Endovascular temperature management system Alsius® (ICY, Alsius Corporation: Irvine,California,USA) has been approved in Europe and United States for the past 10 years and has been used in thousands of patients mainly for the indication of therapeutic cooling and subsequently rewarming of patients. A major potential advantage of this system is that heat is directly added to the thermal core, thus bypassing the heat sink and insulating effects of peripheral tissues. The efficacy of this system is sufficient to allow rapid rewarming in hypothermic trauma victims, even those undergoing major surgery. We therefore propose to test the hypothesis that polytrauma patients rewarmed with the Alsius® system will have better patient outcome (combined perioperative morbidity) than those warmed conventionally with forced-air.