Investigation of an Industrial Ejector Pump Design for the Assisted Bidirectional Glenn Using Multiscale Simulations

The high mortality rate of neonates with single ventricle physiology remains unsatisfactory despite recent advancements in surgical techniques. A recently proposed alternative to the conventional stage-one operation, called the assisted bidirectional Glenn (ABG), has demonstrated marked improvements in pulmonary flow and oxygen delivery while reducing the heart load. Alongside these favorable outcomes, ABG also leads to increased superior vena cava (SVC) pressure to a level that may not be tolerated by infants. This increased pressure was a result of an inadequate performance of the ejector pump that was embedded in the original design of the ABG. Thus, the objective of this study is to find an alternative design for this ejector pump that improves the mechanical efficiency and lowers SVC pressure. For this purpose, a representative three-dimensional model of an ejector pump is created based on an industrial ejector pump design and its performance is simulated as a function of nozzle diameter, diffuser angle, and mixer geometry using a finite element flow solver. The performance of the final optimized geometry is examined in a more realistic model of the patient physiology using a multiscale 3D-0D coupled simulation.