2017 Volume 29 Issue 2 Pages 42-48
Understanding erythrocyte behavior, especially changes in hematocrit in narrow gaps of mechanical circulatory support devices, is important to decrease the pump-derived hemolysis. The present study aimed to propose and evaluate a method of calculating hematocrit in narrow gaps using a high-speed microscope and a laser confocal displacement meter. We calculated hematocrit based on scatter theory and erythrocyte occupancy, mean corpuscular volume, clearance gap, and modeled cross-sectional areas of erythrocytes. The method was initially validated using bovine blood with hematocrit ≤ 1.0% and a comparison of the cross-sectional area modeling. Hematocrit in a spiral groove bearing of a blood pump was then evaluated using bovine blood with hematocrit of 1.0%. As the result, hematocrit calculated using this method was essentially equal to that of the test blood when the circulatory cross-sectional area modeling of biconcave erythrocyte was used. We confirmed that the new method could calculate hematocrit ≤ 1.0% in gaps ≤ 50 μm wide.
