Phenylephrine Prophylaxis for Postspinal Anesthesia Hypotension in Parturients With Preeclampsia

Overview

The purpose of this study is to investigate the suitable infusion dose of phenylephrine for prophylaxis against postspinal anesthesia hypotension in parturients with preeclampsia undergoing cesarean section.

Preeclampsia, which affects 5% to 7% of parturients, is a significant cause of maternal and neonatal morbidity and mortality. Because of constricted myometrial spiral arteries with exaggerated vasomotor responsiveness, though blood pressure in parturients with preeclampsia are apparently higher than healthy parturients, placental hypoperfusion is more common. Spinal anesthesia is still the preferred mode of anesthesia in parturients with preeclampsia for cesarean section. In preeclampsia parturients, spinal anesthesia improve intervillous blood flow (provided that hypotension is avoided) which contribute to increase placental perfusion. Even so, 17-26% parturients with preeclampsia experienced postspinal anesthesia hypotension due to the extensive sympathetic block that occurred with spinal anesthesia. Practical guidelines for obstetric anesthesia from the American Society of Anesthesiologists and an international consensus statement on the management of hypotension with vasopressors indicate either IV ephedrine or phenylephrine may be used to correct hypotension. But the suitable infusion dose of phenylephrine in parturients with preeclampsia is still unknown. The purpose of this study is to investigate the suitable infusion dose of phenylephrine for prophylaxis against post-spinal anesthesia hypotension in parturients with preeclampsia undergoing cesarean section.

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Central Contacts