Comparison of warming methods for core temperature preservation during total knee arthroplasty using a pneumatic tourniquet

BACKGROUND: It is important to ensure that patients are normothermic during surgery. In total knee arthroplasty, the pneumatic tourniquet affects body temperature. We compared the ability of two warming devices to preserve core temperature in patients using a lower limb tourniquet under general anesthesia. METHODS: We included 132 patients with American Society of Anesthesiologists physical status I-II who were scheduled to undergo total knee arthroplasty. The patients were randomly divided into four groups (n = 33): group 1, without any heating method; group 2, with fluid warming; group 3, with forced-air warming; and group 4, with a combination of the two heating methods. After the induction of anesthesia, the esophageal and urinary bladder temperatures were monitored and recorded every 5 min before tourniquet deflation and every 1 min after tourniquet deflation. RESULTS: Before tourniquet deflation, compared with group 1, the odds ratios of groups 3 and 4 were less than 1. After tourniquet deflation, compared with group 1, the odds ratios of all groups using warming devices were less than 1. In particular, group 4 showed the largest hypothermia-preventive effect among the four groups. There was a significant correlation between esophageal temperature and bladder temperature before and after tourniquet deflation. CONCLUSIONS: After tourniquet deflation, a combination of a fluid warmer and forced-air warmer is the most effective method to prevent hypothermia, although either a fluid warmer or forced-air warmer alone could help to prevent hypothermia. Urinary bladder temperature changes correlate well with esophageal temperature changes throughout this operation.

The Effects of Temperature Monitoring Methods and Thermal Management Methods during Spinal Surgery / 대한마취과학회지

BACKGROUND: The precise measurement of body temperature during anesthesia is important to prevent hypothermia.The aim of this study was to compare the urinary bladder temperature to the esophageal, nasopharyngeal, rectal and skin temperatures, and to compare three heating methods during spine surgery. METHODS: Forty-two patients with ASA physical status I-II, who were scheduled to undergo spine surgery in the prone position, were included in this study.The patients were randomly divided into 4 groups:Group I was treated without any heating methods; group 2, with fluid-warmers; group 3, with forced air-warmers; and group 4, with a combination of both heating methods.After the induction of anesthesia, the esophageal, nasopharyngeal, rectal, urinary bladder and skin temperature was monitored every 15 minute for 3 hours.The urinary bladder temperature was compared to the esophageal, nasopharyngeal, rectal and skin temperatures. RESULTS: The urinary bladder temperature was found to be higher than the esophageal and the nasopharyngeal temperatures (P < 0.01).The urinary bladder temperature of group 3 was higher than that of group 1 at 180 minutes after induction of anesthesia (P < 0.05).The urinary bladder temperature of group 4 was higher than that of group 1 at 150 minutes (P < 0.05), as well as at 165 and 180 minutes (P < 0.05).The skin temperatures of groups 3 and 4 were higher than group 1 (P < 0.001). CONCLUSIONS: The urinary bladder temperature was higher than the esophageal temperature and correlated with the esophageal, nasopharyngeal and rectal temperatures.During spine surgery in the prone position, a forced air-warmer was found to be the most effective but a combination of all the methods tested was found to be even more effective.