Fetal and Maternal Effects of Phenylephrine and Ephedrine during Spinal Anesthesia for Cesarean Delivery

Abstract

Giving phenylephrine alone by infusion at cesarean delivery was associated with a lower incidence of fetal acidosis and maternal nausea and vomiting than giving ephedrine alone. There was no advantage to combining phenylephrine and ephedrine because it increased nausea and vomiting, and it did not further improve fetal blood gas values, compared with giving phenylephrine alone.

Randomised double‐blinded comparison of phenylephrine vs ephedrine for maintaining blood pressure during spinal anaesthesia for non‐elective Caesarean section*

“…Although this does not appear to be clinically relevant in healthy, low-risk elective cases [3][4][5], it has not been known whether the same would apply in the presence of [7,8] compared phenylephrine and ephedrine for correcting epidural-induced hypotension after a period of maternal hypoxaemia in a chronically-instrumented sheep model. In an earlier study, they found that, although ephedrine was associated with more favorable effects on uterine and placental circulations, there was no difference in fetal acid-base status or lactate concentration [7].…”

“…However, more recent clinical studies of the use of alpha agonists during spinal anaesthesia for Caesarean section have not shown evidence of detrimental effects [2][3][4][5]. In general, these studies have supported the use of phenylephrine for maintaining maternal blood pressure (BP) during spinal anaesthesia for Caesarean section because of its greater efficacy, ease of titration and less propensity to depress fetal pH and base excess compared with ephedrine [2,3,6]. However, most clinical studies have been performed in healthy, low-risk, elective patients; few data are available for non-elective cases, particularly those in whom there is actual or potential fetal compromise.…”

Closed‐loop feedback computer‐controlled infusion of phenylephrine for maintaining blood pressure during spinal anaesthesia for caesarean section: a preliminary descriptive study*

“…The total dose of phenylephrine given to patients in our study was greater than that reported in studies by other investigators [1,10,11]. However, our technique was based on our previous studies [2][3][4] in which we have not observed adverse neonatal effects despite similarly large doses of phenylephrine.…”

“…Calculated system performance parameters were comparable with those of previously published closed-loop systems and provide a reference for the potential development and comparison of more advanced algorithms. Recent studies have demonstrated the efficacy and clinical utility of phenylephrine infusions for maintaining maternal blood pressure during spinal anaesthesia for caesarean section [1][2][3][4]. Previously, this has been performed using a syringe or infusion pump with titration by manual rate adjustments according to the maternal blood pressure.…”

“…Recent studies have demonstrated the efficacy and clinical utility of phenylephrine infusions for maintaining maternal blood pressure during spinal anaesthesia for caesarean section [1][2][3][4]. Previously, this has been performed using a syringe or infusion pump with titration by manual rate adjustments according to the maternal blood pressure.…”