Shock occurs when the oxygen demands of cells aren’t met, leading to cellular and tissue hypoxia, and it is a life-threatening condition, most commonly manifested as hypotension. Potential etiologies include distributive shock, when there is peripheral vasodilation like you see in sepsis or anaphylaxis; cardiogenic shock like you see in a myocardial infarction or heart failure; obstructive shock, like you see in a massive pulmonary embolism; and hypovolemic shock, like you see in massive bleeding or burns.

Although shock from sepsis can occur in prolonged field care settings, almost all shock in the Tactical Field Care setting is hypovolemic. The most common cause is massive bleeding, but fluid loss from severe burns, usually covering 30% or more of the body surface area, is also an important consideration.

Untreated, the natural progression of shock leads to permanent end-organ damage and death from cellular hypoxia. However, hypoxic injuries are reversible if caught early enough, and organs do recover if adequate oxygenation can be restored.