Simulation Study and Function Analysis of Micro-axial Blood Pumps

During past decades, various micro-axial blood pumps were invented and have gained widespread acceptance as prospective devices as circulatory support of failing hearts. Studies concerned with the effects of the pumps can be divided into two categories: in vivo studies and simulation studies using mathematical model of the pumps and circulatory system. A new mathematical model of the micro-axial blood pumps is established, which can be applied to various micro-axial blood pumps. By inserting the pump model into the model of canine circulatory system according to clinic setting, the pump's effects can be investigated. In this paper, simulation studies of two types of micro-axial blood pumps, Hemopump and dynamic aortic valve (DAV), are made and the results verified that blood pumps decrease the workload of the heart by increasing pump flux, stroke volume, aortic pressure and decreasing left ventricular pressure and volume, left atrial pressure, the blood pumped by the left ventricle. With the increasing of rotation speed, the benefit effects are enhanced, however, too high rotation speed may cause left ventricular collapse. For Hemopump at above 24500 rpm left ventricular collapse is observed and for DAV it is not obtained below 9000 rpm. The simulation results are found in good agreement with the in vivo experimental results