Comparison of ropivacaine 0.1%-fentanyl and bupivacaine 0.125%-fentanyl infusions for epidural labour analgesia

Purpose: To compare analgesic efficacies of ropivacaine-fentanyl and bupivacaine-fentanyl infusions for labour epidural analgesia. Methods: In this double-blind, randomized study 100, term, nulliparous women were enrolled, Lumbar epidural analgesia (LEA) was started at cervical dilatation < 5 cm using either bupivacaine 0.25% followed by bupivacaine 0.125% + 2 mu g.ml(-1) fentanyl infusion (n=50) or ropivacaine 0.2% followed by ropivacaine 0,1% + 2 mu g.ml(-1) fentanyl infusion (n=50). Every hour maternal vital signs, visual analog scale (VAS) pain score, sensory levels, and motor block (Bromage score) were assessed. Data were expressed as mean +/- 1 SD and analyzed using Chi-Squared and Mann-Whitney U tests at < 0.05, Results: The onset times were 10.62 +/- 4.9 and 11.3 +/- 4.7 min for the bupivacaine and ropivacaine groups respectively (P = NS). The median VAS scores were not different between the groups at any of the evaluation periods. However, at least 80% of patients in the ropivacaine group had no demonstrable motor block after the first hour compared with only 55% of patients given bupivacaine (P = 0.01). Conclusions: Both bupivacaine and ropivacaine produce satisfactory labour analgesia. However, ropivacaine infusion is associated with less motor block throughout the first stage of labour and at 10 cm dilatation.