Shear stress related blood damage in laminar Couette flow
Shear stress related blood damage in laminar Couette flow
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DOI：
10.1046/j.1525-1594.2003.07103.x
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发表时间：
2003-06-01
影响因子：
2.4
通讯作者：
Reul, H
中科院分区：
文献类型：
--
作者：
Paul, R;Apel, J;Reul, H
血流内的人造器官通常与流动诱导的血液损伤，特别是红细胞的溶血有关。已知这些破坏作用取决于剪切力和暴露时间。本研究的主题是确定这些流量依赖性特性与实际溶血之间的相关性。为此，开发了一种Couette装置。基于碳氟化合物的流体密封用于将血液与二次外部损伤效应分离。差距内的剪切速率由内圆筒的旋转速度控制，并且暴露时间由每给定时间轴向泵送通过装置的血液量控制。通过溶血指数（IH）量化血液损伤，该指数由光度血浆血红蛋白测量值计算。实验在t（ex）=25 - 1250 ms的暴露时间和tau=30至450 Pa的剪切速率范围内进行，确保泰勒涡流自由流动特性。在很宽的剪切速率和暴露时间范围内，血液损伤非常低。然而，当剪切应力τ大于或等于425 Pa，暴露时间t（exp）大于或等于620 ms时，可观察到血液损伤显著增加。研究范围内的最大溶血为IH= 3.5%。结果表明，血液损伤通常低于早期使用可比器械的研究中报告的血液损伤，并且测量结果清楚地表明，临界水平的剪切应力和暴露时间）比溶血的逐渐增加更有效，至少对于所研究的剪切速率和暴露时间范围。
Artificial organs within the blood stream are generally associated with flow-induced blood damage, particularly hemolysis of red blood cells. These damaging effects are known to be dependent on shear forces and exposure times. The determination of a correlation between these flow-dependent properties and actual hemolysis is the subject of this study. For this purpose, a Couette device has been developed. A fluid seal based on fluorocarbon is used to separate blood from secondary external damage effects. The shear rate within the gap is controlled by the rotational speed of the inner cylinder, and the exposure time by the amount of blood that is axially pumped through the device per given time. Blood damage is quantified by the index of hemolysis (IH), which is calculated from photometric plasma hemoglobin measurements. Experiments are conducted at exposure times from t(exp) =25 - 1250 ms and shear rates ranging from tau=30 up to 450 Pa ensuring Taylor-vortex free flow characteristics. Blood damage is remarkably low over a broad range of shear rates and exposure times. However, a significant increase in blood damage can be observed for shear stresses of taugreater than or equal to 425 Pa and exposure times of t(exp) greater than or equal to 620 ms. Maximum hemolysis within the investigated range is IH=3.5%. The results indicate generally lower blood damage than reported in earlier studies with comparable devices, and the measurements clearly indicate a rather abrupt (i.e., critical levels of shear stresses and exposure times) than gradual increase in hemolysis, at least for the investigated range of shear rates and exposure times.