treating myocardial stunning randomly, with either propofol or isoflurane following transient coronary occlusion and reperfusion in pigs

Propofol and isoflurane may be used during fast track anesthesia for off-pump bypass, where transient ischemia is common. The purpose of this study was to compare the effects of propofol vs isoflurane in a porcine model of acute coronary occlusion. Twenty five pigs were randomized to receive general anesthesia with either isoflurane, 1 MAC (n = 13), or propofol, 3 mg/kg bolus followed by 200 μg/ kg/min infusion (n = 12). Pressure-tipped catheters were placed in the left ventricle (LV) and carotid artery; cardiac output was measured by ultrasound; two pairs of ultrasonic dimension catheters were placed in the subendocardium of LV. The slope of LV end-systolic pressure-volume relationship (E _max ) was calculated. Reversible ischemia for 15 mins was accomplished with an occluder around the left anterior descending artery followed by reperfusion period. Measurements were done at baseline, end ischemia, early (5 min) and late (30 min) reperfusion. The data collected included systemic hemodynamics, LV end-diastolic pressure (LVEDP), dP/dt, E _max , and the presence of ventricular arrhythmias. The number of animals studied to completion was 19 (n = 11 in the isoflurane group; n = 8 in propofol group). There was a significant difference in E _max between isoflurane and propofol during early and late reperfusion [3.4 (0.5) and 4.0 (0.3) vs 2.6 (0.4) and 3.2 (0.5) mmHg/sec, respectively; P < 0.05]. Postreperfusion ventricular fibrillation occurred in 54% animals in the propofol group vs none in the isoflurane group ( P < 0.05). Isoflurane administration was found to be cardioprotective against ventricular depression and arrhythmias compared to propofol.