Comparison of ropivacaine and bupivacaine for epidural analgesia during labor]

OBJECTIVES: To compare the analgesic efficacy and level of motor block using two local anesthetics, ropivacaine and bupivacaine, during labor. MATERIAL AND METHODS: Sixty nulliparous women were enrolled during labor after full-term pregnancies. They were randomly assigned to receive epidural analgesia with ropivacaine (group R) or bupivacaine (group B). Group R patients received 10 ml of 0.18% ropivacaine with 5 microgram/ml of fentanyl followed by continuous epidural infusion of 0.1% ropivacaine with 2 microgram/ml of fentanyl at a rate of 10 ml/h. Group B patients received 10 ml of 0.15% bupivacaine with 5 microgram/ml of fentanyl followed by continuous epidural perfusion of 0.0625% bupivacaine with 2 microgram/ml of fentanyl at the same rate. Pain intensity was assessed on a visual analog scale, motor blockade on a Bromage scale, and level of sensory block at different moments. We also recorded total doses of local anesthetic employed during continuous epidural infusion, manner of final delivery, Apgar score, degree of maternal satisfaction and side effects. RESULTS: The demographic and delivery characteristics were similar in both groups. We found no statistically significant differences between the two groups for level of motor blockade, which was nil for 29 patients (96.66%) in group R and 28 patients (93.33%) in group B. No differences in degree of pain or level of sensory block (T8-T10 in both groups) were observed.The total doses of local anesthetic used were similar at 23.7 +/- 11.6 mg in group R and 16.5 +/- 7.3 mg in group B (non-significant difference). Nor did we find differences in manner of delivery, neonatal Apgar scores, degree of maternal satisfaction or side effects. CONCLUSION: Ropivacaine and bupivacaine are equally effective for epidural analgesia during labor at the doses used and they do not cause a relevant level of motor blockade.