Recovery Profiles After MOAA/S-Guided Remifentanil- Versus Fentanyl-Based Propofol Sedation for Gastrointestinal Endoscopy: An IPTW-Adjusted Retrospective Cohort Study.

Background/Objectives: In high-volume gastrointestinal (GI) endoscopy units, the choice of opioid adjunct may influence awakening, post-anesthesia care unit (PACU) utilization, concomitant sedative requirements, and early cardiorespiratory events. Remifentanil has a rapid and predictable offset, whereas fentanyl may produce more prolonged residual effects. We compared postanesthetic recovery after remifentanil- versus fentanyl-based propofol sedation in routine clinical practice. Methods: This single-center retrospective cohort study included adults undergoing elective upper GI endoscopy, colonoscopy, or combined procedures under anesthesiologist-directed propofol-based sedation between 1 July 2025 and 31 January 2026. Sedation was administered according to an institutional protocol targeting a Modified Observer's Assessment of Alertness/Sedation (MOAA/S) score of 2-3. Patients received either remifentanil or fentanyl as the opioid adjunct. The primary outcome was the interval from procedure completion to the first documented response to verbal command or purposeful awakening. Secondary outcomes included procedure and anesthesia durations, PACU length of stay, propofol and midazolam doses, and early respiratory and hemodynamic events. Stabilized inverse probability of treatment weighting (IPTW) was used to balance measured baseline characteristics. Results: Among 545 patients, 280 received fentanyl and 265 received remifentanil. All assessed covariates achieved acceptable balance after weighting. Median MOAA/S score was 2 [2-2] in both groups before and after IPTW adjustment, and target-range, deeper-than-target, and lighter-than-target MOAA/S categories did not differ significantly between groups. Weighted mean recovery time was shorter with remifentanil than with fentanyl (22.6 vs. 34.1 s; adjusted mean difference, -11.4 s; 95% CI, -13.4 to -9.5; p < 0.001). Remifentanil-based sedation was also associated with shorter procedure and anesthesia durations, shorter PACU length of stay, and lower propofol and midazolam doses; these findings remained significant after false discovery rate (FDR) adjustment. No respiratory, hemodynamic, or PACU adverse outcome differed significantly after multiplicity adjustment. Conclusions: Remifentanil-based propofol sedation was associated with shorter time to first purposeful response, shorter PACU stay, and lower concomitant sedative exposure than fentanyl-based sedation during routine GI endoscopy. Documented MOAA/S findings did not show a higher frequency of lighter-than-target clinically assessed sedation in the remifentanil group. These findings may reflect the combined contribution of remifentanil's rapid offset and lower concomitant sedative exposure, but they should be interpreted as associations within a clinician-directed sedation strategy. The retrospective, nonrandomized design precludes causal or safety-equivalence conclusions.