[Protective effect of hypothermia in cerebral ischemia]

The use of hypothermia to protect the brain from ischaemic insults is an old concept. During the last decades, studies have mainly shown a modulating effect of hypothermia on biochemical cerebral responses to ischaemia, in addition to the basic effect of energy savings. Thus, the beneficial effects of decreased brain temperature, even when limited during transient ischaemic insults, whether global or focal, complete or incomplete, have been established. The deeper the hypothermia, the longer the ischaemia can be prolonged with acceptable neurological outcome. Conversely, the effects of postischaemic hypothermia remain unclear, while extracerebral deleterious effects cannot be overlooked, and many parameters remain to be evaluated before undertaking a beneficial clinical trial. The only indication for therapeutic postischaemic hypothermia in the near future could be in the control of impending intracranial hypertension occurring after cerebral ischaemia.