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). 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 and infusion fluid temperature ( T) were recorded at 15-min intervals. If T 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 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 was higher in group M than group C ( p < 0.05). From 105 min of post-induction to the end of surgery, T 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 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 by delivering warm fluids, compared with the other breathing circuits tested. Trial Registration: Clinicaltrials.gov identifier: NCT01831843. [ABSTRACT FROM AUTHOR]