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

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.

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 < 0.05 was taken as statistically significant.

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.

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.