OBJECTIVETo study the effects of inhalation enflurane (Enf) before aortic clamping on myocardial reperfusion injury in cardiac surgery with cardiopulmonary bypass (CPB).

METHODShirty patents undergoing selective cardiac valve replacement were randomly allocated to three groups. Group I and group II inhaled 1.0 MAC and 0.5 MAC Enf before clamping aorta, respectively. Group III was the control group interval administration with Fentanyl.

RESULTSImmediately upon aortic clamp release (T2), the value of CK-MB, MDA and SOD of all the groups was significantly increased, however,their concentration did not peak significantly until T3 and T4(10 and 30 min after clamp aorta release). The levels at 60 min (T5) and 24 hours (T6) aorta were lower than T4 but still higher than T(0). At T3 and T4, CK-MB levels in group I were significantly higher than those in II and III groups (P=0.0220, 0.0108 and 0.0202, 0.0295). At T6, the CK-MB level of group II was significantly higher than that of group III (P<0.0001). At T4 and T5, the MDA value of group I was higher than that of group II (P=0.0060 and 0.0364). Meanwhile, the SOD level in group I was also higher than that of group II and group III at the T4 point (P<0.0001 and 0.0084). There was a correlation between the CK-MB value and the aorta clamping time,correlation coefficient range being 0.55 - 0.81,(P<0.05). However, there was no correlation between the CK-MB and MDA, SOD.

CONCLUSIONThere is ischemia reperfusion injury during cardiac surgery CPB with the increase of OFR production and elevation of the antioxidant reserve. Inhalation of large dose of enflurane may result in increased myocardial ischemia reperfusion injury manifested by elevated levels of myocardial enzymes and OFR production.