A Randomized Controlled Trial of Three Patient-Controlled Epidural Analgesia Regimens for Labor

BACKGROUND: Patient-controlled epidural analgesia (PCEA) is a safe and effective mode of maintaining labor analgesia; however, the ideal PCEA regimen is controversial. METHODS: In this prospective, randomized, double-blind study, we examined the analgesic efficacy of demand-only PCEA and PCEA with background infusion. We recruited 300 nulliparous parturients. Analgesia was initiated with intrathecal ropivacaine 2 mg and fentanyl 15 mu g and maintained with epidural ropivacame 0.1% with fentanyl 2 mu g/mL. Parturients were randomized to one of three groups. Group 0: demand-only PCEA, bolus of 5 mL, lockout interval of 15 min. Group 5: background infusion of 5 mL/h, bolus of 5 mL, lockout interval of 12 min. Group 10: background infusion of 10 mL/h, bolus of 5 mL, lockout interval of 10 min. The maximum dose of all groups was 20 mL/h. The primary outcome was incidence of breakthrough pain. Secondary outcomes included intrapartum pain scores, neuraxial blockade characteristics, side effects, the total and hourly volume of ropivacaine, neonatal outcomes, and obstetric outcomes. RESULTS: The incidence of breakthrough pain and the maximum visual analog scale (0-100 mm scale) pain scores were higher in Group 0 versus Groups 5 and 10 (43% vs 17% and 11%, P < 0.001 and 37 +/- 28 vs 22 +/- 26 and 16 +/- 25 [mean +/- SD], P < 0.001), respectively. Group 10 had a longer duration of effective analgesia compared with Group 0 (mean 895 min, 95% CI 823-966 vs 565 min, 95%, CI 454-677, P < 0.001) and increased ropivacaine consumption, and was associated with a longer duration of the second stage of labor. CONCLUSION: Demand-only PCEA (5-mL bolus, 15-min lockout interval) resulted in less local anesthetic consumption but an increased incidence of breakthrough pain, higher pain scores, shorter duration of effective analgesia, and lower maternal satisfaction, when compared with PCEA with background infusion (5-mL bolus, 10-12-min lockout interval, and 5-10 mL/h infusion).