SummaryThe analgesic eficacy .f subcutaneous wound injiltration with 20 ml of0.5% bupivacaine after elective lower segment section Cuesarean section was studied in 28 patients in a double-blind randomised controlled manner using a patient-controlled analgesia system. The mean 24-hour morphine consumption of the placebo group and the bupivacaine group was similar (76 mg and 68 mg respectively Key wordsPain, postoperative; patient controlled analgesia. Anaesthetics, local; bupivacaine. Anaesthetic techniques, regional; wound infiltration.The beneficial analgesic effect of subcutaneous wound edge infiltration using bupivacaine has been demonstrated following herniotomy in children and after excision of benign breast lumps.'.* However, the beneficial effects are less clear after upper abdominal surgery; reduction in opioid requirement after cholecystectomy has been demonstrated after infiltration of the peritoneum, muscle and subcutaneous tissues, but not after subcutaneous infiltration a l~n e .~.~ The opioid-sparing effect of subcutaneous wound infiltration with local anaesthetic agents has not been assessed previously after lower abdominal operations in adults, with the exception of herniorrhaphy. Patients undergoing Caesarean section mobilise early and would benefit from a technique which reduces opioid requirements and the incidence of related side-effects, and improves analgesia. Lower segment Caesarean section is performed routinely through a Pfannenstiel incision and is suitable, therefore, for the investigation of supplementary local anaesthetic techniques.The purpose of this study was to assess the value of subcutaneous wound edge infiltration with bupivacaine after elective Caesarean section under general anaesthesia. Analgesia was assessed by reference to the use of intravenous boluses of morphine delivered by a patientcontrolled analgesia system. MethodTwenty-eight patients scheduled for elective Caesarean section under general anaesthesia were investigated in a double-blind, randomised trial. Each patient was visited pre-operatively and familiarised with the use of the PCAS. Patients gave informed consent and the study was approved by the District Ethics Committee. Patients were not studied if they were unable to comprehend the nature of the assessments or the purpose of the PCAS, gave a history of sensitivity to opioids or local anaesthetics or had severe pre-eclampsia or severe hypertension of pregnancy. Premedication comprised ranitidine 150 mg orally administered on the evening before and on the morning of surgery and 30 ml sodium citrate 0.3 molar given orally immediately before induction of anaesthesia. Intravenous access was established and anaesthesia induced with a sleep dose of methohexitone followed by suxamethonium 1-1.5 mg/kg to facilitate tracheal intubation. Anaesthesia was maintained with 50% N,O in 0, and supplemented with enflurane 1 %. Muscle relaxation was accomplished with atracurium 0.5 mg/kg. The Fro, at delivery was reduced to 0.3, and morphine 5-10 mg and syntocinon 10 IU wer...