Incidence and risk factors of delirium in critically ill patients after non-cardiac surgery

<正> Background Delirium is a common and deleterious complication in critically ill patients after surgery. The purpose ofthis study was to determine the incidence and risk factors of delirium in critically ill patients after non-cardiac surgery, andto investigate the relationship between the serum Cortisol level and the occurrence of postoperative delirium.Methods In a prospective cohort study, 164 consecutive patients who were admitted to the surgical intensive care unitafter non-cardiac surgery were enrolled. Baseline characteristics and perioperative variables were collected. Bloodsamples were obtained on the first postoperative day and serum Cortisol concentrations were measured. Delirium wasassessed using the Nursing Delirium Screening Scale until the seventh postoperative day or the disappearance ofdelirious symptoms.Results Postoperative delirium occurred in 44.5% of patients (73 of 164). The median time to first onset of delirium is 0(range 0 to 5 days) and the median duration of delirium is 3 (1 to 13) days. Independent risk factors of postoperativedelirium included increasing age (odds ratio (OR) 2.646, 95% confidence interval (CI) 1.431 to 4.890, P=0.002), a historyof previous stroke (OR 4.499, 95%CI 1.228 to 16.481, P=0.023), high Acute Physiology and Chronic Health Evaluation IIscore on surgical intensive care unite admission (OR 1.391, 95%CI 1.201 to 1.612, P<0.001), and high serum Cortisollevel on the 1st postoperative day (OR 3.381, 95%CI 1.690 to 6.765, P=0.001). The development of delirium was linkedto higher incidence of postoperative complications (28.8% vs. 7.7%, P<0.001), and longer duration of hospitalization (18(7 to 74) days vs. 13 (3 to 48) days, P <0.001).Conclusions Delirium was a frequent complication in critically ill patients after non-cardiac surgery. High serum Cortisollevel was associated with increased incidence of postoperative delirium.