Ephedrine Versus Phenylephrine for Spinal Block - Related Hypotension in Cesarean Delivery

Overview

The study is designed to compare two strategies used in the management of hypotension caused by spinal anesthesia for cesarean section: intravenous phenylephrine given as prophylactic infusion and interventional boluses of intravenous ephedrine. Phenylephrine is currently recommended for battling spinal anesthesia - related sympathectomy, due to some scientific data on possible negative effects of ephedrine on fetal wellbeing. Therefore this study will retrospectively compare both clinical and laboratory data of the newborns delivered by cesarean section where either large dose of ephedrine or continuous infusion of phenylephrine was used for management of hypotension

Single - shot spinal block is a gold standard of anesthesia for cesarean delivery. It has been proven to decrease maternal morbidity and improve neonatal outcomes. Despite being most frequently used type of anesthesia in obstetrics, spinal block - related complications remain frequent in term parturients, of which hypotension is of utmost importance. Two widely accepted medications used in its prevention and treatment are phenylephrine and ephedrine, of which continuous, preventive phenylephrine infusion is considered superior in terms of neonatal safety. Although there is some scientific evidence towards ephedrine having negative effect on neonatal acid - base status, it is still the most popular vasoconstrictor used for management of perioperative hypotension in Poland. It is an indirect adrenergic agonist, acting through release of noradrenaline from peripheral nerve endings. Beta - receptors mediated adrenergic stimulation of neonatal tissues is thought to be responsible for endocrine abnormalities, acid - base disturbances and possibly worse Apgar scores. Phenylephrine on the other hand is a direct and selective alpha-1 agonist and is regarded to exert very little or even no neonatal effects. Maternal complications related to phenylephrine infusion is hypertension and reflex bradycardia. As convincing evidence is still lacking, this study is designed to retrospectively compare neonatal outcomes and perioperative hemodynamic data of mothers where either infusion of phenylephrine or boluses of ephedrine were used to control spinal -related hypotension during cesarean section.