Effect of electrically heated humidifier on intraoperative core body temperature decrease in elderly patients: a prospective observational study

Abstract

BACKGROUND: Core body temperature (TC) can decrease during general anesthesia. Particularly in elderly patients, more aggressive strategies to prevent intraoperative hypothermia may be required. Here, we investigated the effect of a heated humidifier on intraoperative TC decrease in the elderly. METHODS: Twenty-four elderly patients were randomly assigned into two groups: those who used a heated humidifier (group H) and those who used a conventional ventilator circuit with a heat moisture exchanger (group C). TC was measured continuously at the esophagus at several time-points during surgery. RESULTS: In group C, TC significantly decreased 90 minutes after skin incision (P < 0.001), while significant differences were not noted in group H during surgery. Comparing the two groups, TC decreased more in group C than in group H at 60, 90, 120, and 150 minutes after skin incision (group C vs. group H: -0.6℃ vs. -0.3℃, P = 0.025; -0.7℃ vs. -0.4℃, P = 0.012; -0.9℃ vs. -0.4℃, P = 0.006; and -1.0℃ vs. -0.5℃, P = 0.013, respectively). There were no significant differences between the two groups for any other parameters. CONCLUSIONS: A heated humidifier is more effective in preventing intraoperative TC decrease in elderly patients than a heat moisture exchanger. However, further studies with a larger population are required to substantiate its clinical use.