Is epidural analgesia non-inferior to intrathecal fentanyl as initiation for neuraxial analgesia in early non-spontaneous labour?

Background and Aim: Intrathecal fentanyl, using the combined spinal-epidural (CSE) technique, provides rapid analgesia during early labour. Because of the technique's more complex and invasive nature, as its replacement we assessed the use of epidural analgesia in primiparous parturients with induced labour. The study was registered at (NCT04645823). The aim was to compare the efficacy, duration of analgesia and maternal satisfaction. The primary outcome was the difference in pain visual analogue scale (VAS) between the interventions at 20 min after the analgesia administration. Methods: Sixty volunteering parturients were randomly allocated in 1:1 ratio to receive either intrathecal fentanyl 20 mu g or epidural analgesia (fentanyl 100 mu g and lidocaine 80 mg). Contraction pain and maternal satisfaction were assessed by 0-100 mm VAS for 30 min, respectively. Foetal heart rate abnormalities, the time to first epidural dose and the incidence of pruritus were recorded. Non-inferiority margin for mean (95% CI) VAS after epidural analgesia was set at 20 mm above the VAS value for intrathecal fentanyl at 20 min. Results: The contraction pain VAS fell from (median [interquartile range, IQR]) 82 (14) to 13 (20) mm and 76 (17) to 12 (27) mm in 20 min following the intrathecal fentanyl and epidural analgesia, respectively. The absolute mean difference (epidural-intrathecal fentanyl) in the VAS values was 3.3(-0.06 to 6.66) mm indicating non-inferiority. The median time to reach VAS <30 mm was 10 min in both groups. The duration until request for supplemental analgesia was 82(69-95) and 91(75-106) min after intrathecal fentanyl and epidural analgesia, respectively. The difference for the duration (epidural-intrathecal fentanyl) was 9 (6-12) min and for satisfaction-VAS 0.3 (-3.0 to 3.7) mm. There were no differences between the groups in the incidence of foetal heart rate abnormalities, while pruritus was more common after intrathecal fentanyl. Conclusion: After 20 min, epidural analgesia by lidocaine and fentanyl was within the non-inferior threshold compared with intrathecal fentanyl in efficacy. The duration of action was not shorter than that of intrathecal fentanyl and maternal satisfaction was also similar.