Hemolysis testing of a small-sized axial flow pump for implantation in patients with low anthropometric parameters

Abstract

The Biotechnical Systems Laboratory assessed the trauma potential of a newly developed pediatric implantable axial flow pump. A mathematical evaluation was performed to assess shear stress, blood exposure time, and the hemolysis index. Regions contributing to blood trauma were identified at flow rates ranging from 1.5 to 2.5 L/min. A standardized methodology was developed and applied to evaluate blood cell damage (hemolysis) under simulated pediatric hemodynamic conditions, with a pressure gradient of 85 ± 5 mm Hg and three flow rates of 1.5, 2.0, and 2.5 L/min. The operation of the compact implantable axial pump prototype under left ventricular assist conditions was designed to account for the anthropometric characteristics of patients with a body surface area of less than 1.2 m². Hemolysis tests were performed using a hydrodynamic test bench that ensures continuous circulation of donor blood. The testing protocol involved measuring the concentration of free hemoglobin in plasma samples collected during pump operation on the test bench. Based on these measurements, hemolysis and modified hemolysis indices were calculated, demonstrating positive performance dynamics of the pump under the tested conditions.