chapter 9 shock: a state of hypoperfusion. © 2005 by thomson delmar learning,a part of the thomson...

Chapter 9Shock: A State of Hypoperfusion

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Overview

Hypoperfusion Causes of Hypoperfusion Physiologic Response to Shock Assessment Management of Hypoperfusion

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Hypoperfusion

Hypoperfusion means inadequate perfusion Hypoperfused tissue is no longer being given

enough oxygen and will stop working optimally

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Hypoperfusion

The brain is the most sensitive organ in the body to decreases in blood and oxygen supply

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Causes of Hypoperfusion

Three basic components of the circulatory system can affect perfusion:– Fluid– Container– Pump

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Causes of Hypoperfusion

The fluid– Hypoperfusion will occur if

• There is not enough blood in the system • The blood in the system is not carrying enough oxygen

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Causes of Hypoperfusion

Hypovolemic shock– When body fluids are lost and not adequately

replenished, the total body fluid volume is low– When shock results from an actual loss of blood, it

can be specifically called hemorrhagic shock – Other means of fluid loss are excessive vomiting,

diarrhea, sweating, or urinating

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Causes of Hypoperfusion

The container– Blood vessels have the ability to significantly alter

their diameter by contraction or relaxation of the smooth muscles in their walls

– This can be harmful in some circumstances, such as anaphylactic, septic, or neurogenic shock

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Causes of Hypoperfusion

Anaphylactic shock– The result of a severe allergic reaction– Causes vasodilation and subsequent hypotension– Patient will have urticaria (hives), airway swelling,

and hypotension

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Causes of Hypoperfusion

Septic shock– Severe infection may lead to generalized blood

vessel dilation, with a drop in blood pressure and diminished perfusion

– Certain types of bacteria can produce toxins that prevent the vessels from constricting appropriately, causing them to leak

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Causes of Hypoperfusion

Neurogenic shock– Is caused by a loss of control of the smooth

muscles in the vessel walls– May occur as a result of spinal cord injury where

the vessels no longer have the ability to constrict when appropriate

– Also termed spinal shock

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Causes of Hypoperfusion

The pump– Inadequate pumping action of the heart can

result in hypoperfusion– If the pump does not have enough power to

generate adequate forward flow, the amount of blood pumped will be smaller

– The smaller volume will result in a lower cardiac output

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Causes of Hypoperfusion

Cardiogenic shock– If the heart muscle is damaged, as during a heart

attack, it does not pump to full capacity– Shock that results from inadequate cardiac

pumping is called cardiogenic shock

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Physiologic Response to Shock

Compensated shock– The body attempts to compensate for

hypoperfusion by:• Increasing the volume of blood pumped with each

stroke or the heart rate• Increasing respiratory rate• Adjusting blood flow to only core areas (shunting)

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Compensated shock– Signs and symptoms

• Pale• Cool• Clammy• Weakening peripheral pulses• Elevated heart rate• Elevated respiratory rate• Nausea• Altered mental status

Physiologic Response to Shock

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Decompensated shock– Systolic blood pressure drops to less than

90 mm Hg– The body is no longer able to compensate

for an event– When hypotension is noted, the patient is

considered to be in decompensated shock and must be aggressively managed for survival to be possible

Physiologic Response to Shock

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Irreversible shock– Prolonged periods of decompensated shock

resulting in the failure of multiple organs– Patients with irreversible shock often do

not survive

Physiologic Response to Shock

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Stop and Review

What is hypoperfusion? What are the three main causes

of hypoperfusion? List the signs and symptoms

associated with compensated shock. What is the tell-tale sign of

decompensated shock?

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Assessment

In assessing a patient, be careful to look for signs of compensated shock

If you don’t look for it, you won’t find it It is necessary to begin to treat the patient in

shock before she decompensates and becomes hypotensive

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Assessment

The look test– Ensure your own safety and adequate PPE – Form general impression

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Assessment

Mental status– Assess for AVPU

ABCs– Once ABCs have been assessed,

look for signs of hypoperfusion

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Assessment

Vital signs– Obtain a complete set of vital signs

Orthostatic vital signs– Vital signs measured in two different positions– Positive tilt test

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Management of Hypoperfusion

The treatment of shock is geared toward restoring adequate oxygenation, ventilation, and circulation

The EMT must maximize perfusion while rapidly transporting the patient to a hospital, where definitive treatment will be available

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Oxygen– Apply high-flow 100% oxygen in any stage

of shock Control bleeding

– Locate source of bleeding and control it in whatever way possible

Trendelenburg– Elevate the legs and utilize the force of gravity

to increase the blood volume in the thorax and abdomen

Management of Hypoperfusion

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Management of Hypoperfusion

MAST/PASG– Military anti-shock trousers or a pneumatic anti-

shock garment – A device that may support blood pressure in

certain circumstances– MAST/PASG improves the blood supply to the

upper body and vital organs

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Management of Hypoperfusion

MAST/PASG– Indications

• Severe hypotension (systolic BP less than 50 mm Hg • Hypotension (systolic BP less than 90 mm Hg) because

of severe pelvic injuries

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Management of Hypoperfusion

MAST/PASG– Contraindications (absolute)

• Penetrating thoracic injury• Pulmonary edema

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Management of Hypoperfusion

MAST/PASG– Contraindications (relative)

• Pregnancy• Penetrating object• Evisceration

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Management of Hypoperfusion

MAST/PASG– Application

• Trouser method• Wrapper method

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MAST/PASG

Watch this video clip demonstrating the use of MAST/PASG

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Management of Hypoperfusion

MAST/PASG– Removal

• Should never be deflated by the EMT• Physicians should be familiar with the

procedure of slow deflation • Gradual process

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Management of Hypoperfusion

Reduce heat loss– Prevent excessive heat loss during the evaluation

and treatment of the critically ill or injured patient– Cover the patient with blankets once the

assessment has been completed

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Management of Hypoperfusion

Transport– Consider ground or air transport– Reassess patient frequently and monitor vital

signs every five minutes– Consider ALS intercept– Consult local protocols

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Stop and Review

What can the EMT do to manage the patient presenting with shock?

What are the absolute contraindications for using PASG/MAST?