Table 1.

A comparison of core temperatures at, and the duration of intervals between, transitional events during recovery from halothane anesthesia in rats maintained under various thermal regimes

Treatment Group
HypothermicRewarmed Normothermic
Thy during recovery, °C
Termination of anesthesia 32.4 ± 0.2* 38.0 ± 0.2 38.3 ± 0.2
Emergence from anesthesia 32.0 ± 0.3* 37.2 ± 0.437.6 ± 0.2
Behavioral recovery36.7 ± 0.3 37.2 ± 0.3 37.5 ± 0.2
Phases of recovery, min
Termination to emergence 17.3 ± 2.318.4 ± 2.8 18.2 ± 2.3
Emergence to behavioral recovery 54.4 ± 6.0* 7.5 ± 1.410.1 ± 1.9
Termination to behavioral recovery71.8 ± 7.1* 25.9 ± 2.828.3 ± 1.5
  • Values are means ± SE; n = 8 rats for all treatment groups. Hypothermic-treatment group animals were maintained in a 23°C environment during 1 h of anesthesia. Normothermic-treatment group animals were actively maintained at hypothalamic temperature (Thy) = 37–39°C throughout 1 h of anesthesia. Rewarmed-treatment group animals were placed in a 23°C environment during 1st hour of anesthesia but were rewarmed to Thy 37–39°C before termination of anesthesia. Emergence from anesthesia was based on changes in EEG/EMG parameters. Behavioral recovery was based on visual determinations: animals arose from a prone position and initiated coordinated motor activities.

  • * Significantly different from other treatment groups (P < 0.0001).