Role of hypothermia in the management of severe cases of subarachnoid hemorrhage.

Mild hypothermia is thought to have a brain protective effect to pathophysiological conditions, which are caused by severe brain damage including brain injury and cerebral stroke. In this paper, general aspects of this treatment as history, pathophysiological effect, and problems are summarized. Also, the clinical effects of hypothermic therapy for a subarachnoid hemorrhage are reviewed. Main targets of the therapy for this disease are severe primary brain damage caused by the attack itself and secondary ischemic brain damage after delayed vasospasm. But even now, there are no fully established data about the effect of hypothermia at such conditions after subarachnoid hemorrhage. The results of our study of cerebral blood flow and cerebral oxygen metabolism using positron emission tomography are presented to show the physiological effect of hypothermia on human brain after severe brain damage caused by subarachnoid hemorrhage. In conclusion, effect of hypothermia on subarachnoid hemorrhage is not confirmed yet and reported data is limited, so that additional studies, especially controlled studies, would be recommended.