Hypothermia for brain protection

Abstract

During ischemia, neuronal cells remain intact until the onset of anoxic depolarization. Most damage to the cells occurs during anoxic depolarization, although some damage is still sustained after membrane potential has been regained. Hypothermia decreases neuronal damage by delaying the onset of anoxic depolarization during the pre-depolarization period, by suppressing the accumulation of intracellular calcium and/or subsequent processes during the anoxic depolarization period, and by suppressing inflammatory response and the apoptotic process during repolarization. As the majority of neuronal damage is initiated during anoxic depolarization, hypothermia is most effective during this period. Hypothermia is indicated when interruption of cerebral blood flow is planned during neurosurgical procedure and can be initiated before the onset of ischemia. It is also recommended in patients experiencing cardiac arrest to improve neurological outcome. In patients with traumatic injury, hypothermia is induced to control intracranial pressure and should be terminated very slowly.