Comparing hemolysis among extracorporeal pumps: A large-scale retrospective study

Background Hemolysis is a frequent and clinically relevant complication during extracorporeal life support (ECLS, or ECMO), associated with acute kidney injury, systemic inflammation, and increased mortality. Direct comparisons between pumps regarding hemolysis are limited. This study evaluated and compared hemolysis profiles among several devices in clinical practice. Methods We conducted a retrospective, single-center cohort study adult patients who received veno-arterial (V-A) or veno-venous (V-V) ECMO between January 2020 and December 2023 ( N = 230). Patients were categorized by one of four ECMO pump types, and hemolysis was assessed using lactate dehydrogenase (LDH) and plasma-free hemoglobin (pfHb) as primary markers. Multivariable linear mixed-effects models were used to analyze associations between pump type and hemolysis, adjusting for several covariates including revolutions per minute (RPM), hematologic indices, ECMO mode, and severity scores. Results Partial thromboplastin time ( p < 0.005), hemoglobin ( p < 0.001), and use of continuous renal replacement therapy (CRRT, p < 0.001) were positively correlated with both LDH and pfHb concentrations and hemolysis, while fibrinogen ( p < 0.03) was inversely correlated. Without RPM adjustment, NovaLung exhibited the highest LDH (680.3 U/L) and pfHb (29.4 mg/dL), followed by the Cardiohelp, Rotaflow, and CentriMag. In the RPM-adjusted analysis, LDH was highest in Cardiohelp (737.4 U/L), followed by the Rotaflow, CentriMag, and NovaLung; whereas pfHb was highest in Cardiohelp (25.8 mg/dL), followed by the Rotaflow, NovaLung, and CentriMag. Conclusions This study provides a clinical associations of the safety and performance of four centrifugal pumps in real-world ECMO practice in adults. We demonstrate that pump-specific RPM may be potentially correlated with hemolysis during ECMO in clinical practice, illustrating that the diagonal pump, which operated at the highest RPMs, was associated with the highest hemolysis in models without the RPM adjustment. Future studies are warranted to further clarify the impact of hemolysis on outcomes.