ShockBasic Trauma Course

Shock is a condition which results from inadequate organ perfusion and tissue oxygenation.

Compensatory Mechanisms

• Cardiac Output is the most influential factor determining oxygen delivery and is the primary compensatory mechanism for increasing oxygen delivery to the tissues when needed.

• Other compensatory mechanisms are the increased rate and depth of respirations and an increase in the sympathetic response signaled by vasoconstriction , decreased urine output, (in an effort to maintain circulating volume.)

Hypovolemic Shock• The initial goals of the ER are:

– To maximize oxygen delivery to the patient – To control further blood loss – Fluid resuscitation. – Blood ReplacementIf the patient arrives with no IV access, immediately establish Two large

bore IV sites using 14 or 16 gauge IV.

• Fluid Resuscitation• Initial fluid bolus given as rapidly as possible…

Adult: 1-2 litersChild: 20ml/kg

Patient’s response is observed and further therapeutic decisions is based on response.

Cardiogenic Shock• Results from inadequate circulating blood volume.

• Cardiogenic shock is the loss of contractile function of the heart.

• This type of shock can be the result of a myocardial infarction and blunt cardiac injury.

• The result is a decreased ejection fraction and decreased cardiac output.

Case Study• A 65 Year old male, s/p MVC, presents to the ER by EMS. There is an

obvious seatbelt mark across the chest, the patient is dyspneic, cool, and cyanotic. VS: B/P 88/56, P 124, R 28. He is complaining of chest pain and tells you he has a history of a past MI.

• Would you consider that the patient may have had another MI which caused the crash with possible subsequent chest trauma?

• Is this patient exhibiting signs of shock? • What would your initial intervention be? • What types of diagnostic tests would you expect to see ordered? • Would you expect to see dysrythmias in this patient? Why or why not? • In obtaining a history from EMS, with regard to chest trauma, what would

you ask? From the information above, this patient is at risk for what developments?

Obstructive Shock• Results from mechanical obstruction of the flow of blood through the

central circulation system due to obstruction or compression of the major vessels.

• Possible causes of obstructive shock are:– Dissecting Aortic Aneurysm. – Cardiac tamponade. – Tension pneumothorax. – Pulmonary embolism, (most frequent). – Evisceration of the abdominal contents into the thoracic cavity.

Distributive Shock• This type of shock is characterized by abnormal placement of the

intravascular volume. There is a disruption in the SNS control of the tone of the blood vessels, which lead to vasodilation and maldistrubution of blood volume and flow.

• Three forms of distributive shock are:– Septic shock – Neurogenic shock – Anaphylactic shock. Septic and anaphylactic shock in early trauma are rare.

We will focus on Neurogenic Shock

Neurogenic Shock• This type of shock is not the same as spinal shock.• Spinal shock is the loss of spinal reflexes found in acute spinal cord injury

patients. • Neurogenic shock is the loss of sympathetic vasomotor function. • The result is vasodilation in the systemic vasculature. Venous return is

decreased since blood pools in the periphery. The result is a decrease in cardiac output.

• In neurogenic shock the patient will exhibit bradycardia, warm and flushed skin and hypotension.

Treatment of Shock• Administer oxygen via nonrebreather

mask• Control external bleeding• Initiate intravenous fluid replacement• Initiate blood product replacement

– Type-specific and crossmatched blood

– O-negative is universal donor– Fresh frozen plasma, cryoprecipitate,

or platelets• Insert gastric tube• Insert urinary catheter• Attach cardiac leads and monitor• Attach pulse oximeter • Consider peripheral vasoconstrictors for

patients in neurogenic shock• Prepare patient for surgery