Effect of 10-minute prewarming plus intraoperative co-warming on core temperature maintenance during breast surgery compared to intraoperative co-warming alone : a randomized controlled trial

Purpose : We evaluated the effect of 10-min prewarming on core temperature maintenance during general anesthesia. Patients : We randomized 40 women scheduled for breast cancer surgery into 10-min Prewarming and Control groups. In the Prewarming group, a forced-air warming system was used to warm the patients at 43℃ for 10 min immediately before general anesthesia induction. In the Control group, the patients were kept warm using cotton thermal blankets for 10 min. We measured tympanic temperature every 15 min from anesthesia induction for 90 min. Findings : Since two patients deviated from the protocol, we used the data of 38 patients (Prewarming [n = 18] and Control [n = 20]). There was a significant between-group difference in changes in core temperature (P = 0.03), including a significant difference in core temperature decrease during the first 60 min from anesthesia induction (Prewarming : −0.3 [0.3] ℃ vs. Control : −0.6 [0.2] ℃, P = 0.02). In addition, the duration of normal core temperature maintenance was significantly longer in the Prewarming group (66 [34] min vs. 39 [32] min, P = 0.01). Conclusions : Ten-min prewarming decreases core temperature loss and contribute to maintaining normal core temperature during breast surgery.