Predictors of red blood cell transfusion and its association with prognosis in patients undergoing extracorporeal membrane oxygenation.

Purpose: Few data are available on the potential benefits and risks of red blood cell transfusion in patients undergoing extracorporeal membrane oxygenation. The aim of this study was to identify the determinants and prognosis of red blood cell transfusion in patients undergoing extracorporeal membrane oxygenation, with a special focus on biological parameters during extracorporeal membrane oxygenation treatment.

Methods: We conducted a single-center retrospective cohort study including all consecutive patients who underwent extracorporeal membrane oxygenation between January 2010 and December 2015.

Results: The 201 evaluated patients received a median of 0.9 [0.5-1.7] units of red blood cell per day. Significant and clinically relevant variables that best correlated with units of red blood cell transfused per day of extracorporeal membrane oxygenation were lower median daily prothrombin time in percentage (Quick) ( t = -0.016, p < 0.0001), higher median daily free bilirubin level ( t = 0.016, p < 0.0001), and lower pH ( t = -2.434, p < 0.0001). In multivariate analysis, red blood cell transfusion was associated with a significantly higher rate of in-intensive care unit mortality (per red blood cell unit increment; adjusted odds ratio: 1.07, 95% confidence interval: 1.02-1.12, p = 0.005). It was also associated with higher rates of acute renal failure ( p = 0.025), thromboembolic complications ( p = 0.0045), and sepsis ( p = 0.015).

Conclusion: This study suggests that red blood cell transfusion may be associated with a higher mortality rate and with severe complications. However, we cannot conclude a direct causal relationship, as red blood cell transfusion may be only a marker of poor outcome. We recommend that physicians correct acidosis and hemolysis in patients undergoing extracorporeal membrane oxygenation whenever possible.