Restoration of body temperature to normothermia during resuscitation following trauma-hemorrhage improves the depressed cardiovascular and hepatocellular functions

Hypothesis: Rewarming the body to 37 degrees C during resuscitation followi ng trauma-hemorrhage has salutary effects on cardiovascular and hepatocellu lar functions. Design, Interventions, and Main Outcome Measures: Male rats underwent lapar otomy (trauma induced) and were then bled to and maintained at a mean arter ial pressure of 40 mm Hg until 40% of the maximum shed blood volume was ret urned in the form of Ringer lactate solution. Rats were exposed to ambient temperature and allowed to become hypothermic during hemorrhage. The animal s were then resuscitated with 4 times the volume of shed blood with Ringer lactate solution for 60 minutes. In 1 group, the body temperature was rewar med to 37 degrees C during resuscitation. In another group, the body temper ature was maintained at hypothermia (32 degrees C) for 4 hours after resusc itation. In an additional group, the body temperature was kept at 37 degree s C during hemorrhage and resuscitation. At 4 hours after resuscitation, th e rats were returned to a room with ambient temperature. Various in vivo he art performance variables (maximal rate of pressure increase and decrease), cardiac output, hepatocellular function, and plasma IL-6 level were determ ined at 24 hours after resuscitation. Results: Either maintenance of normothermia during hemorrhage or prolonged hypothermia following resuscitation had deleterious effects on cardiovascul ar variables and hepatocellular function and up-regulated plasma IL-B level s. In contrast, rewarming the body to 37 degrees C during resuscitation imp roved cardiac contractility, cardiac output, and hepatocellular function an d reduced plasma IL-6 level. Conclusion: Since rewarming the body temperature to normothermia during res uscitation improved depressed cardiovascular and hepatocellular functions, this should be considered as a useful adjunct to fluid resuscitation after trauma-hemorrhage.