Effects of temperature on partial thromboplastin time in heparinized plasma in vitro.

Background And Objective: Perioperative hypothermia has been found to impair the coagulation cascade and to increase blood loss and transfusion requirements. The effect of concomitant in vitro heparinization on coagulation during hypo- and hyperthermic conditions has not been well defined.

Methods: In the present study, activated partial thromboplastin time was examined in vitro at 33 degrees C, 35 degrees C, 37 degrees C, 39 degrees C and 41 degrees C in normal human plasma in response to unfractionated heparin.

Results: Hypothermia
Conclusions: These observations suggest that both hypo- and hyperthermia increase the response to heparin in vitro. Further studies are needed to identify the effect of patient's body temperature on heparin activity and bleeding tendency in vivo.