Metabolic alterations in trauma: lactate and pyruvate levels after aortic surgery

Arterial lactate and pyruvate concentrations were measured in five patients undergoing abdominal aneurysmectomy. In all cases, a bimodal rise and fall in both lactate and pyruvate levels were observed. Hemodynamic data indicated that cardiac output as well as oxygen delivery and consumption were constant throughout this period. The first lactate peak which was initially related to the cross-clamping of the aorta, but which continued for a period of 5 h after removal of the clamp, was characterized by elevated lactate to pyruvate ratios indicating an anaerobiosis. A transient hyperglycemia was also present during this lactate peak. Ten to 15 h later, when lactate and pyruvate levels were returning to normal levels, a second peak occurred in both lactate and pyruvate lasting 10 h in all five patients. A relatively large increase in pyruvate levels also occurred during this second peak so that the lactate to pyruvate ratios remained normal. This suggests that the second peak was characterized by aerobic metabolism and may have been due to a defect in pyruvate metabolism.