Risk factors for postoperative delirium after colorectal operation.

Background. A clear understanding of risk factors for postoperative delirium helps in the selection of individuals who might benefit from targeted perioperative intervention. The aim of this study was to identify risk factors for postoperative delirium after colorectal operation for malignancy. Methods. All consecutive patients who underwent elective or emergency operation because of malignancy of the colon, sigmoid, or rectum between 2009 and 2012 were included in this study. Potential risk factors for postoperative delirium were selected based on previous studies. These candidate factors were analyzed using univariate and multivariate logistic regression analysis. Based on this analysis, odds ratios and 95 % confidence intervals were estimated. Results. A total of 436 patients underwent an oncologic resection of the colon, sigmoid, or rectum. Postoperative delirium was observed in 45 (10.3 %) patients. Patients with a delirium had a greater in-hospital mortality rate (8.9% vs 3.6 %, P = .09), spent more days in the intensive care unit, and had a longer total hospital stay. Variables associated with postoperative delirium in univariate analyses were age, American Society of Anesthesiologists classification, blood transfusion, history of psychiatric disease, history of cerebrovascular disease, postoperative pain management, postoperative renal impairment, C-reactive protein levels, leukocyte blood count, and postoperative complications. Independent risk factors were history of psychiatric disease (odds ratio 8.38, 95% confidence interval: 1.50-46.82), age (odds ratio 4.01, 95 % confidence interval; 1.55-10.37), and perioperative blood transfusion (odds ratio 2.37, 95% confidence interval; 1.11-5.06). Conclusion. This study shows that postoperative delirium is a frequently encountered complication after colorectal operation. Three independent risk factors for postoperative delirium were identified (history of psychiatric disease, age, and perioperative transfusion) that may contribute to risk estimation in this patient population.