Comparison of different delivery modalities of epidural analgesia and intravenous analgesia in labour: a systematic review and network meta-analysis

Purpose In labour, neuraxial analgesia is the standard in the provision of pain relief. However, the optimal mode of delivering epidural solution has not been determined, and some parturients may need an alternative to epidural analgesia. We sought to conduct a systematic review and network meta-analysis to compare continuous epidural infusion (CEI), programmed intermittent epidural bolus (PIEB), computer-integrated CEI, computer-integrated PIEB, patient-controlled epidural bolus (PCEA), fentanyl patient-controlled analgesia (PCA), and remifentanil PCA, either alone or in combination. Methods We searched CENTRAL, CINAHL, Ovid Embase, Ovid Medline, and Web of Science for randomized controlled trials that included nulliparous and/or multiparous parturients in spontaneous or induced labour. The maintenance epidural solution had to include a low concentration local anesthetic and an opioid. Specific subgroups in the obstetric population such as preeclampsia were excluded. Network meta-analysis was performed with a frequentist method, and continuous and dichotomous outcomes are presented as mean differences and odds ratios, respectively, with 95% confidence intervals. Results Overall, 73 trials were included. For the first coprimary outcome, the need for rescue analgesia, CEI was inferior to PIEB and PIEB + PCEA was superior to PCEA alone, with a low certainty of evidence given the presence of serious limitations and imprecision. The second coprimary outcome, the maternal satisfaction, was improved by PIEB + PCEA compared with CEI + PCEA and PCEA alone, with a low quality of evidence in view of the presence of serious limitations and imprecision. Fentanyl PCA increased the requirement for rescue analgesia and decreased maternal satisfaction relative to many methods of delivering epidural solution. In terms of secondary outcomes, PIEB increased analgesic efficacy compared with CEI, and PCEA reduced local anesthetic consumption at the expense of inferior analgesia relative to CEI and PIEB. PIEB + PCEA was superior to CEI + PCEA in regard to the pain score at 2 h and 4 h, consumption of local anesthetic, incidence of lower lower limb motor blockade and the rate of spontaneous vaginal delivery. Fentanyl and remifentanil PCA did not provide the same level of analgesia as all epidural methods, resulted in increasing analgesic ineffectiveness with time spent in labour, and predisposed to a higher incidence of side effects such as nausea and/or vomiting and sedation. Remifentanil PCA was superior to fentanyl PCA for analgesia at an early time point, and it increased the incidence of oxygen desaturation relative to other strategies of delivering epidural solution. Conclusions Opioid PCA did not provide the same level of analgesia as epidural methods with a higher incidence of side effects. We interpret the findings of our systematic review and network meta-analysis as suggesting PIEB + PCEA to be the optimal delivery mode of epidural solution. Nevertheless, the potential differing importance of the various maternal, fetal, and neonatal outcomes in determining which is optimal has not, to our knowledge, been elucidated yet. Study registration PROSPERO (CRD42021254978); registered 27 May 2021.