Comparison of three different concentrations of epidural ropivacaine (0.05%, 0.1% & 0.2%) for labor analgesia: A prospective randomized and double blind study

Introduction: Epidural infusion of 0.2% ropivacaine is recommended by the manufacturer for labor analgesia, but lower concentrations may be effective. The present work is a clinical comparative study of different doses of ropivacaine i.e. 0.05%, 0.1% and 0.2%, each with 2 mcg/mL of fentanyl to find out minimum effective concentration of ropivacaine that can be used safely in epidural labor analgesia. Materials and Methods: The study was conducted on sixty (60) parturient of ASA grade I and grade II physical status, in labor, with single fetus, vertex position, between 37-42 weeks gestation with regular contractions (true labor pain) with 4-6 cm cervix dilatation and who had requested labor analgesia. Parturients were then allocated randomly to one of three groups with 20 parturients in each group. Group 1 received 0.05% ropivacaine with 2 mcg/mL fentanyl, Group 2 received 0.1% ropivacaine with 2 mcg/mL fentanyl and Group 3 received 0.2% ropivacaine with 2 mcg/mL fentanyl. After completion of the study, the nonparametric data of the study was analyzed with Kruskal Wallis test and parametric data of the study was analyzed with ANOVA test and p value of Results: Patient demographics and labor characteristics were comparable in all the groups. Ropivacaine 0.05% with 2 mcg/mL of fentanyl produced adequate analgesia for labor and delivery in only 50% of parturient while ropivacaine 0.1% & ropivacaine 0.2% with 2 mcg/mL of fentanyl produced adequate analgesia in 90% of parturient in group II and group III. Reduction in local anesthetic was not associated with any change in incidence of motor block or instrumental deliveries. Conclusion: We concluded that the minimum concentration which can be used safely for labor analgesia with no adverse effect is 0.1% of ropivacaine with 2 mcg/mL fentanyl. Keywords: Epidural, Labor analgesia, Ropivacaine, Fentanyl.