Factors Associated with Postoperative Cognitive Dysfunction in Patients Undergoing Cardiac Surgery

Purpose Central nervous system complications continue to be major causes of morbidity and mortality after cardiac surgery. The purpose of this study was to identify the risk factors for postoperative cognitive dysfunction after coronary artery bypass graft (CABG) surgery. Methods Eighty-eight patients scheduled for elective CABG were studied. After the induction of anesthesia, a fiberoptic oximetry oxygen saturation catheter was inserted into the right jugular bulb for the continuous monitoring of jugular venous oxygen hemoglobin saturation (SjvO₂). The hemodynamic parameters and arterial and jugular venous blood gases were measured during cardiopulmonary bypass (CPB). All patients underwent a battery of neurological and neuropsychological tests one day before the operation and at 6 months after the operation. Results The incidence of a cognitive decline at 6 months was 24/88 (27.3%). Greater age (P = 0.04), the presence of renal failure (P < 0.001), and diabetes mellitus (P < 0.001) were more frequent in the patients with postoperative cognitive dysfunction at 6 months after the operation than in patients without cognitive dysfunction. Age (odds ratio [OR], 1.4; 95% confidence interval [CI], 1.0–1.7; P = 0.04), diabetes mellitus (OR, 1.8; 95% CI, 1.2–2.4; P < 0.01), and presence of renal failure (OR, 2.8; 95% CI, 2.4–4.3; P < 0.01) were associated with cognitive impairment at 6 months postoperatively. However, there was no relationship between the presence of atherosclerosis in the ascending aorta and postoperative cognitive dysfunction after CABG surgery. Conclusions A greater age, diabetes mellitus, and renal failure were found to be risk factors for development of cognitive impairment at 6 months after CABG with CPB.