Norepinephrine for Management of Post-spinal Anesthesia Hypotension During Cesarean Delivery: a Comparison of Two Bolus Doses

Maternal hypotension after subarachnoid block is a frequent and deleterious complication during cesarean delivery. Although prophylaxis against hypotension using vasopressors had become a standard recommendation; the incidence of hypotension is still ∼ 20% . Thus; management of maternal hypotension using vasopressor boluses is usually needed .

The commonly used vasopressors during cesarean delivery are ephedrine, phenylephrine, and recently norepinephrine. The use of ephedrine is usually accompanied with maternal tachycardia and fetal acidosis. Phenylephrine had been the first line for prevention and management of maternal hypotension; however, its use might result in bradycardia and decreased maternal cardiac output .

Norepinephrine is an alpha adrenergic agonist with weak beta adrenergic agonistic activity; thus, it does not cause significant cardiac depression as phenylephrine does. Norepinephrine was introduced for use during cesarean delivery with promising results . Few previous studies investigated the efficacy of Norepinephrine infusion for prevention of maternal hypotension. A dose-response study had investigated the best dose of Norepinephrine for prevention of maternal hypotension. In the aforementioned dose-response study, a dose of 6 mcg was reported as the best dose for prophylaxis against maternal hypotension.

No studies had investigated the best bolus dose of norepinephrine for management of a maternal hypotensive episode. In this study the investigators will investigate the efficacy and side effects of two doses of norepinephrine bolus doses (6 mcg and 10 mcg) in management of maternal hypotensive episode after subarachnoid block during cesarean delivery.