Epinephrine vs. phenylephrine infusion for prophylaxis against maternal hypotension after spinal anesthesia for cesarean delivery: a randomized controlled trial

Background The hemodynamic effects of relatively low-dose epinephrine and phenylephrine infusions during cesarean delivery under spinal anesthesia were compared. Methods This randomized controlled trial included full-term pregnant women who underwent elective cesarean delivery. After spinal anesthesia, participants received either epinephrine (0.03 mcg/kg/min) or phenylephrine (0.4 mcg/kg/min) infusion that continued until 5 min after delivery. The primary outcome was a composite outcome of the occurrence of any of hypotension, hypertension, bradycardia, and/or tachycardia. Neonatal outcomes, including umbilical artery blood gas and Apgar scores, were assessed. Results In total, 98 patients in each group were analyzed, and the number of patients with the composite outcome was comparable between the epinephrine and phenylephrine groups (30/98 [31%] vs. 31/98 [32%], respectively; P = 0.877). However, the incidence of hypotension was likely lower in the epinephrine group than in the phenylephrine group ( P = 0.066), and the number of hypotensive episodes per patient was lower in the epinephrine group than in the phenylephrine group. On the other hand, the incidence of tachycardia was higher in the epinephrine group than that in the phenylephrine group. The incidence of hypertension was comparable between the two groups and none of the participants developed bradycardia. Neonatal outcomes were comparable between the two groups. Conclusions Epinephrine and phenylephrine infusion produced comparable maternal hemodynamics and neonatal outcomes. Epinephrine was associated with a higher incidence of maternal tachycardia and likely lower incidence of maternal hypotension than phenylephrine. IRB number: MD-245–2022. Clinical trial registration: This study was registered on May 31, 2023 at clinicaltrials.gov registry, NCT05881915, URL: https://classic.clinicaltrials.gov/ct2/show/NCT05881915term=NCT05881915&draw=2&rank=1