
tia
l co
nfo
un
de
rs w
ere
ad
just
ed
for
in t
he
mu
ltiv
aria
te m
od
el.
�
Da
ta f
or
144
9 p
atie
nts
en
tere
d in
th
e
da
tab
ase
bu
t fu
rth
er
exc
lusi
on
s
red
uc
ed
sa
mp
le s
ize
to
11
23.
Exc
lusi
on
s w
ere
: G
CS>
9 (
n=
71),
GC
S
mo
tor
sco
re >
6 (
n=
14),
fix
ed
an
d
dila
ted
pu
pils
an
d n
ot
pa
raly
sed
(n=
126
), G
CS>
3 a
nd
bila
tera
lly f
ixe
d
an
d d
ilate
d o
r m
issi
ng
pu
pil
info
rma
tio
n (
n=
79
), t
ime
to
ho
spita
l >
24 h
ou
rs (
n=
13),
tra
nsp
ort
tim
e <
10
min
ute
s (n
=17
), m
issi
ng
ou
tco
me
ass
ess
me
nt
(n=
6).
Co
mm
en
ts
�
Aim
ed
to
exp
lore
th
e e
ffe
ct
of
pre
-
ho
spita
l ma
na
ge
me
nt
de
cis
ion
s o
n
ea
rly m
ort
alit
y a
fte
r se
ve
re T
BI.
�
Tim
e o
f in
jury
wa
s b
ase
d o
n t
ime
of
dis
pa
tch
of
EM
S.
�
20 o
f 22 t
rau
ma
ce
ntr
es
we
re le
ve
l 1
tra
um
a c
en
tre
s.
TRANSPORTATION OF EMERGENCY PATIENTS
11
0
Ta
ble
16
E
vid
ence
ta
ble
s o
f st
ud
ies
exa
min
ing
tim
e fr
om
am
bu
lan
ce c
all
ou
t to
em
erg
ency
dep
art
men
t a
rriv
al
(co
nti
nu
ed)
Au
tho
rs
Co
un
try
Stu
dy D
esig
n
Sam
ple
an
d In
terv
en
tio
ns
Meth
od
s
Resu
lts
Lim
itati
on
s a
nd
Co
nclu
sio
ns
(Ha
rtl e
t a
l. 2
006
)
USA
Co
ntin
ue
d
An
aly
sis
Ch
i sq
ua
re t
est
use
d t
o e
va
lua
te
pre
-ho
spita
l ch
ara
cte
ristic
s ve
rsu
s
dire
ct/
ind
ire
ct
tra
nsp
ort
atio
n.
Stu
de
nt’
s t
test
use
d f
or
co
mp
arin
g
me
an
s o
f c
on
tin
uo
us
va
riab
les.
Ma
nn
-Wh
itn
ey t
est
wa
s u
sed
wh
en
sam
ple
siz
es
we
re t
oo
sm
all
for
the
t
test
. Lo
gis
tic
re
gre
ssio
n a
na
lyse
s
pre
dic
tin
g t
wo
we
ek m
ort
alit
y w
ere
use
d t
o e
stim
ate
od
ds
ratio
s.
R
ep
ort
ed
co
nc
lusi
on
s (b
y a
uth
ors
).
The
pre
sen
t st
ud
y p
rov
ide
s c
lass
II e
vid
en
ce
tha
t d
em
on
stra
tes
a 5
0%
inc
rea
se in
mo
rta
lity a
sso
cia
ted
with
ind
irec
t tr
an
sfe
r o
f
TBI p
atie
nts
TRANSPORTATION OF EMERGENCY PATIENTS
111
Summary and Conclusions
There were 21 articles selected for the time component of the review. The selection criteria required that the time from receipt of alarm to the time of arrival at hospital should be recorded. This criterion effectively resulted in a focus on trauma. Medical emergencies were frequently ruled out because the time interval started with the time symptoms started (rather than the time the alarm was received by emergency services) or, in the case of out of hospital cardiac arrest, the time interval recorded was usually from the time of alarm until either arrival at the scene or time of first defibrillation. There was a large body of literature on cardiac arrest that was excluded for that reason. As a consequence there was only one study included that examined out of hospital cardiac arrest.
In general, most studies were retrospective and thus relied on the accuracy of recording. The original purpose of recording was for reasons other than the studies of this nature. There is also likely to be variation in recording practices by different staff within the settings studied. For example, in some studies there may have been rounding of the time component by some staff and not by others. There is certainly the potential for misclassification of time components and also potentially in other variables that may have resulted in residual confounding.
There was wide variation in sample sizes and eligibility criteria as shown through Table 16. The results have been summarised into four sections:
1. Studies that found an association between prolonged pre-hospital time and poor prognosis.
2. Studies where there was no direct comparison between pre-hospital time and outcome. These studies assessed various groupings that happened to have different mean pre-hospital times.
3. Studies that did not identify a statistically significant association between pre-hospital time and outcome.
4. Studies that found an association between shorter pre-hospital time and increased mortality.
Three of the seven studies that found a statistically significant association between prolonged pre-hospital time and poor outcome included multivariate analyses. These three studies were all conducted by Sampalis et al and two had overlapping populations. The largest study (Sampalis et al. 1999) had over 12,000 participants and the study population was distinct from two earlier studies (Sampalis et al. 1992; Sampalis et al. 1993) by the same group. In this study there was a linear association between pre-hospital duration and odds of death such that the odds of death increased by 1.046 for an additional minute of pre-hospital time. On that basis, the odds of death would increase by 1.252 for a five minute increase in pre-hospital time. This study was well conducted. The focus was on patients with severe trauma. This large study was conducted during and after regionalisation of emergency services. The two other studies were conducted before regionalisation. One used a case control design and the other a cohort design. Although there was overlap in the study populations, the estimated odds ratios were quite different (varying between 3 and 30) although both were statistically significant.
The other four studies in this section were limited by their lack of control over potential confounders. Two of these studies focussed on set pre-hospital times. One dichotomised pre-hospital time at 1 hour (Gao et al. 2006) and one at 30 minutes (Frezza and Mezghebe 1999). In both cases mortality was significantly higher in the group with longer pre-hospital times. The other two studies focussed on survivors or unexpected survivors versus deaths and unexpected deaths. The mean times for each respective group across the two studies were quite different although there was also a difference in the mean pre-hospital time between survivors and deaths within each study. For example the mean pre-hospital time in the unexpected survivors in one study was 20.8 minutes (Feero et al. 1995) whereas the mean pre-hospital time in the survivors from the other study was 42.8 minutes (Grzybowski et al. 2000). Based on the information presented from these studies it is not clear that there is a threshold in the pre-hospital time that should be aimed at. The findings from the largest study would support the hypothesis that the shorter the pre-hospital time the better. These results are summarised in Table 17.
TRANSPORTATION OF EMERGENCY PATIENTS
112
Table 17 Key results for studies examining time from ambulance callout to emergency
department arrival that found an association between prolonged pre-hospital time
and poor outcome
Reference Sample size Multivariate analysis
Results
(Sampalis et al. 1999) 12,208 Yes Odds of death for each additional minute
of pre-hospital time: OR 1.046 (1.044-1.050)
(Sampalis et al. 1993) 360 Yes OR (mortality by 6 days, pre-hospital time >
60 minutes compared with up to 60
minutes): 3.01 (1.27-5.06)
(Sampalis et al. 1992) 355 Yes OR (mortality, pre-hospital time > 60 minutes
compared with up to 60 minutes): 29.9 (2.7-
33.3)
(Gao et al. 2006) 1,540 No Preadmission < 1 hour: 3.9% mortality
Preadmission ≥ 1 hour: 7.7% mortality
P<0.01
(Feero et al. 1995) 848 No Mean pre-hospital time
Unexpected survivors: 20.8 minutes
Unexpected deaths: 29.3 minutes
P=0.02
(Grzybowski et al.
2000)
244 No Mean total EMS time
Survivors: 42.8 minutes
Deaths: 50.6 minutes
P≤0.01
(Frezza and
Mezghebe 1999)
58 No Pre-hospital time < 30 minutes: 63% survival
Pre-hospital time > 30 minutes: 0% survival
P=0.002
The second group of studies that compared groups that had different mean pre-hospital times have the limitation that it could not be established if there was a relationship between pre-hospital time and outcome. For example, the studies comparing ground ambulance with helicopters, although having different pre-hospital times may also have other factors that explain any difference in outcome. Such differences could include a difference in crew mix that also contributes to a difference in outcome. In general, crews with a doctor on board may tend to spend a longer time at the scene than other crews. It is therefore possible that the longer pre-hospital time may be balanced by the presence of a doctor. These studies have elements of an ecological analysis weakening the study design. There were six studies in this group. A statistically significant difference in mortality between groups was not observed in these studies. Two studies found a significantly longer length of hospital stay in groups transported by the mode of transport with the longer pre-hospital time (Berns et al. 2001; Phillips et al. 1999). However, neither of these studies conducted multivariate analyses so confounding is likely to be a problem. These results are summarised in Table 18.
TRANSPORTATION OF EMERGENCY PATIENTS
113
Table 18 Key results for studies examining time from ambulance callout to emergency
department arrival in studies that did not directly compare pre-hospital time with
outcome
Reference Sample size Multivariate analysis
Results
(Biewener et al.
2004)
403 Yes Mortality comparing ambulance use with
HEMS use): OR 1.06 (0.427-2.635).
Pre-hospital times: helicopter 90 minutes,
ambulance 68 minutes
(Phillips et al. 1999) 792 No Ground transport: 54 minutes, length of stay
4.21 days
Air transport, 77 minutes, length of stay 8.97
days
P<0.001
Nil significant in mortality findings
(Schiller et al. 1988) 606 No Ambulance: mission time 39 minutes,
mortality 13%
Helicopter: mission time 50 minutes,
mortality 18%
(Young et al. 1998) 316 No Transfer group: 480 minutes pre-hospital
time
Direct group: 92 minutes pre-hospital time
No significant difference in mortality within
24 hours of injury or beyond 24 hours of
injury
(Berns et al. 2001) 294 No Ground, 142 minutes, length of stay 8 days
Helicopter, 104 minutes, length of stay 6.4
days
P=0.04
Nil significant in mortality
(Schwartz et al. 1990) 126 No Air ambulance, 65 minutes, Z=2.23
(improved compared with MTOS)
Ground ambulance, 34 minutes, Z=-2.69
(worse than MTOS)
There were also seven studies that found no association between pre-hospital time and outcome. It should be noted that two of these studies found an association between improved survival and shorter pre-hospital times on univariate analysis but both disappeared on multivariate analysis (Lerner et al. 2003). It should be observed that Lerner et al. (2003) estimated the odds of mortality were higher in patients with shorter pre-hospital time, but this finding was of borderline significance (OR 0.987, 95% CI 0.97-1.00). There were two other multivariate analyses conducted. One examined risk ratios for death by minutes to ED and found increased risk of death in the pre-hospital period 31-60 minutes but this association was not sustained in the 61-90 minutes and 91-185 minutes groups (Clarke et al. 2002). There were also three other studies that did not find a significant association on univariate analysis.
TRANSPORTATION OF EMERGENCY PATIENTS
114
Table 19 Key results for studies examining time from ambulance callout to emergency
department arrival in studies that did not find an association between pre-hospital
time and outcome
Reference Sample size Multivariate analysis
Results
(Bonatti et al. 1995) 2139 Yes No significant difference between total
mission time and survival on multivariate
analysis (there was a significant decrease in
survival with longer mission times on
univariate analysis)
(Lerner et al. 2003) 1877 Yes Total out of hospital time and mortality
OR 0.987 (0.97-1.00).
Note univariate analysis significantly longer
pre-hospital time in the survivors (difference
3.69 minutes, 95% CI 0.52-6.85 minutes)
(Hartl et al. 2006) 1123 Yes Mortality for each extra minute in transport
time
OR 1.00 (1.00-1.00)
(Clarke et al. 2002) 250 Yes Risk ratios for death by minutes to ED (95%
CI)
1-30 minutes RR 0.773 (0.501-1.194)
31-60 minutes RR 1.268 (0.980-1.641)
61-90 minutes RR 0.832 (0.496-1.396)
91-185 minutes RR 0.740 (0.189-2.888)
(Pepe et al. 1987) 498 No Results stratified across four different trauma
score categories. No association between
pre-hospital time and mortality within each
trauma score stratum
(Sloan et al. 1989) 203 No Total run time (minutes):
Mortality group 32
Survival group 35
(Lim and Seow 2002) 93 No Pre-hospital time
Survivors: 38.3 minutes
Non-survivors: 35.4 minutes
One study estimated that a pre-hospital time up to 60 minutes was associated with an increased odds of mortality when compared with a pre-hospital time more than 60 minutes (OR 8, 95% CI 1.7-38.5), (Osterwalder 2002). This finding may have been due to a tendency to shorten the on scene time in patients who appeared critical, recognising the need for urgent definitive care. This study had a sample size of 254 and included a multivariate analysis.
There was some information provided that was helpful in considering whether pre-hospital time had an effect on outcome after controlling for crew mix. The two smaller studies by Sampalis et al. (1992; 1993) both controlled for crew mix and in-hospital parameters. In these studies, physicians were available to attend the scene although their attendance was reserved for severe cases. In both studies (which had overlapping populations), there was a significant association between shorter pre-hospital time and improved survival after controlling for crew mix but there was no association between crew mix and survival after controlling for pre-hospital time. However, Bonatti et al. (1995) did not identify any association between pre-hospital time and outcome after controlling for crew mix and they also did not find any association between the attendance of a physician and outcome after controlling for pre-hospital time.
In conclusion, there was some inconsistent support for shorter pre-hospital times being associated with improved survival. However, it is not clear if there is a threshold time to aim for or if any reduction in pre-hospital time is associated with improved outcome. There is therefore no clear pre-hospital time to aim for based on the literature reviewed. It seems biologically plausible that severity of injury may operate as an effect modifier in the relationship between pre-hospital time and outcome. In other words, the relationship between pre-hospital time and outcome may be influenced by measures of severity. Unfortunately, there was insufficient information to investigate this further within the studies eligible for this review.
TRANSPORTATION OF EMERGENCY PATIENTS
115
OVERVIEW
Main findings
This report has four main areas of assessment:
1. In adults and children with a medical or trauma related emergency, does the presence of a medical doctor on emergency helicopter services improve health outcome when compared with transportation by emergency helicopter without a medical doctor?
2. In adults and children with a medical or trauma related emergency, does the presence of a medical doctor on a road ambulance service improve health outcome when compared with transportation by a road ambulance service without a medical doctor?
3. In adults and children with a medical or trauma related emergency, does the presence of a medical crew able to perform rapid sequence intubation and/or thoracostomy improve health outcome when compared with a medical crew unable to perform rapid sequence intubation and/or tube thoracostomy and/or thoracotomy?
4. In adults and children with a medical or trauma related emergency how does variation in the time from callout to arrival at a medical facility with definitive care influence health outcome?
Summaries and conclusions have been included for each question earlier in this report. This overview provides links across the sections and identifies unanswered issues.
The first three questions were intended to examine the usefulness of including medical doctors on emergency transportation. The inclusion of medical doctors on emergency transportation is more consistent with the “stay and treat” strategy described earlier. That is, a period of stabilisation is implied before transportation to a definitive care hospital. In contrast, question four was particularly designed to assess whether there was a set time to aim for in relation to total pre-hospital transportation time. A short time would be consistent with the “scoop and run” strategy. Key results of these issues have been summarised earlier but, to reiterate the major points:
1. There was generally more support for the inclusion of doctors on helicopters in the seven studies appraised in this section. However, there were uncertainties due to study design issues (levels of evidence ranged between III-1 and III-3), lack of consideration about whether non-doctor groups can be trained to perform certain procedures that would improve patient outcome and whether there may be different clinical scenarios that would favour one crew mix type over another.
2. Similar considerations applied in the studies examining the use of doctors on board road ambulances. There were four studies in this section with levels of evidence ranging between III-2 and III-3.
3. When considering the outcome in patients who were treated by crews able to perform rapid sequence intubation and/or thoracostomy with other crews who were not able to perform these procedures, the only studies identified that met the study eligibility criteria included doctors amongst those able to perform the procedures of interest. It was therefore not possible to examine this issue in relation to non doctor groups. There were five studies in this section with levels of evidence ranging between III-1 and III-3.
4. There was inconsistent evidence on the association between pre-hospital time and patient outcome. There were 21 studies in this section with levels of evidence all being III-2. However, the general direction was to support improved outcome in association with shorter pre-hospital times. There was no clear time threshold to aim for. Two studies provided information to consider whether crew mix or rapid transport had a more significant bearing on outcome. The results were conflicting across these two studies.
5. Most of the studies included related to trauma rather than medical emergencies.
6. There was insufficient information to consider subgroups based on injury severity or age group.
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Limitations
The studies included ranged from evidence level III-1 to III-3. Study limitations are described in earlier sections of this report. In addition, it is important to note that this Technical Brief is not a full systematic review, although a systematic approach to search for and retrieve relevant studies was used. This report constitutes a rapidly produced assessment and summary of the best available evidence. Wider searches of the Internet, hand searching of journals and contacting of authors for unpublished research were not undertaken.
Research gaps
Specific study designs that would be useful to further consider the review questions have been detailed throughout this report. Some general areas of future research that would be helpful include:
1. Is there some form of interaction between pre-hospital time and pre-hospital crew that has impact on patient outcome? Linked to this is whether the same pre-hospital approach (time and crew) results in improved outcome in all emergency patients or whether the best approach is dependent on the clinical situation.
2. Given differences in procedures performed and clinical assessment processes adopted by doctors compared with non-doctor pre-hospital personnel, to what extent would enhanced procedure training for non-doctor groups be helpful?
3. There are cost differences between the “scoop and run” and “stay and treat” approaches, along with the crew mixes used that ideally should be examined in relation to cost effectiveness of different approaches. However, given current uncertainties in effectiveness of the different strategies, incremental cost effectiveness can not be robustly examined at this time.
Conclusions
While the balance of studies support improved outcome associated with doctors on board emergency transportation, the robustness of these studies and the areas of uncertainty that remain (see under research gaps) provide uncertainty about the best approach. The best study supported the use of doctors on board helicopters. The balance of studies supported improved outcome associated with more rapid pre-hospital times. The studies identifying such improved outcome frequently assessed the linear relationship between pre-hospital outcome and time, meaning that the focus was on any improvement in outcome rather than a set threshold of pre-hospital time to meet in order to achieve improved outcome.
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APPENDIX 1: SEARCH STRATEGY
Medline 1
1 air ambulances/ (1024) 2 aircraft/ (5261) 3 helicopter$.mp. (1541) 4 (medevac or medivac or casivac or casevac).mp. (31) 5 aeromedic$.mp. (673) 6 (air ambulanc$ or flight ambulan$).mp. (1125) 7 or/1-6 (7198) 8 "personnel staffing and scheduling"/ (9920) 9 personnel selection/ (7837) 10 patient care team/ (36954) 11 physician's role/ (19199) 12 (doctor$ or staff$ or personnel$ or physician$).tw. (291307) 13 exp physicians/ (56725) 14 medical practitioner$.tw. (2394) 15 (medical$ adj qualif$).tw. (187) 16 ma.fs. (43025) 17 or/8-16 (398761) 18 7 and 17 (1113) 19 limit 18 to english (918) 20 limit 19 to yr=1980-2006 (853) 21 (letter or news or historical article).pt. (916855) 22 20 not 21 (802) 23 (commercial adj (airline$ or aircrew)).tw. (151) 24 (spaceflight or space flight).tw. (3422) 25 22 not (23 or 24) (788) 26 allied health personnel/ (8563) 27 (paramedic$ or medic or medics).tw. (4114) 28 nurse's role/ (15545) 29 nurses/ (21869) 30 flight nurse$.mp. (138) 31 or/26-30 (48520) 32 7 and 31 (267) 33 limit 32 to english (249) 34 limit 33 to yr=1980-2006 (241) 35 34 not (21 or 23 or 24) (226) 36 35 not 25 (118) 37 emergency medical technicians/ (3409) 38 7 and 37 (160) 39 limit 38 to english (155) 40 limit 39 to yr=1980-2006 (153) 41 40 not (21 or 23 or 24) (150) 42 41 not (25 or 36) (52)
Medline 2
1 ambulances/ (3697) 2 ambulance$.tw. (4057) 3 1 or 2 (5887) 4 aircraft/ (5261) 5 air ambulances/ (1024) 6 helicopter$.mp. (1541) 7 or/4-6 (6776) 8 3 not 7 (5131)
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9 (doctor$ or staff$ or personnel).mp. (303172) 10 personnel selection/ (7837) 11 "personnel staffing and scheduling"/ (9920) 12 patient care team/ (36954) 13 physician's role/ (19199) 14 exp physicians/ (56725) 15 (medical practitioner$ or physician$).tw. (167891) 16 (medic$ adj qualif$).tw. (214) 17 emergency medical technicians/ (3409) 18 allied health personnel/ (8563) 19 (paramedic$ or medic or medics).tw. (4114) 20 ma.fs. (43025) 21 nurse's role/ (15545) 22 nurses/ (21869) 23 or/9-22 (547961) 24 8 and 23 (2153) 25 mortality/ (25412) 26 survival analysis/ (65471) 27 survival rate/ (83848) 28 length of stay/ (35751) 29 (mortality or survival).tw. (544897) 30 exp treatment outcome/ (300617) 31 "outcome assessment (health care)"/ (25927) 32 or/25-31 (873880) 33 24 and 32 (392) 34 limit 33 to english (319) 35 (letter or news).pt. (689225) 36 34 not 35 (317) 37 neonat$.ti. (61473) 38 36 not 37 (315)
Medline 3
1 *time factors/ (904) 2 (time adj3 delay$).tw. (6849) 3 (time or delay).ti. (88449) 4 ((prehospital or pre-hospital) adj (time or care or treatment)).tw. (1157) 5 ((call-out or callout) and (arrival or admission or admit$ or hospital or emergency department or
ED)).tw. (20) 6 (delay$ adj3 (arrival or admission or admit$ or hospital or medical facility or definitive care or
emergency department or ED)).tw. (1246) 7 (time adj3 (arrival or admission or admit$ or hospital or medical facility or definitive care or
emergency department or ED)).tw. (8465) 8 ((call-out or callout) and (arrival or admission or admit$ or hospital or medical facility or
definitive care or emergency department or ED)).tw. (20) 9 (scene time or "out of hospital time").tw. (105) 10 (transport adj time$).tw. (506) 11 (transfer$ adj time$).tw. (281) 12 (prehospital index or pre-hospital index).tw. (21) 13 or/1-12 (105221) 14 survival analysis/ (65345) 15 exp treatment outcome/ (299801) 16 length of stay/ (35699) 17 patient discharge/ (12043) 18 morbidity/ (17555) 19 mortality/ (25394) 20 "Outcome Assessment (Health Care)"/ (25869) 21 (survival or outcome).tw. (599960) 22 or/14-21 (900262) 23 *emergencies/ (7692) 24 exp emergency medical services/ (58193)
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25 emergency service, hospital/ (24370) 26 transportation of patients/ (6348) 27 ambulances/ (3694) 28 air ambulances/ (1024) 29 helicopters/ (5256) 30 or/23-29 (68719) 31 13 and 22 and 30 (908) 32 (news or letter).pt. (688417) 33 infant, newborn/ or infant, premature/ or neonat$.ti. (406994) 34 case reports.pt. (1291342) 35 or/32-34 (2194216) 36 31 not 35 (855) 37 (golden hour or golden minute$).mp. (76) 38 36 or 37 (927) 39 limit 38 to yr=1980-2006 (918) 40 limit 39 to english (832)
Embase 1
1 air medical transport/ (70) 2 AIRCRAFT/ (1958) 3 HELICOPTER/ (786) 4 aeromedic$.tw. (384) 5 flight ambulance$.tw. (0) 6 air ambulance$.tw. (91) 7 (medevac or medivac or casivac or casevac).tw. (21) 8 or/1-7 (3043) 9 medical personnel/ (2810) 10 Airplane Crew/ (1080) 11 health care personnel/ (23462) 12 manpower/ (1093) 13 Health Care Manpower/ (1025) 14 (doctor$ or staff$ or personnel$ or physician$).tw. (164842) 15 medical practitioner$.tw. (1560) 16 (medical$ adj qualif$).tw. (135) 17 patient care team.tw. (37) 18 physician/ or emergency physician/ (33974) 19 or/9-18 (199007) 20 8 and 19 (687) 21 limit 20 to english (621) 22 letter.pt. (330316) 23 21 not 22 (600) 24 (commercial adj (airline$ or aircrew or attendant$)).tw. (113) 25 (spaceflight or space flight).tw. (1262) 26 24 or 25 (1375) 27 23 not 26 (580) 28 Paramedical Personnel/ (1706) 29 paramedical personnel/ (1706) 30 rescue personnel/ (1043) 31 (medic or medics or paramedic$).tw. (2030) 32 Nursing Role/ (25) 33 nurse/ (11528) 34 nursing staff/ (2233) 35 flight nurse$.tw. (34) 36 or/28-35 (17487) 37 8 and 36 (224) 38 limit 37 to english (196) 39 38 not (22 or 26) (181) 40 39 not 27 (68)
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125
Embase 2
1 ambulance/ (1942) 2 ambulance$.tw. (2198) 3 1 or 2 (2915) 4 air medical transport/ (70) 5 aircraft/ (1958) 6 helicopter/ (786) 7 (aeromedic$ or flight ambulance$ or air ambulance$).tw. (460) 8 or/4-7 (3031) 9 3 not 8 (2606) 10 medical personnel/ (2810) 11 health care personnel/ (23462) 12 manpower/ (1093) 13 health care manpower/ (1025) 14 (doctor$ or staff$ or personnel$ or physician$).tw. (164842) 15 medical practitioner$.tw. (1560) 16 (medic$ adj qualif$).tw. (154) 17 patient care team.tw. (37) 18 physician/ or emergency physician/ (33974) 19 paramedical personnel/ (1706) 20 rescue personnel/ (1043) 21 (medic or medics or paramedic$).tw. (2030) 22 nursing role/ (25) 23 nurse/ (11528) 24 nursing staff/ (2233) 25 or/10-24 (207253) 26 9 and 25 (1149) 27 MORTALITY/ (124790) 28 Survival/ (46091) 29 Survival Rate/ (42525) 30 (mortality or survival).tw. (372312) 31 "Length of Stay"/ (17989) 32 exp Treatment Outcome/ (348062) 33 Outcome Assessment/ (10452) 34 or/27-33 (730660) 35 26 and 34 (298) 36 limit 35 to english (256) 37 letter.pt. (330316) 38 36 not 37 (250)
Embase 3
1 exp *time/ (2667) 2 time factor$.tw. (455) 3 (time or delay).ti. (51255) 4 (time adj3 delay).tw. (3194) 5 ((prehospital or pre-hospital) adj (time or care or treatment or delay)).tw. (859) 6 (delay$ adj3 (arrival or admission or admit$ or hospital or medical facility or definitive care or
emergency department or ED)).tw. (922) 7 (time adj3 (arrival or admission or admit$ or hospital or medical facility or definitive care or
emergency department or ED)).tw. (6337) 8 ((callout or call-out) and (arrival or admission or admit$ or hospital or medical facility or
definitive care or emergency department or ED)).tw. (15) 9 (scene time or "out of hospital time").tw. (68) 10 (transport adj time$).tw. (360) 11 (transfer$ adj time$).tw. (211) 12 (prehospital index or pre-hospital index).tw. (17) 13 or/1-12 (63376) 14 Survival/ (45956) 15 exp treatment outcome/ (345878)
TRANSPORTATION OF EMERGENCY PATIENTS
126
16 length of stay/ (17884) 17 hospital discharge/ (18041) 18 morbidity/ (63032) 19 mortality/ (124143) 20 (survival or outcome).tw. (452728) 21 survival rate/ (42297) 22 Outcome Assessment/ (9819) 23 or/14-22 (830528) 24 Emergency Care/ (1145) 25 Emergency Health Service/ (9413) 26 emergency/ (3558) 27 Emergency Treatment/ (7782) 28 ambulance/ (1930) 29 HELICOPTER/ (777) 30 Patient Transport/ (5227) 31 air ambulan$.tw. (91) 32 or/24-31 (26070) 33 13 and 23 and 32 (597) 34 letter.pt. (329150) 35 Case Report/ (680614) 36 33 not (34 or 35) (575) 37 Newborn/ (127209) 38 Prematurity/ (20771) 39 neonat$.ti. (33939) 40 or/37-39 (146969) 41 36 not 40 (565) 42 (golden hour or golden minutes).mp. (58) 43 41 or 42 (620) 44 limit 43 to english (539)
Cinahl 1
1 Aeromedical Transport/ (1390) 2 aircraft/ (528) 3 helicopter$.mp. (352) 4 (medevac or casevac or medivac or casivac or evac).tw. (19) 5 (aeromedic$ or aero medic$).tw. (94) 6 (air ambulance$ or flight ambulance$).tw. (77) 7 or/1-6 (1918) 8 "Personnel Staffing and Scheduling"/ (7243) 9 Multidisciplinary Care Team/ (9627) 10 personnel selection/ (1476) 11 exp PHYSICIANS/ (20310) 12 Physician's Role/ (1736) 13 (medical practitioner$ or (medic$ adj qualif$)).tw. (427) 14 (doctor$ or physician$ or staff$ or personnel$).tw. (69968) 15 (medical$ adj2 (staff$ or personnel)).tw. (1303) 16 or/8-15 (96867) 17 7 and 16 (249) 18 limit 17 to english (249) 19 letter.pt. (37113) 20 (book or book chapter).pt. (18610) 21 pamphlet.pt. (2446) 22 18 not (19 or 20 or 21) (247) 23 (commercial adj2 (airline or aircraft)).tw. (22) 24 (spaceflight or space flight).tw. (43) 25 22 not (23 or 24) (243) 26 biography.pt. (2712) 27 25 not 26 (242)
TRANSPORTATION OF EMERGENCY PATIENTS
127
Cinahl 2
1 AMBULANCES/ (1030) 2 ambulance$.tw. (1408) 3 1 or 2 (1916) 4 AIRCRAFT/ (528) 5 helicopter$.mp. (352) 6 Aeromedical Transport/ (1391) 7 air ambulance$.tw. (77) 8 or/4-7 (1884) 9 3 not 8 (1747) 10 (doctor$ or staff$ or personnel).mp. (95811) 11 "personnel staffing and scheduling"/ (7270) 12 Personnel Selection/ (1485) 13 Multidisciplinary Care Team/ (9658) 14 Physician's Role/ (1742) 15 exp physicians/ (20428) 16 (medical practitioner$ or physician$).tw. (26538) 17 (medic$ adj qualif$).tw. (17) 18 Emergency Medical Technicians/ (3793) 19 allied health personnel/ (824) 20 (paramedic$ or medic or medics).tw. (1367) 21 ma.fs. (4504) 22 Nursing Role/ (18909) 23 nurses/ (23300) 24 or/10-23 (176466) 25 9 and 24 (687) 26 mortality/ (5012) 27 survival/ (4141) 28 Survival Analysis/ (3532) 29 (survival or mortality).tw. (25643) 30 "Length of Stay"/ (6142) 31 exp Treatment Outcomes/ (32058) 32 Outcome Assessment/ (4204) 33 or/26-32 (67621) 34 25 and 33 (67) 35 limit 34 to english (66) 36 neonat$.ti. (5674) 37 35 not 36 (66) 38 letter.pt. (37444) 39 37 not 38 (66)
Cinahl 3
1 *Time Factors/ (1377) 2 (time adj3 delay$).tw. (283) 3 (time or delay).ti. (12147) 4 ((prehospital or pre-hospital) adj (time or care or treatment or index)).tw. (427) 5 ((call-out or callout) and (arrival or admission or admit$ or hospital or emergency department or
ED)).tw. (1) 6 (delay adj3 (arrival or admission or admit$ or hospital or definitive care or medical facility or
emergency department or ED)).tw. (78) 7 (time adj3 (arrival or admission or admit$ or hospital or definitive care or medical facility or
emergency department or ED)).tw. (1124) 8 ((call-out or callout) and (definitive care or medical facility)).tw. (0) 9 (scene time or "out of hospital time").tw. (48) 10 (transport$ adj time$).tw. (71) 11 (transfer$ adj time$).tw. (12) 12 or/1-11 (14842) 13 Survival Analysis/ (3508) 14 exp Treatment Outcomes/ (31790)
TRANSPORTATION OF EMERGENCY PATIENTS
128
15 length of stay/ (6118) 16 Patient Discharge/ (3187) 17 Outcome Assessment/ (4172) 18 (survival or outcome).tw. (42380) 19 morbidity/ (1503) 20 mortality/ (4997) 21 or/13-20 (81805) 22 *EMERGENCIES/ (1205) 23 Emergency Service/ (8794) 24 exp Emergency Medical Services/ (23036) 25 "Transportation of Patients"/ (1527) 26 AMBULANCES/ (1025) 27 Aircraft/ (528) 28 Aeromedical Transport/ (1390) 29 (ambulan$ or helicopter$).tw. (1791) 30 or/22-29 (24871) 31 12 and 21 and 30 (162) 32 (biography or book or book chapter or interview or case study).pt. (93767) 33 31 not 32 (162) 34 letter.pt. (37113) 35 33 not 34 (160) 36 (golden hour or golden minutes).mp. (35) 37 35 or 36 (195) 38 limit 37 to english (195) 39 Infant, Newborn/ (29078) 40 Infant, Premature/ (4504) 41 neonat$.ti. (5660) 42 or/39-41 (31082) 43 38 not 42 (189)
Current Contents/ Citation Indexes 1
1. Helicopter* OR air ambulance* OR flight ambulance* 2. Aircraft 3. Medevac OR medivac OR casevac OR casivac OR evac 4. Aeromedic* 5. Commercial SAME (airline OR aircraft OR aircrew) 6. Spaceflight OR space flight 7. Personnel OR medical practitioner* 8. (medic* SAME qualif*) 9. Doctor * OR physician* 10. Staffing OR staffed OR staff 11. #1 OR #2 OR #3 OR #4 12. #7 OR #8 OR #9 OR #10 13. #11 AND #12 14. Allied health OR paramedic* OR medic OR medics 15. Flight nurse* 16. Nurse OR nurses OR nursing 17. #14 OR #15 OR #16 18. #12 AND #17 19. #18 NOT #13 20. #19 NOT (#5 OR #6)
Current Contents/ Citation Indexes 2
1. Ambulance* 2. Aircraft OR helicopter* OR aeromedical or air ambulance* 3. #1 NOT #2 4. personnel OR staff OR staffing OR staffed 5. patient SAME care SAME team 6. doctor* OR physician* 7. medical practitioner* OR (medic* SAME qualif*) OR paramedic* OR medic OR medics
TRANSPORTATION OF EMERGENCY PATIENTS
129
8. emergency technician* OR allied health OR manpower 9. nurse’s role OR physician’s role OR nursing role 10. nurse OR nurses 11. #4 OR #5 OR #6 OR #7 OR #8 OR #9 OR #10 12. #3 AND #11 13. #12 AND (survival OR mortality) 14. #12 AND outcome 15. #12 AND (length SAME stay) 16. #13 OR #14 OR #15
Current Contents/ Citation Indexes 3
1. (Prehospital OR pre-hospital) SAME (index OR care OR time OR treatment OR delay) 2. (transport* OR transfer*) SAME time 3. Scene time OR “out of hospital time” 4. (callout OR call out) SAME (arrival OR admission OR admit* OR hospital OR emergency
department OR emergency room OR definitive care OR medical facilit* OR ED OR ER) 5. (time OR delay) SAME (arrival OR admission OR admit* OR hospital OR emergency
department OR emergency room OR definitive care OR medical facilit* OR ED OR ER) 6. Emergency OR emergencies 7. Patient SAME (transport* OR transfer*) 8. Ambulan* OR helicopter* 9. #6 OR #7 OR #8 10. (newborn OR neonat*) 11. (infant* OR baby OR babies) SAME premature 12. Case study 13. Case report 14. Golden hour 15. #1 OR #2 OR #3 OR #4 OR #5 16. #9 AND #15 17. #16 NOT (#10 OR #11 OR #12 OR #13) 18. #17 AND (survival OR outcome) 19. #14 OR #18
PubMed (last 90 days)
PubMed searches were substantially the same as the strategies for Current Contents and the Citation Indexes.
Additional searching
Several small additional searches were carried out as required during the course of the project to obtain information on the merits of the respective scales for predicting mortality and morbidity after trauma.
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APPENDIX 2: LEVELS OF EVIDENCE∗∗∗∗
Level I Evidence obtained from a systematic review (or meta-analysis) of relevant randomised controlled trials.
Level II Evidence obtained from at least one randomised controlled trial.
Level III. 1 Evidence obtained from pseudorandomised controlled trials (alternate allocation or some other method).
2 Evidence obtained from comparative studies (including systematic reviews of such studies) with concurrent controls and allocation not randomised, cohort studies, case control studies or interrupted time series with a control group).
3 Evidence obtained from comparative studies with historical control, two or more single-arm studies or interrupted time series without a parallel control group.
Level IV Evidence obtained from case series, either post-test or pre-test/post-test.
∗ From National Health and Medical Research Council (2000)
TRANSPORTATION OF EMERGENCY PATIENTS
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APPENDIX 3: EXCLUDED RETRIEVED PAPERS: DOCTOR VERSUS
NO DOCTOR ON HELICOPTERS
Bartolacci, R. A., Munford, B. J., Lee, A., & McDougall, P. A. (1998). Air medical scene response to blunt trauma: effect on early survival. Medical Journal of Australia, 169, 612-616.
Baxt, W. G., & Moody, P. (1983). The impact of a rotorcraft aeromedical emergency care service on trauma mortality. JAMA, 249, 3047-3051.
Baxt, W. G., & Moody, P. (1987). The impact of advanced prehospital emergency care on the mortality of severely brain-injured patients. Journal of Trauma-Injury Infection & Critical Care, 27, 365-369.
Blumen, I. J., & Gordon, R. S. (1989). Taking to the skies. Emergency, 21, 32-38.
Brismar, B., Alveryd, A., Johnsson, O., & Ohrvall, U. (1986). The ambulance helicopter is a prerequisite for centralised emergency care. Acta Chirurgica Scandinavica - Supplementum, 530, 89-93.
Burillo-Putze, G., Duarte, I. H., & Alvarez Fernandez, J. A. (2001). Helicopter emergency medical service in Spain. Air Medical Journal, 20, 21-23.
Cameron, P. A., Flett, K., Kaan, E., Atkin, C., & Dziukas, L. (1993). Helicopter retrieval of primary trauma patients by a paramedic helicopter service. Australian and New Zealand Journal of
Surgery, 63, 790-797.
Cannell, H., Silvester, K. C., & O'Regan, M. B. (1993). Early management of multiply injured patients with maxillofacial injuries transferred to hospital by helicopter. British Journal of Oral &
Maxillofacial Surgery, 31, 207-212.
Celli, P., Fruin, A., & Cervoni, L. (1997). Severe head trauma. Review of the factors influencing the prognosis. Minerva Chirurgica, 52, 1467-1480.
Cline Jr, C. T., Smith, S., & Davenport, P. (2006). Carilion Life-Guard: A quarter century of air medical service. Air Medical Journal, 25, 118-121.
Cocanour, C. S., Fischer, R. P., & Ursic, C. M. (1997). Are scene flights for penetrating trauma justified? Journal of Trauma-Injury Infection & Critical Care, 43, 83-86; discussion 86-88.
Collier, J. (2006). Air Evac Services: improving Arizona's health over 36 years. Air Medical Journal, 25, 196-199.
Conroy, M. B., Rodriguez, S. U., Kimmel, S. E., & Kasner, S. E. (1999). Helicopter transfer offers a potential benefit to patients with acute stroke. Stroke, 30, 2580-2584.
Corfield, A. R., Thomas, L., Inglis, A., & Hearns, S. (2006). A rural emergency medical retrieval service: the first year. Emergency Medicine Journal, 23, 679-683.
Davis, D. P., Ochs, M., Hoyt, D. B., Bailey, D., Marshall, L. K., & Rosen, P. (2003). Paramedic-administered neuromuscular blockade improves prehospital intubation success in severely head-injured patients. Journal of Trauma-Injury Infection & Critical Care, 55, 713-719.
Davis, D. P., Pettit, K., Rom, C. D., Poste, J. C., Sise, M. J., Hoyt, D. B., & Vilke, G. M. (2005a). The safety and efficacy of prehospital needle and tube thoracostomy by aeromedical personnel. Prehospital Emergency Care, 9, 191-197.
TRANSPORTATION OF EMERGENCY PATIENTS
132
Davis, D. P., Vadeboncoeur, T. F., Ochs, M., Poste, J. C., Vilke, G. M., & Hoyt, D. B. (2005b). The association between field Glasgow Coma Scale score and outcome in patients undergoing paramedic rapid sequence intubation. Journal of Emergency Medicine, 29, 391-397.
Garner, A., Crooks, J., Lee, A., & Bishop, R. (2001). Efficacy of prehospital critical care teams for severe blunt head injury in the Australian setting. Injury, 32, 455-460.
Gisvold, S. E. (2002). Helicopter emergency medical service with specially trained physicians - does it make a difference? Acta Anaesthesiologica Scandinavica, 46, 757-758.
Gomes, E., Araujo, R., Soares-Oliveira, M., & Pereira, N. (2004). International EMS systems: Portugal. Resuscitation, 62, 257-260.
Hachinski, V. (2001). Sky doc. CMAJ Canadian Medical Association Journal, 165, 1621-1622.
Holcomb, J. B., Niles, S. E., Miller, C. C., Hinds, D., Duke, J. H., & Moore, F. A. (2005). Prehospital physiologic data and lifesaving interventions in trauma patients. Military Medicine, 170, 7-13.
Isakov, A. P. (2006). Souls on board: helicopter emergency medical services and safety. Annals of
Emergency Medicine, 47, 357-360.
Isenberg, D. L., & Bissell, R. (2005). Does advanced life support provide benefits to patients?: a literature review. Prehospital & Disaster Medicine, 20, 265-270.
Kuper, P. (2005). Austin-Travis County STAR flight. Air Medical Journal, 24, 192-194.
Lechleuthner, A., Bouillon, B., Neugebauer, E., Mennigen, R., & Tiling, T. (1994). Prehospital chest tubes incidence and analysis of iatrogenic injuries in the Emergency Medical-Service Cologne. Theoretical Surgery, 9, 220-226.
Little, M. (1994). Another kind of flying doctor. Medical Journal of Australia, 160, 214-216.
Lyons, T. J., & Connor, S. B. (1995). Increased flight surgeon role in military aeromedical evacuation. Aviation Space & Environmental Medicine, 66, 927-929.
Macintyre, I. (1994). Another kind of flying doctor. BMJ, 309, 1745-1746.
Mackenzie, C. F., Shin, B., & Matjasko, M. J. (1987). Physicians on aeromedical teams. JAMA-Journal
of the American Medical Association, 258, 2377-2378.
Macrae, D. J. (1994). Paediatric intensive care transport. Archives of Disease in Childhood, 71, 175-178.
Matsumoto, H., Mashiko, K., Hara, Y., Sakamoto, Y., Kutsukata, N., Takei, K., Tomita, Y., et al. (2006). Effectiveness of a "doctor-helicopter" system in Japan. Israel Medical Association
Journal: IMAJ, 8, 8-11.
Munford, B., & Manning, R. (1994). Paramedic helicopter retrieval of trauma patients. Australian and
New Zealand Journal of Surgery, 64, 640-641.
Nocera, A., & Dalton, A. M. (1994). Disaster alert! The role of physician-staffed helicopter emergency medical services. Medical Journal of Australia, 161, 689-692.
Oppe, S., & De Charro, F. T. (2001). The effect of medical care by a helicopter trauma team on the probability of survival and the quality of life of hospitalised victims. Accident Analysis &
Prevention, 33, 129-138.
Orlando, R., Schwartz, R., Lee, M., & Jacobs, L. (1987). The role of the flight physician in helicopter critical care transport. Critical Care Medicine, 15, 367-367.
TRANSPORTATION OF EMERGENCY PATIENTS
133
Osterwalder, J. J. (2002). Can the "golden hour of shock" safely be extended in blunt polytrauma patients? Prospective cohort study at a level I hospital in eastern Switzerland. Prehospital &
Disaster Medicine, 17, 75-80.
Osterwalder, J. J. (2003). Mortality of blunt polytrauma: a comparison between emergency physicians and emergency medical technicians - prospective cohort study at a level I hospital in eastern Switzerland. Journal of Trauma-Injury Infection and Critical Care, 55, 355-361.
Rodenberg, H. (1992a). Effect of aeromedical aircraft on care of trauma patients - evaluation using the revised trauma score. Southern Medical Journal, 85, 1065-1071.
Rodenberg, H. (1992b). The revised trauma score: a means to evaluate aeromedical staffing patterns. Aviation Space & Environmental Medicine, 63, 308-313.
Schwartz, R. J., Jacobs, L. M., & Juda, R. J. (1990). A comparison of ground paramedics and aeromedical treatment of severe blunt trauma patients. Connecticut Medicine, 54, 660-662.
Shufflebarger, C., & Townsend, R. (1987). Physicians on aeromedical teams. JAMA-Journal of the
American Medical Association, 258, 2378-2378.
Slagt, C., Zondervan, A., Patka, P., & de Lange, J. J. (2004). A retrospective analysis of the intubations performed during 5 years of helicopter emergency medical service in Amsterdam. Air Medical
Journal, 23, 36-37.
Snow, N., Hull, C., & Severns, J. (1986). Physician presence on a helicopter emergency medical service: necessary or desirable? Aviation Space & Environmental Medicine, 57, 1176-1178.
Spangler, D. E., Jr., Rogers, W. J., Gore, J. M., Griffith, M., Maske, L. E., Morgan, T. E., & Corrao, J. (1991). Early tPA treatment and aeromedical transport of patients with acute myocardial infarction. Journal of Interventional Cardiology, 4, 81-89.
Stansbury, D. (1996). Flying high: EMS in the air. Journal of Emergency Medical Services, 21, 59-61.
Stauffer, U. G. (1995). Surgical and critical care management of children with life-threatening injuries: the Swiss experience. Journal of Pediatric Surgery, 30, 903-910.
Suominen, P., Baillie, C., Kivioja, A., Korpela, R., Rintala, R., Silfvast, T., & Olkkola, K. T. (1998). Prehospital care and survival of pediatric patients with blunt trauma. Journal of Pediatric
Surgery, 33, 1388-1392.
Thomas, S. H., Harrison, T. H., Buras, W. R., Ahmed, W., Cheema, F., & Wedel, S. K. (2002). Helicopter transport and blunt trauma mortality: A multicenter trial. Journal of Trauma-Injury
Infection and Critical Care, 52, 136-145.
van Wijngaarden, M., Kortbeek, J., Lafreniere, R., Cunningham, R., Joughin, E., & Yim, R. (1996). Air ambulance trauma transport: a quality review. Journal of Trauma-Injury Infection & Critical
Care, 41, 26-31.
Vilke, G. M., Hoyt, D. B., Epperson, M., Fortlage, D., Hutton, K. C., & Rosen, P. (1994). Intubation techniques in the helicopter. Journal of Emergency Medicine, 12, 217-224.
Wirtz, M. H., Cayten, C. G., Kohrs, D. A., Atwater, R., & Larsen, E. A. (2002). Paramedic versus nurse crews in the helicopter transport of trauma patients. Air Medical Journal, 21, 17-21.
Zalstein, S., & Cameron, P. A. (1997). Helicopter emergency medical services: their role in integrated trauma care. Australian & New Zealand Journal of Surgery, 67, 593-598.
TRANSPORTATION OF EMERGENCY PATIENTS
134
APPENDIX 4: EXCLUDED RETRIEVED PAPERS: DOCTOR VERSUS
NO DOCTOR ON ROAD AMBULANCES
Adams, J., Aldag, G., & Wolford, R. (1996). Does the level of prehospital care influence the outcome of patients with altered levels of consciousness? Prehospital & Disaster Medicine, 11, 101-104.
Arntz, H. R., Oeff, M., Willich, S. N., Storch, W. H., & Schroder, R. (1993). Establishment and results of an EMT-D program in a two-tiered physician-escorted rescue system. The experience in Berlin, Germany. Resuscitation, 26, 39-46.
Bjerre, S. K., Hansen, T. M., Melchiorsen, H., & Christensen, E. F. (2002). Prehospital treatment of patients with acute exacerbation of chronic pulmonary disease - before and after introduction of a Mobile Emergency Care Unit. Ugeskrift for Laeger, 164, 1349-1352.
Bjorklund, P., & O'Rourke, M. F. (1984). Pre-hospital emergency care: evaluation of an Australian system. Australian & New Zealand Journal of Medicine, 14, 419-423.
Einav, S., Donchin, Y., Weissman, C., & Drenger, B. (2003). Anesthesiologists on ambulances: where do we stand? Current Opinion in Anaesthesiology, 16, 585-591.
Eisen, J. S., & Dubinsky, I. (1998). Advanced life support vs. basic life support field care: an outcome study. Academic Emergency Medicine, 5, 592-598.
Eisenburger, P., Czappek, G., Sterz, F., Vergeiner, G., Losert, H., Holzer, M., & Laggner, A. N. (2001). Cardiac arrest patients in an alpine area during a six year period. Resuscitation, 51, 39-46.
Erich, J. (2003). Road trauma. Emergency Medical Services, 32, 55-56, 58, 60 passim.
Giraud, F., Rascle, C., & Guignand, M. (1996). Out-of-hospital cardiac arrest. Evaluation of one year of activity in Saint-Etienne's emergency medical system using the Utstein style. Resuscitation, 33, 19-27.
Guly, U. M., Mitchell, R. G., Cook, R., Steedman, D. J., & Robertson, C. E. (1995). Paramedics and technicians are equally successful at managing cardiac arrest outside hospital. BMJ, 310, 1091-1094.
Hillis, M., Sinclair, D., Butler, G., & Cain, E. (1993). Prehospital cardiac arrest survival and neurologic recovery. Journal of Emergency Medicine, 11, 245-252.
Ladwig, K. H., Schoefinius, A., Danner, R., Gurtler, R., Herman, R., Koeppel, A., & Hauber, P. (1997). Effects of early defibrillation by ambulance personnel on short- and long-term outcome of cardiac arrest survival: the Munich experiment. Chest, 112, 1584-1591.
Liberman, M., Mulder, D., & Sampalis, J. (2000). Advanced or basic life support for trauma: meta-analysis and critical review of the literature. Journal of Trauma-Injury Infection and Critical
Care, 49, 584-599.
Maio, R. F., Green, P. E., Becker, M. P., Burney, R. E., & Compton, C. (1992). Rural motor vehicle crash mortality: the role of crash severity and medical resources. Accident Analysis &
Prevention, 24, 631-642.
Martin, S. K., Shatney, C. H., Sherck, J. P., Ho, C. C., Homan, S. J., & Neff, J. (2002). Blunt trauma patients with prehospital pulseless electrical activity (PEA): poor ending assured. Journal of
Trauma-Injury Infection & Critical Care, 53, 876-880.
TRANSPORTATION OF EMERGENCY PATIENTS
135
Nguyen-Van-Tam, J. S., Dove, A. F., Bradley, M. P., Pearson, J. C., Durston, P., & Madeley, R. J. (1997). Effectiveness of ambulance paramedics versus ambulance technicians in managing out of hospital cardiac arrest. Journal of Accident & Emergency Medicine, 14, 142-148.
Nichol, G., Detsky, A. S., Stiell, I. G., Orourke, K., Wells, G., & Laupacis, A. (1996). Effectiveness of emergency medical services for victims of out-of-hospital cardiac arrest: a metaanalysis. Annals of Emergency Medicine, 27, 700-710.
Nicholl, J., & Turner, J. (1997). Effectiveness of a regional trauma system in reducing mortality from major trauma: before and after study. BMJ, 315, 1349-1354.
Pitetti, R., Glustein, J. Z., & Bhende, M. S. (2002). Prehospital care and outcome of pediatric out-of-hospital cardiac arrest. Prehospital Emergency Care, 6, 283-290.
Rainer, T. H., Houlihan, K. P., Robertson, C. E., Beard, D., Henry, J. M., & Gordon, M. W. (1997). An evaluation of paramedic activities in prehospital trauma care. Injury, 28, 623-627.
Sethi, D., Kwan, I., Kelly, A. M., Roberts, I., & Bunn, F. (2001). Advanced trauma life support training for ambulance crews. Cochrane Database of Systematic Reviews, 2, CD003109.
Shuster, M., Keller, J., & Shannon, H. (1995). Effects of prehospital care on outcome in patients with cardiac illness. Annals of Emergency Medicine, 26, 138-145.
Shuster, M., & Shannon, H. S. (1994). Differential prehospital benefit from paramedic care. Annals of
Emergency Medicine, 23, 1014-1021.
Soo, L. H., Gray, D., Young, T., Huff, N., Skene, A., & Hampton, J. R. (1999). Resuscitation from out-of-hospital cardiac arrest: is survival dependent on who is available at the scene? Heart, 81, 47-52.
Sukumaran, S., Henry, J. M., Beard, D., Lawrenson, R., Gordon, M. W., O'Donnell, J. J., & Gray, A. J. (2005). Prehospital trauma management: a national study of paramedic activities. Emergency
Medicine Journal, 22, 60-63.
Svensson, L., Karlsson, T., Nordlander, R., Wahlin, M., Zedigh, C., & Herlitz, J. (2003a). Implementation of prehospital thrombolysis in Sweden: components of delay until delivery of treatment and examination of treatment feasibility. International Journal of Cardiology, 88, 247-256.
Svensson, L., Karlsson, T., Nordlander, R., Wahlin, M., Zedigh, C., & Herlitz, J. (2003b). Safety and delay time in prehospital thrombolysis of acute myocardial infarction in urban and rural areas in Sweden. American Journal of Emergency Medicine, 21, 263-270.
Vertesi, L., Wilson, L., & Glick, N. (1983). Cardiac arrest: comparison of paramedic and conventional ambulance services. Canadian Medical Association Journal, 128, 809-812.
Weston, C. F. M., Jones, S. D., & Wilson, R. J. (1997). Outcome of out-of-hospital cardiorespiratory arrest in south Glamorgan. Resuscitation, 34, 227-233.
White, R. D., Asplin, B. R., Bugliosi, T. F., & Hankins, D. G. (1996). High discharge survival rate after out-of-hospital ventricular fibrillation with rapid defibrillation by police and paramedics. Annals of Emergency Medicine, 28, 480-485.
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136
APPENDIX 5: EXCLUDED RETRIEVED PAPERS: COMPARISON OF
OUTCOMES AMONGST CREWS THAT DO AND DO NOT PERFORM
RAPID SEQUENCE INTUBATION AND/OR THORACOSTOMY
Adams, J., Aldag, G., & Wolford, R. (1996). Does the level of prehospital care influence the outcome of patients with altered levels of consciousness? Prehospital & Disaster Medicine, 11, 101-104.
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Burney, R. E., Passini, L., Hubert, D., & Maio, R. (1992). Comparison of aeromedical crew performance by patient severity and outcome. Annals of Emergency Medicine, 21, 375-378.
Cameron, P. A., Flett, K., Kaan, E., Atkin, C., & Dziukas, L. (1993). Helicopter retrieval of primary trauma patients by a paramedic helicopter service. Australian and New Zealand Journal of
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Cannell, H., Silvester, K. C., & O'Regan, M. B. (1993). Early management of multiply injured patients with maxillofacial injuries transferred to hospital by helicopter. British Journal of Oral &
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APPENDIX 6: EXCLUDED RETRIEVED PAPERS: OUTCOMES BY
TIME FROM AMBULANCE CALL OUT TO EMERGENCY
DEPARTMENT DELIVERY
Acosta, J. A., Hatzigeorgiou, C., & Smith, L. S. (2006). Developing a trauma registry in a forward deployed military hospital: preliminary report. Journal of Trauma-Injury Infection & Critical
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Anderson, T. E., Rose, W. D., & Leicht, M. J. (1987). Physician-staffed helicopter scene response from a rural trauma center. Annals of Emergency Medicine, 16, 58-61.
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Bartolacci, R. A., Munford, B. J., Lee, A., & McDougall, P. A. (1998). Air medical scene response to blunt trauma: effect on early survival. Medical Journal of Australia, 169, 612-616.
Battistella, F. D., Nugent, W., Owings, J. T., & Anderson, J. T. (1999). Field triage of the pulseless trauma patient. Archives of Surgery, 134, 742-745; discussion 745-746.
Bickell, W. H., Wall, M. J., Pepe, P. E., Martin, R. R., Ginger, V. F., Allen, M. K., & Mattox, K. L. (1994). Immediate versus delayed fluid resuscitation for hypotensive patients with penetrating torso injuries. New England Journal of Medicine, 331, 1105-1109.
Bjerre, S. K., Hansen, T. M., Melchiorsen, H., & Christensen, E. F. (2002). Prehospital treatment of patients with acute exacerbation of chronic pulmonary disease - Before and after introduction of a Mobile Emergency Care Unit. Ugeskrift for Laeger, 164, 1349-1352.
Blackwell, T. H., & Kaufman, J. S. (2002). Response time effectiveness: comparison of response time and survival in an urban emergency medical services system. Academic Emergency Medicine, 9, 288-295.
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Burger, T., Meyer, F., Tautenhahn, J., & Halloul, Z. (1999). Ruptured infrarenal aortic aneurysm--a critical evaluation. Vasa, 28, 30-33.
Burney, R. E., Passini, L., Hubert, D., & Maio, R. (1992). Comparison of aeromedical crew performance by patient severity and outcome. Annals of Emergency Medicine, 21, 375-378.
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Journal, 139, 788-796.
Cameron, P. A., Flett, K., Kaan, E., Atkin, C., & Dziukas, L. (1993). Helicopter retrieval of primary trauma patients by a paramedic helicopter service. Australian and New Zealand Journal of
Surgery, 63, 790-797.
Chappell, V. L., Mileski, W. J., Wolf, S. E., & Gore, D. C. (2002). Impact of discontinuing a hospital-based air ambulance service on trauma patient outcomes. Journal of Trauma-Injury Infection
& Critical Care, 52, 486-491.
Christenszen, E. F., Melchiorsen, H., Kilsmark, J., Foldspang, A., & Sogaard, J. (2003). Anesthesiologists in prehospital care make a difference to certain groups of patients. Acta
Anaesthesiologica Scandinavica, 47, 146-152.
Citerio, G., Galli, D., Cesana, G. C., Bosio, M., Landriscina, M., Raimondi, M., Rossi, G. P., et al. (2002). Emergency system prospective performance evaluation for cardiac arrest in Lombardia, an Italian region. Resuscitation, 55, 247-254.
Citerio, G., Galli, D., & Pesenti, A. (2006). Early stroke care in Italy - a steep way ahead: an observational study. Emergency Medicine Journal, 23, 608-611.
Clevenger, F. W., Yarbrough, D. R., & Reines, H. D. (1988). Resuscitative thoracotomy: the effect of field time on outcome. Journal of Trauma-Injury Infection & Critical Care, 28, 441-445.
Cooke, W. H., Salinas, J., Convertino, V. A., Ludwig, D. A., Hinds, D., Duke, J. H., Moore, F. A., et al. (2006). Heart rate variability and its association with mortality in prehospital trauma patients. Journal of Trauma-Injury Infection & Critical Care, 60, 363-370; discussion 370.
Cornwell, E. E., 3rd, Belzberg, H., Hennigan, K., Maxson, C., Montoya, G., Rosenbluth, A., Velmahos, G. C., et al. (2000). Emergency medical services (EMS) vs non-EMS transport of critically injured patients: a prospective evaluation. Archives of Surgery, 135, 315-319.
Cunningham, P., Rutledge, R., Baker, C. C., & Clancy, T. V. (1997). A comparison of the association of helicopter and ground ambulance transport with the outcome of injury in trauma patients transported from the scene. Journal of Trauma-Injury Infection & Critical Care, 43, 940-946.
Dash, H. H., & Kaul, N. (2004). Prehospital care of the head trauma patients. Journal of
Anaesthesiology Clinical Pharmacology, 20, 333-337.
de Vreede-Swagemakers, J. J., Gorgels, A. P., Dubois-Arbouw, W. I., Dalstra, J., Daemen, M. J., van Ree, J. W., Stijns, R. E., et al. (1998). Circumstances and causes of out-of-hospital cardiac arrest in sudden death survivors. Heart, 79, 356-361.
Dean, N. C., Haug, P. J., & Hawker, P. J. (1988). Effect of mobile paramedic units on outcome in patients with myocardial infarction. Annals of Emergency Medicine, 17, 1034-1041.
Demetriades, D., Chan, L., Cornwell, E., Belzberg, H., Berne, T. V., Asensio, J., Chan, D., et al. (1996). Paramedic vs private transportation of trauma patients - effect on outcome. Archives of
Surgery, 131, 133-138.
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Devlin, J., Wendon, J., Heaton, N., Tan, K. C., & Williams, R. (1995). Pretransplantation clinical status and outcome of emergency transplantation for acute liver-failure. Hepatology, 21, 1018-1024.
Di Bartolomeo, S., Sanson, G., Michelutto, V., Nardi, G., Burba, I., Francescutti, C., Lattuada, L., et al. (2004). Epidemiology of major injury in the population of Friuli Venezia Giulia-Italy. Injury, 35, 391-400.
Di Bartolomeo, S., Sanson, G., Nardi, G., Scian, F., Michelutto, V., & Lattuada, L. (2001). Effects of 2 patterns of prehospital care on the outcome of patients with severe head injury. Archives of
Surgery, 136, 1293-1300.
Di Chiara, A., Chiarella, F., Savonitto, S., Lucci, D., Bolognese, L., De Servi, S., Greco, C., et al. (2003). Epidemiology of acute myocardial infarction in the Italian CCU network: the BLITZ study. European Heart Journal, 24, 1616-1629.
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APPENDIX 7: INCLUDED PAPERS
Baxt, W. G., & Moody, P. (1987). The impact of a physician as part of the aeromedical prehospital team in patients with blunt trauma. JAMA, 257, 3246-3250.
Berns, K. S., Hankins, D. G., & Zietlow, S. P. (2001). Comparison of air and ground transport of cardiac patients. Air Medical Journal, 20, 33-36.
Biewener, A., Aschenbrenner, U., Rammelt, S., Grass, R., & Zwipp, H. (2004). Impact of helicopter transport and hospital level on mortality of polytrauma patients. Journal of Trauma-Injury
Infection and Critical Care, 56, 94-98.
Bonatti, J., Goschl, O., Larcher, P., Wodlinger, R., & Flora, G. (1995). Predictors of short-term survival after helicopter rescue. Resuscitation, 30, 133-140.
Burney, R. E., Hubert, D., Passini, L., & Maio, R. (1995). Variation in air medical outcomes by crew composition: a two-year follow-up. Annals of Emergency Medicine, 25, 187-192.
Burney, R. E., Passini, L., Hubert, D., & Maio, R. (1992). Comparison of aeromedical crew performance by patient severity and outcome. Annals of Emergency Medicine, 21, 375-378.
Cameron, S., Pereira, P., Mulcahy, R., & Seymour, J. (2005). Helicopter primary retrieval: tasking who should do it? Emergency Medicine Australasia, 17, 387-391.
Christenszen, E. F., Melchiorsen, H., Kilsmark, J., Foldspang, A., & Sogaard, J. (2003). Anesthesiologists in prehospital care make a difference to certain groups of patients. Acta
Anaesthesiologica Scandinavica, 47, 146-152.
Clarke, J. R., Trooskin, S. Z., Doshi, P. J., Greenwald, L., & Mode, C. J. (2002). Time to laparotomy for intra-abdominal bleeding from trauma does affect survival for delays up to 90 minutes. Journal of Trauma-Injury Infection & Critical Care, 52, 420-425.
Feero, S., Hedges, J. R., Simmons, E., & Irwin, L. (1995). Does out-of-hospital EMS time affect trauma survival? American Journal of Emergency Medicine, 13, 133-135.
Frandsen, F., Nielsen, J. R., Gram, L., Larsen, C. F., Jorgensen, H. R., Hole, P., & Haghfelt, T. (1991). Evaluation of intensified prehospital treatment in out-of-hospital cardiac arrest: survival and cerebral prognosis. The Odense ambulance study. Cardiology, 79, 256-264.
Frezza, E. E., & Mezghebe, H. (1999). Is 30 minutes the golden period to perform emergency room thoratomy (ERT) in penetrating chest injuries? Journal of Cardiovascular Surgery, 40, 147-151.
Gao, J. M., Gao, Y. H., Zeng, J. B., Wang, J. B., He, P., Wei, G. B., & Xiang, Z. (2006). Polytrauma with thoracic and/or abdominal injuries: experience in 1 540 cases. Chinese Journal of
Traumatology, 9, 108-114.
Garner, A., Rashford, S., Lee, A., & Bartolacci, R. (1999). Addition of physicians to paramedic helicopter services decreases blunt trauma mortality. Australian & New Zealand Journal of
Surgery, 69, 697-701.
Grzybowski, M., Zalenski, R. J., Ross, M. A., & Bock, B. (2000). A prediction model for prehospital triage of patients with suspected cardiac ischemia. Journal of Electrocardiology, 33 Suppl, 253-258.
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Hamman, B. L., Cue, J. I., Miller, F. B., O'Brien, D. A., House, T., Polk, H. C., Jr., & Richardson, J. D. (1991). Helicopter transport of trauma victims: does a physician make a difference? Journal of
Trauma-Injury Infection & Critical Care, 31, 490-494.
Hartl, R., Gerber, L. M., Iacono, L., Ni, Q. H., Lyons, K., & Ghajar, J. (2006). Direct transport within an organized state trauma system reduces mortality in patients with severe traumatic brain injury. Journal of Trauma-Injury Infection and Critical Care, 60, 1250-1256.
Kearney, P. A., Terry, L., & Burney, R. E. (1991). Outcome of patients with blunt trauma transferred after diagnostic or treatment procedures or four-hour delay. Annals of Emergency Medicine, 20, 882-886.
Koefoed-Nielsen, J., Christensen, E. F., Melchiorsen, H., & Foldspang, A. (2002). Acute myocardial infarction: does pre-hospital treatment increase survival? European Journal of Emergency
Medicine, 9, 210-216.
Lee, A., Garner, A., Fearnside, M., & Harrison, K. (2003). Level of prehospital care and risk of mortality in patients with and without severe blunt head injury. Injury, 34, 815-819.
Lerner, E. B., Billittier, A. J., Dorn, J. M., & Wu, Y. W. (2003). Is total out-of-hospital time a significant predictor of trauma patient mortality? Academic Emergency Medicine, 10, 949-954.
Lim, G. H., & Seow, E. (2002). Resuscitation for patients with out-of-hospital cardiac arrest: Singapore. Prehospital & Disaster Medicine, 17, 96-101.
Osterwalder, J. J. (2002). Can the "golden hour of shock" safely be extended in blunt polytrauma patients? Prospective cohort study at a level I hospital in eastern Switzerland. Prehospital &
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