A comparison of epidural diamorphine with intravenous patient-controlled analgesia using the Baxter infusor following caesarean section.

In a randomised study of analgesia following Caesarean section, we compared the efficacy and side effects of on-demand epidural diamorphine 2.5 mg with intravenous patient-controlled analgesia using diamorphine from the Baxter infusor system. Pain scores fell more rapidly in the epidural group, but by the fourth hour, and thereafter, both techniques had a similar analgesic effect. The patient-controlled analgesia group used significantly more diamorphine (p < 0.001), median 62 mg (range 18-120 mg) compared to the epidural group, median 10 mg (range 2.5-20 mg), over a significantly longer time period (p < 0.001), median 54.25 h (range 38-68 h) compared to the epidural group, median 40.75 h (range 6-70 h). The frequency and severity of nausea, vomiting and pruritus were similar in the two groups, however, the patient-controlled analgesia group were more sedated during the first postoperative day. This reached statistical significance (p < 0.05) between 9-24 h. Overall satisfaction scores (0-100) were high, but the patient-controlled analgesia group scored significantly higher: mean 85.5 (SD 12.2) compared to mean 77.0 (SD 11.7) in the epidural group.