Postoperative Delirium is Associated with Postoperative Cognitive Dysfunction at One Week after Cardiac Surgery with Cardiopulmonary Bypass

Postoperative delirium with cognitive impairment frequently occurs after cardiac surgery. It was hypothesized that delirium is associated with residual postoperative cognitive dysfunction in patients after surgery using cardiopulmonary bypass. Male cardiac surgical patients (M age = 66 yr., SD = 8; M education = 13 yr., SD = 2) and nonsurgical controls (M age = 62, SD = 7; M education = 12, SD = 2) 55 years of age or older were balanced on age and education. Delirium was assessed by the Intensive Care Delirium Screening Checklist preoperatively and for up to 5 days postoperatively. Recent verbal and nonverbal memory and executive functions were assessed (as scores on particular tests) before and 1 wk. after surgery. In 56 patients studied (n = 28 Surgery; n=28 Nonsurgery), nine patients from the Surgery group developed delirium. In the Surgery group, the proportion of patients having postoperative cognitive dysfunction was significantly greater in those who experienced delirium (89%) compared with those who did not (37%). The odds of developing this dysfunction in patients with delirium were 14 times greater than those who did not. Postoperative delirium is associated with scores for residual postoperative cognitive dysfunction 1 wk. after cardiac surgery.