Lipid peroxide and leukotriene B₃ production in patients undergoing cardiopulmonary bypass

Cardiac surgery with cardiopulmonary bypass (CPB) is frequently associated with a complex array of post-operative clinical abnormalities, including low-output syndrome and pulmonary dysfunction. It has been reported that oxygen free radicals are one of the important factors causing reperfusion injury. To determine whether oxygen free radicals are produced during cardiac surgery, we studied nine patients anesthetized with high doses of fentanyl. Lipid peroxide (LPO) and leukotriene B₄ (LTB₄) levels increased significantly from 60 min after aortic ligation to 180 min after reperfusion (aortic declamping), compared with the levels before surgery, while superoxide dismutase (SOD) was not affected markedly. Creatine kinase (CK), CK muscle-brain (CK-MB), and neutrophils increased from 60 min after aortic declamping. Correlations were not observed between LPO and CK nor between LPO and CK-MB. These results suggest that free radicals are generated during cardiac surgery with cardiopulmonary bypass (CPB), but it is unclear whether free radicals cause tissue injury after cardiac surgery with CPB.