Optimum programmed intermittent epidural bolus interval time between 8 mL boluses of Ropivacaine 0.1% with sufentanil 0.3 μg/mL with dural puncture epidural technique for labor analgesia: A biased-coin up-and-down sequential allocation trial

The combination of dural puncture epidural (DPE) technique and programmed intermittent epidural bolus (PIEB) is a novel alternative labor analgesia regimen providing rapid analgesia onset and improved analgesia quality. However, the optimum PIEB settings for using the DPE technique remain unclear.Biased-coin up-and-down sequential allocation design.Labor analgesia.Forty nulliparous women requesting labor analgesia.Dural was punctured using a 25-gauge Whitacre needle. 12 mL of 0.1% ropivacaine with 0.3 μg/mL of sufentanil was used for initiation. Labor analgesia was maintained using the same solution with a fixed 8 mL volume beginning 1 h after initiation. The interval for the first patient was 60 min and varied for subsequent patients according to the biased-coin design (groups 60, 50, 40, and 30; interval 60, 50, 40, and 30 min, respectively).The primary outcome was adequate analgesia, defined as no request of patient-controlled epidural analgesia or provider boluses for 6 h after the epidural analgesia initiation or until the maternal cervix was fully dilated, whichever came first. The secondary outcomes included sensory blockade level, motor strength, maternal hypotension, and pruritus.The estimated effective interval in 90% of participants was 41.5 min (95% CI 39.5-43.5 min) and 40.5 min (95% CI 33.7-47.5 min) by the truncated Dixon and Mood method and the isotonic regression method, respectively, for the 40 women included. The proportions of patients with the highest sensory block level achieving or above T6 were 60%, 26%, 27%, and 0% in groups 30, 40, 50, and 60, respectively. One patient presented a Bromage score of 1. There was a low incidence of hypotension in all the groups with no need for vasopressor treatment.The optimum PIEB interval time between 8 mL boluses of ropivacaine 0.1% and sufentanil 0.3 μg/mL when using the DPE technique was approximately 41 min.