Analgesic effects of different patient-controlled intravenous analgesia infusion modes post cesarean section under multimodal analgesia: a retrospective cohort study.

Background: Background infusion is frequently employed in postoperative patient controlled intravenous analgesia. This study aimed to compare the analgesic efficacy of patient-controlled intravenous analgesia with and without background infusion for parturients receiving multimodal analgesia incorporating liposomal bupivacaine transversus abdominis plane block post cesarean delivery. Methods: A total of 250 parturients who underwent elective cesarean section with multimodal postoperative analgesia between January 2025 and December 2025 were divided into background infusion and no background infusion group. Parturients received epidural hydromorphone, bilateral transversus abdominis plane block with 266 mg liposomal bupivacaine and routine oral acetaminophen. Patient controlled intravenous analgesia settings differed in background infusion (1.0 vs. 0 ml/h), with the same bolus (2.0 ml) and lockout interval (10 min); the solution contained oxycodone or hydromorphone. Patient controlled analgesia demands, intravenous morphine equivalent dose of opioids, rest/ambulation pain scores, adverse reactions and analgesic effect were compared. Results: No significant differences were found in patient-controlled analgesia demands during 0-24 h (3 [0, 6] vs. 2 [1, 6], Conclusion: In parturients receiving multimodal analgesia consisting of transversus abdominis plane block with liposomal bupivacaine, epidural hydromorphone and routine oral acetaminophen, the addition of background infusion to patient-controlled intravenous analgesia failed to enhance analgesic efficacy and increased opioid exposure. Patient-controlled intravenous analgesia without background infusion may be considered in such cases.