EFFECTS OF TEMPERATURE ON BLEEDING-TIME AND CLOTTING TIME IN NORMAL-MALE AND FEMALE VOLUNTEERS

Objective: This study was done to assess the effects of temperature on bleeding time and clotting time in normal male and female volunteers. Design: Open study utilizing normal volunteers. Setting: University r esearch laboratory. Subjects: Fifty-four healthy male and female volun teers, ranging in age from 19 to 35 yrs, who were not receiving medica tions. The study was done and the samples of venous blood and shed blo od collected at the template bleeding time site were obtained at a con venient time for each volunteer. Interventions: Skin temperature was c hanged from +20 degrees to +38 degrees C and blood samples were obtain ed from the antecubital vein of each volunteer, Measurements and Main Results: The effect of local skin temperature ranging from +20 degrees to +38 degrees C on bleeding time was evaluated in 38 normal voluntee rs (19 male and 19 female). Skin temperature was maintained at +20 deg rees to +38 degrees C by cooling or warming the forearm. At each tempe rature, measurements were made of complete blood count, bleeding time, and thromboxane B-2 concentrations in shed blood collected at the tem plate bleeding time site and in serum and plasma isolated from blood c ollected from the antecubital vein. Clotting time studies were measure d in 16 normal volunteers (eight male and eight female) at temperature s ranging from +22 degrees to +37 degrees C. At +32 degrees C, the ble eding time was longer and hematocrit was lower in female than in male volunteers. However, at local skin temperatures of <+32 degrees C, bot h the males and females exhibited significantly increased bleeding tim es, which were associated with a reduction in shed blood thromboxane B -2. Each 1 degrees C decrease in temperature was associated with a 15% decrease in the shed blood thromboxane B-2 concentration. Clotting ti mes were three times longer at +22 degrees C than at +37 degrees C. Ea ch 1 degrees C reduction in the temperature of the clotted blood was a ssociated with a 15% reduction in the serum thromboxane B-2 concentrat ion. Conclusion: Our data indicate that during surgical procedures, it is important to maintain normothermia to ensure that platelets and cl otting proteins function optimally.