Venovenous versus venoarterial extracorporeal membrane oxygenation in respiratory failure: a meta-analysis of mortality and complication rates

To compare short-term mortality and complication rates between venovenous (VV) and venoarterial (VA) extracorporeal membrane oxygenation (ECMO) in patients with severe respiratory failure. A systematic review and meta-analysis was conducted following PRISMA guidelines. PubMed/MEDLINE, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL), and the Scopus database were searched for pertinent studies and clinical trials comparing VV- and VA-ECMO in respiratory failure. Statistical analysis was performed using the REVMAN 5.4 software. Pooled odds ratios (ORs) and mean differences (MD) with 95% confidence intervals (CIs) were calculated using a random-effects model. Eleven studies comprising 3,598 patients were included. VV-ECMO was associated with significantly higher survival to hospital discharge in both pediatric (OR: 2.01; 95% CI: 1.03–3.95; p = 0.04) and adult (OR: 1.90; 95% CI: 1.32–2.75; p = 0.0006) populations. VA-ECMO patients were consistently sicker at baseline, demonstrating significant confounding by indication. VA-ECMO was associated with a higher rate of hemolysis in adults (7.3% vs. 12.7%; p = 0.05), while VV-ECMO was linked to a higher risk of renal complications in pediatric patients (OR: 1.33; p = 0.005). Adult VV-ECMO patients had a significantly shorter ICU length of stay (MD: -20.00 days; p = 0.001). In patients with severe respiratory failure, VV-ECMO is associated with a significant survival advantage over VA-ECMO, despite being used in less critically ill patients. VV-ECMO should be the default strategy for isolated respiratory failure, with VA-ECMO reserved for cases of clear, refractory cardiogenic shock.