Background: Pain management following cesarean section remains a challenge, with many puerpera suffering from severe acute postoperative pain. And for a second cesarean section the degree of uterine contraction pain is more severe and frequent than that of a primipara. This study investigated the effect of different doses of nalbuphine combined with sufentanil for postoperative analgesia in patients undergoing a second cesarean section.
Methods: We prospectively recruited 168 women with a scarred uterus undergoing elective second cesarean section and they were randomly divided into 4 groups by random number extraction. A single intravenous injection of different doses of nalbuphine was given before the intravenous drip of oxytocin, and visual analogue scale (VAS) scores of uterine contraction pain were recorded 10 minutes before intravenous infusion of oxytocin (T1) and 10 minutes (T2), 30 minutes (T3), and 60 minutes (T4) after intravenous infusion of oxytocin. At 4, 8, 12, 24, and 48 hours after patient-controlled intravenous analgesia (PCIA), pain intensity was reassessed using the VAS score.
Results: One hundred and sixty patients underwent elective second cesarean section in between December 2020 and May 2021 completed the study. The VAS scores of uterine contractions at T1 and T4 were 3 (1.0), while the VAS scores at T2 and T3 were 7 (1.0), 6 (1.0), 5 (1.0), 5 (1.0) and 8 (1.0), 5 (2.0), 3 (1.0), 3 (0.75). The VAS scores at 12 hours after surgery of nalbuphine10mg and sufentanil (NS1), nalbuphine 10 mg and sufentanil 20 mg (NS2) and nalbuphine 30 mg and sufentanil 20 mg (NS3) were lower than sufentanil (S) group (P<0.001). Compared with the S group, total amount of sufentanil and PCIA compression numbers in the NS1, NS2, and NS3 groups at 4-8 and 8-12 hours after surgery decreased (P<0.001), with a more significant decrease in the NS2 and NS3 groups than in the NS1 group (P<0.001). The NS3 group had a significantly higher incidence of dizziness and sleepiness (P=0.02, P=0.001). Compared with the NS2 and NS3 groups, the incidence of respiratory depression in the S group was significantly higher (P=0.001).
Conclusions: A single intravenous injection of nalbuphine 20 mg 10 minutes before the infusion of oxytocin combined with sufentanil 2 µg/kg could be safely used for postoperative analgesia in patients undergoing a second cesarean section and could effectively inhibit uterine contractions induced by oxytocin and reduce adverse reactions.
Trial registration: Clinical Trial Registry ChiCTR2100042382.
Keywords: Analgesic effect; nalbuphine; scarred uterus; second cesarean section; sufentanil.