Magnetic levitation motor for pediatric cardiac and cardiopulmonary therapies

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Abstract This Phase I STTR application proposes development of an innovative, low cost, magnetic levitation motor specifically designed for pediatric extracorporeal cardiac and cardiopulmonary therapies. Magnetic levitation enables contact-free impeller operation thereby eliminating critical areas of wear and heat generation that can contribute to hemolysis and thrombosis. The extracorporeal pediatric market is currently served by a single magnetically levitated blood pump (St. Jude Medical's PediMag (formerly Thoratec)). As with many pediatric medical products, the PediMag is a scaled-down version of a prior adult device originally designed for post- cardiotomy support (CentriMag). While PediMag has been used successfully in a range of post-cardiotomy support applications, broader usage is complicated by several factors including lack of ancillary componentry designed specifically for the pump system (e.g., pediatric blood oxygenator and heat exchanger), complex control algorithms, and a high disposable cost (approximately $8000 per disposable PediMag pump head). To address these shortcomings, we propose an innovative magnetic levitation system based on a hysteresis motor concept that permits a smaller overall configuration, eliminates magnetic field safety concerns, reduces vibration, and relocates the costly rare earth magnetic elements from the disposable blood-contacting component to the reusable motor stator. The hysteresis motor design also permits simplified control algorithms for enhanced robustness and reduced power requirements enhancing patient transport and mobility. The rotor/impeller portion of the proposed hysteresis motor will be based on the same impeller geometry as is currently used in the existing pCAS pump-oxygenator replacing the current mechanical bearings, rotating shaft, and blood contacting seal. This strategy will lower overall development costs and permit the use of existing comprehensive in vitro and in vivo test data to allow direct and efficient comparison of the performance of the new magnetically levitated prototype to the existing blood seal-based pCAS pump- oxygenator. In Phase I, we will perform two acute and one 3-day chronic animal study. This permits us to demonstrate basic feasibility while simultaneously minimizing costs and the Phase I project timeline. However, as part of a subsequent Phase II effort we plan to significantly expand our chronic in vivo studies to include multiple evaluations of at least 30 days. !