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

The study should evaluate how long patients undergoing major abdominal surgery under combined general/epidural anaesthesia have to be actively warmed preoperatively to prevent perioperative hypothermia and postoperative shivering. 99 patients will receive forced-air skin-surface warming for different duration. 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.