VISCERAL LIPID-PEROXIDATION OCCURS AT REPERFUSION AFTER SUPRACELIAC AORTIC CROSS-CLAMPING

Purpose: Recently, we have reported that lipid peroxidation specific t o oxygen free radical-mediated injury increased immediately after repe rfusion of human liver allografts. However, in the human liver transpl antation setting it was impossible to disassociate the contributions t o lipid peroxidation caused by the warm and cold ischemic phases from those caused by reperfusion. Therefore we now have studied lipid perox idation at reperfusion after supraceliac aortic cross-clamping in pati ents with normal livers. Methods: Ethane, a noninvasive biomarker of l ipid peroxidation, was measured in exhaled breath of patients before a nd during cross-clamping of the thoracic aorta and at sequential time intervals after visceral reperfusion. Results: Approximately a two-fol d transient increase in the ethane level was observed at around 15 min utes after reperfusion in those patients whose aortas were cross-clamp ed for more than 18 minutes. Conclusions: These results indicate that free radical-mediated lipid peroxidation occurs at reperfusion of warm ischemic viscera in the clinical setting of aortic repair. This obser vation supports the hypothesis that substantial lipid peroxidation occ urs when tissues are subjected to cold or warm ischemia followed by re perfusion.