The cerebral sequelae of cardiopulmonary bypass

Abstract

Continuing improvements in anaesthetic, surgical and perfusion techniques have led to a substantial reduction in the mortality and morbidity associated with cardiac operations. However, cerebral injury related to cardiopulmonary bypass (CPB) remains a leading cause of morbidity. The cerebral effects of CPB may be considered in terms of neurological and neuropsychological complications. Neurological complications, reported to occur in l-6% of patients following CPB,‘-’ largely consist of stroke or impairment of conscious level. Neuropyschological changes consist of intellectual deficits, mainly of concentration, memory, learning, and speed of visual-motor response. Studies have shown an alarming number of neuropyschological deficits following CPB, with an incidence of up to 80% in the early postoperative period* and 35 % at one year.’ However, these deficits are generally subtle and only about a third of patients will notice any change. As all cerebral injury relates to changes in global or local cerebral blood flow, regardless of aetiology, we will consider this aspect first.