Increased Oxygen Free Radical Activity in Patients on Cardiopulmonary Bypass

To observe the changes of surgical reperfusion injury, plasma malonyl dialdehyde （MDA）, diened with conjugated double bond （DCDB）, whole blood superoxide dismutase （SOD） activity and plasma manganese-containing SOD （Mn-SOD） activity were determined during cardiopulmonary bypass （CPB） in 5 cases undergoing cardiosurgery. The results showed that reperfusion period on CPB was associated with a significant increase in the products of lipid peroxidation, MDA and DCDB （P＜0.05 for each）. However, it indicated that SOD of suppress superoxide anion （O₂^-） fell signiticantly （P＜0.05）. Of interest was the finding that plasma Mn-SOD activity rose signiticantly （P＜0.05）during reperfusion period.