Hemolysis at low blood flow rates: in-vitro and in-silico evaluation of a centrifugal blood pump

Malte Schöps,Sascha H Groß-Hardt,Johanna C Clauser,Daniel Brodie,Thomas Schmitz-Rode,Christian Karagiannidis,Ulrich Steinseifer

doi:10.1186/s12967-020-02599-z

Abstract

BackgroundTreating severe forms of the acute respiratory distress syndrome and cardiac failure, extracorporeal membrane oxygenation (ECMO) has become an established therapeutic option. Neonatal or pediatric patients receiving ECMO, and patients undergoing extracorporeal CO2 removal (ECCO2R) represent low-flow applications of the technology, requiring lower blood flow than conventional ECMO. Centrifugal blood pumps as a core element of modern ECMO therapy present favorable operating characteristics in the high blood flow range (4 L/min–8 L/min). However, during low-flow applications in the range of 0.5 L/min–2 L/min, adverse events such as increased hemolysis, platelet activation and bleeding complications are reported frequently.MethodsIn this study, the hemolysis of the centrifugal pump DP3 is evaluated both in vitro and in silico, comparing the low-flow operation at 1 L/min to the high-flow operation at 4 L/min.ResultsIncreased hemolysis occurs at low-flow, both in vitro and in silico. The in-vitro experiments present a sixfold higher relative increased hemolysis at low-flow. Compared to high-flow operation, a more than 3.5-fold increase in blood recirculation within the pump head can be observed in the low-flow range in silico.ConclusionsThis study highlights the underappreciated hemolysis in centrifugal pumps within the low-flow range, i.e. during pediatric ECMO or ECCO2R treatment. The in-vitro results of hemolysis and the in-silico computational fluid dynamic simulations of flow paths within the pumps raise awareness about blood damage that occurs when using centrifugal pumps at low-flow operating points. These findings underline the urgent need for a specific pump optimized for low-flow treatment. Due to the inherent problems of available centrifugal pumps in the low-flow range, clinicians should use the current centrifugal pumps with caution, alternatively other pumping principles such as positive displacement pumps may be discussed in the future.

Highlights

The use of extracorporeal membrane oxygenation (ECMO) in adult patients has been increasing rapidly in recent years [1]
ECMO therapy has become an established alternative as a rescue therapy in the treatment of severe forms of the acute respiratory distress syndrome (ARDS) with promising case series of extracorporeal C O2 removal (ECCO2R) in chronic obstructive pulmonary
We evaluated the hemolysis of a blood pump at both operating points in-vitro and compared the results with in-silico computational fluid dynamics (CFD) simulations and flow paths within the pump

Summary

Introduction

The use of extracorporeal membrane oxygenation (ECMO) in adult patients has been increasing rapidly in recent years [1]. During low-flow applications, i.e. neonatal or pediatric ECMO or ECCO2R, the operating ranges are markedly lower at 0.5 L/min–2 L/min. These low-flow operating points contribute to adverse events such as increased hemolysis, platelet activation and bleeding complications [7, 8]. This may be a important issue in vulnerable pediatric patients, where blood trauma should be carefully avoided [6, 9,10,11,12,13,14]. During low-flow applications in the range of 0.5 L/min–2 L/min, adverse events such as increased hemolysis, platelet activation and bleeding complications are reported frequently

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Discussion

Conclusion