Myocardial Metabolism in Dogs during Hemorrhagic Shock.

摘要

Nine mongrel dogs under Nembutal anesthesia, receiving a constant infusion of palmitate-1-C14 and oleate-9-10-H(3) in the form of free fatty acids (FFA), were subjected to a total blood loss of 4.4% of body weight. Metabolites were analyzed in blood samples taken from the femoral artery and coronary sinus. Coronary sinus blood flow was measured both before and after 45 min following hemorrhage. Blood pressure and cardiac output fell to half of the control levels, coronary sinus blood flow decreased by 25%. Both the myocardial uptake and oxidation of FFA decreased markedly; lactate uptake did not change significantly. During the control period FFA was the major and lactate the second most important substrate utilized by the myocardium, followed by triglyceride fatty acids (TGFA). After hemorrhage FFA supplied only a minor portion of oxidizable substrates, while the major portion came from lactate. Thus, it appears that following severe hemorrhage, and prior to manifestations of myocardial hypoxia, an early change in myocardial metabolism is a decreased uptake and oxidation of FFA and an increased reliance on substrates of carbohydrate sources.