Evaluation of Erythrocyte Flow at a Bearing Gap in a Hydrodynamically Levitated Centrifugal Blood Pump

Daisuke Sakota, Masahiro Nishida, Osamu Maruyama, Ryo Kosaka, Takashi Yamane, Tomotaka Murashige, Yasuo Kawaguchi

Details

Category

Contributed papers (Oral)

Theme

05. Cardiovascular and Respiratory Systems Engineering

Sessions

08:30 - 10:00 | Wed 26 Aug | Suite 5 | 5.1

Therapeutic Intravascular Devices I

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.

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