Trauma is the leading cause of death in young adults and a major cause of morbidity and mortality at all ages. The acute problem is often uncontrollable bleeding. Subsequently, infection becomes a leading cause of morbidity. Polytrauma patients are at high risk for accidental hypothermia. Mild perioperative hypothermia causes a coagulopathy that significantly augments blood loss and increases allogeneic transfusion requirements. Hypothermia also impairs numerous immune functions - even slight decreases in core temperature triple the risk of surgical wound infection.