Neonatal effects after vasopressor during spinal anesthesia for cesarean section: a multicenter, randomized...

Placental transfer of ephedrine causes fetal effects when compared with phenylephrine. This study compared their drug effects on neonatal parameters after cesarean delivery under spinal anesthesia.

Three-hundred-and-fifty-four women undergoing elective cesarean delivery who needed intravenous vasopressor following spinal anesthesia were randomized into two groups. Group E received boluses of ephedrine 6mg, and Group P phenylephrine 100µg, titrated to maintain systolic blood pressure near baseline values. Neonatal heart rates at 10 and 30-45min of age, oxygen saturation and capillary blood glucose at 30min, and capillary blood lactate and urine metamphetamine were recorded.

Neonatal heart rate at 10min was significantly higher (mean difference 4.0, 95%CI 0.6 to 7.3, P=0.02) in Group E versus Group P, but this was not clinically relevant. There was a linear correlation between neonatal heart rate at 10min and ephedrine dose in Group E (r²=0.29, 95%CI 0.22, 0.74, p<0.01). The decremental changes in neonatal heart rate at 10 and 30min were significantly greater in Group E. Urine metamphetamine tests were positive in 19% of 44 neonatal urine samples. Neonatal heart rates at 30min, oxygen saturation, capillary blood glucose and the incidence of tachycardia, respiratory problems or abnormal glucose, were not significantly different.

Ephedrine, compared to phenylephrine as a vasopressor during cesarean delivery, was associated with higher neonatal heart rate in the early post-birth period, but without a significant difference in clinical outcomes in uncomplicated pregnancies.