In blood vessels and in artificial tubes with diameters of less than 500 μm, both the blood viscosity and the hematocrit decrease with decreasing tube diameter. The present study was designed to measure the dependence of viscosity reduction on hematocrit reduction of red blood cell (RBC) suspensions of neonates and adults by means of a capillary viscometer. RBC were suspended in buffer solution at hematocrits of 0.40, 0.50 and 0.601/l. Glass tubes with diameters of 270, 100 and 50 μm were perfused with these suspensions. Tube hematocrit and viscosity decreased significantly at each feed Hct when going from 270 μm tubes to 50 μm tubes. Hematocrit and viscosity reductions were more pronounced for neonatal RBC than for adult cells at each feed hematocrit. At a feed Hct of 0.60 l/l viscosity reduction was 37% for neonates and 29% for adults, whereas at a Hct of 401/l viscosity reductions were only 30% and 25%, respectively. Hct reductions in 50-μm tubes were 27% for neonates and 20% for adults at a feed Hct of 0.60 l/l and 45% for neonates and 40% for adults at a feed hematocrit of 0.40 l/l. Tube viscosities increased exponentially with increasing tube hematocrit. We conclude that the stronger viscosity reduction of neonatal RBC in 50-μm tubes results from the stronger hematocrit reduction of neonatal cells.
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机译：在直径小于500μm的血管和人造管中，血液粘度和血细胞比容均随管直径的减小而降低。本研究旨在通过毛细管粘度计测量粘度降低对新生儿和成人红细胞（RBC）悬浮液的血细胞比容降低的依赖性。将RBC以0.40、0.50和0.601 / l的血细胞比容悬浮在缓冲溶液中。用这些悬浮液灌注直径为270、100和50μm的玻璃管。当从270μm管变为50μm管时，每次进料Hct的管血细胞比容和粘度均显着降低。在每种饲料中，新生儿红细胞的血细胞比容和粘度降低比成年细胞更明显。饲料的Hct为0.60 l / l时，新生儿的粘度降低为37％，成人为29％，而饲料的Hct为401 / l时，粘度降低分别仅为30％和25％。饲喂血细胞比容为0.40 l / l的Hct为0.60 l / l时，新生儿的50μm管的Hct减少为27％，成人为20％，新生儿血细胞比容为40％的新生儿和40％。试管粘度随试管血细胞比容的增加呈指数增加。我们得出的结论是，在50μm的试管中，新生儿RBC的粘度降低更强，这是由于新生儿细胞的血细胞比容降低了。
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