Coma Following Cardiac Arrest: A Review of the Clinical Features, Management, and Prognosis

Abstract

Sudden cardiac death is an important clinical problem that accounts for 750,000 deaths in the United States each year. There are 200,000 cardiac resuscitations each year, of which only 70,000 are successful. Survival depends upon early cardiopulmonary resuscitation and defibrillation. The brain's ability to tolerate no more than a few minutes of circulatory arrest is the major factor limiting the success of cardiopulmonary resusci tation. Cardiac arrest results in a spectrum of clinical disorders depending on the severity of cerebral anoxia. Neurological sequelae in survivors range from transient states of confusion and amnesia to prolonged uncon sciousness in a coma or in the vegetative state. Sequen tial neurological examinations alone or in conjunction with evoked potentials, electroencephalogram, com puted tomography, and positron emission tomography can indicate the degree of central nervous system dam age and the likely outcome. The clinical management of patients in coma following cardiac arrest involves resto ration of cardiopulmonary and metabolic homeostasis. No effective delayed therapy yet exists that can reverse anoxic damage, but several promising therapeutic agents are under laboratory and clinical investigation.