Labor epidural analgesia: Comparison of intermittent boluses of ropivacaine with three different concentrations of fentanyl – A randomized controlled trial

Background and Aims: Labor epidural analgesia can be provided with local anesthetics alone or in combination with opioids. The aim of this study was to compare the duration of analgesia, onset time, and obstetric and fetal outcomes with three different concentrations of fentanyl. Methods: This double-blinded trial was conducted on 75 parturients who delivered with epidural analgesia. They were randomly assigned to three groups by the closed envelope technique. Groups A, B, and C received a bolus dose of 20 ml 0.1% ropivacaine with 1 μgml-1, 1.5 μgml-1, and 2 μgml-1 fentanyl, respectively, as an initial epidural dose. The duration, time to onset of analgesia, top-up doses required, hemodynamics, fetal-maternal outcomes, and complications were compared. Results: The mean duration of analgesia with the first epidural dose was 57.4 ± 14.207, 121.52 ± 33.951, and 165.08 ± 34.271 min in the A, B, and C groups, respectively, with a P of <.001. There was a higher duration of analgesia in the B group than in the A group (p-value <.001), in the C group than in the B group (p. 016), and in the C group than in the A group (p-value <.001). The onset of analgesia was faster in the C group than in the A and B groups (7.960 ± 1.695, 6.800 ± 1.607, and 5.960 ± 1.645 min in groups A, B, and C, respectively, with a P of. 001). The number of epidural boluses required was 3.480 ± 0.509, 2.640 ± 0.489, and 2.120 ± 0.331 in the A, B, and C groups, respectively. Conclusion: Labor epidural analgesia with a higher concentration of fentanyl produces a prolonged and faster onset of analgesia with fewer requirements for top-up boluses.