Prevention of post-spinal hypotension in high risk cesarean delivery: A systematic review and updated network meta-analysis of prophylactic vasopressor infusions.

Background and Aims: Post-spinal hypotension (PSH) is a common complication of neuraxial anaesthesia in high risk cesarean delivery (CD). This systematic review and network meta-analysis evaluate the comparative efficacy and safety of prophylactic intravenous infusions of norepinephrine, phenylephrine, and ephedrine to prevent PSH in this population. Methods: Randomised controlled trials comparing intravenous prophylactic norepinephrine, phenylephrine, and ephedrine in high risk CD and reporting maternal or fetal outcomes were considered. Two reviewers screened studies, extracted data, and assessed risk of bias using the Cochrane Risk of Bias 2 tool. A frequentist network meta-analysis was carried out. Heterogeneity was inspected with I² and Q statistics, and treatment ranking was estimated by Results: Eighteen trials involving 3331 participants were included. Administration of vasopressors reduced the incidence of PSH compared with placebo or no treatment [odds ratios (OR): 1.5; 95% confidence interval (CI) 1.12, 1.67; I²: 10.5%]. Norepinephrine and phenylephrine were superior to ephedrine. There was greater cardiac stability and less bradycardia and nausea with norepinephrine. In preeclamptic and in infusion treated patients, vasopressors were more effective, yet the advantage of norepinephrine was not consistently statistically significant. Neonatal outcomes such as APGAR scores and umbilical artery pH did not differ significantly between agents (OR: 1.1; 95% CI: 0.8, 1.5; Conclusion: Both norepinephrine and phenylephrine are effective for the prevention of PSH in high-risk cesarean delivery receiving neuraxial anaesthesia, with norepinephrine offering more favourable maternal safety and tolerability. These findings justify the use of norepinephrine and phenylephrine over ephedrine in this patient population.