Thermal suit connected to a forced‐air warming unit for preventing intraoperative hypothermia: a randomised controlled trial

BACKGROUND Inadvertent intraoperative hypothermia is a common occurrence in surgical patients. A thermal suit is an option for passive insulation. However, active warming is known to be more effective. Therefore, we hypothesised a forced-air warming unit connected to the thermal suit is superior to a commercial forced-air warming blanket and a warming mattress in breast cancer surgery. METHODS Forty patients were randomised to this prospective, clinical trial to wear either the thermal suit or conventional hospital clothes under general anaesthesia. The Thermal suit group had a forced-air warming unit set to 38 °C and connected to the legs of the suit. The Hospital clothes group had a lower body blanket set to 38 °C and a warming mattress set to 37 °C. Core temperature was measured with zero-heat-flux sensor. The primary outcome was core temperature on admission to the recovery room. RESULTS There was no difference in mean core temperatures at anaesthetic induction (P=0.4) or on admission to the recovery room (P=0.07). One patient in the Thermal suit group (5%) vs. six patients in the Hospital clothes group (32%) suffered from intraoperative hypothermia (P=0.04, 95% CI 1.9 to 49%). Mean skin temperatures were higher in the Thermal suit group during anaesthesia. No burns or skin irritations were reported. Two patients in the Thermal suit group sweated. CONCLUSIONS A thermal suit connected to a forced-air warming unit was not superior to a commercial forced-air warming blanket, although the incidence of intraoperative hypothermia was lower in patients treated with a thermal suit.