Coagulation disturbance in profound hypothermia: the influence of anti-fibrinolytic therapy.

Extensive thoracic aortic resections often require a period of profoundly hypothermic circulatory arrest. The extent of surgical dissection, damaging effects of cardiopulmonary bypass, and coagulation disturbances of hypothermia predispose to bleeding. Although impervious vascular grafts and biological glues have made an important contribution to eliminating the vicious cycle of transfusion of stored blood and worsening coagulopathy, hemorrhage remains an important cause of morbidity in these patients. Thrombin generation by activation of the coagulation cascades also leads to excessive fibrinolytic activity with the potential to disrupt the hemostatic process. Pharmacological antifibrinolytic therapy with aprotinin or other agents has been shown to preserve hemostasis, but the efficacy of antifibrinolytic therapy remains unproven in thoracic aortic operations with hypothermic circulatory arrest. This report discusses the interactions of hypothermia with the coagulation system, together with the efficacy of fibrinolytic therapy from existing surgical experience.