Ethane: A marker of lipid peroxidation during cardiopulmonary bypass in humans

The goals of this study were to (1) determine the utility of quantification of ethane as a marker of ischemia-reperfusion during human cardiopulmonary bypass (CPB); and (2) determine, using an animal model for this surgical p rocedure, whether the mode of surgical approach produced increases the quan tity of exhaled ethane. Human CPR was initiated following standard anesthet ic and monitoring regimens. Samples of gas were collected at baseline and a t multiple defined time points throughout the studies. Ethane was determine d using cryogenic concentration and gas chromatography. Sternotomy increase d exhaled ethane compared to baseline (p < .007; 5.8 +/- 1.7 vs. 3.0 +/- 0. 7 nmol/m(2) . min); ethane returned to baseline levels prior to the initiat ion of CPB. Aortic unclamping produced ethane elevation (p < .05; 2.3 +/- 0 .8 vs. 1.5 +/- 0.4 nmol/m(2) . min) with the levels being related to a lowe r cardiac index and a higher systemic vascular resistance post aortic uncla mping. Termination of CPB significantly increased ethane levels compared to baseline (p < .002; 4.8 +/- 1.7 vs. 3.0 +/- 0.7 nmol/m(2) . min). Independ ent variables that correlated with increased ethane measurements included a higher arterial blood pH on bypass and the change in hemoglobin pre- and p ost-CPB. Electrocautery, but not scalpel, incision of the porcine abdominal wall increased ethane levels significantly (p < .02). These results indica te that exhaled ethane may be a valuable marker of lipid peroxidation durin g and following CPB. (C) 1998 Elsevier Science Inc.