Development of a Compact, Sealless, Tripod Supported, Magnetically Driven Centrifugal Blood Pump

Yuhki, A; Nogawa, M.; Takatani, Setsuo

doi:10.1046/j.1525-1594.2000.06588.x

Cited by 11 publications

(7 citation statements)

References 13 publications

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“…In a centrifugal pump, it is known that the difference in pressure between the top slope and the bottom surface of the impeller generated by the difference between the flow velocities results in an axial thrust (13). As a result, the vanes mounted on the impeller may make contact with the top housing (14,15). Therefore, we investigated whether or not the impeller made contact with the housing during pump operation.…”

Section: Resultsmentioning

confidence: 99%

A Compact Highly Efficient and Low Hemolytic Centrifugal Blood Pump With a Magnetically Levitated Impeller

Asama¹,

Shinshi

Hoshi

et al. 2006

Artificial Organs

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A 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 against a head pressure of 105 mm Hg were 6.5 W and 21%, respectively. To evaluate the characteristics of the maglev CBP when subjected to a disturbance, excitation of the base, simulating the movement of the patient in various directions, and the sudden interception of the outlet tube connected with the pump in a mock circulatory loop, simulating an unexpected kink and emergent clamp during a heart surgery, were tested by monitoring the five-degree-of-freedom motion of the impeller. Furthermore, 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.

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Section: Resultsmentioning

confidence: 99%

A Compact Highly Efficient and Low Hemolytic Centrifugal Blood Pump With a Magnetically Levitated Impeller

Asama¹,

Shinshi

Hoshi

et al. 2006

Artificial Organs

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“…In this article, the control strategy for continuous flow centrifugal pumps is discussed. The study was organized using a tripod supported sealless centrifugal blood pump that was developed in our laboratory (19). The prototype tripod pump has good performance that meets the basic requirement for either left or right heart bypass application.…”

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confidence: 99%

Control Strategy for Rotary Blood Pumps

et al. 2001

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The control strategy for ventricular support with a centrifugal blood pump was examined in this study. The control parameter was the pump rpm that determines pump flow. Optimum control of pump rpm that reflects the body's demand is important for long-term, effective, and safe circulatory support. Moreover, continuous, reliable monitoring of ventricular function will help successfully wean the patients from the ventricular assist device (VAD). The control strategy in this study includes determination of the target pump rpm that can provide the flow required by the body, fine-rpm-tuning to minimize deleterious effects such as suction in the ventricle, and assessment of ventricular function for successful weaning from VADs. To determine the target pump rpm, we proposed to use the relation between the native heart rate and cardiac output, and the relation between the pump rpm and centrifugal pump output. For fine-tuning of the pump rpm, the motor current waveform was used. We computed the power spectral density of the motor current waveform and calculated the ratio of the fundamental to the higher order components. When this ratio was larger than approximately 0.2, we assumed there would be a suction effect in the ventricle. As for assessment of ventricular function, we used the amplitude of the motor current waveform. The control system implemented using a DSP functioned properly in the mock circulatory loop as well as in acute animal experiments. The motor current also showed a good correlation with the ventricular pressure in acute animal experiments.

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“…The pump can provide flows of 4 to 5 L/min against the 100 mm Hg head pressure at 2,000 rpm. Compared with the head pressure‐flow curves of the tripod supported centrifugal pump previously reported (6,7), pump efficiency was roughly twice due to reduction in the friction loss at the pivot bearing. Optimization in the coupling distance between the driver and follower magnets and selection of the permanent magnet materials should improve pump performance by reducing the friction loss at the pivot bearing and hence the required power.…”

Section: Discussionmentioning

confidence: 70%

“…To meet this need, previously we reported the concept and performance of a tripod supported, sealless, ultracompact centrifugal blood pump that was originally proposed by Nosé and Ohara (5). The hydrodynamic characteristics of the tripod supported centrifugal blood pump showed acceptable performance as a left and/or right ventricular support device (6–8). However, the effect of the friction between the tripod and polyethylene groove was shown not to be suitable for long‐term use.…”

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confidence: 99%

Design and Evaluation of a Single‐Pivot Supported Centrifugal Blood Pump

et al. 2001

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In order to develop a centrifugal blood pump that meets the requirements of a long-term, implantable circulatory support device, in this study a single-pivot bearing supported centrifugal blood pump was designed to evaluate its basic performance. The single-pivot structure consisted of a ceramic ball male pivot mounted on the bottom surface of the impeller and a polyethylene female pivot incorporated in the bottom pump casing. The follower magnet mounted inside the impeller was magnetically coupled to the driver magnet mounted on the shaft of the direct current brushless motor. As the motor rotated, the impeller rotated supported entirely by a single-pivot bearing system. The static pump performance obtained in the mock circulatory loop revealed an acceptable performance as a left ventricular assist device in terms of flow and head pressure. The pump flow of 5 L/min against the head pressure of 100 mm Hg was obtained at rotational speeds of 2,000 to 2,200 rpm. The maximum pump flow was 9 L/min with 2,200 rpm. The maximum electrical-to-hydraulic power conversion efficiency was around 14% at pump flows of 4 to 5 L/min. The stability of the impeller was demonstrated at the pump rpm higher than 1,400 with a single-pivot bearing without an additional support at its top. The single-pivot supported centrifugal pump can provide adequate flow and pressure as a ventricular assist device, but its mechanical stability and hemolytic as well as thrombotic performances must be tested prior to clinical use.

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Development of a Compact, Sealless, Tripod Supported, Magnetically Driven Centrifugal Blood Pump

Cited by 11 publications

References 13 publications

A Compact Highly Efficient and Low Hemolytic Centrifugal Blood Pump With a Magnetically Levitated Impeller

A Compact Highly Efficient and Low Hemolytic Centrifugal Blood Pump With a Magnetically Levitated Impeller

Control Strategy for Rotary Blood Pumps

Design and Evaluation of a Single‐Pivot Supported Centrifugal Blood Pump

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