Yan Lu,1,* Yueqi Zhang,1,* Yuhan Zheng,1,* Yujie Song,1 Yu Zang,2 Zhiqiang Liu,3 Zhendong Xu1 

1Department of Anesthesiology, Shanghai Key Laboratory of Maternal Fetal Medicine, Shanghai Institute of Maternal-Fetal Medicine and Gynecologic Oncology, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, Shanghai, 200092, People’s Republic of China; 2Department of Anesthesiology, Yangpu Hospital, School of Medicine, Tongji University, Shanghai, 200090, People’s Republic of China; 3Department of Anesthesiology, Obstetrics and Gynecology Hospital, Fudan University, Shanghai, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Zhendong Xu, Department of Anesthesiology, Shanghai Key Laboratory of Maternal Fetal Medicine, Shanghai Institute of Maternal-Fetal Medicine and Gynecologic Oncology, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, Shanghai, 200092, People’s Republic of China, Email btxzd123@126.com

Purpose: Typically, labor analgesia is initiated with a manual loading dose. The programmed intermittent epidural bolus (PIEB) effectively maintains labor analgesia. However, no PIEB method has been studied for the initial loading dose. This study aimed to compare the effectiveness of loading doses administered via a PIEB versus a manual bolus.
Patients and Methods: In total, 164 full-term singleton parturients were randomly assigned to receive a 12 mL loading dose (0.1% ropivacaine and 0.3 μg·mL− 1 sufentanil) via manual or pump-driven injection. A standardized maintenance protocol was employed. The primary outcome was the percentage of parturients with adequate analgesia 20 min after the initial epidural injection. Adequate analgesia was defined as a numeric rating score (NRS) of ≤ 3 during two consecutive uterine contractions, without an additional analgesia request. Kaplan–Meier survival curves were constructed for the time interval needed to achieve adequate analgesia. A non-inferiority analysis was conducted by comparing the 90% confidence interval of the pain score difference with the non-inferiority margin.
Results: The percentage of parturients achieving adequate analgesia was comparable (75.61% manual injection vs 76.83% pump injection, P=0.05 for non-inferiority). The median NRS was similar, except at 2 min (7 [5– 8] manual injection vs 8 [6– 9] pump injection, P=0.04). Median time to adequate analgesia, median ropivacaine consumption, median duration of epidural analgesia, incidence of requests for patient-controlled epidural analgesia (PCEA), median number of PCEA boluses, percentage of bilateral S2 blocks at 20 min, incidence of breakthrough pain, percentage of highest block level ≥T6 at 20 min, adverse effects, and obstetric and neonatal outcomes were similar between the groups.
Conclusion: Within 20 min of administering a loading dose through a PIEB pump, non-inferior analgesia comparable to that achieved with manual injection was observed. This hands-free approach could help mitigate the impact of individual operational differences on analgesic efficacy.
Registration: This trial was registered at chictr.org.cn (ChiCTR2300074063).

Keywords: epidural, labor analgesia, loading dose, programmed intermittent epidural bolus