Systemic vascular performance in endotoxic shock

Sixteen dogs were studied in an effort to investigate certain peripheral vascular and metabolic parameters in endotoxic shock. Cardiopulmonary bypass was instituted for 12 of the dogs to study systemic parameters at constant circulatory flow rates. From these studies, it appears that endotoxin is capable of initiating profound hemodynamic and metabolic changes. Initially, cardiac output and arterial pressure drop precipitiously, despite a transient rise in systemic and pulmonary vascular resistance. Subsequently, peripheral arterial pressures and systemic vascular resistance continue to decline, even if arterial flow remains at constant levels. Oxygen extraction by peripheral tissues decreases after endotoxin injection, despite adequate oxygen availability and constant hemoglobin levels.