Comparison of three modes of patient-controlled epidural analgesia during labour

Background and objectives: This study compares three modes of patient-controlled epidural analgesia in parturients during tabour. Methods: Eighty-four women were randomized to one of three groups. The epidural solution used in all the three groups was 0.1% bupivacaine with fentanyl 2 mu g mL(-1). Patients were able to self administer a demand dose of 3 mL with a lockout interval of 6 min in Group A, 6 mL with a lockout interval of 12 min in Group B and 9 mL with lockout interval of 18 min in Group C. All patients received a background infusion at a rate of 6 mLh(-1). Visual analogue pain scores, pinprick analgesia and motor block were assessed hourly by a blinded observer. The physician-administered supplementation and the cumulative dose of bupivacaine were also compared between the three groups. Results: Pain scores, sensory level and motor block were not different among the study groups. Patients' satisfaction was rated good to excellent with no difference among groups. The cumulative dose of bupivacaine was not significantly different. However, there was a trend towards a decreased need for rescue analgesia in Group C. Within each group, the physician-administered supplementations were significantly higher during the second stage of tabour than during the first stage (P < 0.05). Conclusion: The three modes of patient-controlled epidural analgesia supplemented by a background infusion of 6 mL h(-1) were equally effective for tabour analgesia with a trend for decreased rescue analgesia in the group with a larger bolus dose and a longer lockout interval.