Preoperative Patient Warming for Prevention of Perioperative Hypothermia in Major Abdominal Surgery

The aim of our study is to evaluate the performance of different durations of active preoperative skin-surface warming (prewarming) to prevent perioperative hypothermia in patients undergoing major abdominal surgery under combined general/epidural anaesthesia. The investigators plan to enroll 99 patients in 3 groups. Body temperature will be measured at the tympanic membrane. The investigators hypothesize that active warming before starting the epidural anaesthesia will decrease the incidence of perioperative hypothermia.