Feedback-Regulated versus Constant-Rate Sufentanil Patient-Controlled Analgesia for Postoperative Nausea and Vomiting After Laparoscopic Myomectomy: A Randomized Controlled Trial

Background: Postoperative nausea and vomiting (PONV) remains a common and distressing side effect of opioid-based patient-controlled analgesia (PCA). Although continuous background infusion stabilizes analgesia, it often induces excessive opioid exposure and related adverse events. This study evaluates a novel smart PCA system featuring feedback-regulated background infusion (FRBI) designed to dynamically adjust opioid delivery based on real-time pain feedback, aiming to reduce PONV without compromising analgesia. Methods: In this prospective, randomized, controlled, single-center trial, 132 patients undergoing laparoscopic myomectomy were assigned in a 1:1 parallel-group design to either constant-rate background infusion (CRBI) at 2 mL/h (Group A) or FRBI with adjustable rates of 1– 4 mL/h (Group B). Both groups received a standardized sufentanil–flurbiprofen solution via PCA. The FRBI algorithm dynamically adjusted the infusion rate: a 20% increase was triggered by ≥ 2 bolus demands within 30 minutes, and a 20% decrease followed 4 consecutive demand-free hours. The primary outcome was the incidence of PONV (defined as nausea and/or vomiting) within 48 hours postoperatively. Secondary outcomes included pain scores (NRS), total opioid consumption, occurrence of other adverse events, and patient satisfaction. Results: The FRBI group demonstrated a significantly lower incidence of PONV (nausea and/or vomiting) compared to the CRBI group (41.7% vs 62.7%, risk difference: − 21.0% [95% CI: − 38.1% to − 3.9%]; risk ratio: 0.66 [95% CI: 0.46 to 0.96], P = 0.022). Total sufentanil consumption was reduced by approximately 30% in the FRBI group (P < 0.01). Pain scores were comparable between groups at all time points. Patient satisfaction was significantly higher in the FRBI group (P < 0.01). No cases of respiratory depression were observed in either group. Conclusion: The feedback-regulated background infusion mode significantly reduces the incidence of PONV and total opioid consumption while maintaining effective analgesia in patients undergoing laparoscopic myomectomy. This strategy suggests a favorable safety profile in this specific surgical population and may represent a promising strategy for opioid-sparing analgesia. Further studies are needed to validate these findings in broader patient populations and to assess economic feasibility. Keywords: patient-controlled analgesia, feedback-regulated infusion, postoperative nausea and vomiting, opioid reduction, smart pump, laparoscopic myomectomy