Temperature Influence on Erythrocytes’ Threshold Limit for Hemolysis in Shear Flow Based on the Immersed Boundary-Lattice Boltzmann Method

Abstract

The temperature of blood pumps and other left ventricular assistance devices (LVAD) increases during operation due to the effects of the electromagnetic drive and mechanical work. The blood is heated when passing through an LVAD. Temperature can influence erythrocytes’ mechanical properties and erythrocytes’ threshold shear stress for hemolysis in shear flow. A nonlinear two-dimensional membrane model was introduced based on the linear spring network model and non-linear worm-like-chains (WLC) model. The simulation of erythrocytes in shear flow was performed in the framework of the immersed boundary-lattice Boltzmann method (IB-LBM). When the shear stress was set to the often-cited threshold for hemolysis of 400 Pa and the temperature was 37°C, the free energy change of the erythrocyte membrane was calculated to be 3.5 × 10 −15J, which was defined as the threshold value of erythrocytes’ membrane energy change for hemolysis. As the temperature rose to 39°C, 41°C and 43°C, the shear stress varied from 200 to 400 Pa, the free energy changed, and the shape parameters were studied. By comparing the threshold energy changes, we found the threshold shear stress values at 39°C, 41°C and 43°C to be 340, 315 and 295 Pa, respectively. Whether red blood cells (RBCs) are damaged when passing through an LVAD can be determined according to these data. This work should provide a basis for LVAD design and optimization.