Summary The postoperative respiratory and analgesic effects of dexmedetomidine and morphine have not been compared in children with sleep apnoea having adenotonsillectomy. In a randomised double‐blind study we recruited 60 children, aged 2–13 years, who received either intravenous dexmedetomidine 1 μg.kg−1 or morphine 100 μg.kg−1 on anaesthetic induction. End‐tidal carbon dioxide, Children’s Hospital of Eastern Ontario Pain Scale score and supplementary morphine administration were recorded every 15 min for 60 min postoperatively. Over 60 min, mean (SD) end‐tidal carbon dioxide was consistently lower with dexmedetomidine compared with morphine (5.4 (0.7) kPa vs 6.0 (0.6) kPa, respectively; p = 0.001). Mean (SD) pain scores were higher with dexmedetomidine (8.1 (2.0) immediately postoperatively and 6.7 (1.0) at 60 min vs 7.6 (1.8) and 6.3 (0.7), respectively, with morphine (p = 0.023)). More patients required supplementary morphine with dexmedetomidine (13/30 (43%) vs 21/30 (70%); p = 0.037). Postoperatively, dexmedetomidine produced less respiratory depression than morphine, but less effective analgesia. You can respond to this article at http://www.anaesthesiacorrespondence.com

Purpose: Patient-controlled intravenous analgesia (PCIA) is an option for pain cesarean section analgesia. However, the effect of a background infusion on the analgesic requirements of parturients is still debated. In order to attempt to identify the optimal cesarean section analgesia infusion regime, we evaluated the benefit of the background infusion in this randomized study.Patients and methods: 60 Parturients had a PCIA analgesia protocol initiated consisting of a 0.5mL bolus, and compared 2 Groups: no background infusion, 6 min lockout time (Group A). 2 mL/h infusion, 10 min lockout time (Group B). The total amount of sufentanil consumed, two categories of pain scores, sedation score, postpartum hemorrhage, Injection/attempt (I/A) ratio, side effects, satisfaction were calculated for both groups.Results: Group B significantly reduce visual analog scale（VAS）pain scores 6, 12h. Group A and Group B were not significantly different regarding wound pain at rest (VAS-R) and uterine cramping pain (VAS-U) at postoperative 24, 36 hours. In terms of I/A, Group A was lower than Group B, there was no significant difference. Group B showed significantly higher satisfaction than Group A. Total consumption of sufentanil at 36 hours postoperative was much greater in Group B. Group B can significantly reduce the postpartum hemorrhage within 1 hour. The minimal respiration rates were not significantly different among groups. The side effect were not observed among groups. All parturients had the same Ramsey sedation score.Conclusion: In comparison with the without background infusion, total consumption of sufentanil at 36 hours postoperative was much greater in the background infusion, but it can significantly reduce the uterine contraction pain and wound pain of 12 hours after cesarean section, significantly improve patient satisfaction, reduce the postpartum hemorrhage within 1 hour, and does not increase the incidence of PONV and respiratory depression in parturients.

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