Power Points for EMS Education

1. Barry Kidd 2010 1
CirculatoryCirculatory SHOCKSHOCK

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DefinitionDefinition
Inadequate perfusion (oxygen supply) of tissues,Inadequate perfusion (oxygen supply) of tissues,
resulting in:resulting in:
 Organ dysfunctionOrgan dysfunction
 Cellular and organ damageCellular and organ damage
And if not quickly corrected…And if not quickly corrected…
 DeathDeath

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Causes of Shock – a quick list:Causes of Shock – a quick list:
 Heart AttackHeart Attack
 AnaphylaxisAnaphylaxis
 Loss of Circulating Blood Volume (bleeding ,Loss of Circulating Blood Volume (bleeding ,
burns, dehydration)burns, dehydration)
 Venous Dilation (allergy, pain, drugs, heatVenous Dilation (allergy, pain, drugs, heat
stroke, infection)stroke, infection)
 High or Low Body TemperatureHigh or Low Body Temperature

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Signs of ShockSigns of Shock
 Pulse: Rapid, weak, threadyPulse: Rapid, weak, thready
 TachycardiaTachycardia
 RespirationsRespirations
 Shallow, irregular, laboredShallow, irregular, labored
 May be tachypnea (increased respiratory rate.)May be tachypnea (increased respiratory rate.)

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Signs of ShockSigns of Shock
 Due to hypoperfusion:Due to hypoperfusion:
 Decreased “mentation” - confused, sluggish, anxiousDecreased “mentation” - confused, sluggish, anxious
 Skin cold, mottledSkin cold, mottled

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Emergency TreatmentEmergency Treatment
 Evaluate vital signsEvaluate vital signs
 BP, Respiration Rate, Pulse Oximeter, Temp.BP, Respiration Rate, Pulse Oximeter, Temp.
 Control bleedingControl bleeding
 Prevent loss of body heatPrevent loss of body heat

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Causes of Shock:Causes of Shock:
Classification (the real list)Classification (the real list)
 Low Output Circulatory FailureLow Output Circulatory Failure
 Hypovolemic shock (too little volume)Hypovolemic shock (too little volume)
 Cardiogenic shock (pump failure)Cardiogenic shock (pump failure)
 Obstructive shockObstructive shock
 Distributive shock: Venous poolingDistributive shock: Venous pooling
 High Output Circulatory FailureHigh Output Circulatory Failure
 Distributive Shock: Sepsis, toxic shock,Distributive Shock: Sepsis, toxic shock,
anaphylaxis:anaphylaxis:

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Hypovolemic ShockHypovolemic Shock
 CO reduced due to loss of intravascularCO reduced due to loss of intravascular
VOLUMEVOLUME
 Reduced venous returnReduced venous return
 CausesCauses
 Most often, blood loss (hemorrhage)Most often, blood loss (hemorrhage)
 DehydrationDehydration
 BurnsBurns
 Fluid lost into peritoneal cavity w/Fluid lost into peritoneal cavity w/
pancreatitispancreatitis

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Cardiogenic ShockCardiogenic Shock
 Myocardial Infarction (most frequent cause)Myocardial Infarction (most frequent cause)
 Acute Valvular Dysfunction – e.g. papillaryAcute Valvular Dysfunction – e.g. papillary
muscle rupture post-MImuscle rupture post-MI
 Arrhythmia – e.g., heart block, ventricularArrhythmia – e.g., heart block, ventricular
tachycardiatachycardia

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Obstructive ShockObstructive Shock
 CO reduced by vascular obstruction:CO reduced by vascular obstruction:
 Obstruction of Venous return (vena cava syndromeObstruction of Venous return (vena cava syndrome
– usually neoplasms)– usually neoplasms)
 Compression of the heart (pericardial tamponade*)Compression of the heart (pericardial tamponade*)
 Outflow from heart (Massive pulmonary embolism,Outflow from heart (Massive pulmonary embolism,
aortic dissection)aortic dissection)

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Obstructive ShockObstructive Shock
 CO reduced by vascular obstruction:CO reduced by vascular obstruction:
 Obstruction of Venous return (vena cavaObstruction of Venous return (vena cava
syndrome – usually neoplasms)syndrome – usually neoplasms)
 Compression of the heart (pericardialCompression of the heart (pericardial
tamponade*)tamponade*)
 Outflow from heart (Massive pulmonaryOutflow from heart (Massive pulmonary
embolism, aortic dissection)embolism, aortic dissection)

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Pericardial TamponadePericardial Tamponade
 Life threateningLife threatening
condition caused by fluidcondition caused by fluid
(blood, effusion fluid)(blood, effusion fluid)
under pressure aroundunder pressure around
the heart.the heart.
 Decreases CO byDecreases CO by
decreasing fillingdecreasing filling
 Causes includeCauses include
pericarditis and MIpericarditis and MI

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Distributive ShockDistributive Shock
 Maldistribution of flowMaldistribution of flow
 Two Categories:Two Categories:
 Low Output - Venous pooling due to loss ofLow Output - Venous pooling due to loss of
venous tonevenous tone
 High Output Circulatory FailureHigh Output Circulatory Failure

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Venous PoolingVenous Pooling
 A Low Output Circulatory FailureA Low Output Circulatory Failure
 Often due to spinal shock or drug overdoseOften due to spinal shock or drug overdose
 Behaves like hypovolemic shockBehaves like hypovolemic shock
 CO severely reduced because blood is pooledCO severely reduced because blood is pooled
in peripheral veins, rather than returned toin peripheral veins, rather than returned to
heartheart

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Distributive Shock: High OutputDistributive Shock: High Output
 Cardiac Output is normal or elevated;Cardiac Output is normal or elevated;
distribution inappropriatedistribution inappropriate
 Shock is due to loss of vascular resistanceShock is due to loss of vascular resistance
 Examples:Examples:
 Sepsis, Toxic Shock:Sepsis, Toxic Shock:
 Bacterial endotoxin triggers vasodilationBacterial endotoxin triggers vasodilation
 AnaphylaxisAnaphylaxis

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AnaphylaxisAnaphylaxis

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Anaphylactic ShockAnaphylactic Shock
 Histamine triggers vasodilation, increasedHistamine triggers vasodilation, increased
capillary permeabilitycapillary permeability
 Can lead to low-output distributive shockCan lead to low-output distributive shock

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Physiological Response to ShockPhysiological Response to Shock
 The pressure drop is compensated for byThe pressure drop is compensated for by
regulatory mechanismsregulatory mechanisms
 This = “Nonprogressive” / “Compensated”This = “Nonprogressive” / “Compensated”
ShockShock

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Progressive ShockProgressive Shock
 Compensatory mechanisms inadequate toCompensatory mechanisms inadequate to
compensate for loss of blood volumecompensate for loss of blood volume
 Cardiac circulation compromisedCardiac circulation compromised  decreaseddecreased
heart functionheart function  decreased flowdecreased flow
 Positive feedback cycle: Shock worsensPositive feedback cycle: Shock worsens  lessless
compensationcompensation  shock worsens…shock worsens…
 Clotting in small vesselsClotting in small vessels
 Vessels dilate and permeability increasesVessels dilate and permeability increases

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Irreversible ShockIrreversible Shock
 Cardiac and other tissue irreversibly damagedCardiac and other tissue irreversibly damaged
 Characterized by:Characterized by:
 Decreasing cardiac functionDecreasing cardiac function
 Progressive blood vessel dilationProgressive blood vessel dilation
 Progressive increase in vessel permeabilityProgressive increase in vessel permeability

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Irreversible ShockIrreversible Shock
 Cardiac and other tissues are irreversiblyCardiac and other tissues are irreversibly
damageddamaged
 Characterized by:Characterized by:
 Decreasing cardiac functionDecreasing cardiac function
 Progressive blood vessel dilationProgressive blood vessel dilation
 Progressive increase in vessel permeabilityProgressive increase in vessel permeability

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The SHOCK Of Your Life !
SUMMARYSUMMARY

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Physiology
Basic unit of life = cell
Cells get energy needed to stay
alive by reacting oxygen with
fuel (usually glucose)
No oxygen, no energy
No energy, no life

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Flow = Perfusion
Adequate Flow =
Adequate Perfusion
Inadequate Flow =
Indequate Perfusion
(Hypoperfusion)
Hypoperfusion =
Shock

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Circulatory Shock
“Pathophysiologic state in which tissue perfusion is
totally inadequate to meet the oxygen or nutritional
needs of the cells”
Shock described as “momentary pause in the act of
death”
Shock is not a disease entity in itself, but a response to
some assault or injury the body has experienced
Whatever the initiating event, the cause of death in
irreversible shock is microcirculatory failure and the
subsequent depression of cellular metabolism

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What is needed to maintain
perfusion?
Pump
Pipes
Fluid
Heart
Blood Vessels
Blood

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How can perfusion fail?
Pump Failure
Pipe Failure
Loss of Volume

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