[Influence of isoflurane and sevoflurane on metabolism of oxygen free radicals in cardiac valve replacement].

To investigate effects of isoflurane and sevoflurane on the levels of lipid peroxides (LPO) in plasma and superoxide dismutase (SOD) in red blood cells during myocardial ischemia/reperfusion, and to study myocardial protection of these two volatile anesthetcs, 30 patients undergoing cardiac valve replacement were randomly divided into isoflurane (Group I), sevoflurane (Group S), and controlled group (Group C). Patients of Group I were anesthetized with isoflurane mainly, Group S with sevoflurane, and Group C with fentanyl. LPO and SOD levels were measured at five points before and during the operation. The results were as follows: SOD levels in all groups did not change significantly. LPO levels in Group C increased during the operation, while in other two groups didn't. Rates of automatical rebeating of hearts in Group C were lower than that of hearts in other two groups. It is suggested that isoflurane and sevoflurane can inhibit increasing of LPO levels to attenuate myocardial ischemia/reperfusion injuries mediated by oxygen free radicals during open-heart surgery.