Abstract:

Objective To determine the minimum local analgesic concentration (MLAC) of ropivacaine for the application of ropivacaine combined with sufentanil to epidural analgesia at the first and the second stage of labor by sequential allocation method and observe its adverse reactions. Methods A total of 30 nulliparous full-term primiparas were enrolled. The epidural analgesia was performed when cervical dilation reached 3 cm at the first stage of labor. The initial concentration of ropivacaine was 0.1% combined with sufentanil of 0.3 μg/mL. According to the response of the previous primipara, the concentration of ropivacaine was increased or decreased by 0.01% for the next primipara. The analgesia was defined as effective if the visual analogue scale (VAS) score was no more than 3 from 30 min after administration to the end of the second stage of labor. The Brownlee up-and-down sequential allocation was used to calculate the MLAC and 95%CI of ropivacaine. Results For epidural analgesia at the first and the second stage of labor, the MLAC and 95%CI of ropivacaine were 0.092 3% and 0.091 8%-0.092 8%. Five primiparas had PONV and the incidence was 16.7%. One primipara had pruritus and the incidence was 3.3%. Conclusion The MLAC of ropivacaine is 0.092 3% when applying ropivacaine with sufentanil of 0.3 μg/mL to epidural analgesia at the first and the second stage of labor.

Key words: ropivacaine, sufentanil, epidural labor analgesia, dose effect relation