A randomised, double-blind comparison of subarachnoid and epidural diamorphine for elective caesarean section using a combined spinal-epidural technique

Abstract

We have compared the quality of analgesia and incidence of side-effects from subarachnoid and epidural diamorphine for caesarean section, as part of a combined spinal-epidural technique. Sixty patients were studied in a randomised, double-blind, double-dummy assessment. The doses of diamorphine reflect current practice in our hospital and are close to optimal. All patients received 13.25 mg subarachnoid bupivacaine and 37.5 mg epidural bupivacaine. In addition, patients in group 1 received 0.3 mg subarachnoid diamorphine and patients in group 2 received 3 mg epidural diamorphine. All patients were premedicated with ranitidine 150 mg and metoclopramide 10 mg and after surgery received diclofenac regularly and co-dydramol as needed. The duration and quality of analgesia, assessed by verbal rating score, was the same in the two groups. The incidence and severity of pruritus were higher (P< 0.005) in group 1. Postoperative nausea and vomiting were uncommon; 83% of patients in group 1 and 77% in group 2 had none. Subarachnoid and epidural diamorphine provided similar quality analgesia with a low incidence of emetic symptoms. However, pruritus was more common and more severe after subarachnoid diamorphine.