The protective effect of low dose nicardipine on myocardium against ischemia reperfusion injury during cardiac surgery / 中华麻醉学杂志

ABSTRACT

ve To investigate the mechanism of myocardial ischemia-reperfusion injury during cardiac surgery and the protective effect of low dose nicardipine. Methods Sixteen patients undergoing valve replacement under cardiopulmonary bypass (CPB) were randomized to one of the two groups control group (group C, n = 8) and nicardipine group (group N, n = 8) . In group N low dose nicardipine (O.5?g?kg-1 ?min-1) was infused after induction of anesthesia until beginning of CPB, a total dose of 0.05 mg?kg-1 was given. All patients were premedicated with intramuscular morphine 0.1-0.2 mg?kg-1 and scopolamine 0.3 mg 30 min before surgery. Anesthesia was induced with midazolam 0.05-0.1 mg?kg-1, fentanyl 15-20 ?g?kg-1 and pipecuronium 0.1 mg?kg-1 and maintained with intermittent boluses of midazolam 0.05 mg? kg-1, fentanyl 10-30?g?kg-1 and pipecuronium 2 mg. After induction of anesthesia Swan-Ganz catheter was placed for hemodynamic monitoring. Moderate hypothermia (26℃-28℃) was maintained and Hct was diluted to 20%-24% during CPB. Hyperkalemic cardioplegia was used for myocardial protection. Arterial blood (a) and coronary sinus (cs) blood were taken simultaneously for determination of tumor necrosis factor a (TNF-a), superoxide dismutase (SOD), lipid peroxide (LPO), creative kinase(CK-MB) before CPB and at 5 and 30 min after release of aortic cross-clamp (RACC), at the end of operation (EO) and at 6h and 18h after operation. Myocardial net release of TNF-a (TNF-anr) and LPO (LPOnr) and net consumption of SOD (SODnc) were calculated. The number of defibrillation after RACC, weaning index from CPB and dopamine requirement after CPB were recorded simultaneously. Results In group C LPOa and LPOcs increased significantly after RACC until the end of operation as compared with the baseline (P