Comparison of different hydromorphone bolus doses in patient-controlled intravenous analgesia for post-laparoscopic surgery: a randomized controlled trial

Purpose: This study aimed to evaluate the analgesic efficacy and safety profile of varying bolus doses of hydromorphone administered via patient-controlled intravenous analgesia (PCIA) in patients undergoing laparoscopic surgery. Patients and methods: In this randomized controlled trial, 111 patients undergoing laparoscopic surgery were randomly allocated into three groups, each receiving hydromorphone PCIA without background infusion. The groups differed by bolus dose: Group A (0.20 mg, n = 39), Group B (0.25 mg, n = 34), and Group C (0.30 mg, n = 38). All PCIA solutions consisted of hydromorphone with same concentration (10 mg diluted in 100 mL normal saline, concentration 0.1 mg/mL), with a lockout interval of 10 min. VAS scores for pain at rest and during activity at 24 h postoperatively were assessed as the primary endpoint measures. Secondary outcomes included pain intensity at rest and during activity at other time points (PACU admission, and 4, 8, 12 h postoperatively), bolus frequency, cumulative hydromorphone consumption, catheter removal time, recovery indices (time to first flatus, oral intake, ambulation), vital signs (oxygen saturation, MAP, heart rate, respiratory rate), and postoperative adverse events (postoperative nausea and vomiting [PONV], pruritus, dizzy and respiratory depression). Results: There were no significant differences among the three groups in VAS scores at rest and during activity at 24 h postoperatively. Similarly, VAS scores at rest and during activity at PACU, 4, 8, and 12 h after surgery did not differ significantly among groups. The frequency of bolus administration was significantly higher in Group A compared to Groups B and C (P = 0.002). No significant differences were observed in total hydromorphone consumption, catheter removal time, bowel function recovery, or other recovery parameters. Although the differences were not statistically significant, the incidence of postoperative adverse events—including nausea and vomiting, pruritus, and dizziness-was lowest in Group B. No cases of respiratory depression occurred in any group. Conclusion: Hydromorphone PCIA at bolus doses of 0.20 mg, 0.25 mg, and 0.30 mg provided equivalent analgesic effectiveness in patients following laparoscopic surgery. The 0.20 mg dose group exhibited higher bolus administration frequency, whereas the 0.25 mg dose demonstrated the lowest incidence of adverse events, suggesting an optimal balance between analgesic efficacy and side-effect profile. © The Author(s) 2025.