Duration of fluid fasting and choice of analgesic are modifiable factors for early postoperative delirium

Background and objective Most therapeutic options for postoperative delirium are only symptom oriented; therefore, the best approach remains prevention. The aim of this study was to identify predisposing and precipitating factors for early postoperative delirium. Methods A total of 1002 patients were screened for delirium in an observational, cohort study. Nine hundred and ten patients were observed in the recovery room and 862 patients on the first postoperative day in the ward at the Charite - Universitaetsmedizin, Berlin. Delirium was measured with the nursing delirium screening scale. Risk factors were analysed in a multivariate analysis. Results Delirium was seen in 11.0% of the patients in the recovery room and in 4.2% of the patients on the ward. Delirium in the recovery room was associated with delirium on the ward (McNemar's test P = <0.001). Apart from age and site of surgery, we found the duration of preoperative fluid fasting to be a modifiable precipitating factor for delirium in the recovery room (odds ratio 2.69, 95% confidence interval 1.4-5.2) and on the ward (odds ratio 10.57, 95% confidence interval 1.4-78.6) and the choice of intraoperative opioid for delirium on the ward (odds ratio 2.27, 95% confidence interval 1.0-5.1). Conclusion Duration of preoperative fluid fasting and the choice of intraoperative analgesic are risk factors for postoperative delirium, and their modification provides a promising approach to reduce the incidence of postoperative delirium. Eur J Anaesthesiol 2010;27:411-416