In trauma, both physical injury and physiological deterioration can impact mortality. A patient is extracted from a road traffic collision. The injury is potentially survivable. We stop the haemorrhage, secure the airway, ensure respiration and circulation are stable and then consider hypothermia. This is all in line with the MARCH protocols for trauma. By the time that patient reaches the resuscitation room, their core temperature is dangerously below 35 ℃, that is below the