Evaluation of an extended viscoelastic model to predict hemolysis in cannulas and blood pumps

While the power-law model has been used widely to predict hemolysis numerically, it has a few inherent limitations that may result in inaccurate prediction. As an alternative, the viscoelastic model is a strain-based model derived using the mechanical properties of the red blood cell and erythrocyte. The model assumes two different time scales that lead to modified exponential trends versus the exposure time. As a zero-dimensional model, the viscoelastic model is not applicable to a complex multi-dimensional problem. In the present study, it is extended to a form based on partial differential equations for multi-dimensional hemodynamic flows such as cannulas and blood pumps. The extended method is revised further to comply with a physical constraint. When evaluated using experimental data and relative hemolysis indices, the extended viscoelastic model does not show a clear advantage over the power-law model for cannula problems with relatively short residence times. In contrast, the viscoelastic model shows improved agreement with experimental data consistently for flows inside blood pumps with relatively long residence times. Considering that the viscoelastic model was targeted originally at improving prediction at a long residence time, the present results are consistent with a previous study. As a result, it is implied that the extended viscoelastic model is useful for specific applications such as blood pumps compared to the previous methods.