Severe hemorrhage leads to a significant loss of blood volume, which directly reduces the preload and cardiac output. This causes inadequate tissue perfusion and oxygen delivery, hallmark features of hypovolemic shock. Unlike cardiogenic or septic shocks, the primary problem in hemorrhagic shock is the decreased circulating blood volume, not heart pump failure or infection-induced vasodilation. Prompt recognition and restoration of intravascular volume through fluid resuscitation or blood transfusion are critical surgical interventions.

Reference: Harrison's Principles of Internal Medicine, J. Larry Jameson, 20th Edition.