Early Postanesthesia Recovery Room Markers Associated With Delayed Respiratory Depression

Background Postoperative respiratory depression (PRD) is potentially preventable yet remains difficult to preemptively detect. We evaluated whether three post anesthesia care unit (PACU) events—oversedation, caffeine administration for impaired arousal, and naloxone administration—can serve as early markers of delayed PRD requiring naloxone administration on wards. Methods We retrospectively identified patients who underwent general anesthesia between 2018 and 2023 at a quaternary care academic medical center. From electronic medical records, we retrieved PACU naloxone and caffeine treatments, scores of sedation assessments using the Richmond Agitation-Sedation Scale (RASS), and ward naloxone administrations within 24 hours after PACU discharge. Results Among 95 870 patients, 186 (0.19%, 95% CI 0.17-0.22) required naloxone for respiratory depression after PACU discharge. Ward naloxone administration was independently associated with naloxone (OR 9.11, 95% CI 4.69-17.71, P < 0.001) and caffeine (OR 2.00, 95% CI 1.21-3.32, P = 0.007) administrations, and with PACU RASS scores ≤ −3 (OR 2.16, 95% CI 1.56-2.99, P < 0.001). Conclusions Naloxone administration in PACU was the strongest predictor of delayed PRD, followed by oversedation and PACU caffeine administration, indicating that information routinely collected during PACU recovery may offer insight into delayed respiratory risk before transition to hospital wards. In light of the overall low incidence of ward naloxone use, these findings support selective, risk-based vigilance for patients exhibiting these PACU events rather than broad adjustments to existing monitoring practices.