Comparison Between Different Norepinephrine Bolus Doses for Management of Post-spinal Hypotension During Ceaserian Section for Patients With Preeclampsia

Maternal hypotension after subarachnoid block is a frequent and deleterious complication during lower segment caesarean section (LSCS). Prophylaxis against hypotension using vasopressors had become a standard recommendation. In mothers with preeclampsia, post-spinal hypotension is less frequent compared to healthy mothers; thus, the latest guidelines do not recommend using vasopressors in preeclampsia patients unless there is a hypotensive episode . The incidence of post-spinal hypotension in mother with preeclampsia is nearly 25%. The commonly used vasopressors during CS are ephedrine, phenylephrine, and recently norepinephrine. The use of ephedrine is usually accompanied with maternal tachycardia and foetal acidosis. Phenylephrine (PE) had been the first line for prevention and management of maternal hypotension; however, its use in mothers with preeclampsia had not been adequately investigated. Thus, the best vasopressor for management of hypotension in mothers with preeclampsia is unknown. Norepinephrine (NE) is an alpha adrenergic agonist with weak beta adrenergic agonistic activity; thus, it does not cause significant cardiac depression as phenylephrine does. NE was introduced for use during CS with promising results when used as infusion and as boluses in healthy mothers .

The use of NE boluses in management of hypotension in preeclamptic mothers was not adequately investigated. A dose 4 mcg NE was recently evaluated in preeclamptic mothers. In this study, we will compare 3 NE bolus doses (3 mcg, 4 mcg, and 5 mcg) in management of maternal hypotension after spinal block during CS in preeclamptic mothers.