Surface Cooling, Which Fails to Reduce the Core Temperature Rapidly, Hastens Death during Severe Hemorrhagic Shock in Pigs

Abstract

To examine whether surface cooling (SC) would rapidly decrease the core temperatures and prolong the survival time during volume-controlled lethal hemorrhagic shock in pigs. Twelve pigs were randomly assigned to the SC group (group 1, n = 6) or the no cooling control group (group 2, n = 6), after blood withdrawal of 30 mL/kg over 15 minutes, and maintained under spontaneous breathing by light anesthesia with 1.0% halothane. SC was performed by applying ethanol to the skin, blowing with an electric fan, and placing ice packs. Pigs were observed without fluid resuscitation until their death (apnea and no pulse). SC did not lower the rectal temperature (Tr) to 35 degrees C at any time point until death, except one pig; in that animal, Tr was decreased to 34 degrees C after 135 minutes from the start of SC. The survival time was 108 +/- 43 minutes in group 1 and 175 +/- 55 minutes in group 2 (p < 0.05, life table analysis). In lightly anesthetized pigs during hemorrhagic shock, SC without resuscitation did not rapidly reduce the core temperature and rather hastened death for reasons that remain to be explored.