The Assessment of Immediate Postoperative Delirium in Neurologically Intact Adult Patients Admitted to the Post-anesthesia Care Unit: A Cross-Sectional Study

Background Immediate postoperative delirium (IPD) in the post-anesthesia care unit (PACU) can cause significant morbidity affecting everyday activities and length of stay with cost implications. This study was undertaken to find the proportion of IPD in PACU and its association with anesthesia and other perioperative factors. Methods After obtaining ethical approval and informed consent, this cross-sectional study was conducted in the PACU. A total of 600 consecutive adult patients (American Society of Anesthesiologists (ASA) 1-3) posted for surgery were approached between January and March 2019, of which 402 patients without neurological diseases and language and hearing discrepancies were studied. All patients had the intervention of surgery under anesthesia in a usual manner. Delirium was assessed preoperatively, postoperatively at 15 and 30 minutes, and before discharge from the PACU. IPD was assessed using the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) score, while sedation/agitation was assessed using the Richmond Agitation-Sedation Scale (RASS). The primary outcomes were the proportion of IPD, association with anesthesia, and perioperative risk factors. The secondary outcomes were the length of stay, delirium treatment, and mortality. Results Overall, the IPD proportion was 14.7%. A significant association was demonstrated with premedication with midazolam (odds ration (OR): 3.2; 95% confidence interval (CI): 1.42-7.35; P=0.003), general anesthesia (GA) (OR: 6.3; 95% CI: 2.23-17.8; P<0.001), duration of anesthesia (126 versus 95 minutes; P=0.001), laparoscopic mode of surgical access (OR: 3.4; 95% CI: 1.8-6.4; P<0.001), and postoperative RASS >/< 0 (OR: 10.6; 95% CI: 4.69-24.11; P<0.001) at 30 minutes and before discharge from the PACU. Multivariate analysis showed the strongest association of RASS at 30 minutes with IPD. Conclusion The proportion of IPD was found to be 14.7% in this study, and the chances of developing IPD are high if the patient is not awake and calm in the PACU, especially if midazolam is administered as premedication, followed by general anesthesia (GA) for a long duration.