A randomized trial comparing prophylactic phenylephrine and ephedrine infusion during spinal anesthesia for emergency cesarean delivery in cases of acute fetal compromise.

Background: Previous evidence showed that use of phenylephrine was associated with higher umbilical artery pH (UA pH) than ephedrine after elective cesarean delivery (CD). However, the best choice of vasopressor and its effect on funic gases in cases of acute fetal compromise require additional studies.

Methods: Ninety parturients showing acute fetal compromise during intrapartum period and taken up for CD (category II) under spinal anesthesia were randomized to receive prophylactic infusion of ephedrine 2.5mg/min or phenylephrine 30μg/min. Systolic blood pressure was targeted between 90% and 110% of baseline. Incidence of fetal acidosis (UA pH <7.2 and/or base deficit >12mmol/L) was recorded. Other parameters of cord gases, Apgar score, need for immediate resuscitation, maternal hemodynamics, and adverse events were also compared.

Results: Number of neonates showing acidosis with ephedrine or phenylephrine was comparable (P=.22). Of these, newborns with base deficit >12mmol had low 1-minute Apgar scores (n=15/23). The ephedrine group had higher oxygen content in UA (P=.03). There was no adverse neonatal outcome during the period of observation. Incidence of maternal nausea and vomiting was higher with ephedrine than with phenylephrine (22.2% vs 4.4%; P=.02). Maternal bradycardia was observed with phenylephrine (P=.02).

Conclusion: Our data report similar fetal acidosis with either phenylephrine or ephedrine administered during spinal anesthesia for treating maternal hypotension in cases of emergency CD.