Perioperative risk factors for recovery room delirium after elective non-cardiovascular surgery under general anaesthesia

Background Although postoperative delirium is a frequent complication of surgery, little is known about risk factors for delirium occurring in the post-anaesthesia care unit (PACU). The aim of this study was to determine pre- and intraoperative risk factors for the development of recovery room delirium (RRD) in patients undergoing elective non-cardiovascular surgery. Methods RRD was diagnosed according to the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU). We collected perioperative data in 228 patients undergoing elective non-cardiovascular surgery under general anaesthesia and performed univariate and multivariate logistic regression to identify risk factors related to RRD. PACU and postoperative events were recorded to assess the outcome of RRD. Results Fifty-seven patients (25%) developed RRD. On multivariate analysis, maintenance of anaesthesia with inhalation anaesthetic agents (OR = 6.294, 95% CI 1.4-28.8, corrected p = 0.03), malignant primary disease (OR = 3.464, 95% CI = 1.396-8.592, corrected p = 0.018), American Society of Anaesthesiologists Physical Status (ASA-PS) III-V (OR = 3.389, 95% CI = 1.401-8.201, corrected p = 0.018), elevated serum total or direct bilirubin (OR = 2.535, 95% CI = 1.006-6.388, corrected p = 0.049), and invasive surgery (OR = 2.431, 95% CI = 1.103-5.357, corrected p = 0.035) were identified as independent risk factors for RRD. RRD was associated with higher healthcare costs (31,428 yuan [17,872-43,674] versus 16,555 yuan [12,618-27,788], corrected p = 0.002), a longer median hospital stay (17 days [12-23.5] versus 11 days [9-17], corrected p = 0.002), and a longer postoperative stay (11 days [7-15] versus 7 days [5-10], corrected p = 0.002]). Conclusions Identifying patients at high odds for RRD preoperatively would enable the formation of more timely postoperative delirium management programmes.