Analgesic Efficacy and Adverse Effects of Epidural Ropivacaine Combined with Equipotent Alfentanil or Sufentanil for Labor Analgesia: A Multicenter Randomized Controlled Single-Blind Trial

Epidural analgesia has shown high maternal-fetal safety and satisfactory analgesia. Sufentanil is associated with a high risk of pruritus, nausea, and vomiting for epidural labor analgesia. Alfentanil is characterized by a rapid onset and is also used for labor analgesia. The study aimed to compare the analgesic efficacy and adverse effects of epidural ropivacaine combined with equipotent doses of alfentanil or sufentanil for labor analgesia, and to provide evidence for optimizing obstetric analgesic regimens.

In this multicenter, randomized, controlled, single-blind trial conducted at four tertiary hospitals in China between June 2023 and June 2024, 442 nulliparous women with singleton, term pregnancies were enrolled. Participants were randomly assigned (1:1) to receive epidural 0.075% ropivacaine combined with either 4 μg/ml alfentanil (group A) or 0.2 μg/ml sufentanil (group S). Analgesia was delivered via a programmed intermittent epidural bolus (PIEB) plus patient-controlled epidural analgesia (PCEA) regimen (10 ml bolus, 50-min interval, 3 ml/h background infusion, 8-ml patient-controlled bolus, 20-min lockout). The onset of analgesia, defined as the median time from drug administration to the first recording of a visual analogue scale (VAS) score ≤ 3 within 30 min was the primary outcome. Hemodynamic parameters, labor characteristics, analgesic consumption, maternal satisfaction, neonatal outcomes, and adverse events were recorded as secondary outcomes.

The median onset time of analgesia was significantly shorter in the alfentanil group compared with the sufentanil group (8.0 min vs. 10.0 min, P < 0.001). No significant differences were observed between groups in blood pressure, heart rate, SpO₂, fetal heart rate, Bromage scores, VAS scores at subsequent time points, uterine pressure, sensory block level, body temperature, duration of analgesia, labor duration, mode of delivery, oxytocin use, total drug consumption, maternal satisfaction, or neonatal Apgar scores (all P > 0.05). Adverse events such as pruritus, nausea, vomiting, urinary retention, and lower limb numbness were infrequent and comparable between groups.

Both alfentanil and sufentanil, when combined with 0.075% ropivacaine, provide effective and safe epidural labor analgesia. However, alfentanil offers the advantage of a faster onset of analgesia, making it a valuable alternative to sufentanil in clinical practice.

Chinese Clinical Trial Registry, ChiCTR2300072104, Date of registration: June 2, 2023.