Double-blind comparison of epidural diamorphine and intramuscular morphine after elective caesarean section, with computerised analysis of continuous pulse oximetry.

A randomised, double-blind comparison of the efficacy, duration of action and side effects of two analgesic regimens following elective epidural Caesarean section is described. Patients received epidural diamorphine 3 mg or intramuscular morphine 10 mg in the immediate postoperative period. Time to next analgesia was longer after epidural diamorphine (11.0 hours) compared to intramuscular morphine (6.5 hours) (p less than 0.05). In addition, a greater number of patients in the diamorphine group had a pain score less than 2.5 cm at 5 hours (p less than 0.05). However, more patients in the diamorphine group required catheterisation and suffered emetic sequelae, whereas more patients in the morphine group were sedated at 8 hours. Ten patients in each group had continuous pulse oximetry performed overnight after administration of the trial medications. Neither group demonstrated evidence of hypoxia.