Centrifugal type artificial heart of high durability using a magnetic bearing

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Implantable ventricular assist devises and disposable blood pumps have been developed for heart disease patients.1)Implantable ventricular assist deviseA magnetically levitated (maglev) centrifugal blood pump (CBP), intended for use as a ventricular assist device, needs to be highly durable and reliable for long term use without any mechanical failure. Furthermore, maglev CBPs should be small enough to be implanted into patients of various size and weight. We have developed a compact maglev CBP employing a two-degree-of-freedom controlled magnetic bearing, with a magnetically suspended impeller directly driven by an internal brushless direct current (DC) motor. The magnetic bearing actively controls the radial motion of the impeller and passively supports axial and angular motions using a permanent magnet embedded in the impeller. The overall dimensions of the maglev CBP are 65 mm in diameter and 40 mm in height. The total power consumption and pump efficiency for pumping 6 L/min again … More st a head pressure of 105 mm Hg were 6.5 W and 21%, respectively. The hemolytic characteristics of the maglev CBP were compared with those of the Medtronic Biomedicus BPX-80, which demonstrated the superiority of the maglev CBP.2)Disposable blood pumpA magnetically levitated (MagLev) centrifugal blood pump (MedTech Dispo) has been developed for a disposable extracorporeal system. The pump design is aimed at eliminating mechanical contact of an impeller, realization of a simple disposable mechanism, and reduction of the heating effect on blood due to a motor and a magnetic bearing. The disposable pump head with priming volume of 23 mL consists of top and bottom housings, the impeller and the rotor with diameter of 50 mm. The pump can provide more than 300 mmHg against 5 L/min. Normalized index of hemolysis (NIH) of the MedTech Dispo is 0.0025 ± 0.0005 g/100L at 5 L/min against 250 mmHg. This is one seventh of that of Bio Pump BPX-80 (Medtronic Inc, U.S.A.) of 0.0170 ± 0.0096 g/100L. These results show that the MedTech Dispo realizes high pump performance and low blood trauma. Less