title: Safety margin of magnetic coupling distance in decoupling of a pivot bearing-supported Gyro centrifugal pump (C1E3).
abstract: The pivot bearing-supported Gyro C1E3 centrifugal pump is driven by magnetic coupling. The magnetic coupling distance (MCD) between the impeller magnet and the driver magnet affects both hydraulic performance and hemolysis. Although a greater MCD causes less hemolysis, it increases the risk of decoupling of the impeller magnet. Therefore, it is important to consider the effect of the MCD on both hemolysis and decoupling when the C1E3 pump is applied in various circulatory assist conditions. This study investigates the effect of the MCD on decoupling in a C1E3 pump that is driven by the Nd-Fe-B composite ring-shaped magnets. The results will determine which MCD is the most practical in all assist device conditions. The MCD of the C1E3 pump was varied from 9.5 to 14.5 mm by inserting spacers between the bottom pump housing and the driver magnet. At a rotational speed just before the decoupling occurred, the flow rate and total pressure head were measured. The results revealed that a MCD between 9.5 and 14.5 mm was enough to produce a flow rate of more than 10 L/min without decoupling, and a MCD of less than 11.5 mm was required when the total pressure head was more than 500 mm Hg. Thus, the limiting factor for the MCD of the C1E3 pump is the total pressure head rather than the flow rate. An MCD of less than 11.5 mm is required to prevent decoupling of the impeller of the C1E3 pump with the specific Nd-Fe-B magnets in the full range of clinical circulatory assist conditions.
authors.affiliation: Department of Surgery, Baylor College of Medicine, Houston, Texas 77030, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Takami
authors.forename: T
authors.initials: T
authors.lastname: Nakazawa
authors.forename: K
authors.initials: K
authors.lastname: Makinouchi
authors.forename: J
authors.initials: J
authors.lastname: Glueck
authors.forename: R
authors.initials: R
authors.lastname: Benkowski
authors.forename: Y
authors.initials: Y
authors.lastname: Nosé
mesh_terms: D002498:Centrifugation; D004574:Electromagnetic Fields; D006353:Heart-Assist Devices / Q000145:classification / Q000592:standards*; D006461:Hemolysis; D011312:Pressure