The importance of brain temperature in cerebral injury.

The recent finding that small variations in brain temperature can critically determine the extent of histopathological injury in animal models of brain injury has generated renewed interest in hypothermic brain protection. Whereas mild hypothermia protects the brain from ischemic and traumatic brain injury, mild hyperthermia worsens ischemic outcome. Selective brain cooling has many advantages over whole body cooling, including the elimination of harmful side effects, such as cardiac arrhythmias. In addition to the clinical issue of brain protection, manipulating brain temperature has become a powerful tool with which to investigate the pathophysiology of ischemic and traumatic brain injury. The purpose of this article is to review and discuss recent findings demonstrating the importance of brain temperature in ischemic and traumatic brain injury. Potential mechanisms by which mild hypothermia may attenuate and mild hyperthermia accentuate the detrimental consequences of brain injury are reviewed.