Remifentanil as an alternative to epidural analgesia for vaginal delivery: A meta-analysis of randomized trials.

Objectives: Although epidural analgesia is considered the gold standard for labor pain management, its use may be restricted in some conditions due to clinical contraindications or availability, and suitable alternatives may be required. The objective of this meta-analysis was to determine whether evidence from randomized trials suggests remifentanil PCA (R-PCA) results in significant differences in maternal satisfaction, analgesic efficacy, and safety compared with conventional epidural analgesia (EA).

Design: We conducted a meta-analysis after systematically searching MEDLINE, EMBASE and Cochrane Library for all randomized controlled trials (RCTs) allocating parturients to R-PCA or EA and reporting at least one outcome of interest.

Patients: Eight randomized trials of R-PCA vs EA with 2351 patients were included.

Measurements: The primary outcome of interest was maternal satisfaction. Secondary outcomes included visual analog pain score (VAS at 1, 2, 3h postoperatively), nausea, vomiting, pruritus, hypoxemia, acute respiratory depression or death (maternal or neonatal), need for Cesarean section, and neonatal Apgar score.

Main Results: Meta-analysis of the randomized trials showed no significant differences between the R-PCA and EA groups for maternal satisfaction, VAS at 2 or 3h, nausea, vomiting, need for cesarean section, respiratory depression, umbilical pH, and neonatal Apgar score at 1min and 5min. However, incidence of hypoxemia was higher [OR 7.48, 95%CI 3.42-16.36] and VAS at 1h was slightly higher [WMD 1.33, 95%CI 0.30-2.36] with R-PCA versus EA. Pruritus was less frequent in the R-PCA group [OR 0.54, 95%CI 0.32-0.89]. Acute respiratory failure and death were not reported in any of the studies.

Conclusions: While no significant differences were detected for maternal satisfaction or for most clinical outcomes, this meta-analysis remains underpowered to rule out clinically-important differences due to the few existing randomized trials. For obstetric patients who are not candidates for EA, R-PCA may provide an alternative for analgesia in the peri-partum period, but caution is warranted particularly regarding hypoxemia, and suggests the need for increased surveillance and monitoring for R-PCA. Further adequately powered randomized trials with a focus on clinically-relevant maternal and neonatal outcomes are required to more accurately characterize the relative benefits and risks of R-PCA versus EA in this population.