Effect of two perfluorocarbon emulsions on reperfusion injury after coronary artery occlusion in rabbits.

Because of their high oxygen-carrying capability and small particle size, it has been suggested that perfluorochemical emulsions may be useful to reduce reperfusion injury after coronary artery occlusion and reperfusion. We tested the ability of Fluosol and a more concentrated perfluorochemical emulsion (perflubron) to decrease infarct size in anesthetized rabbits undergoing 30 min of coronary occlusion and 4 h of reperfusion. All rabbits were ventilated with 100% oxygen. Treatment was begun at 25 min of coronary occlusion, 5 min before reperfusion. Rabbits were randomized to receive saline (10 ml/kg, n = 15), Fluosol (30 ml/kg, n = 15), or a perflubron emulsion (10 ml/kg, n = 16), or the perflubron emulsion vehicle (10 ml/kg, n = 15). Collateral blood flow during occlusion was measured with radioactive microspheres. The size of the ischemic region at risk was determined by in vivo injection of blue dye and infarct size by in vitro tetrazolium staining. We found that all groups were equally ischemic during occlusion, and that risk zone sizes were comparable. Heart rate and systemic arterial pressure were also similar among groups. Infarct size expressed as a percentage of the risk zone was 30 +/- 4% in saline-treated rabbits, 27 +/- 4% in Fluosol-treated rabbits, and 21 +/- 4% and 21 +/- 3% in perflubron emulsion and perflubron emulsion vehicle treated rabbits, respectively. There was a trend for both perflubron emulsion and perflubron emulsion vehicle groups to have smaller infarcts; however, neither perfluorocarbon emulsion nor the emulsion vehicle significantly reduced infarct size compared with saline treatment. Thus, at the doses used in this study neither Fluosol nor perflubron emulsion, when given just before reperfusion, significantly reduced infarct size in this rabbit model.