Development of a Reversing Electrohydraulic Energy Converter for Left Ventricular Assist Devices

摘要

A complete LVAS system utilizing the Jarvik-7 ventricle, reversing electrohydraulic energy converter, reservoir chamber, and Utah motor commutator, has been developed. Achievements include: energy converter volume = 30 cc, weight = 90 gm, energy converter efficiency >20%; peak motor efficiency >80%; peak axial flow pump efficiency >75%, hydraulic fluid flow (mean) >12l/min at 120 beats/min, 120 mm Hg mean systolic axial flow pump (AFP) differential pressures; blood pump flow >10l/min at 120 beats/min, 120 mm HgAoP, 0 mm Hg filling pressure; implantable LVAS system <400 cc, <400 gm (energy converter, blood pump, hydraulic fluid, and reservoir chamber). A magnetic thrust bearing prototype was developed. Durability tests, however, indicate ball bearings are likely to meet the 2-year requirement. There were no failures and insignificant wear after 540 million reversals (accelerated reversal test) and 1-1/2 years uni-directional operation. Consistent, reliable motor commutation with rapid reversal (under load in <16 milliseconds) has been achieved. Mathematical modelling of AFP performance was inititated for AFP design optimization.