BACKGROUND Current generation mechanical circulatory assist devices are designed to minimize high shears to blood for prolonged durations to avoid hemolysis. However, red blood cells (RBC) demonstrate impaired capacity to deform when exposed to shear stress (SS) well below the "hemolytic threshold". OBJECTIVE We endeavored to identify how changes in the magnitude and duration of SS exposure alter RBC deformability and subsequently develop a model to predict erythrocyte subhemolytic damage. METHODS RBC suspensions were exposed to discrete magnitudes of SS (1-64 Pa) for specific durations (1-64 s), immediately prior to RBC deformability being measured. Analyses included exploring the maximal RBC deformation (EImax) and SS required for half EImax (SS1/2). A surface-mesh was interpolated onto the raw data to predict impaired RBC deformability. RESULTS When SS was applied at <16Pa, limited changes were observed. When RBC were exposed to 32 Pa, mild impairments in EImax and SS1/2 occurred, although 64 Pa caused a dramatic impairment of RBC deformability. A clear relation between SS duration and magnitude was determined, which could predict impaired RBC deformability. CONCLUSION The present results provide a model that may be used to predict whether RBC deformability is decreased following exposure to a given level and duration of SS, and may guide design of future generations of mechanical circulatory assist devices.

中文翻译：

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预测剪切应力暴露的水平和持续时间，该水平和持续时间会引起对红细胞的亚溶血性损伤。

背景技术当前世代的机械循环辅助装置被设计成在长时间内最小化对血液的高剪切以避免溶血。然而，当暴露于远低于“溶血阈值”的切应力（SS）时，红细胞（RBC）的变形能力受损。目的我们努力确定SS暴露的幅度和持续时间的变化如何改变RBC的可变形性，并随后开发一种预测红细胞亚溶血性损伤的模型。方法在测量RBC的可变形性之前，将RBC悬浮液暴露于特定强度（1-64 s）的SS（1-64 Pa）离散量。分析包括探索最大EImax（SS1 / 2）一半所需的最大RBC变形（EImax）和SS。将表面网格插值到原始数据上，以预测受损的RBC变形能力。结果当在小于16Pa的条件下使用SS时，观察到的变化很小。当RBC暴露于32 Pa时，尽管64 Pa引起RBC变形能力的显着损害，但EImax和SS1 / 2均出现了轻度损害。确定了SS持续时间和幅度之间的明确关系，这可以预测RBC的可变形性受损。结论本结果提供了可用于预测在暴露于给定水平和持续时间的SS后RBC变形能力是否降低的模型，并且可指导下一代机械循环辅助设备的设计。尽管64 Pa导致RBC变形能力大大降低。确定了SS持续时间和幅度之间的明确关系，这可以预测RBC的可变形性受损。结论本结果提供了可用于预测在暴露于给定水平和持续时间的SS后RBC变形能力是否降低的模型，并且可指导下一代机械循环辅助设备的设计。尽管64 Pa导致RBC变形能力大大降低。确定了SS持续时间和幅度之间的明确关系，这可以预测RBC的可变形性受损。结论本结果提供了可用于预测在暴露于给定水平和持续时间的SS后RBC变形能力是否降低的模型，并且可指导下一代机械循环辅助设备的设计。