Evidence for the role of leucosequestration in injury mediated by oxygen free radicals during cardiopulmonary bypass in humans

The purpose of this study was to determine the role of pulmonary leucosequestration in oxygen free radical generation and lipid peroxidation. it comprised 10 patients undergoing cardiopulmonary bypass. Plasma malondialdehyde levels, erythrocyte superoxide dismutase activity and glutathione levels were measured in blood samples obtained from the left atrium at multiple time points before and during cardiopulmonary bypass. Erythrocyte superoxide dismutase activity declined throughout the period of measurement. The significant decreases occurred in the ischaemia and early reperfusion periods. Activity rose to control levels in the late reperfusion specimens. The levels of malondialdehyde and glutathione and leucocyte count increased significantly, especially in ischaemia and early reperfusion periods (P < 0.001 for malondialdehyde, P < 0.05 for glutathione). These results confirm pulmonary leucosequestration and oxidative stress during cardiopulmonary bypass. They indicate that oxygen free radical generation exceeds the capacity of the endogenous antioxidant enzyme systems during cardiopulmonary bypass. Med Sci Res 26:635-637 (C) 1998 Lippincott Williams & Wilkins.