Optimal Interval for Intermittent Epidural Bolus with Ropivacaine-Dexmedetomidine Using the Epidural Dural Puncture...

This study aimed to establish the 90% effective interval time for programmed intermittent epidural bolus (PIEB) following dural puncture epidural (DPE) analgesia with a dexmedetomidine ropivacaine combination for primiparas in the first stage of labor.

This biased coin up and down sequential allocation trial enrolled 40 nulliparous women requesting labor analgesia. After an initial loading dose, analgesia was maintained with PIEB of a fixed volume of 8 mL of the same solution, starting 1 hour later. The initial PIEB interval was set at 60 minutes for the first patient and subsequently adjusted by ± 5 minutes based on the outcome of the previous patient, following the biased-coin design. A successful interval was defined as no requirement for supplemental analgesia. The primary outcome was the 90% effective PIEB interval (ED90) for the first stage of labor. Secondary outcomes included patient satisfaction, the incidence of motor and sensory block, and adverse events.

Isotonic regression analysis estimated the 90% effective PIEB interval as 34.5 min (95% confidence interval: 31.0-37.0 min). All patients reported a very high level of satisfaction. The incidence of motor block was 10%, while 37.5% of patients achieved the highest sensory block at the T6 level or above. Notably, no cases of excessive sedation, hypotension, or bradycardia.

For DPE labor analgesia using 8 mL of 0.075% ropivacaine combined with 0.4 μg/mL dexmedetomidine, the optimal PIEB interval is approximately 35 min. This interval can reduce breakthrough pain and the need for rescue analgesia. This finding provides a practical, evidence-based reference for optimizing PIEB regimens in clinical labor analgesia, contributing to improved maternal comfort and labor experience while ensuring safety.