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document
Deliberate mild intraoperative hypothermia for craniotomy . BACKGROUND Despite enthusiasm for the use of mild hypothermia during neurosurgical procedures , this therapy has not been evaluated systematically . This study examined the feasibility and safety of deliberate mild hypothermia and rewarming . METHODS Thirty patients scheduled for craniotomy were assigned to either a normothermic or mildly hypothermic group . Tympanic membrane temperature was monitored at anesthetic induction , throughout the isoflurane-fentanyl-N2O-O2 anesthetic , and for 18 h postoperatively . Normothermic patients were warmed to 36.5-37.0 degrees C after an initial temperature decrease , and hypothermic patients were cooled to 35 degrees C. In the hypothermic group temperatures were allowed to drift to 34.5 degrees C before rewarming was initiated . Water blankets and convective heating devices were used to cool and rewarm . RESULTS The minimum temperature achieved by the hypothermic group was 34.3 +/- 0.4 degrees C. Cooling occurred at a rate of 1.0 +/- 0.4 degrees C/h . Rewarming took place at a rate of 0.7 +/- 0.6 degrees C/h ( range 0.1-1.8 ) in the hypothermic group . Hypothermia did not delay emergence from anesthesia ( 20 +/- 15 min ) compared with normothermia ( 15 +/- 15 min , P = .45 ) . Mean temperature upon intensive care unit admission was 35.8 +/- 1.0 degrees C for the hypothermic group and 37.1 +/- 0.5 degrees C for the normothermic group ( P < 0.0001 ) . The hypothermic patients had more postoperative shivering . From 8 to 18 h postoperatively the temperatures of the two groups were similar except for a slightly greater temperature in the hypothermic patients at 12 h ( 37.6 +/- 0.5 vs. 37.3 +/- 0.4 degrees C , P = .029 ) . CONCLUSIONS Although deliberate mild hypothermia is easily achieved intraoperatively , complete rewarming may be difficult to attain during craniotomy with current methods . In addition to the need for determining whether deliberate mild hypothermia confers cerebral protection in humans , the potential risks of the therapy need to be further characterized .
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Intervention_Physical
mild intraoperative hypothermia
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Intervention_Physical
mild hypothermia
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Intervention_Physical
normothermic or mildly hypothermic
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Intervention_Pharmacological
isoflurane-fentanyl-N2O-O2 anesthetic
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Intervention_Physical
Hypothermia
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Outcome_Physical
minimum temperature
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Outcome_Physical
Cooling
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Outcome_Mental
Rewarming
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Outcome_Mental
Hypothermia
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Outcome_Physical
anesthesia
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Outcome_Other
Mean temperature upon intensive care unit admission
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Outcome_Other
postoperative shivering .
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Outcome_Physical
temperatures
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Outcome_Other
temperature