Effect of epidural epinephrine infusion with bupivacaine on labor pain and mother-fetus outcome in humans

Background and Objectives: Epinephrine is used with local anesthetics to prolong the duration of epidural analgesia and decrease the peak plasma concentrations of local anesthetics. In the practice of obstetric anesthesia, the utero-placental and fetal effects of epinephrine are controversial issues. We designed a prospective, randomized, and double-blind study to examine the effects of epinephrine infusion on the quality of analgesia and uterine or umbilical blood flows with Doppler ultrasound, as well as the duration of the first or the second stage of labor, and fetal outcome. Methods: Twenty-eight parturients received continuous epidural bupivacaine 0.25% (4 mL/h) combined either with epinephrine (20 μg/h) (n = 13) or without epinephrine (n = 15) for analgesia during labor. If patients requested additional analgesia, an additional bolus of 1% or 1.5% lidocaine (6 to 10 mL) was administered. Results: The total amount of additional lidocaine was greater in the plain bupivacaine group (130 [0, 280] mg; median [25th, 75th percentile] with P < .05) than in the epinephrine group (0 [0, 60] mg). Epinephrine infusion did not alter the resistance of the uterine and umbilical arteries as measured by resistance index. The duration of the first or second stages of labor did not significantly differ in the 2 groups. Epinephrine infusion did not change the fetal heart rate or the blood gas data in the umbilical artery. Conclusions: A low-dose epidural infusion of epinephrine decreased anesthetic requirements.