Comparison of the Effect of Incremental Bolus and Incremental Infusion Regimens of Remifentanil on Labour Pain

Abstract

Background: Most pregnant women who deliver in obstetrics units require pharmacological or non-pharmacological pain relievers that could provide potent analgesic effects with least maternal and neonatal adverse effects. Objectives: The aim of this investigation was to compare the efficacy and adverse maternal and neonatal effects of Remifentanil given by bolus patient-controlled analgesia (PCA) versus continuous intravenous (IV) infusion for labor analgesia. Patients and Methods: This randomized, single-blind clinical trial was conducted on 82 nulliparous parturient women in the active phase of labor, admitted to Ali Ebn-e Abitaleb Hospital, Zahedan, Iran from January 2010 to March 2013. The participants were randomly assigned into two equal groups of 41. In the infusion group, patients received incremental Remifentanil IV infusion from 0.025 to 0.1 µg/kg/min. In the bolus group, participants received incremental PCA bolus Remifentanil from 0.25 to 0.4 µg/kg with a lock-out time of four minutes. Average Visual Analog Scale (AVAS) pain scores in stages 1 and 2, labor duration, adverse effects, neonatal outcomes, total amount of administered Remifentanil and maternal satisfaction were assessed. Results: In both methods, the pain scores were significantly reduced after Remifentanil administration in both stages of labor (P < 0.001). There were no statistically significant differences in the pain intensity reduction between the groups (P = 0.49, P = 0.36, in the stages I and II of labor, respectively). There were no statistically remarkable differences between the two groups for labor duration (P = 0.4), neonatal outcomes (P = 0.9) and maternal satisfaction (P = 0.8). The total amount of administered Remifentanil was significantly lower in infusion group compared to bolus group (P = 0.001). Conclusions: Remifentanil in both infusion and bolus methods could decrease labor pain in both stages without serious maternal or neonatal adverse effects and without increasing the duration of labor. The average dose of Remifentanil needed to reduce pain was significantly lower in the infusion method compared to the bolus method.