Efficacy and safety of opioid analgesia with hydromorphone combined with nalbuphine in patient-controlled intravenous analgesia following cesarean section: A retrospective cohort study

Abstract: Background: Cesarean section serves as a widely employed surgical procedure in obstetric care. Intraoperative tissue trauma and postoperative uterine contractions are prone to cause moderate to severe acute pain. Effective postoperative analgesia can alleviate maternal suffering and promote physical recovery. Currently, strong opioids are widely used for postoperative intravenous analgesia, but the efficacy and safety of single drugs and multi-drug combinations for postoperative intravenous analgesia remain to be explored. Objectives: This study was conducted to assess the analgesic efficacy and safety of hydromorphone combined with nalbuphine versus hydromorphone monotherapy in patient-controlled intravenous analgesia (PCIA) following cesarean section, to optimize the analgesic protocol for clinical application. Methods: Based on retrospective medical records, parturients meeting the inclusion criteria were assigned to either the combination group (hydromorphone + nalbuphine, n=162) or the control group (hydromorphone alone, n=162) according to their postoperative PCIA regimens. Primary and secondary outcome indicators were compared between the two groups. Primary indicators included Visual Analog Scale (VAS) scores at 2 h, 6 h, 12 h, 24 h and 48 h postoperatively, as well as PCIA button-pressing times. Secondary indicators encompassed Ramsay Sedation Scale scores at 2 h, 6 h, 12 h, 24 h and 48 h postoperatively, the incidence of analgesia-related adverse reactions (such as nausea, vomiting, dizziness, pruritus and respiratory depression) and patient satisfaction levels. Results: The combination group achieved significantly lower VAS scores than the control group at all time points (p≤0.001), fewer PCIA presses (p<0.001) and slightly higher Ramsay Sedation Scale scores (p＜0.05), all maintaining within 2-4 points (optimal sedation range). The incidence of common adverse reactions was markedly decreased (32.1% vs 50.0%, p<0.001) and the satisfaction rate was higher (82.7% vs 65.4%, p<0.001). Conclusion: Hydromorphone combined with nalbuphine exerts synergistic analgesic effects, with a lower incidence of adverse reactions and higher satisfaction. This optimized regimen is safe and worthy of clinical promotion