Risk factors for postoperative delirium in patients after coronary artery bypass grafting: A prospective cohort study

This study was designed to identify the incidence and independent perioperative risk factors associated with postoperative delirium of patients who underwent coronary artery bypass grafting (CABG) in a large intensive care unit setting in China.

Delirium was diagnosed by the confusion assessment method for the intensive care unit (CAM-ICU). Baseline demographics, perioperative data, and postoperative outcomes of 249 consecutive patients who underwent CABG were recorded prospectively and analyzed via univariate analysis and multivariate logistic regression to determine the independent risk factors of postoperative delirium.

Postoperative delirium was detected in 76 patients according to CAM-ICU criteria. The incidence was 30.52%. Patients with and without delirium differed significantly on 34 variables (P < .05). Multivariate logistic regression analysis revealed that preoperative atrial fibrillation (odds ratio [OR], 3.957; 95% confidence interval [CI], 1.727-9.066), elevated European system for cardiac operative risk evaluation (OR, 1.178; 95% CI, 1.018-1.364), cognitive impairment (OR, 3.231; 95% CI, 1.008-10.356), prolonged surgery duration (OR, 1.008; 95% CI, 1.003-1.014), postoperative poor quality of sleep (OR, 5.001; 95% CI, 2.476-10.101), and electrolyte disturbance (OR, 2.095; 95% CI, 1.041-4.216) were independently associated with postoperative delirium after CABG.

Delirium is a frequent complication. Factors independently associated with delirium are preoperative atrial fibrillation, elevated European system for cardiac operative risk evaluation and cognitive impairment, longer surgery duration, postoperative poor quality of sleep, and electrolyte disturbance. The study may be helpful in decreasing the incidence of postoperative delirium after CABG by treating these predictors properly.