A comparison between remifentanil and meperidine for labor analgesia: a systematic review.

Abstract

Remifentanil is an ultrashort-acting opioid with favorable pharmacokinetic properties that make it suitable as a labor analgesic. Although it crosses the placenta freely, it is eliminated quickly in the neonate by rapid metabolism and redistribution. We aimed to determine whether remifentanil compared with meperidine is effective in reducing pain scores in laboring parturients. Other effects on the mother, the labor process, and the neonate were also examined. MEDLINE, CINAHL, Embase, Cochrane CENTRAL, and Maternity and Infant Care databases were searched without language restriction using multiple keywords for labor analgesia, remifentanil, and meperidine. Published abstracts from 5 key research meetings and references from retrieved articles were examined for additional studies. Randomized controlled trials in laboring parturients comparing remifentanil with meperidine were selected. Risk of bias was assessed using criteria outlined in the Cochrane Handbook for Systematic Reviews of Interventions. We assessed for adequacy of sequence generation, allocation concealment, blinding, and completeness of follow-up. Data were extracted from each study using a standardized data collection form. The primary outcome was reduction in pain scores (visual analog scale [VAS], 0-100 mm). We also evaluated maternal side effects (sedation, oxygen desaturation, and bradypnea) and effects on the neonate (Apgar scores, umbilical cord pH, and Neurologic and Adaptive Capacity Scores). Seven studies (349 patients) were identified for inclusion; only 3 studies were suitable for quantitative synthesis in a meta-analysis (233 patients). We found that remifentanil reduces the mean VAS score at 1 hour by 25 mm more than meperidine (P < 0.001) (95% confidence interval = 19-31 mm). Limited conclusions can be made regarding the side-effect profile of remifentanil because of insufficient data. Compared with meperidine, remifentanil is superior in reducing mean VAS scores for labor pain after 1 hour.