ABSTRACT
Objective To determine the optimum dose of nalbuphine prepared for patient-controlled intravenous analgesia (PCIA) after caesarean section.Methods A total of 100 parturients,aged 22-40 yr,weighing 60-90 kg,of American Society of Anesthesiologists physical status Ⅰ or Ⅱ,at ≥ 37 weeks of gestation,scheduled for elective caesarean section,were divided into 4 groups (n=25 each) using a random number table:sufentanil 2.0 μ,g/kg group (group S),nalbuphine 1.5 mg/kg group (group N1),nalbuphine 2.0 mg/kggroup (group N2,) and nalbuphine2.5 mg/kggroup (group N3).In S,N1,N2 and N3 groups,sufentanil 2.0 μg/kg and nalbuphine 1.5,2.0 and 2.5 mg/kg were added to PCIA solution,respectively,tropisetron 12 mg was added,and PCIA solution was then diluted to 100 ml in normal saline.The PCA pump was set up to deliver a 1 ml bolus dose with a 10-min lockout interval and background infusion at 2 ml/h after a loading dose of 3 ml.Tramadol 50 mg was intravenously injected as a rescue analgesic to maintain visual analogue scale score at rest ≤ 4 or during activity (cough) ≤ 6.The highest Ramsay sedation score,requirement for rescue analgesics,the number of unsuccessfully delivered doses,the number of attempts and occurrence of nausea and vomiting,pruritus and somnolence within 48 h after operation were recorded.Results Compared with group S,the number of unsuccessfully delivered doses,the number of attempts and requirement for rescue analgesics were significantly decreased in N2 and N3 groups,the incidence of somnolence and the highest Ramsay sedation scores were increased in group N3 (P＜0.05),and no significant change was found in the parameters mentioned above in group N1 (P＞ 0.05).Compared with group N1,the number of unsuccessfully delivered doses,the number of attempts and requirement for rescue analgesics were significantly decreased in N2 and N3 groups,and the incidence of somnolence and the highest Ramnsay sedation scores were increased in group N3 (P＜0.05).Compared with group N2,the incidence of somnolence and the highest Ramsay sedation scores were significantly increased (P＜0.05),and no significant difference was found in the number of unsuccessfully delivered doses,the number of attempts or requirement for rescue analgesics in group N3 (P＞0.05).Conclusion The optimum dose of nalbuphine prepared for PCIA after caesarean section is 2.0 mg/kg.