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

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)). 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 A degrees C, a forced-air warmer was used. Baseline temperatures were 36.7 +/- A 0.3, 36.6 +/- A 0.2, and 36.6 +/- A 0.2 A degrees C in groups C, M, and F, respectively. T (c) at the end of surgery dropped from baseline values by 1.0 +/- A 0.4, 0.5 +/- A 0.5, and 0.8 +/- A 0.5 A degrees 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 +/- A 1.0 vs. 23.5 +/- A 0.5 and 24.0 +/- A 0.4 A degrees C; p < 0.01). The Mega significantly reduced the drop in intraoperative T (c) by delivering warm fluids, compared with the other breathing circuits tested. Clinicaltrials.gov identifier: NCT01831843.