[Whole body heat production as a quantitative marker of anesthetic management under general anesthesia]

In order to evaluate the effects of the rapid induction and the slow induction of general anesthesia on the management of anesthesia and the circadian rhythm, the time-dependent whole body heat production in mice (ICR, male, 6 to 10 weeks after birth) was measured by calorimeter. In the single administration of either an i.v. anesthetic (thiamylal) or a volatile anesthetic (isoflurane), the minimum heat production and its duration time were similar. In the co-administration of i.v. and volatile anesthetics, the minimum heat production was significantly lower (P < 0.01) and the duration of this minimum production was significantly more sustained (P < 0.01) compared to those seen in the single administration of each anesthetic. Moreover, by measurement of the whole body heat production, the slow induction of general anesthesia markedly affected the circadian rhythm on the next postoperative day. These results indicate that the measurement of the whole body heat production will be a marker for the recovery from general anesthesia and the return to the usual life style (such as the QOL).