WHAT IS SHOCK AND HOW COMMON IS IT IN THE ICU? Jason D. Christie, MD, MSCE Assistant Professor of Medicine Assistant Professor of Epidemiology Division

WHAT IS SHOCK AND HOW WHAT IS SHOCK AND HOW COMMON IS IT IN THE ICU?COMMON IS IT IN THE ICU?

Jason D. Christie, MD, MSCEJason D. Christie, MD, MSCE

Assistant Professor of MedicineAssistant Professor of MedicineAssistant Professor of EpidemiologyAssistant Professor of Epidemiology

Division of Pulmonary, Allergy, and Critical CareDivision of Pulmonary, Allergy, and Critical CareCenter for Clinical Epidemiology and BiostatisticsCenter for Clinical Epidemiology and BiostatisticsUniversity of Pennsylvania, Philadelphia, USA University of Pennsylvania, Philadelphia, USA

RoadmapRoadmap

• Definition of ShockDefinition of Shock– Global Definition of ShockGlobal Definition of Shock– Epidemiological Considerations of Operational Epidemiological Considerations of Operational

DefinitionsDefinitions

• Specific Definitions of ShockSpecific Definitions of Shock– SepsisSepsis– CardiogenicCardiogenic– OtherOther

• Incidence of Different forms of ShockIncidence of Different forms of Shock– SepsisSepsis– CardiogenicCardiogenic– OtherOther

Global Definition of ShockGlobal Definition of Shock

• ““A state of profound depression of the vital processes A state of profound depression of the vital processes associated with reduced blood volume and pressure and associated with reduced blood volume and pressure and caused usually by severe especially crushing injuries, caused usually by severe especially crushing injuries, hemorrhage, or burns.”hemorrhage, or burns.”

• Merriam-Webster DictionaryMerriam-Webster Dictionary

• Alternative definitions:Alternative definitions:• ““a violent shake or jar,”a violent shake or jar,”• ““disturbance in the equilibrium or permanence of something.” disturbance in the equilibrium or permanence of something.”

• EtymologyEtymology– Middle French Middle French chocchoc, from , from choquerchoquer “to strike against” “to strike against”– Middle Dutch Middle Dutch schockenschocken “to jolt.” “to jolt.”

““Shock” Definition in Critical IllnessShock” Definition in Critical Illness

• Useful to categorize of shock asUseful to categorize of shock as– CardiogenicCardiogenic– Distributive Distributive

– SepticSeptic– AnaphylacticAnaphylactic

– HypovolemicHypovolemic

• These groups have been studied These groups have been studied separately by researchers from each separately by researchers from each disciplinediscipline

Global “Shock” DefinitionGlobal “Shock” Definition

• The Global definition of shock has The Global definition of shock has remained relatively consistent in clinical remained relatively consistent in clinical studies, and generally includes:studies, and generally includes:

• ““Persistence of arterial hypotension Persistence of arterial hypotension despite adequate volume resuscitationdespite adequate volume resuscitation””

– Definition forms most of the clinical research Definition forms most of the clinical research on incidence of the various forms of shockon incidence of the various forms of shock

Shock DefinitionShock Definition

• Is it Valid?Is it Valid?– Capture what you think it does?Capture what you think it does?

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Shock DefinitionShock Definition

• Is it Valid?Is it Valid?– Capture what you think it does?Capture what you think it does?

• Reliable?Reliable?– Can it be reproduced?Can it be reproduced?– Do different researchers call the same Do different researchers call the same

patients “shock”?patients “shock”?

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Validity of clinical criteriaValidity of clinical criteria

SBP<90SBP<90

DespiteDespite

adequateadequate

volume loadvolume load

Validity of clinical criteriaValidity of clinical criteria

SBP<90SBP<90

DespiteDespite

adequateadequate

volume loadvolume load

Validity of Shock DefinitionValidity of Shock Definition

• Face ValidityFace Validity– Does it make senseDoes it make sense

• Content ValidityContent Validity– Have panels of experts agreed it makes sense Have panels of experts agreed it makes sense

and includes all components of “shock”and includes all components of “shock”

• For several shock subsets, these forms of For several shock subsets, these forms of validity exist (e.g. cardiogenic and septic)validity exist (e.g. cardiogenic and septic)

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• Criterion (Gold Standard) ValidityCriterion (Gold Standard) Validity– Measured against a Gold StandardMeasured against a Gold Standard– This does not exist in ShockThis does not exist in Shock– ““Tarnished Gold Standard”Tarnished Gold Standard”

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• Criterion (Gold Standard) ValidityCriterion (Gold Standard) Validity– Measured against a Gold StandardMeasured against a Gold Standard– This does not exist in ShockThis does not exist in Shock– ““Tarnished Gold Standard”Tarnished Gold Standard”

• Discriminant “Predictive” validityDiscriminant “Predictive” validity– Do different forms of the definition predict mortality Do different forms of the definition predict mortality

differently?differently?

• Construct ValidityConstruct Validity– Is the definition related to different biological Is the definition related to different biological

physiological signals?physiological signals?

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Reliability of Shock definitionReliability of Shock definition

• Agreement between investigators:Agreement between investigators:

– Septic ShockSeptic Shock

– CUB-Rea study, agreement on coding of CUB-Rea study, agreement on coding of cardiovascular failure was 89%cardiovascular failure was 89%

Annane, AJRCCM 2003; 168:165-72

Reliability and Validity of Shock Reliability and Validity of Shock DefinitionsDefinitions

• Although not perfect, some validity and Although not perfect, some validity and reliability data exist on septic and reliability data exist on septic and cardiogenic shockcardiogenic shock

• Studies of incidence are reasonable Studies of incidence are reasonable given these operational definitionsgiven these operational definitions

RoadmapRoadmap





Septic Shock DefinitionSeptic Shock Definition

• Early 1990s, Bone et al. defined “septic shock”:Early 1990s, Bone et al. defined “septic shock”:

““Sepsis with arterial hypotension, despite Sepsis with arterial hypotension, despite adequate fluid resuscitation.”adequate fluid resuscitation.”

– Sepsis: SIRS plus infectionSepsis: SIRS plus infection– Severe sepsis: sepsis with organ dysfunction.Severe sepsis: sepsis with organ dysfunction.

– SIRS defined as two or more of: SIRS defined as two or more of: » Temp >38°C or <36°CTemp >38°C or <36°C» HR >90 minHR >90 min» RR >20 min or a PaCO2 <32 mm HgRR >20 min or a PaCO2 <32 mm Hg» WBC >12,000 or <4,000. WBC >12,000 or <4,000.

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Septic Shock DefinitionSeptic Shock Definition

• In 2001, Joint Consensus Conference:In 2001, Joint Consensus Conference:

““A state of acute circulatory failure characterized A state of acute circulatory failure characterized by persistent arterial hypotension unexplained by persistent arterial hypotension unexplained by other causesby other causes.” .”

– Arterial hypotension Arterial hypotension • systolic BP <90 mm Hgsystolic BP <90 mm Hg• MAP <60mmHgMAP <60mmHg• reduction in systolic BP of <40 mm Hg from baseline reduction in systolic BP of <40 mm Hg from baseline • despite adequate volume resuscitationdespite adequate volume resuscitation• in the absence of other causes for hypotensionin the absence of other causes for hypotension

Levy, CCM. 2003; 31:1250-6

Adapted from SCCM/ACCP Consensus Guidelines

InfectionInfection

BSIBSI

ParasiteParasite

VirusVirus

FungusFungus

BacteriaBacteriaTraumaTrauma

BurnsBurns

SepsisSepsis SIRSSIRSSevereSevereSepsisSepsis

SevereSevereSIRSSIRS

shock


International Sepsis Definitions Conf.International Sepsis Definitions Conf.

• Systemic inflammationSystemic inflammation• Concept remains validConcept remains valid• Specific “2 or 3 out of 4” criteria are arbitrary and Specific “2 or 3 out of 4” criteria are arbitrary and

unhelpfulunhelpful• Biomarkers may eventually be more usefulBiomarkers may eventually be more useful

– IL-6 vs. tachycardiaIL-6 vs. tachycardia

• RecommendationRecommendation• Stop using SIRS to define sepsisStop using SIRS to define sepsis

– Expand clinical criteria for evidence of sepsisExpand clinical criteria for evidence of sepsis• Consider ‘staging’ classification analogous to TNMConsider ‘staging’ classification analogous to TNM

Levy et al. Crit Care Med 2003.

Diagnostic criteria for sepsisDiagnostic criteria for sepsis

– FeverFever– Arterial hypotensionArterial hypotension– Increased CRPIncreased CRP– Increased PCTIncreased PCT– Increased SvO2Increased SvO2– Increased cardiac outputIncreased cardiac output– TachycardiaTachycardia– Arterial hypoxemiaArterial hypoxemia– Acute oliguriaAcute oliguria– Increased creatinineIncreased creatinine– Coagulation abnormalitiesCoagulation abnormalities

– HyperlactatemiaHyperlactatemia– ThrombocytopeniaThrombocytopenia– Decreased capillary refill or mottlingDecreased capillary refill or mottling– LeukocytosisLeukocytosis– LeukopeniaLeukopenia– HypothermiaHypothermia– IleusIleus– Altered mental statusAltered mental status– Significant edema or positive fluid Significant edema or positive fluid

balancebalance– HyperbilirubinemiaHyperbilirubinemia– HyperglycemiaHyperglycemia

Infection PLUS some of the following

Levy et al. Crit Care Med 2003.

Cardiogenic Shock DefinitionCardiogenic Shock Definition

• Sustained systemic hypotension:Sustained systemic hypotension:• Systolic BP <90 mm HgSystolic BP <90 mm Hg• MAP 30 mm Hg or more below basal levelsMAP 30 mm Hg or more below basal levels• Adequate or elevated left ventricular filling pressuresAdequate or elevated left ventricular filling pressures

– PAOP >15 mm HgPAOP >15 mm Hg

• cardiac index <2.2 L/min/m2cardiac index <2.2 L/min/m2

• Some studies use clinical signs indicative of Some studies use clinical signs indicative of poor tissue perfusionpoor tissue perfusion

• OliguriaOliguria• clouded sensoriumclouded sensorium• cool, mottled extremities cool, mottled extremities

Hollenberg, Ann Intern Med. 1999; 131:47-59.

Other Shock DefinitionsOther Shock Definitions

• Studies are less complete/consistentStudies are less complete/consistent

• Anaphylactic shockAnaphylactic shock– signs of anaphylaxissigns of anaphylaxis– hypotension requiring urgent medical hypotension requiring urgent medical

attention. attention.

• Burns, blunt and penetrating traumaBurns, blunt and penetrating trauma• persistent hypotension, despite volume persistent hypotension, despite volume

resuscitationresuscitation• similar to septic shocksimilar to septic shock

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RoadmapRoadmap





Incidence and “Treatable shock”Incidence and “Treatable shock”

• Most Incidence estimates are actually for “Treatable Most Incidence estimates are actually for “Treatable Shock” (Linde-Zwirble, Crit Care 2004)Shock” (Linde-Zwirble, Crit Care 2004)– Subjects must be in a setting where shock criteria can be Subjects must be in a setting where shock criteria can be

applied (hospital or ICU)applied (hospital or ICU)– Shock and death at home or a nursing home are not counted Shock and death at home or a nursing home are not counted

(e.g. following sepsis or MI) (e.g. following sepsis or MI) • Most Incidence Estimates are expressed as “incidence Most Incidence Estimates are expressed as “incidence

of shock per ICU admissions” of shock per ICU admissions” – Pragmatically this makes sensePragmatically this makes sense– Define the population we want to intervene uponDefine the population we want to intervene upon

• However, given the reliance on admission to the ICU, However, given the reliance on admission to the ICU, incidence estimates may vary between countries and incidence estimates may vary between countries and setting, depending on the number of ICU beds and setting, depending on the number of ICU beds and treatment decisions.treatment decisions.

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Incidence of Septic shockIncidence of Septic shock

• Much of the epidemiology of sepsis has focused Much of the epidemiology of sepsis has focused on severe sepsis (sepsis with the presence of on severe sepsis (sepsis with the presence of organ dysfunction). organ dysfunction).

• However, septic shock has been the focus of However, septic shock has been the focus of multiple large epidemiological studies.multiple large epidemiological studies.

• In general, the incidence of septic shock has In general, the incidence of septic shock has been relatively consistentbeen relatively consistent– 6-10 per 100 ICU admissions (6-10%).6-10 per 100 ICU admissions (6-10%).

• The incidence of septic shock may be increasingThe incidence of septic shock may be increasing– affecting nearly 10% of patients during ICU stay affecting nearly 10% of patients during ICU stay

CCEB

Earlier studiesEarlier studies

• Rangel-Frausto (1995)Rangel-Frausto (1995)– 9 month study in surgical ICUs in Iowa9 month study in surgical ICUs in Iowa– 2527 individuals with SIRS criteria. 2527 individuals with SIRS criteria. – 10 individuals developed shock10 individuals developed shock– defined as a SBP<90 unresponsive to fluids. defined as a SBP<90 unresponsive to fluids. – The incidence of septic shock was estimated The incidence of septic shock was estimated

at 6.3 per 100 SICU admissions at 6.3 per 100 SICU admissions

Rangel-Frausto JAMA 1995; 273:117-23


• Brun-Buisson 1995Brun-Buisson 1995– French ICU Group for Severe SepsisFrench ICU Group for Severe Sepsis– 170 adult ICUs in France170 adult ICUs in France– Data collected over two monthsData collected over two months– 11828 admissions 11828 admissions – The incidence of septic shock was estimated The incidence of septic shock was estimated

at 6.4 per 100 ICU admissions at 6.4 per 100 ICU admissions

Brun-Buisson JAMA. 1995; 274:968-74.


• Brun-Buisson 1996Brun-Buisson 1996– French Bacteremia Sepsis Study GroupFrench Bacteremia Sepsis Study Group– 2345 individuals collected over 2 months2345 individuals collected over 2 months– 24 hospitals France24 hospitals France– Estimate of 8.7 per 100 ICU admissions Estimate of 8.7 per 100 ICU admissions

Brun-Buisson AJRCCM 1996; 154:617-24


• Italian SEPSIS study 1995Italian SEPSIS study 1995– one year study of 99 Italian ICUsone year study of 99 Italian ICUs– data collected between 1993 and 1994data collected between 1993 and 1994– 1101 subjects 1101 subjects – The reported incidence was 6.1 per 100 ICU The reported incidence was 6.1 per 100 ICU

admissions admissions

Salvo, Intensive Care Med. 1995; 21:S244-9

More recent studiesMore recent studies

• CUB-Rea 2003CUB-Rea 2003– 100,554 ICU admissions in France 100,554 ICU admissions in France – Between 1993 and 2000. Between 1993 and 2000. – 8,251 episodes of septic shock. 8,251 episodes of septic shock. – Overall incidence 8.2 per 100 admissions. Overall incidence 8.2 per 100 admissions. – Incidence of septic shock increased from 7.0 Incidence of septic shock increased from 7.0

in 1993 to 9.7 per 100 admissions in 2000 in 1993 to 9.7 per 100 admissions in 2000

Annane AJRCCM 2003; 168:165-72

Incidence and Mortality Over TimeIncidence and Mortality Over Time

Annane AJRCCM 2003; 168:165-72


• EPISEPSIS 2004 EPISEPSIS 2004 – Collected data during a 2 week study period Collected data during a 2 week study period – 3738 ICU admissions were screened for severe 3738 ICU admissions were screened for severe

sepsissepsis– 621 (16.6%) were identified as having a first episode 621 (16.6%) were identified as having a first episode

of clinically suspected severe sepsis of clinically suspected severe sepsis – Of these, 58.8% had cardiovascular failure Of these, 58.8% had cardiovascular failure – If “cardiovascular failure” defines shockIf “cardiovascular failure” defines shock

• Incidence 9.8 per 100 ICU admissions.Incidence 9.8 per 100 ICU admissions.

– Extrapolating these findings to FranceExtrapolating these findings to France• 0.56 per 1000 residents per year for septic shock0.56 per 1000 residents per year for septic shock

Brun-Buisson, Intensive Care Med. 2004; 30:580-8.


• Alberti 2005Alberti 2005– Studied the incidence and progression to septic shock Studied the incidence and progression to septic shock

among ICU admissionsamong ICU admissions– May 1, 1997 and April 30, 1998May 1, 1997 and April 30, 1998– 8 countries from Europe, Canada and Israel8 countries from Europe, Canada and Israel– 13906 individuals with complete data13906 individuals with complete data– Combined data from shock on presentation, with Combined data from shock on presentation, with

those that developed shock during hospitalization those that developed shock during hospitalization yields 1117 + 201 = 1318 individuals with shockyields 1117 + 201 = 1318 individuals with shock

– Incidence of septic shock for all ICU admissions was Incidence of septic shock for all ICU admissions was 1318/13906 or 9.5 per 100 ICU admissions.1318/13906 or 9.5 per 100 ICU admissions.

Alberti AJRCCM. 2005; 171:461-8

Alberti AJRCCM. 2005; 171:461-8


• Brazilian Sepsis Epidemiology Study Brazilian Sepsis Epidemiology Study (BASES) 2004(BASES) 2004– 4 ICUs across Brazil4 ICUs across Brazil– 1383 subjects 1383 subjects

• Higher reported incidence than France and USHigher reported incidence than France and US

Silva, Critical Care 2004

Silva, Critical Care 2004

Incidence of Septic ShockIncidence of Septic Shock

• Septic shock occurs commonly in the ICUSeptic shock occurs commonly in the ICU

• Incidence is rising slightlyIncidence is rising slightly

• Current estimates approach 10% of all Current estimates approach 10% of all ICU admissions having septic shock ICU admissions having septic shock

• Approximately 1 in 2000 individuals in Approximately 1 in 2000 individuals in France will get Septic Shock each yearFrance will get Septic Shock each year

Incidence of Cardiogenic ShockIncidence of Cardiogenic Shock

• The incidence of cardiogenic shock has been The incidence of cardiogenic shock has been mostly studied in the context of occurrence of mostly studied in the context of occurrence of shock following acute myocardial infarctionshock following acute myocardial infarction

• Over the past 20 years, the incidence of shock Over the past 20 years, the incidence of shock complicating acute MI has been relatively stable complicating acute MI has been relatively stable between 6% and 9%between 6% and 9%

• Probably underestimates cardiogenic shock from Probably underestimates cardiogenic shock from all causesall causes

• Significant proportion have overlap with sepsisSignificant proportion have overlap with sepsis

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Studies of Cardiogenic ShockStudies of Cardiogenic Shock

• MILIS study group 1989 MILIS study group 1989 – 845 patients with acute MI845 patients with acute MI– In this cohort, there was an overall incidence In this cohort, there was an overall incidence

of 7.1%.of 7.1%.– Shock largely defined clinicallyShock largely defined clinically

• GUSTO-1 1995GUSTO-1 1995– 2972 of the 41278 patients enrolled 2972 of the 41278 patients enrolled

developed shock (7.2%) developed shock (7.2%)

Hands JACC 1989; 14:40-6Holmes JACC. 1995; 26:668-74

More Recent StudiesMore Recent Studies

• Goldberg 1999Goldberg 1999– 9076 Worcester, Mass residents9076 Worcester, Mass residents– Hospitalized with MI Hospitalized with MI – 11 one-year periods between 1975 – 199711 one-year periods between 1975 – 1997– The incidence of cardiogenic shock remained The incidence of cardiogenic shock remained

relatively stable over this time period, relatively stable over this time period, averaging 7.1% of all acute MI averaging 7.1% of all acute MI

Goldberg NEJM. 1999; 340:1162-8

Studies using National Registry of Studies using National Registry of Myocardial Infarction (NRMI) Myocardial Infarction (NRMI)

• Goldberg 2001Goldberg 2001– 426,253 patients in NRMI 426,253 patients in NRMI – hospitalized with MI at 1662 hospitals in USA hospitalized with MI at 1662 hospitals in USA – Data collected between 1994 and 1997. Data collected between 1994 and 1997. – The incidence rates of cardiogenic shock over The incidence rates of cardiogenic shock over

this time period averaged 6.2%. this time period averaged 6.2%. – Slight decline in incidence rates between Slight decline in incidence rates between

1994 (6.6%) and 1997 (6.0%) 1994 (6.6%) and 1997 (6.0%)

Goldberg Am Heart J. 2001; 141:65-72

Studies using NRMI Studies using NRMI

• Babaev 2005Babaev 2005– NRMI from 775 hospitals in USANRMI from 775 hospitals in USA– 1995 and 2004 1995 and 2004 – 293 633 patients with ST-elevation MI293 633 patients with ST-elevation MI– 25 311 developed cardiogenic shock25 311 developed cardiogenic shock– Incidence of 8.6 per 100 ST-elevation MI Incidence of 8.6 per 100 ST-elevation MI

Babaev JAMA. 2005; 294:448-54.

Babaev JAMA. 2005; 294:448-54.

Sepsis and Cardiogenic Shock Sepsis and Cardiogenic Shock

• SHOCK Trial 2005SHOCK Trial 2005– 18% of subjects with cardiogenic shock had 18% of subjects with cardiogenic shock had

suspected sepsis as cause of shock, suspected sepsis as cause of shock, • indicated by leukocytosisindicated by leukocytosis• inappropriately low systemic vascular resistance.inappropriately low systemic vascular resistance.

– Of subjects with suspected sepsis, 74% had culture-Of subjects with suspected sepsis, 74% had culture-positive infection. positive infection.

– This and other observations have led investigators to This and other observations have led investigators to challenge paradigms of cardiogenic shockchallenge paradigms of cardiogenic shock

• inappropriate vasodilatation may be involvedinappropriate vasodilatation may be involved

Kohsaka Arch Intern Med. 2005; 165:1643-50

Anaphylactic Shock Anaphylactic Shock

• Considerably rarer and less fatal than Considerably rarer and less fatal than either septic shock or cardiogenic shockeither septic shock or cardiogenic shock

• In the USA:In the USA:– 1 percent of all emergency dept visits1 percent of all emergency dept visits– 500 to 1000 fatalities per year500 to 1000 fatalities per year– True incidence is difficult to determine True incidence is difficult to determine

accurately because of underdiagnosis and accurately because of underdiagnosis and underreporting underreporting

Neugut Arch Intern Med. 2001; 161:15-21

Anaphylactic Shock Anaphylactic Shock

• Yocum 1999Yocum 1999– Population based study in Olmsted County, MNPopulation based study in Olmsted County, MN– 1255 residents between 1983 and 1987, 1255 residents between 1983 and 1987, – 133 residents had 133 residents had >> one episode of anaphylaxis. one episode of anaphylaxis.– estimated incidence was 21 per 100,000 person-years. Death in estimated incidence was 21 per 100,000 person-years. Death in

this cohort was very rare this cohort was very rare

• Peng 2004Peng 2004– General Practice Research Database in the UKGeneral Practice Research Database in the UK– 1994-1999 675 cases of anaphylaxis1994-1999 675 cases of anaphylaxis– Incidence was estimated to be 8.4 per 100 000 person-years.Incidence was estimated to be 8.4 per 100 000 person-years.– 10% of cases had hypotension and shock that required urgent 10% of cases had hypotension and shock that required urgent

treatment.treatment.

Yocum, J Allergy Clin Immunol. 1999; 104:452-6Peng, Arch Intern Med. 2004; 164:317-9

Burns, Trauma and HemorrhageBurns, Trauma and Hemorrhage

• Not as rigorously studiedNot as rigorously studied

• Definitions difficult to applyDefinitions difficult to apply

• Most studies of trauma have focused on Most studies of trauma have focused on organ failure and mortality as outcomesorgan failure and mortality as outcomes

Burns, Trauma and HemorrhageBurns, Trauma and Hemorrhage

• Muckart 1997Muckart 1997– 450 critically injured patients450 critically injured patients– determine rates of septic and sterile shock determine rates of septic and sterile shock

following ICU admission for traumafollowing ICU admission for trauma– Majority had penetrating traumaMajority had penetrating trauma– Incidence of septic shock was 20.2%Incidence of septic shock was 20.2%– Sterile shock was 9.3%Sterile shock was 9.3%

Muckart CCM 1997; 25:1789-95

Burns, Trauma and Hemorrhage:Burns, Trauma and Hemorrhage:Other definitionsOther definitions

• Schulman 2004Schulman 2004– Prolonged Occult Hypoperfusion (POH)Prolonged Occult Hypoperfusion (POH)

• defined as serum lactate >2.4 mmol/L persisting defined as serum lactate >2.4 mmol/L persisting >12 hours from admission>12 hours from admission

• 378 trauma ICU patients378 trauma ICU patients• 129 (34.1%) developed POH during ICU stay 129 (34.1%) developed POH during ICU stay

Schulman J Trauma. 2004; 57:795-800.

Conclusions Conclusions

• Septic shock occurs in approximately 6-10% of Septic shock occurs in approximately 6-10% of all ICU admissionsall ICU admissions– Incidence is clearly increasingIncidence is clearly increasing

• Cardiogenic shock complicates 6-10% of MIsCardiogenic shock complicates 6-10% of MIs• The majority of Cardiogenic and Septic shock The majority of Cardiogenic and Septic shock

develops days after initial ICU admissiondevelops days after initial ICU admission– Early monitoring for prediction may be usefulEarly monitoring for prediction may be useful

• There is emerging evidence that there may be There is emerging evidence that there may be overlap between distributive forms of shock and overlap between distributive forms of shock and cardiogenic shock cardiogenic shock

• Shock following trauma, burns and hemorrhage, Shock following trauma, burns and hemorrhage, has not been as well characterizedhas not been as well characterized

Conclusions Conclusions

• Current definitions of septic and cardiogenic Current definitions of septic and cardiogenic shock may be imperfect and rely primarily on shock may be imperfect and rely primarily on arterial hypotension, but they have yielded arterial hypotension, but they have yielded consistent results for incidence of shock in the consistent results for incidence of shock in the ICU.ICU.

• Newer monitoring measures may eventually Newer monitoring measures may eventually prove to be more valid than clinical definitions in prove to be more valid than clinical definitions in the futurethe future

• For example:For example:– If hypotension and cardiac output are optimized, If hypotension and cardiac output are optimized,

tissue microcirculation may still be affected and lead tissue microcirculation may still be affected and lead to adverse outcomesto adverse outcomes

– Monitoring tissue microcirculation may provide more Monitoring tissue microcirculation may provide more beneficial than the clinical definition of shock beneficial than the clinical definition of shock

Documents

WHAT IS SHOCK AND HOW COMMON IS IT IN THE ICU? Jason D. Christie, MD, MSCE Assistant Professor of Medicine Assistant Professor of Epidemiology Division