A comparative evaluation of humidifier with heated wire breathing circuit under general anesthesia

Abstract

Background: Dry and cold anesthetic gas deteriorates patient's respiratory function and body heat balance. We examined whether a humidifier with heated wire circuit might maintain core temperature and humidity of inspired gas in patient undergoing general anesthesia. Methods: We enrolled forty ASA physical status I, II patients under general anesthesia for this study. We allocated the patients randomly into two groups with (experimental group) or without (control group) Humitube Ⓡ anesthesia circuit, which delivered heated and humidified inspired anesthetic gases. We recorded the temperatures and humidity of the inspired gases throughout the surgery. Results: The temperatures and relative humidity of the inspired gases in experimental group were significantly greater compared to control group (36.2 ± 0.9 o C, 89.5 ± 4.8% vs. 30.4 ± 1.8 o C, 37.9 ± 5.9%, P ＜ 0.05) during anesthesia. The core temperatures in experimental group were significantly greater compared to control group (36.1 ± 0.3 o C vs. 35.7 ± 0.1 o C, P ＜ 0.05) during anesthesia. Conclusions: A humidifier with heated wire system for anesthesia breathing circuit is helpful to maintain core temperature and adequate