A prospective, randomized study of cardiopulmonary bypass temperature and blood transfusion

Background. We hypothesized that normothermic cardiopulmonary bypass (CPB) would be associated with decreased blood loss and allogeneic transfusion re quirements relative to hypothermic CPB. Methods. After obtaining institutional review board approval and informed p atient consent, we conducted a prospective, randomized study of 79 patients undergoing CPB for a primary cardiac operation at normothermic (37 degrees C) (n = 44) or hypothermic temperature (25 degrees C) (n = 35). Blood loss and transfusion requirements in the operating room and for the first 24 ho urs in the intensive care unit were determined. A paired t test and rank su m tests were used. A p value of less than 0.05 was considered significant. Results. The normothermic and hypothermic CPB groups did not differ in demo graphic variables, CPB or cross-clamp duration, heparin sodium or protamine sulfate dose, prothrombin time, or thromboelastogram results. There were n o differences between the two CPB groups in blood loss or transfusion requi rements. Conclusions. We found that when there was no difference in duration of CPB, normothermic and hypothermic CPB groups demonstrated similar blood loss an d transfusion requirements even though other studies have shown hypothermia induces platelet dysfunction and alters the activity of the coagulation ca scade. (Ann Thorac Surg 1999;67:711-5) (C) 1999 by The Society of Thoracic Surgeons.