AUTHOR=Mei Zhong , Wang Qingtao , Song Shaobo , Lu Wenying , Yu Jing 

TITLE=Optimum programmed intermittent epidural bolus interval time of ropivacaine 0.0625% with dexmedetomidine 0.4 μg/ml at a fixed volume of 10 mL: a randomized controlled trial

JOURNAL=Frontiers in Pharmacology

VOLUME=Volume 15 - 2024

YEAR=2024

URL=https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2024.1368222

DOI=10.3389/fphar.2024.1368222

ISSN=1663-9812

ABSTRACT=Background: The aim of our study was to administer adequate local anesthetic in programmed intermittent epidural bolus (PIEB) to avoid breakthrough pain and decrease the use of manual and PCEA boluses. We therefore conducted this study to determine the effective PIEB interval time between boluses of ropivacaine 0.0625% with dexmedetomidine 0.4 μg/ml at a fixed volume of 10 mL in ninety percent of subjects (EI90), without the use of patient-controlled epidural analgesia (PCEA).

Methods: A total of eighty subjects were included in the final statistical analysis from August 23, 2022 to November 22, 2022. Subjects were randomly assigned to one of four different PIEB time intervals: 40, 50, 60 and 70 minutes (group 40, 50, 60 and 70), respectively. The primary outcome was the effective epidural labor analgesia, defined as no use of PCEA bolus or a manual bolus until the end of the first stage of labor or within six hours after loading dose administration. The PIEB EI90 (95%CI) between boluses of ropivacaine 0.0625% with dexmedetomidine 0.4 μg/ml at a fixed volume of 10 mL was estimated using probit regression.

Results: The effective PIEB interval time between boluses of ropivacaine 0.0625% with dexmedetomidine 0.4 μg/ml at a fixed volume of 10 mL in ninety percent of subjects, without the use of PCEA was 45.4 (35.5 to 50.5) minutes using probit regression. No statistical differences were found in proportion of subjects with Bromage score > 0, hypotension, pruritus, nausea and vomiting between groups. However, the highest sensory block (pinprick) in the 40-min group was significantly higher than that in other groups.

Conclusions: The estimated value for EI90 for PIEB between boluses of ropivacaine 0.0625% with dexmedetomidine 0.4 μg/ml at a fixed volume of 10 mL using probit regression was 45.4 (35.5 to 50.5) minutes. Furthermore, future studies are warranted to be established to determine the optimal parameters for different regimen in clinical practice.