Coma after global ischemic brain injury: pathophysiology and emerging therapies

Cardiac arrest is a major cause of death and morbidity in the United States, and neurological injury contributes significantly to this. Neurological complications associated with global cerebral ischemia include disorders of responsiveness, such as coma and the vegetative state, seizures, motor deficits, and brain death. Coma, complete unresponsiveness, is the most pervasive of these. Therapies that improve neurological outcomes in general after cardiac arrest and therapies that stimulate arousal from coma could have enormous clinical impact. The authors review the physiology of arousal and describe the biochemical and pathophysiological derangements that develop after global cerebral ischemia. We then describe the potential therapeutic mechanisms of hypothermia and deep brain stimulation, which provide hope for better neurological outcomes after global cerebral ischemia.