Retrospective comparison of ephedrine and phenylephrine for the treatment of spinal anesthesia induced hypotension in pre-eclamptic patients

Objective: To compare neonatal acid base status in parturients who underwent cesarean delivery and received either ephedrine or phenylephrine boluses for the treatment of spinal anesthesia induced hypotension. Research design and methods: After institutional review board approval, the perioperative database of the University of Iowa Hospitals and Clinics was used to identify all women diagnosed with pre-eclampsia and had cesarean delivery under spinal anesthesia for the period 1 January 2005 to 31 July 2014. Data retrieved included patient demographics, indication for cesarean delivery, severity of pre-eclampsia, dose of vasopressor, neonatal umbilical artery pH and Apgar scores. Main outcome measures: Primary outcome was umbilical artery pH. Results: Data for 146 patients was included in the analysis. Ephedrine was used in 57 patients (group E) and phenylephrine in 89 (group PE) patients. The median umbilical artery pH was 7.30 (IQR 7.20-7.30) and 7.30 (IQR 7.20-7.30) in the ephedrine and phenylephrine groups respectively (P = 0.41). Non-reassuring fetal heart trace was the only factor significantly associated with lower umbilical artery pH on multivariable regression analysis (beta = -0.09, P = 0.002). Conclusions: We found no difference in neonatal umbilical artery pH between ephedrine and phenylephrine when used to treat spinal anesthesia induced hypotension during cesarean delivery in pre-eclamptic patients. Limitations of the study include its retrospective single center design and the fact that the choice of vasopressor was not randomized.