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.
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.