TRAUMATIC HYPOTHERMIA IS RELATED TO HYPOTENSION, NOT RESUSCITATION

Study objective: To determine whether posttraumatic hypothermia is ass ociated with hemorrhage or with resuscitation. Methods: We used a sequ ential hemorrhage-resuscitation rat model. Rats were subjected to hemo rrhage (30 mL/kg), then 1 hour of shock, followed by 2:1 crystalloid/b lood resuscitation (60 mL/kg) at ambient temperature. A control group underwent neither hemorrhage nor resuscitation. Results: We recorded c ore temperature and blood pressure every 10 minutes. Temperature drop averaged 3.4 degrees C and was fastest during hypotensive shock. Rate of temperature change correlated with blood pressure (beta=.0102, P<.0 01), shock phase (beta=.4504, P=.041), and blood pressure during shock phase (beta=.0116, P<.001), but not with resuscitation phase or with duration of shock or resuscitation. Three of 14 rats died during shock , none during resuscitation. An increase in temperature was noted in 1 of 14 rats during shock and in 7 of 11 rats during resuscitation. Con clusion: Hemorrhage-associated hypothermia occurs during hypotensive s hock, not during fluid resuscitation.