Neuropsychiatric complications of cardiac surgery

Abstract

Historically, intracardiac operations have carried a higher risk of neurologic complications than coronary artery bypass grafting (CABG) procedures, although the incidence of such complications has been increasing after CABG in recent years. In both intracardiac and extracardiac surgery, macroemboli from the surgical field cause most neurologic complications. The periods of highest risk for emboli are during aortic cannulation, onset of bypass, and weaning from bypass. Risk factors include atherosclerosis of the ascending aorta, advanced age, presence of concomitant cerebral vascular disease, previous neurologic abnormality, duration of surgery, diabetes, and history of failure of the native circulation. Although hypothermia is beneficial in elective circulatory arrest, its usefulness in reducing postoperative central nervous system deficits during routine cardiac operations may be limited. Studies suggest a role for barbiturate protection in intracardiac but not in extracardiac surgery. Studies have not shown better neurologic or neuropsychological outcome with the use of membrane oxygenation and arterial filtration. Recent studies suggest no correlation of neurologic injury with serum glucose levels during CABG, with either duration or severity of hypotension during hypothermic CABG, or with blood gas management during hypothermic CABG.