Effect of a new heated and humidified breathing circuit with a fluid-warming device on intraoperative core temperature: a prospective randomized study.

BACKGROUND: The effect of the Mega Acer kit(@), a new heated and humidified breathing circuit (HHBC) containing a fluid-warming device, was investigated on intraoperative core temperature (T c). METHODS: A total of 102 patients undergoing elective craniotomies were randomly divided into three groups based on the breathing circuit used: a conventional breathing circuit (group C, n = 34), a Fisher & Paykel HHBC (group F, n = 34), and the Mega (group M, n = 34). From baseline to the end of the surgery, T c and infusion fluid temperature (T f) were recorded at 15-min intervals. If T c became lower than 35.5 °C, a forced-air warmer was used. RESULTS: Baseline temperatures were 36.7 ± 0.3, 36.6 ± 0.2, and 36.6 ± 0.2 °C in groups C, M, and F, respectively. T c at the end of surgery dropped from baseline values by 1.0 ± 0.4, 0.5 ± 0.5, and 0.8 ± 0.5 °C in groups C, M, and F, respectively. From 60 min of post-induction to the end of surgery, T c was higher in group M than group C (p < 0.05). From 105 min of post-induction to the end of surgery, T c was higher in group M than group F (p < 0.05). The number of patients receiving forced-air warmer and total forced-air warmer using time were significantly lower in group M than groups C and F (p < 0.05). T f was higher in group M than groups C and F throughout the study period (31.0 ± 1.0 vs. 23.5 ± 0.5 and 24.0 ± 0.4 °C; p < 0.01). CONCLUSIONS: The Mega significantly reduced the drop in intraoperative T c by delivering warm fluids, compared with the other breathing circuits tested. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT01831843.