Prognostic of red blood cell transfusion during extracorporeal membrane oxygenation therapy on mortality: A meta-analysis

Background This meta-analysis aimed to explore the impact of red blood cell (RBC) transfusion on mortality during extracorporeal membrane oxygenation (ECMO). Previous studies investigated the prognostic impact of RBC transfusion during ECMO on the risk of mortality, but no meta-analysis has been published before. Methods The PubMed, Embase, and the Cochrane library were systematically searched for papers published up to 13 December 2021, using the MeSH terms "ECMO", "'Erythrocytes", and "Mortality" to identify meta-analyses. Total or daily RBC transfusion during ECMO and mortality were examined. Results The random-effect model was used. Eight studies (794 patients, including 354 dead) were included. The total volume of RBC was associated with higher mortality standardized weighted difference (SWD = -0.62, 95% CI: -1.06,-0.18, p = .006; I2 = 79.7%, P-heterogeneity = 0.001). The daily volume of RBC was associated with higher mortality (SWD = -0.77, 95% CI: -1.11,-0.42, p < .001; I2 = 65.7%, P-heterogeneity = 0.020). The total volume of RBC was associated with mortality for venovenous (VV) (SWD = -0.72, 95% CI: -1.23, -0.20, p = .006) but not venoarterial ECMO (p = .126) or when reported together (p = .089). The daily volume of RBC was associated with mortality for VV (SWD = -0.72, 95% CI: -1.18, -0.26, p = 0.002; I2 = 0.0%, P-heterogeneity = 0.642) and venoarterial (SWD = -0.95, 95% CI: -1.32, -0.57, p < .001) ECMO, but not when reported together (p = .067). The sensitivity analysis suggested the robustness of the results. Conclusion When considering the total and daily volumes of RBC transfusion during ECMO, the patients who survived received smaller total and daily volumes of RBC transfusion. This meta-analysis suggests that RBC transfusion might be associated with a higher risk of mortality during ECMO.