Ambulatory labor epidural analgesia: Bupivacaine versus ropivacaine

Dilute concentrations of bupivacaine combined with fentanyl have recently b een used to initiate labor epidural analgesia in an attempt to balance adeq uate analgesia and minimal maternal motorblockade. Similar concentrations o f ropivacaine have not been evaluated. This prospective, randomized, double -blinded study was designed to compare the efficacy of 20 mL of either 0.08 % bupivacaine plus 2 mu g/mL fentanyl or 0.08% ropivacaine plus 2 mu g/mL f entanyl to initiate ambulatory labor epidural analgesia. Forty nulliparous women in early (less than or equal to 5 cm) established labor received eith er 20 mt of 0.08% bupivacaine plus 2 mu g/mL fentanyl (BF) or 0.08% ropivac aine plus 2 mu g/mL fentanyl (RF) to initiate epidural analgesia. One woman (BF) required supplemental analgesia, and two (one BF and one RF) had visu al analog scale scores > 0 but < 20 at 20 min. The time (mean +/-SD) to vis ual analog scale score = 0 was BF (n = 18):12.0 +/- 4.5 min and RF (n = 19) : 12.4 +/- 4.0 min (P > 0.05). Spontaneous micturition was observed in 65% (13 of 20) BF compared with 100% (20 of 20) RF (P < 0.01), and ambulation w as demonstrated in 75% (15 of 20) BF compared with 100% (20 of 20) RF (P < 0.03). The incidence of forceps delivery was 35% (7 of 20) BF compared with 10% (2 of 20) RF (P < 0.04). The results of this study indicate that dilut e ropivacaine combined with fentanyl effectively initiates epidural analges ia while concurrently preserving maternal ability to void and ambulate.