Comparison of efficacy of active forced-air warming for preventing perioperative hypothermia between the elderly and young patients

Objective To observe whether the active forced-air warming has the same efficacy on the prevention of perioperative hypothermia in the elderly as compared with young patients. Methods This was a prospective, randomized, controlled clinical trial.Forty patients scheduled for abdominal surgery under general anesthesia were allocated to two groups: the elderly group and the young group(n=20, each). All patients received active forced-air warming at 20-30 min before induction of anaesthesia till leaving the operation room.Blood products and peritoneal lavage fluids were warmed to 37℃, and other intravenous fluids were at room-temperature.The core temperatures were recorded after entering the operation room(baseline), before induction of anaesthesia, at 15 min intervals after induction of anaesthesia, at the end of surgery and before leaving the operation room.The postoperative shivering and adverse reactions were also recorded. Results The core temperature was lower in elderly patients than in young patients at baseline and at each time points after 30 min of induction of anaesthesia(P<0.05). In elderly patients, the core temperature was significantly lower before leaving operation room than at the baseline(t=2.353, P=0.03), but in young patients, no significant difference was found in the core temperature between at the baseline and before leaving operation room(t=0.233, P=0.818). The incidence of intra-operative hypothermia was higher in elderly patients than in young patients(40.0% or 8/20 vs.5.0% or 1/20, c2=7.025, P=0.008). Conclusions During abdominal surgery under general anesthesia, active forced-air warming cannot effectively prevent perioperative hypothermia in elderly patients as compared with young patients. Key words: Anesthesia, general; Body temperature regulation