[Utility of an infrared ear thermometer as an intraoperative core temperature monitor]

We investigated the utility of an infrared ear thermometer (M 10, Terumo) as an intraoperative core temperature monitor. Temperatures of the axilla and inner ear were measured before and after anesthesia. Bladder, rectal, and forehead deep temperatures were continuously measured using a core temperature monitor (CTM-205, Terumo) during anesthesia. At the same time, the temperature of the inner ear was measured 4 times every 15 minutes (twice from cephalad and twice from caudal directions). There were no significant differences in the measured inner ear temperatures, either between directions of measurement or between the 1st and 2nd measurements. The inner ear temperature showed a close correlation with rectal, bladder, forehead deep, and axillary temperatures (r = 0.72-0.79, P < 0.01). The smallest temperature difference in this study was found to be that between the inner ear and forehead deep temperatures (-0.10), and the limit of agreement between these temperatures was also the smallest (0.81). In conclusion, we recommended the use of an infrared ear thermometer as an intraoperative core temperature monitor, especially in lower abdominal surgery, in which neither rectal nor bladder temperature monitoring is reliable.