The impact of hypothermia on dilutional coagulopathy

The control of hemorrhage in hypothermic patients with platelet and clotting factor depletion is often impossible. Determining the cause of coagulopathic bleeding (CB) will enable physicians to appropriately focus on rewarming, clotting factor repletion, or both. Objective: To determine the contribution of hypothermia in producing CB and ascertain if simultaneous hypothermia and dilutional coagulopathy (DC) interact synergistically. Method: Prothrombin time, partial thromboplastin time, and platelet function were determined at assay temperatures of 29 degrees to 37 degrees C on normal and critically ill, noncoagulopathic (NC) individuals. Dilutional coagulopathy was created using buffered saline and the assays repeated. Results: Hypothermic assay at < or = 35 degrees C significantly prolonged coagulation times. The effect of hypothermia on NC and DC samples was not different. Conclusion: Assays performed at 37 degrees C underestimate coagulopathy in hypothermic patients. The effect of hypothermia on NC and DC is not different, indicating the lack of a synergistic effect. Normalization of clotting requires both rewarming and clotting factor repletion.