Randomised double-blind comparison of bolus phenylephrine or ephedrine for treatment of hypotension in women with pre-eclampsia undergoing caesarean section

Abstract

Treatment of post-spinal hypotension during caesarean section assumes special concern in pre-eclamptic patients due to a compromised fetoplacental circulation and increased risk of placental hypoperfusion. Phenylephrine and ephedrine are the most commonly used vasopressors, although the best choice is still not clear. We studied 80 pre-eclamptic women with a singleton pregnancy who underwent caesarean section with spinal anaesthesia, and who developed hypotension defined as a decrease in systolic arterial pressure ≥ 20% from baseline or absolute value < 100 mmHg. Women were randomly allocated to receive phenylephrine 50 μg or ephedrine 4 mg boluses for treatment of hypotension. Blood pressure changes following vasopressor administration were similar in both groups, but heart rate remained higher after ephedrine at all time-points. The primary outcome measure of umbilical artery pH was 7.26 (0.11) in the phenylephrine group and 7.25 (0.09) in the ephedrine group (p = 0.86). The incidence of neonatal acidosis (umbilical artery pH < 7.20) was 9 (22.5%) in the phenylephrine group and 11 (27.5%) in the ephedrine group (p = 0.80). Other secondary outcome measures were comparable. In conclusion, phenylephrine 50 μg and ephedrine 4 mg, administered as intravenous boluses to treat post-spinal hypotension during caesarean section in pre-eclamptic patients, resulted in similar fetal acid-base values, were equally effective in treating hypotension and were associated with good maternal and neonatal outcome.

Keywords: caesarean section: morbidity; ephedrine; phenylephrine; pre-eclampsia; spinal hypotension: treatment.