Report of a substudy on warm versus cold cardiopulmonary bypass: Changes in creatinine clearance

Background. Renal dysfunction remains a major complication of cardiac opera tions. There is concern regarding the possibility of increased renal injury during warm cardiopulmonary bypass (CPB). Therefore, we tested the hypothe sis that warm CPB is associated with a greater reduction in creatinine clea rance after cardiac surgery than hypothermic CPB. Methods. We randomly assigned 300 patients who had elective coronary artery bypass grafting to warm (35.5 to 36.5 degreesC) or cold (28 degreesC to 30 degreesC) CPB. Preoperative and peak postoperative serum creatinine values were recorded. Creatinine clearance was estimated using the Cockroft Gault equation. Univariate and multivariable analyses were performed to test the association of CPB temperature and perioperative change in creatinine clea rance. Results. Demographic variables were similar between groups. Multivariable a nalysis did not confirm an association between temperature and change in cr eatinine clearance (p = 0.87). Conclusions. We did not confirm an association between warm CPB and increas ed renal dysfunction after cardiac operations compared with hypothermic CPB . (C) 2001 by The Society of Thoracic Surgeons.