Adjuvant Sufentanil Decreased the EC50 of Epidural Ropivacaine for Labor Analgesia in Healthy Term Pregnancy

Abstract

Objective

The optimal concentration of ropivacaine as epidural labor analgesia combined with sufentanil has not been established. This study aimed to determine the median effective concentration (EC50) of epidural ropivacaine for labor analgesia in healthy term pregnancy when co-administered with sufentanil as an adjuvant or alone.

Patients and Methods

Sixty healthy parturients scheduled for epidural labor analgesia were enrolled in the study. They were divided into a saline group (Group C) and an epidural sufentanil (0.5 µg/mL) group (Group S). The initial concentration of ropivacaine was set at 0.125%, which was then varied by 0.01% using the up-and-down sequential allocation method. The hemodynamics were continuously monitored during delivery. A visual analog scale was used to evaluate the degree of pain. The Ramsay sedation score, duration of the labor stages, the onset of epidural analgesia, and adverse effects were recorded. Neonatal outcomes were evaluated using the Apgar scores and umbilical artery blood gas analysis.

Results

The EC50 of ropivacaine was 0.085% (95% CI, 0.079–0.090%) in Group S and 0.109% (95% CI, 0.105–0.112%) in Group C. The EC95 of ropivacaine was 0.096% (95% CI, 0.090–0.118%) in Group S, and 0.116% (95% CI, 0.113–0.127%) in Group C. The difference between the groups was statistically significant (p < 0.001). The stable hemodynamics, satisfactory analgesia, and good neonatal outcomes were comparable in both groups (P > 0.05).

Conclusion

The EC50 of ropivacaine was reduced by 22% when co-administered with sufentanil for epidural labor analgesia in primipara. (www.chictr.org.cn; registration number: ChiCTR2000039547).

Keywords:

• median effective concentration
• ropivacaine
• sufentanil
• labor analgesia

Acknowledgments

The authors would like to thank Professor Youchang Li (Chongqing health Center for Women and Children) for the supervision of clinical performs and assistance. This study was supported by Institutional Research Grants of Chongqing Health Center for Women and Children (No. 2019YJMS02).

Data Sharing Statement

The individual participant’s data underlying published results reported in this study can be accessed with approval from the corresponding authors after publication. The study protocol, statistical analysis plan, and clinical study report will also be available.

Disclosure

The authors report no conflicts of interest in this work.