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Hemolytic Performance of a MagLev Disposable Rotary Blood Pump (MedTech Dispo): Effects of MagLev Gap Clearance and Surface Roughness
Author(s) -
Hoshi Hideo,
Asama Junichi,
Hijikata Wataru,
Hara Chikara,
Shinshi Tadahiko,
Yasuda Toshitaka,
Ohuchi Katsuhiro,
Shimokohbe Akira,
Takatani Setsuo
Publication year - 2006
Publication title -
artificial organs
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.684
H-Index - 76
eISSN - 1525-1594
pISSN - 0160-564X
DOI - 10.1111/j.1525-1594.2006.00332.x
Subject(s) - maglev , magnetic bearing , materials science , surface roughness , bearing (navigation) , mechanical engineering , biomedical engineering , engineering , rotor (electric) , composite material , physics , astronomy , electrical engineering
Mechanical shaft seal bearing incorporated in the centrifugal blood pumps contributes to hemolysis and thrombus formation. In addition, the problem of durability and corrosion of mechanical shaft seal bearing has been recently reported from the safety point of view. To amend the shortcomings of the blood‐immersed mechanical bearings, a magnetic levitated centrifugal rotary blood pump (MedTech Dispo Model 1; Tokyo Medical and Dental University, Tokyo, Japan) has been developed for extracorporeal disposable application. In this study, the hemolytic performance of the MedTech Dispo Model 1 centrifugal blood pump system was evaluated, with special focus on the narrow blood path clearance at the magnetic bearing between rotor and stator, and on the pump housing surface roughness. A pump flow of 5 L/min against the head pressure of 100 mm Hg for 4 h was included in the hemolytic test conditions. Anticoagulated fresh porcine blood was used as a working fluid. The clearance of blood path at the magnetic bearing was in the range of 100–250 μm. Pump housing surface roughness was controlled to be around Ra = 0.1–1.5 μm. The lowest hemolytic results were obtained at the clearance of 250 μm and with the polished surface (Ra = 0.1 μm) yielding the normalized index of hemolysis (NIH) of less than 0.001 g/100 L, which was 1/5 of the Biopump BP‐80 (Medtronic Inc., Minneapolis, MN, USA, and 1/4 of the BPX‐80. In spite of rough surface and narrow blood path, NIH levels were less than clinically acceptable level of 0.005 g/100 L. The noncontact, levitated impeller system is useful to improve pump performance in blood environment.