EFFECTS OF HYPOTHERMIA ON THROMBELASTOGRAPHY IN PATIENTS UNDERGOING CARDIOPULMONARY BYPASS

Thrombelastography (TEG) correlates with postoperative chest drain out put in patients undergoing cardiopulmonary bypass (CPB). In vitro incu bation with heparinase allows TEG monitoring during CPB, despite hepar in anticoagulation. Hypothermia impairs coagulation, but these effects cannot be assessed by standard coagulation tests performed at 37 degr ees C. The aim of this study was to assess the effects of hypothermia on TEG. Therefore, we have compared normothermic and temperature-adapt ed TEG in 30 patients undergoing CPB. Our data showed significantly im paired reaction time (r), kinetic time (k), and angle alpha (alpha) in temperature-adapted compared with normothermic TEG. Maximum amplitude (MA), reflecting absolute clot strength, was not affected at temperat ures of 33-37 degrees C. These findings indicate a decrease in the spe ed of clot formation, but not absolute deterioration in clot quality. Furthermore, heparinase-modified TEG indicated that there were nine ca ses in which heparin effects persisted after heparin reversal with pro tamine, providing a rational guide to protamine therapy.