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Objective: Controlled hypothermia induced during hemorrhagic shock (HS) has been shown previously to improve survival in HS rat outcome models. We hypothesized that hypothermia (34 degrees C) induced immediately with reperfusion would also improve survival., Methods: Twenty-four rats were lightly anesthetized with halothane and maintained spontaneous breathing. The rats underwent: an HS phase I of 75 min, with an initial blood withdrawal of 2.5 mL/100 g over 15 min, followed by either additional blood withdrawal or re-infusion in order to maintain a mean arterial pressure (MAP) of 30 mmHg over 60 min; a resuscitation phase II of 60 min with return of shed blood and infusion of lactated Ringer's solution to maintain a MAP of 75 mmHg; and an observation phase III without anesthesia for 72 h. Five minutes before the start of phase II, 12 rats were randomized into either a normothermia (38 degrees C) group or hypothermia (34 degrees C) group. The rectal temperature in each group was carefully maintained during the 60-min period of phase II. Survival at 72 h, as well as gut damage were assessed., Results: All 24 rats survived beyond phases I and II. At 72 h, 8 of 12 rats survived in the hypothermia group, while and 6 of 12 survived in the normothermia group (p=0.64). Intestines of the 72 h survivors were macroscopically normal. In rats that died during phase III, total gut scores did not differ statistically between the groups (1.2+/-0.6 versus 1.0+/-0.9)., Conclusion: Brief resuscitative hypothermia of 60 min duration induced immediately with reperfusion after HS did not improve survival in this model.

Purpose: To evaluate whether cerebral CT findings taken immediately after successful resuscitation from cardiopulmonary arrest (CPA) correlate with the outcome or not., Material and Methods: We analyzed retrospectively brain sections with the Housfield unit (CT number). Between May 2001 and March 2004, 16 consecutive patients, who recovered from CPA, were included as subjects in this study. They satisfied all of the following criteria: (a) a helical multislice head CT was performed within 1 h of the return of the spontaneous circulation (ROSC); (b) patients died within 24 h after ROSC, and any patients with trauma or cerebral vascular disease were excluded. The subjects were divided into two groups; those with a cerebral performance category of 1-3 (GR group) and those with a cerebral performance category of 4-5 (VD group)., Results: There were no significant differences between the two groups except for age. The average ventricle size on the brain CT showed no significant difference between the two groups. The average CT number of the putamen and cerebral cortex, and the corticomedullary contrast in the GR group were higher than those in the VD group., Conclusion: Although the influence of age cannot be disregarded, the CT number of the putamen and cortex, and also the corticomedullary contrast correlated with outcome of hypoxic encephalopathy even when cerebral CT was performed within 1 h after ROSC following CPA.

Female C57BL/6 mice were decapitated and their brains were removed and cultured at either 37 or 33 degrees C for 48 h to investigate whether or not moderate hypothermia alters the cytokine reactions in the ischemic brain. The interleukin-6 and interleukin-1alpha levels in the culture media were significantly elevated in a time-dependent manner. The interleukin-6 levels after the incubation at 33 degrees C were significantly lower than those at 37 degrees C. The interleukin-1alpha levels at 33 degrees C were significantly higher than those at 37 degrees C. The interleukin-1alpha levels incubated with interleukin-6 antibody were significantly higher than those without IL-6 antibody. At 37 degrees C, the mRNA expression of interleukin-6 was observed from 2 to 48 h after incubation, but the same expression of interleukin-1alpha was only detected until 12 h. Accordingly, the ischemic brain incubated at 33 degrees C showed a decreased interleukin-6 production in comparison with that at 37 degrees C and the level of interleukin-6 showed negative feedback for the production of interleukin-1alpha. The temperature should, therefore, be carefully considered when evaluating the cytokine reaction for cerebral ischemia.