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Mechanical Ventilation in Emergency Room
Dr.Venugopalan P P DA,DNB,MNAMS,MEM [GWU] Director ,Emergency Medicine Aster DM Healthcare -India
Executive Director -Active Network Group of Emergency Life Savers
Faculty presentation in Second annual conference on `Emergency medicine conducted by Ananthapuri Hospital Trivandrum
19.06.2016
Background Intubation &mechanical ventilation, is a common life-saving intervention Good understanding of techniques to optimise mechanical ventilation will minimise complications.Effects of ventilator-induced lung injury are delayed and not seen while patients are in the EDMechanical ventilation - ED approach is different .Ventilatory strategies - different disease processes to protect pulmonary parenchyma while maintaining adequate gas exchangeNoninvasive ventilation - avoid the risks and complications of tracheal intubation
Understanding of Mechanical Ventilation in ED
Basics and beyond ….
Session tries to answer this
Why ventilation in ED?
How to initiate ?
What are the problems involved ?
What are the special situations to be considered?
What are the trouble shoots and how it be managed ?
What are the ED role in preventive care ?
Why mechanical ventilation in ED?
Clinical- Airway-Breathing- Circulation-Disability
Lab
Clinical Airway
Airway protection
Clinical Breathing
Apnea Hypoventilation
Respiratory distress +AMS
Increased work of breathing unrelieved by noninvasive methods
Clinical Circulation
Severe circulatory shock
Clinical Disability
Controlled hyperventilation
GCS less than 8
Laboratory Indications
“8” Sets of Indications to start mechanical ventilation in ED
1 Airway Airway protection2 Breathing Apnea,Distress3 Circulation Shock4 Disability Low GCS5 Arterial Blood Gas PaO2,PaCO2&PH6 Volume VC<10ml/Kg7 Pressure Neg.Insp.Pr<25cmH2O8 Flow FEV1<10ml/Kg
Pearls No absolute contraindications exist to mechanical ventilation. The need for mechanical ventilation is best made early on clinical grounds.A good rule of thumb - if the practitioner is thinking that mechanical ventilation is needed, then it probably yes. Waiting for return of laboratory values can result in unnecessary morbidity or mortality.
How to do it?Know the modes and supports
Know how to set it
Modes
Volume -cycled
Pressure -cycled
High frequency oscillatory support
Volume cycled
Inhalation till pre-set Tidal volume delivered
Passive exhaustion
Constant inspiratory flow
Peak inspiratory pressure >Plateau Pressure
Volume cycled mode Constant volume - Varied Airway pressure with Compliance[Plateau Pr] and Airway resistance [Peak Pr]
Choice as initial ventilation mode in ED
Ventilator pressure act a monitor for Pulm. Compliance
Barotrauma
Pressure cycled mode Inhalation continue till pre-set peak inspiratory pressure attained
Tidal volume vary with pulmonary and thoracic compliance
Decelerating inspiratory flow
Homogenous gas distribution
Pressure cycled mode
Tidal volume changes with pulmonary dynamics
Demands Close monitoring
Limits its use in ED
Dual mode Volume cycled - pressure limited is ideal for
Emergency departments
HFOUltra high respiratory rates [180 to 900breaths per minute]
Tiny tidal volume [1 -4ml /kg]
High airway pressure [25 to 30 mmof H2O]
Useful in Premature infants and ARDS
Limited role in ED
Supports Control mode - Preset volume delivery regardless patient effort, Choice in Apnea , Poor respiratory drive
Support mode -Provides inspiratory assistance through Pressure,Terminate with expiratory pause, Need adequate respiratory drive
“8” Methods of Support
1. CMV
2. ACV
3. IMV
4. SIMV
“8”Methods of Support
1. PSV
2. PEEP
3. CPAP
4. BiPAP
CMV Continous Mandatory Ventilation
Deliver breaths in preset intervals regardless pt efforts
Paralysed /Apneic pts
Increase WOB if pt is having efforts
ACV Assist Control Mode
Deliver preset breaths in coordination with pt efforts
Useful for Pts with intact respiratory efforts
Triggered inspiration
IMV Intermittent Mandatory
VentilationDeliver breaths in preset interval , Preset mandatory volume
Spontaneous breaths in between cause resistance of tubings and valves
Baro trauma
SIMV Synchronous Intermittent
Mandatory Ventilation Deliver preset breaths and volume in coordination with pt respiratory efforts
Limits barotrauma
Disadvantage -increased WOB [Adding PSV will reduce it ]
PSV Pressure support Ventilation
For spontaneously breathing patients
Mode will support every inspiration at preset pressure levels
Airway pressure will maintain till the cut off level reaches
Limits barotrauma
Decrease WOB
Pt decide RR,VT and Flow rate
Pearls ACV/SIMV with full support is the choice in patients require high MV
Reduces Oxygen consumption and carbon dioxide production
ACV in Obstructive airway diseases causes air trapping and Breath staking
Full support ventilation with paralysis ACV=SIMV
PSV is the choice in Pts with adequate respiratory drive
PSV- better pt outcome ,reduced CVS effects ,Less Barotrauma and better gas distribution
Non Invasive ventilationMost commonly used in Ed
Most useful Less complications
NIV Biphasic Positive Airway Pressure
[BiPAP]Ventilatory support though mask in place of ETT
Very useful in mild to moderate respiratory failure
Pt must be mentally alert
BiPAP is not pressure support.
Form of CPAP-alternates high and low positive airway pressures
NIV 4-Indications
Acute exacerbations -COPD
Acute exacerbations -Asthma
Decompensated CHF with mild to moderate pulmonary oedema
Hypervolemic pulmonary oedema
NIV Recommended as an adjunct to Standard
medical therapy [4 clinical scenarios ]
Severe COPD exacerbations[PH,7.35,Relative hypercarbia]
Cariogenic Pulmonary oedema
Respiratory failure with out shock
ACS for urgent PCTA
How do I set ventilator in Ed?Guideline for initial setting
and Special clinical situations
Set “8”parameters
Mode of ventilation
Tidal volume -TV
Respiratory rate -RR
Fractional inspiratory concentration of Oxygen-FiO2
Set “8” parameters
Inspiration/Expiration Ratio
Inspiratory flow rate
Positive End Expiratory Pressure-PEEP
Sensitivity
Mode Based on the need of the patients
Need to order quickly in ED
SIMV and ACV are best modes for initial setting
PSV - for pts with good respiratory drive
Tidal Volume IPPV -10ml/ Kg
Spontaneous breaths 7ml/kg
Obstructive airway diseases and ARDS- 5 -8 ml/kg [ Target to maintain plateau pressure <35cm of water
Respiratory rate
8-12 per minute for Pts not requiring hyperventilation
5-6 per minute is enough for Asthma Pts
Permissive hypercapnia in Asthma is acceptable
“4”Reasons not to set high RR in obstructive airway diseases
Less time for exhalation
increase mean airway pressure
Air trapping
Hypotension
FiO2
Lowest FiO2 to get SaO2<90% and PaO2>60 mm of Hg
A FiO2 of 0.4 is acceptable
Inspiration/Expiration ratio [I/E]
I/E to start with 1:2
Obstructive airway disease 1:4 or 1:5[To avoid air trapping and auto PEEP]
ARDS - 2:1[Inverse ratio]
Inspiratory Flow rateIFR is a function of TV,I/E and RR
Controlled by these parameters
Typical setting 60L/mt
Obstructive airway disease up to 100L/mt
PEEP Positive End Expiratory Pressure
Beneficial if used optimally with low tidal volume
Decreases ventilator induced lung injury
Reduce atelectasis trauma
Minimise trauma due to cyclical collapse and reopening
PEEP Positive End Expiratory Pressure
Shift lung water from alveolar space to perivascular interstitial space
Provide acceptable O2 level & Reduce FiO2 to non toxic level [0.5]
PEEP must be balanced with excessive intra thoracic pressures
PEEP Positive End Expiratory Pressure
“4” indications ARDS
Cariogenic Pulmonary oedema
Non cariogenic Pulmonary Oedema
Congestive heart failure
PEEP Positive End Expiratory Pressure
“8” adverse effectsIncreased intra thoracic pressure
Decreased Preload
Decreased cardiac out put
Hypotension
Dead space ventilation
Barotrauma
Increased ICP
Tension Pneumothorax
PEEP Positive End Expiratory Pressure
Setting start with 3-5 cm of H2O
Titrate against FiO2
FiO2 target less than 0.5 and PaO2 >60mm of Hg
Sensitivity Assist ventilation [ -1 to -2cm of H2O
iPEEP increases the difficulty to generate a negative inspiratory force
New Gen ventilators senses flow instead of negative pressure - Flow by Mode
Flow sensing decreases WOB
How do I monitor a patient on ventilator
Titrate parameters setting against clinical outcome and safe target values
Monitor “8” parameters in pts on ventilator
Heart rate
Blood pressure
Oximetry
ETCO2
ABG/VBG
Peak inspiratory pressure
Plateau Pressure
Exhaled tidal volume
Monitoring pt on Ventilator
Stable patient - Titrate FiO2 to Minimum using SpO2 or SaO2 as guide
ABG A baseline value and repeat 30 mts after a major change in the setting
PaCO2 is the indicator of ventilatory function.
PIP &PP reflects Ventilatory dysfunction and lung compliance
Exhaled volume to detect leaks and disconnect
SpO2 and ETCO2SpO2 reflect beat to beat oxygenation status ETCO2 reflect breath to breath ventilation status
ETCO2 detects
Ventilation status
Detects ventilator dysfunction
ETT obstruction
Tube dislodgement
Fight with ventilator
What are the consequences ?Cautions and Precautions
Adverse consequences of Mechanical ventilationSystemic inflammatory effects and biochemical pulmonary injury
Barotrauma and volutrauma
High FiO2 related free radical lung injury - Atelectasis and shunt
Dead space ventilation
Adverse consequences of Mechanical ventilationBacterial translocation and Bacteremia
Increased Intra thoracic pressure ,decreased venous return and COP, RV and LV dysfunction
Hypotension
Adverse consequences of Mechanical ventilationDecline in renal function
Increased hepatic vascular resistance and bile duct pressure
Gastric mucosal ischemia and GI bleed
Trouble shooting in ventilation How do I manage complications in the ED ?
Clinically deteriorating Mechanically ventilated Pt
EET/Ventilator dysfunction
Improper Ventilator settings
Pain
Anxiety
Pulmonary or Extra Pulmonary disease process
“4” most common presentations of ventilator trouble shoots in the ED
1. Hypoxia
2. Hypotension
3. High pressure alarms
4. Low exhaled volume alarms
Intubated and ventilator patient with Heamodynamic and respiratory instability …
Disconnect from ventilator
Initiate manual ventilation
Set 100% oxygen
Look for DOPE
Displacement -Obstruction-Pneumothorax-Equipment failure
Displacement -ETT
Obstruction - ET Tube and Tubings
Pneumothorax -Tension
Equipment failure
DOPE
“4” reasons for Cardio-Respiratory instability in Pts on ventilators
1. Tension Pneumothorax
2. Intrinsic PEEP
3. Obstructed Tube
4. ETT cuff leak
Tension Pneumothorax
Needle decompression
Tube thoracotomy
Clinical diagnosis
Should wait for Chest radiograph
Intrinsic PEEP
Asthma & COPD patients
Incomplete exhalation and hyper inflation
Confirmation - Perform an End expiratory Hold or Non zero End expiratory flow on ventilator
Intrinsic PEEP
Allow lung deflation
Change setting by longer expiratory timings
Decrease RR ,Decrease TV or Change I/E Ratio
Obstructed tube Significant airway resistance
High pressure alarms
Extrinsic compression,Tube plugs and Mucus,Blood ,FB, Kinks and Bites
Suction and Sedation
PIP and Pplat helps to locate resistance
PIP = resistance to air flow [measured by ventilator ]
Plato = pulmonary compliance [measured by a brief inspiratory pause ]
PIP and Pplat locate resistance
High PIP +Normal Pplat= Increased resistance to flow [ETT obstruction or Bronchospasm]
High PIP +High Pplat= Decreased lung compliance [Pneumonia,ARDS,Pulmonary Oedema,Abdominal distension]
“8” causes for High pressure PIP and Pplat
High pressure alarm? “8”Causes
1. Worsening ARDS
2. Pneumothorax
3. Endobrochial Intubation
4. Tube Bite and Block
5. Pulmonary oedema
6. Chest wall rigidity
7. Increased Intra abdominal pressure
8. Psychomotor agitation
Low exhaled volume Alarm
Air leak
Ventilatory Tube disconnection
Balloon deflation
Tracheal tube dislodgement
Treat- Tube placement ,Ballon inflation& Reconnect to ventilator
“8” causes for Hypoxia
following intubation and Mechanical ventilation
1. Secondary to hypoventilation
2. Worsening cardiac shunting
3. Inadequate FiO2
4. Main stem intubation
5. Aspiration
6. Tube dislodgement
7. Pulmonary Oedema
8. Wrong gas- compressed air or Nitrous oxide
Hypoxia following intubation and Mechanical ventilation
Increase Oxygen -FiO2
Change ventilator setting
Increase PEEP ,RR
Exclude DOPE
Hypotension following intubation and Mechanical ventilation
Decreased venous return and Increased Intrathorvacic pressure
Vasovagal reaction to intubation
RSI
Sedation
Tension pneumothorax
Hypoxia following intubation and Mechanical ventilation
IV fluids
Change Ventilatory setting
Reduce PEEP
Reduce VT and RR
Supportive care Anticipatory …
how to reduce morbidity and mortality
How does ED physician responsible for secondary complication
Traditionally limited to Intubation and Initiation of ventilation
Long ED stay is due to non availability of ICU beds
EP should initiate preventive measures to decrease secondary complications
Secondary complications
Ventilator associated pneumonia -VAP
Venous thromboembolism -VTE
Stress Related Mucosal injury
VAP
Most common infectious complication
Prolonged ICU & Hospital stay
Prolonged Ventilator days
Increases cost of care
VAP ED related independent risk factors
Pre-hospital intubation
ED intubation
ED length of stay
ED level measures to decrease VAP
Due to Aspiration and bacterial colonisation
Semi upright position -3o to 45 degree head end elevation
NG Tube
Oral care with soft tooth brush
Chlorhexidine rinses
Cuff pressure monitoring 4 hourly [20 to 30cm of H2O
VTE
VTE prophylaxis from ED
Unfractionated Heparin
Low molecular weight Heparin
Stress related GI mucosal injury
75% ICU patients develops SRGIM injury within 24 hours
Proton pump inhibitors
Sucralfate
Histamine receptor antagonist
Identify high risk patients to develop Stress induced GI injuries
High risk patients Coagulopathy
GI bleeds
Gastritis
Peptic ulcer
Mechanical ventilation more than 48 hours
Summary EP has to initiate mechanical ventilation in critical scenarios
EP should know basics and beyond
ED based mechanical ventilation strategy is different
Close monitoring and targeted titration is essential to bring successful outcome
EP has pivotal role in preventive care in ICU complications
Core reference article
Thank you so much critically
yours dr.venu
www.drvenu.net www.drvenu.me