Epidural labor analgesia: A comparison of ropivacaine 0.125% versus 0.2% with fentanyl

Background: Minimum effective concentration of local anesthetics for providing optimal labor epidural analgesia and the strategies aiming to reduce their consumption are continuously being searched. Objectives: The objective of this study was to evaluate the efficacy of 0.125% and 0.2% ropivacaine both mixed with fentanyl 2 mcg/ml for epidural labor analgesia. Materials and Methods: A total of 80 parturients in active labor were randomly assigned to two groups of 40 each, to receive an epidural injection of 15 ml ropivacaine 0.125% with fentanyl (2 mcg/ml) in group R1 and 15 ml of ropivacaine 0.2% with fentanyl (2 mcg/ml) in group R2 as initial bolus dose. Same dose regimen was used as subsequent top-up dose on patients demand for pain relief. The duration and quality of analgesia, motor block, top-up doses required consumption of ropivacaine and fentanyl and feto-maternal outcome in both groups were compared. Results: Effective labor analgesia with no motor blockade was observed in both groups with no failure rate. Onset of analgesia was significantly faster in group R2 (75% parturients in 0-5 min) as compared to group R1 (25% parturients in 0-5 min), P < 0.001. Duration of analgesia after initial bolus dose was also significantly longer in group R2 (132 ± 56.81 min) than in group R1 (72.25 ± 40.26 min), P < 0.001. Mean VAS scores were significantly less in group R2 than in group R1 at 5, 60, and 90 min, P < 0.01. Requirement of top-up doses was significantly less in group R2 (0.05 ± 0.22) as compared to group R1 (0.80 ± 0.65), P < 0.001. Consumption of ropivacaine was comparable in both the groups (33.75 ± 12.16 mg in group R1 and 31.50 ± 6.62 mg in group R2 P > 0.05), but consumption of fentanyl was significantly more in group R1 (54.00 ± 19.45) as compared to group R2 (31.50 ± 6.62), P < 0.001. There were no significant changes in hemodynamics, nor adverse effects related to neonatal or maternal outcomes in both groups. Conclusion: We conclude that both the concentrations of ropivacaine (0.2% and 0.125%) with fentanyl are effective in producing epidural labor analgesia. However, 0.2% concentration was found superior in terms of faster onset, prolonged duration, lesser breakthrough pain requiring lesser top-ups, and hence a lesser consumption of opioids.