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

ABSTRACT

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.