title: Evaluation of erythrocyte flow at a bearing gap in a hydrodynamically levitated centrifugal blood pump.
abstract: We have developed a hydrodynamically levitated centrifugal blood pump for extracorporeal circulatory support. In the blood pump, a spiral groove bearing was adopted for a thrust bearing. In the spiral groove bearing, separation of erythrocytes and plasma by plasma skimming has been postulated to occur. However, it is not clarified that plasma skimming occurs in a spiral groove bearing. The purpose of this study is to verify whether plasma skimming occurs in the spiral groove bearing of a hydrodynamically levitated centrifugal blood pump. For evaluation of plasma skimming in the spiral groove bearing, an impeller levitation performance test using a laser focus displacement meter and a microscopic visualization test of erythrocyte flow using a high-speed microscope were conducted. Bovine blood diluted with autologous plasma to adjust hematocrit to 1.0% was used as a working fluid. Hematocrit on the ridge region in the spiral groove bearing was estimated using image analysis. As a result, hematocrits on the ridge region with gaps of 45 μm, 31 μm, and 25 μm were calculated as 1.0%, 0.6%, and 0.3%, respectively. Maximum skimming efficiency in this study was calculated as 70% with a gap of 25 μm. We confirmed that separation of erythrocyte and plasma occurred in the spiral groove bearing with decrease in bearing gap in a hydrodynamically levitated centrifugal blood pump.
authors.forename: Tomotaka
authors.initials: T
authors.lastname: Murashige
authors.forename: Ryo
authors.initials: R
authors.lastname: Kosaka
authors.forename: Daisuke
authors.initials: D
authors.lastname: Sakota
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nishida
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Kawaguchi
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamane
authors.forename: Osamu
authors.initials: O
authors.lastname: Maruyama
mesh_terms: D000818:Animals; D002417:Cattle; D002498:Centrifugation / Q000295:instrumentation*; D004867:Equipment Design; D004912:Erythrocytes / Q000378:metabolism*; D006400:Hematocrit; D057446:Hydrodynamics; D008962:Models, Theoretical; D010949:Plasma / Q000378:metabolism; D011312:Pressure