(435) Vasopressors for Prevention of Postspinal Hypotension During High-Risk Cesarean Delivery: A Network Meta-analysis

Objective:
Although numerous randomized controlled trials (RCTs) have compared the safety and efficacy of norepinephrine (NE), phenylephrine (PE) and ephedrine (EP) for the prevention of postspinal hypotension (PSH) during high-risk cesarean delivery (CD), findings are discordant. Methodologic limitations include small sample sizes, variable definitions of PSH, and heterogeneity of parturients.

Study

Design:
This systematic review and network meta-analysis (NMA) compared RCTs of NE, PE and EP administered via bolus or infusion for the prevention of PSH in high-risk CD (PROSPERO CRD420251050322). Endpoints included maternal hemodynamic outcomes (SBP, DBP, MAP, HR), fetal outcomes (Apgar scores, UA pH), and adverse effects (AE). Pairwise meta-analyses for direct comparison were conducted using a random-effects model, and for NMA, using a frequentist approach. Treatment rankings were based on P-scores. Heterogeneity was assessed using the I² statistic and Cochran's Q test. Subgroup analysis, data quality, sensitivity analysis and publication bias were examined.

Results:
A majority of the 24 eligible RCTs (n = 2,843) included in the NMA showed a low risk of bias. Sensitivity analysis indicated robustness and consistency of the combined outcome. Vasopressors significantly reduced PSH incidence (OR = 1.5, 95% CI: 1.12–1.67) with low heterogeneity (I² = 10.5%). Hemodynamic outcomes also favored vasopressors: SBP (OR = 0.75), DBP (OR = 0.68), and MAP (OR = 0.67). NE and PE were more effective than EP, with NE demonstrating superior cardiac stability and fewer AEs. Subgroup analysis revealed enhanced benefits in preeclamptic patients and with infusion-based strategies. Fetal outcomes were similar across all groups.

Conclusion:
This NMA provided strong evidence for vasopressor use in the prevention of PSH during neuraxial anesthesia in high-risk CD. Both NE and PE were highly effective, with NE having benefits in safety and cardiac stability. EP was associated with more AEs and suboptimal maternal profiles. This evidence supports the preferential use of NE and PE over EP in such clinical settings.