Understanding Shock
Shock is inadequate tissue perfusion resulting in cellular hypoxia. At the EMT level, recognizing shock early and initiating appropriate interventions can save lives. The NREMT frequently tests your ability to identify the type of shock based on patient presentation and choose the correct management.
Types of Shock
Hypovolemic Shock
Caused by decreased blood volume from hemorrhage, severe dehydration, burns, or fluid loss. This is the most common type of shock in trauma patients.
Signs: Tachycardia, weak/thready pulse, pale/cool/diaphoretic skin, delayed capillary refill, altered mental status, narrowing pulse pressure, hypotension (late sign)
EMT Management: Control bleeding, position supine with legs elevated (if no spinal injury or respiratory distress), keep warm, high-flow oxygen, rapid transport
Cardiogenic Shock
Caused by pump failure, most commonly from acute myocardial infarction, heart failure, or dysrhythmia.
Signs: Tachycardia or bradycardia, jugular vein distension (JVD), pulmonary edema (crackles/rales), chest pain, dyspnea, peripheral edema
EMT Management: Position of comfort (usually sitting upright), high-flow oxygen, assist with prescribed nitroglycerin if indicated, monitor closely, rapid transport. Do NOT elevate legs as this increases preload and worsens pulmonary edema.
Distributive Shock
Caused by widespread vasodilation leading to relative hypovolemia. Three subtypes:
Anaphylactic: Severe allergic reaction causing vasodilation and bronchoconstriction. Signs include urticaria (hives), angioedema, wheezing, stridor, hypotension. Treat with epinephrine auto-injector.
Neurogenic: Spinal cord injury causing loss of sympathetic tone below the injury. Signs include hypotension with bradycardia (unlike other shock types), warm/dry/flushed skin below the injury. Maintain spinal precautions, keep warm.
Septic: Systemic infection causing vasodilation and capillary leak. Signs include fever or hypothermia, tachycardia, altered mental status, warm/flushed skin (early) or cool/mottled skin (late). Rapid transport for antibiotics.
Obstructive Shock
Caused by mechanical obstruction of blood flow. Most common causes in the prehospital setting:
Tension pneumothorax: Air trapped in the pleural space compresses the heart and great vessels. Signs include absent breath sounds on affected side, tracheal deviation (late), JVD, hypotension. Requires needle decompression (paramedic level) and rapid transport.
Cardiac tamponade: Blood in the pericardial sac compresses the heart. Signs include Beck's triad: JVD, muffled heart sounds, hypotension. Rapid transport for pericardiocentesis.
Compensated vs. Decompensated Shock
In compensated shock, the body's compensatory mechanisms (tachycardia, vasoconstriction) maintain blood pressure. The patient has a normal blood pressure but shows other signs of poor perfusion: tachycardia, pale skin, delayed capillary refill, anxiety.
In decompensated shock, these mechanisms fail and blood pressure drops. Hypotension in shock is a late and ominous sign indicating significant blood loss or cardiovascular compromise. Do not wait for hypotension to recognize and treat shock.