Hypothermia has been proposed as a potentially beneficial treatment for traumatic brain injury, with rationale that a reduced cerebral metabolic rate may bring clinical benefits. Despite early trials demonstrating some promise of benefit of prophylactic hypothermia in traumatic brain injury, the evidence remains mixed and its use is not recommended in current guidelines20. Some centres may choose not to rewarm patients presenting hypothermic on the basis of subgroup analysis suggesting that this group may do less well with a rapid return to normothermia23.