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GSACEP core man LECTURE series:

SCHOCK

Brian Kitamura

MD, CPT, USARNGUpdated: 20APR2013

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Disclaimer

Views and opinions expressed do not necessarily reflect those of GS-ACEP, The Department of Defense, the U.S. Army, the U.S. Government, or any other governmental or nongovernmental organization unless explicitly stated.

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Outline

Shock Definition

Types of Shock

Cardiogenic

Distributive

Obstructive

Hypovolemic3

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Definition of Shock

“Shock is circulatory insufficiency that creates an imbalance between tissue oxygen supply (delivery) and oxygen demand (consumption).”

Tintinalli’s Emergency Medicine, 7th ed

“In philosophic terms, shock [is the] transition between life and death”

Rosen’s Emergency Medicine, 7th ed4

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Definition of Shock

In short, the tissues are not getting the oxygen they require

Can often be qualified as a “fluids,” “pump,” or “pipes” problem

It really is all plumbing

Pulmonary and toxicologic causes of shock are outside the scope of the lecture 5

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Definition of Shock

Bedside determination of shock

Systolic Blood Pressure < 90

Mean Arterial Pressure < 65

Shock index > 1 (Heart Rate/Systoilc BP)

Elevated Lactate

Decreased level of consciousness with brain injury

All just general guidlelines

Pulmonary and toxicologic causes of shock are outside the scope of the lecture 6

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Cardiogenic Shock“Pump Problems”Essentially heart failure

Caused by:Acute Myocardial IschemiaCardiomyopathyDysrhythmiasStructural damage

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Cardiogenic ShockAcute MIHeart Muscle is stunned or dead

Blood flow is restricted to an area of muscleMuscle doesn’t contract properly

TreatmentRelieve the blockage: Aspirin, thrombolytics, stents/angioplasty, bypass 8

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Cardiogenic ShockCongestive Heart Failure

Heart muscle is globally weakMultiple heart attacks, high blood pressure, weakened ventricles, stiff ventriclesFluid overload stretches the heart

TreatmentOptimize the physiology

Decrease blood pressureDecrease volume

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Cardiogenic ShockDysrhythmia

Irregular rhythm prevents forward flow of blood

TreatmentCardioversion/Defibrilation, antiarrhythmics 10

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Cardiogenic ShockStructural Disturbances

Penetrating traumaValve disorders

Treatment:Cold steel

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Cardiogenic ShockStructural Disturbances

Penetrating traumaValve disorders

Treatment:Cold steel

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Distributive Shock

“Pipe Problem”Leaky blood vessels (microscopic)Lack of vascular tone or “squeeze”“Warm Shock”

Septic ShockAnaphylactic ShockNeurogenic Shock

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Septic ShockInfection causes release of inflammatory signals

Blood vessels “leak” to allow more blood flow, infection fighting cells out into the tissues

System is overrun in shock

TreatmentProvide fluids first, then pressors

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Anaphylactic ShockMassive, rapid, histamine release in response to a specific antigen

Blood vessels dilate and leak

TreatmentEPINEPHRINE!Benadryl, Steroids

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Neurogenic ShockBrain or spinal cord injury

Neurologic system has constant control over vascular tone

If input is lost, vessels dilate

TreatmentVasopressors

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Obstructive Shock

Blockage prevents forward movement of blood

Pulmonary Embolism

Tension Pneumothorax

Cardiac Tamponade

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Pulmonary Embolism

Blood clot from the venous system gets lodged in the lungs

Common post traumatic patients

Treatment:Difficult, but we use anticoagulants, lytics

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Tension Pneumothorax

Pressure builds up in the chest preventing return of venous blood

Seen in

chest trauma

Treatment:Needle decompression, chest tube

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Cardiac Tamponade

Pressure builds up in the pericardial sacSeen in

chest trauma

Treatment:Pericardiocentesis 20

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Hypovolemic Shock

“Fluid Problem”Loss of fluid

Loss of blood

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Hypovolemia

Non-blood losses decrease plasma volume

Sweating

GI Losses

Inadequate

Intake

Treatment: Replace fluids - oral or IV22

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Hemorrhage

Just like is sounds, someone is bleeding out

Trauma

GI Bleeding

Stop the bleedingResuscitate with crystalloids first, blood if needed.

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In summary

Shock is inadequate perfusionTreat underlying causes if possibleResuscitate based on cause

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References

Tintinalli’s Emergency Medicine 7th Edition

Rosen’s Emergency Medicine7th Edition

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