Emergence delirium in adults in the post-anaesthesia care unit

Background. Emergence delirium in the post-anaesthesia care unit (PACU) is poorly understood. The goal of this prospective study was to determine frequency and risk factors of emergence delirium in adults after general anaesthesia. Methods. In this prospective study, 1359 consecutive patients were included. Contextual risk factors and occurrence of delirium according to the Riker sedation scale were documented. Groups were defined for the analysis according to the occurrence or not of agitation, then after exclusion of patients with preoperative anxiety and neuroleptics, or both, and antidepressants or benzodiazepines treatments. Results. Sixty-four (4.7%) patients developed delirium in the PACU, which can go from thrashing to violent behaviour and removal of tubes and catheters. Preoperative anxiety was not found to be a risk factor. Preoperative medication by benzodiazepines (OR=1.910, 95% CI=1.101-3.315, P=0.021), breast surgery (OR=5.190, 95% CI=1.422-18.947, P=0.013), abdominal surgery (OR=3.206, 95% CI=1.262-8.143, P=0.014), and long duration of surgery increased the risk of delirium (OR=1.005, 95% CI=1.002-1.008, P=0.001), while a previous history of illness and long-term treatment by antidepressants decreased the risk (respectively, OR=0.544, 95% CI=0.315-0.939, P=0.029 and OR=0.245, 95% CI=0.084-0.710, P=0.010). Conclusions. Preoperative benzodiazepines, breast and abdominal surgery and surgery of long duration are risk factors for emergence delirium.