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Antioxidant properties of propofol in coronary artery bypass surgery Sun, Jianhang

Abstract

Ischaemia reperfusion injury (IRI) is considered one of the major causes of cardiopulmonary dysfunction in cardiopulmonary bypass (CPB) surgery. Reactive oxygen intermediates have been linked to IRI. Measures to increase antioxidant capacity, with vitamin C, vitamin E, and allopurinol, have markedly reduced tissue lipid peroxidation and resulted in improved cardiopulmonary function. An intravenous anaesthetic, propofol has been found to have antioxidant properties in cell culture and in animal studies. The antioxidant potential of propofol during CPB surgery has not been reported. Following institutional approval and informed patient consent, 26 patients scheduled for CPB surgery were enrolled. Patients were anaesthetized with sufentanil-isoflurane (control, n=11) , sufentanil-low dose propofol (1.5- 2.5 mg/kg bolus then 100 μg/kg/min preCPB , 50 ug/kg/min intra-CPB; n=7), or high dose propofol (1.5-2.5 mg/kg then 200 μg/kg/min continous infusion; n=8). Venous blood was sampled for determination of red cell antioxidant capacity as MDA (malondialdehyde) production against in vitro oxidative challenge and plasma concentration of propofol. Clinical parameters of interest included perioperative inotropic requirement, haemodynamic changes, and lung oxygenation. Red cell antioxidant capacity increased significantly only with high dose propofol. This effect continued 2 hours after separation from bypass. High dose and low dose propofol were associated with significantly less inotropic (dopamine 3-5 μg/kg/min) requirement. Low dose propofol significantly increased the percentage of patients with normal cardiac index postoperatively. Improvement of cardiac function did not parallel the reduction of lipid peroxidation. Propofol's effects were limited to lipid membranes. The cardiodepresant effect of high dose propofol was manifested as relatively low cardiac index within the first three hours after operation. Lung oxygenation was superior with low dose propofol and isoflurane after 6 to 12 hours after operation, comparing to that within one hour after operation (P<0.05).

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