Effect of prewarming on post-induction core temperature and the incidence of inadvertent perioperative hypothermia in patients undergoing general anaesthesia

Abstract

Background. Inadvertent perioperative hypothermia (IPH) occurs in many patients because warming techniques are insufficient to counteract thermal redistribution resulting from the ablation of thermoregulatory vasoconstriction associated with anaesthesia. We tested the efficiency of a preoperative forced-air warming (FAW) device (Bair Paws®) in preventing IPH. Methods. Sixty-eight adult patients undergoing spinal surgery under general anaesthesia were randomized to receive either normal care or prewarming for 60 min, at 38°C, using the Bair Paws® system. All patients received routine FAW intraoperatively. Results. Thirty-one patients were prewarmed and 37 patients were in the control group. There was a 0.3°C smaller decrease in mean core temperature in the prewarmed group at 40, 60, and 80 min post-induction (P≤0.05). Temperature was maintained above the hypothermic threshold of 36°C in 21 (68%) patients in the prewarmed group, compared with 16 (43%) patients in the control group (P<0.05). Conclusions. Preoperative warming using the Bair Paws® system results in smaller decreases in core temperature intraoperatively and less IPH in patients undergoing spinal surgery under general anaesthesia. © The Board of Management and Trustees of the British Journal of Anaesthesia 2008. All rights reserved.