Hemorrhage has two immediate sequelae which limit tissue oxygenation: depressed intravascular fluid volume and anemia. Hypotension in acute hemorrhage depresses venous return and, subsequently, cardiac output. In protracted shock, the metabolic consequences of tissue ischemia may lead to the release of myocardial depressant factor from the splanchnic circulation, thus depressing cardiac output further.

With activation of hemodynamic and metabolic autoregulatory responses, up to 20 to 30 per cent fluid loss may be compensated during hemorrhage without marked effects on blood pressure. If this volume is exceeded, or pre-existing diseases such as coronary heart disease or cardiac failure blunt the autoregulatory mechanisms, hypotension results and O2 delivery falls.

Your Heart and Nutrition

Your Heart and Nutrition

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