[Effect of ulinastatin on the free radical during cardiopulmonary bypass]

Cardiopulmonary bypass (CPB) involves many factors for generating free radicals. It is difficult to detect free radical directly in clinical situations. Vitamin E is recognized as an intrinsic radical scavenger. We examined the change of vitamin E level to prove indirectly the evidence of free radical generation during CPB. Moreover, we investigated the effect of ulinastatin on the free radical during CPB by determining the vitamin E level. Twenty patients who received cardiac surgery were divided into the membrane oxygenator group and the bubble oxygenator group. In each group, five patients received 12,000 units.kg-1 of ulinastatin 15 min after starting CPB. Blood samples were obtained 15 min after starting CPB and 15 min after reperfusion of coronary artery. In the bubble oxygenator group without ulinastatin, vitamin E level at reperfusion phase decreased significantly compared with that at the start of CPB. In the bubble oxygenator group with ulinastatin, vitamin E level at reperfusion phase showed no decrease compared with the level at the start of CPB. In the membrane oxygenator group, there was no significant change in vitamin E level. Therefore, we suspect that a decrease of vitamin E during CPB with bubble oxygenator demonstrates the evidence of free radical generation and these results suggest that ulinastatin may scavenge free radicals during CPB.