Difference in Core temperature in response to propofol-remifentanil anesthesia and sevoflurane-remifentanil anesthesia

Hypothermia following the induction of anesthesia is caused by core to peripheral redistribution of body heat. It has been reported that propofol causes more severe hypothermia than sevoflurane by inhibiting thermoregulatory vasoconstriction during surgical procedures. Therefore, we evaluated the induction and maintenance of anesthesia with intravenous propofol to determine if it causes more core hypothermia than inhaled sevoflurane. Forty-five patients who underwent hysterectomy were divided into two groups randomly, a propofol-remifentanil (PR) anesthesia group and a sevoflurane-remifentanil (SR) anesthesia group. Each group was subjected to anesthetic induction with either 1.5 mg/kg propofol or inhalation of 5% sevoflurane, respectively. Anesthesia in the former group was maintained with propofol while it was maintained with sevoflurane in the latter group. Specifically, 6-10 mg/kg/hr propofol, 3 L/min medical air, 2 L/min O2, and 0.25 mg/kg/hr remifentanil were used in the PR group for maintenance, while 1.5 vol% sevoflurane, 3 L/min medical air, 2 L/min O2 and 0.25 mg/kg/hr remifentanil were used for maintenance in the SR group. We measured the core temperature 8 times, prior to induction and 10, 20, 30, 45, 60, 75 and 90 minutes after induction. Core temperatures decreased in both the PR and SR group during surgical operation, but there was no significant difference between the two groups. Anesthesia induced and maintained by propofol did not cause a greater degree of hypothermia than sevoflurane.