Definition and Definition and Classification of ShockClassification of Shock

ד"ר אסתר דהאןד"ר אסתר דהאן

Definition of ShockDefinition of Shock

Shock Shock is an acute clinical syndrome is an acute clinical syndrome initiated by ineffective perfusion, initiated by ineffective perfusion, resulting in severe dysfunction of resulting in severe dysfunction of organs vital to survivalorgans vital to survival..Shock is not a synonym to Shock is not a synonym to hypotensionhypotension!!

Ineffective perfusionIneffective perfusion

Organ perfusion compromised by an overall Organ perfusion compromised by an overall

decrease or maldistribution in cardiac decrease or maldistribution in cardiac

output Worsened by abnormalities of output Worsened by abnormalities of

distribution of blood flow within the distribution of blood flow within the

organsorgans..

Shock syndromesShock syndromes

Relatively constant set of signs Relatively constant set of signs and symptoms that predictably and symptoms that predictably result from pathophysiologic result from pathophysiologic events events

Clinical presentation can be Clinical presentation can be variablevariable

Severity of the perfusion defect Severity of the perfusion defect Underlying cause Underlying cause Prior organ dysfunctionPrior organ dysfunction

Symptoms/SignsSymptoms/Signs

Related to decreased tissue Related to decreased tissue perfusion perfusion Pale, cool, clammy skin Pale, cool, clammy skin capillary refill capillary refill urine output urine output mental statusmental status

ClassificationClassification

Hypovolemic Hypovolemic

Cardiogenic Cardiogenic

Extracardiac obstructive Extracardiac obstructive

Distributive Distributive

HypovolemicHypovolemic

Primary defect is a decrease in Primary defect is a decrease in intravascular volumeintravascular volume

Bleeding Bleeding GI losses GI losses Urinary Urinary ““Third spacingThird spacing””

MechanismsMechanisms

in cardiac diastolic filling pressures in cardiac diastolic filling pressures stroke volume stroke volume

CO partially maintained by HR CO partially maintained by HR PVR, myocardial contractility PVR, myocardial contractility

Brain, heart protected through auto Brain, heart protected through auto regulation Failure of compensation regulation Failure of compensation

20-25% 20-25%

Clinical manifestationsClinical manifestations

Tachycardia Tachycardia

Tachypnea Tachypnea

Flat veins Flat veins

Signs of hypo perfusionSigns of hypo perfusion

Effects of COEffects of CO

Decreased oxygen deliveryDecreased oxygen delivery

Tissues initially compensate through increased Tissues initially compensate through increased oxygen extraction oxygen extraction

Eventual tissue hypoxia and lactic acidosisEventual tissue hypoxia and lactic acidosis

Diversion of flow to brain, heartDiversion of flow to brain, heart

Eventually fails worsening COEventually fails worsening CO

Cardiogenic ShockCardiogenic Shock

Primary defect is CO with elevated Primary defect is CO with elevated cardiac chamber filling pressurescardiac chamber filling pressures

Pulmonary oedema Pulmonary oedema JVPJVP

Presentation otherwise similar to hypovolemiaPresentation otherwise similar to hypovolemia Can be confused by underlyingCan be confused by underlying

hypovolemia hypovolemia CI <2L/min/m2CI <2L/min/m2 PAOP >17-20 mmHgPAOP >17-20 mmHg

Causes of COCauses of CO

Contractile failureContractile failure Ischemia/infarction Ischemia/infarction Cardiomyopathy Cardiomyopathy

myocarditismyocarditis Arrhythmias Arrhythmias Conduction disturbances Conduction disturbances Valve lesions Valve lesions AMI complicationsAMI complications

Left ventricular MILeft ventricular MI

>40% of LV infracted>40% of LV infracted 10-20% of Q-wave AMI10-20% of Q-wave AMI

Mortality >75% unless surgically Mortality >75% unless surgically correctable lesion correctable lesion

Mortality associated with level of Mortality associated with level of acidosisacidosis

Right Ventricular AMIRight Ventricular AMI

RV involved in 50% of inferior RV involved in 50% of inferior infarctsinfarcts

10-20% results in cardiogenic shock10-20% results in cardiogenic shock Clear lungs Clear lungs JVP JVP Kussmaul’s signKussmaul’s sign

Prominent venous distention with inspirationProminent venous distention with inspiration

Extracardiac Obstructive Extracardiac Obstructive ShockShock

Impaired diastolic Impaired diastolic fillingfilling

Cardiac tamponade Cardiac tamponade Tension Tension

pneumothorax pneumothorax Constrictive Constrictive

pericarditis pericarditis Compression of Compression of

great vessels by great vessels by mediastinal massesmediastinal masses

Increase the R or L Increase the R or L ventricular after ventricular after load load

PE PE Acute pulmonary Acute pulmonary

hypertension hypertension Aortic dissection Aortic dissection Systemic Systemic

embolizationembolization

Varied Clinical Varied Clinical PresentationPresentation

Signs of decreased perfusion Signs of decreased perfusion Symptoms/signs related to causeSymptoms/signs related to cause

Neck veins may be present or absent Neck veins may be present or absent Muffled heart sounds Muffled heart sounds Pulses paradoxus Pulses paradoxus Symptoms of underlying causeSymptoms of underlying cause

Varied hemodynamic patternsVaried hemodynamic patterns

Distributive ShockDistributive Shock SIRSSIRS

Sepsis Sepsis Pancreatitis Pancreatitis Multitrauma Multitrauma BurnsBurns

Late hemorrhage Late hemorrhage Neurogenic Neurogenic Anaphylaxis Anaphylaxis AdrenalAdrenal

Hemodynamic patternHemodynamic pattern Hyperdynamic patternHyperdynamic pattern Primary defect is a in SVR Primary defect is a in SVR

secondary to NO productionsecondary to NO production in CO in CO Normal to low filling pressures Normal to low filling pressures Normal to mixed venous O2 tension Normal to mixed venous O2 tension

? AV shunt? AV shunt

Sepsis/SIRSSepsis/SIRS

Two or more of the following Two or more of the following Temp > 38C, < 36C Temp > 38C, < 36C Tachycardia Tachycardia Tachypnea or respiratory alkalosis Tachypnea or respiratory alkalosis WBC >12, <4, or >10% bands WBC >12, <4, or >10% bands

Severe sepsis Severe sepsis Hypotension or hypo perfusion Hypotension or hypo perfusion

Shock Shock Vasopressors or ionotropesVasopressors or ionotropes