What defines hypovolemic shock?

Hypovolemic shock is characterized by a significant reduction in blood volume, often due to severe fluid loss. When a person loses more than 20% of their body fluids, the body is unable to maintain adequate blood pressure and circulation, leading to insufficient perfusion of vital organs. This state is critical, as it can result in organ dysfunction or failure if not promptly addressed.

The defined threshold of fluid loss—over 20%—is important because it indicates the point at which the body's compensatory mechanisms become overwhelmed. During hypovolemic shock, the body attempts to compensate through mechanisms such as increased heart rate and peripheral vasoconstriction, but if the fluid loss is severe enough, these mechanisms are insufficient to prevent the progression to shock.

Other conditions listed, such as severe infections leading to systemic inflammation or excess fluid accumulation in the lungs, refer to different types of shock or complications unrelated to fluid volume depletion. Decreased heart rate due to medication can occur in various clinical scenarios but does not relate to the definition of hypovolemic shock, which focuses specifically on fluid loss.