Preventing Spinal Hypotension During Cesarean Birth With Two Initial Boluses of Norepinephrine

Spinal anesthesia is used during cesarean section to provide rapid onset and dense block of motor and sensory nerves, intraoperative analgesia, and help patients remain conscious (1,2).Hypotension is common during induction of spinal anesthesia for cesarean delivery (CD) (3).If not promptly treated, a decrease in blood pressure (BP) can have deleterious effects, which include maternal nausea, vomiting, dizziness, and cardiovascular instability as well as decreased uteroplacental blood flow with resultant fetal acidosis, hypoxia, and bradycardia.In the last decade, the α-agonist phenylephrine (PE) has been the vasopressor of choice for the prevention and treatment of spinal induced hypotension (4).To prevent and treat postspinal anesthesia hypotension during cesarean section, vasopressors are recommended. Vasopressors (especially potent α-adrenergic receptor agonists) help offset the decrease in arteriolar dilation and peripheral vascular resistance caused by sympathetic nerve blockade after spinal anesthesia and may be associated with decreased incidence of neonatal acidosis.(5,6). Norepinephrine is another vasopressor that was recently introduced in obstetric anesthesia (7). Norepinephrine is characterized by α-adrenergic agonistic activity in addition to a weak β-adrenergic agonistic activity; thus, norepinephrine is considered a vasopressor with minimal cardiac depressant effect(7).; these pharmacologic properties would make norepinephrine an attractive alternative to phenylephrine and ephedrine in obstetric anesthesia. Although the use of norepinephrine for prophylaxis against postspinal hypotension has shown promising results,(7,8) evidence is lacking on the optimum dose for norepinephrine infusion during cesarean delivery.