Prophylactic Phenylephrine Infusions to Reduce Severe Spinal Anesthesia Hypotension During Cesarean Delivery in a...

Phenylephrine infusions are considered as standard management for obstetric spinal hypotension, but there remains reluctance to implement them in resource-limited contexts. This prospective, alternating intervention study of patients undergoing elective or urgent cesarean delivery under spinal anesthesia compared a vasopressor bolus strategy to fixed-rate, low-dose prophylactic phenylephrine infusion with supplemental boluses. The primary outcome was the incidence of severe hypotension (mean arterial pressure <70% baseline or systolic blood pressure <80 mm Hg). Fewer patients receiving prophylactic phenylephrine infusions had severe hypotension (47.4% [n = 120/253] vs 62.1% [n = 157/253], P = .001, estimated relative risk 0.84, 95% confidence interval, 0.69-1.02), with no significant difference in the rate of hypertension (15% [n = 39/253] vs 11% [n = 27/253], P = .11, estimated relative risk 1.39, confidence interval 0.87-2.20). Guidelines for resource-constrained settings should consider a fixed, low-dose phenylephrine infusion in combination with rescue vasopressor bolus therapy.