The Present Role of Hypothermia in Cardiac Surgery

A survey of the current use of hypothermia during cardiac surgery has been presented. Hypothermia remains a simple and safe method to permit the surgical correction of uncomplicated atrial septal defects, although it is gradually being displaced by pump-oxygenators as they become better understood. In conjunction with extracorporeal circulation moderate and extreme ("deep") hypothermia has been employed. Moderate hypothermia is without any known deleterious effects and may be of benefit by lowering perfusion rates and decreasing intracardiac aspiration of blood. The role of deep hypothermia with circulatory arrest remains uncertain. It is a condition associated with extreme physiologic alterations, many of which are poorly understood, and the safe limits are not yet clearly defined. Finally, hypothermia remains a beneficial technic for neurologic injury following resuscitation from cardiac arrest. Recent evidence indicates that the mechanism of benefit involves considerably more than simple reduction of cerebral edema.