Role and efficacy of vasopressors in post-spinal hypotension in cesarean section. Is norepinephrine a newer choice?

Abstract

In elective cesarean section, spinal anesthesia-related hypotension is routinely prevented or treated with fluids and vasopressors. From the use of fluid preloading to co-loading and different vasopressors, Phenylephrine remains the vasopressor of choice in the management of hypotension during cesarean section under spinal anesthesia for a long time. However, in recent studies, Norepinephrine has also been found as effective as phenylephrine but its routine use has not been recommended till now for the same as a vasopressor agent, and among all the vasopressors, phenylephrine has emerged as the recommended one. Phenylephrine is chosen as a vasopressor over mephenteramine, metaraminol, and ephedrine due to the lack of conclusive evidence about the clinical benefits of one over the other, especially in emergency and high-risk Cesarean sections, and is determined by indirect evidence on fetal acid-base status. Norepinephrine is preferable to phenylephrine, according to recent studies, the present recommendations are mostly based on studies done in elective Cesarean sections. Further studies are warranted in elective, emergency, and high-risk Cesarean sections to use phenylephrine over other vasopressors.