Rheologic behavior of sickle and normal red blood cell mixtures in sickle plasma: implications for transfusion therapy
Rheologic behavior of sickle and normal red blood cell mixtures in sickle plasma: implications for transfusion therapy
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DOI：
10.1111/j.1537-2995.2006.00823.x
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发表时间：
2006-06-01
期刊：
影响因子：
2.9
通讯作者：
Fisher, Timothy C.
中科院分区：
文献类型：
--
作者：
Alexy, Tamas;Pais, Eszter;Fisher, Timothy C.
背景技术背景：镰状细胞病输血指南通常将红细胞压积（Hct）上限定义为0.30至0.35，以避免血液高粘滞。缓冲液中正常（AA）和镰状（SS）红细胞（RBC）混合物的体外粘度研究似乎证实，根据Hct与粘度的比值判断，该Hct限值对于向血管床输送氧气是最佳的，该比值通常称为“氧气或RBC输送效率”。“然而，在没有血浆的情况下，不能评估由血浆蛋白介导的RBC-RBC相互作用的影响。为了探讨红细胞在血浆中的最佳红细胞压积与粘度比，（0.20-0.40），SS红细胞比例（0-100%），和剪切速率（1-1000/秒）的混合物的氧合和脱氧SS和AA RBC在37 ℃下在镰状血浆中进行评价。RBC悬浮液粘度是剪切依赖性的（即，粘度随着剪切速率的增加而降低），并且随着Hct和SS RBC的比例而增加。仅在高于50/sec的剪切速率下观察到“最佳”Hct水平（定义为Hct与粘度比的最大值）。在较低的剪切速率下（例如，5/sec），其中血浆介导的RBC-RBC相互作用占主导地位，Hct的任何增加都被粘度成比例的更大增加所抵消，从而导致较低的Hct-粘度比。剪切速率）和器官特异性血流动力学。
BACKGROUND: Guidelines for transfusion in sickle cell disease usually define an upper hematocrit (Hct) limit of 0.30 to 0.35 to avoid blood hyperviscosity. In vitro viscosity studies of normal (AA) and sickle (SS) red blood cell (RBC) mixtures in buffer appear to confirm that this Hct limit is optimal for oxygen delivery to vascular beds as judged by the ratio of Hct to viscosity, with this ratio often termed "oxygen or RBC transport effectiveness." In the absence of plasma, however, effects due to RBC-RBC interactions mediated by plasma proteins cannot be assessed.STUDY DESIGNS AND METHODS: To investigate the optimal Hct-to-viscosity ratio of RBCs in plasma, the rheologic effects of Hct (0.20-0.40), the proportion of SS RBCs (0-100%), and shear rate (1-1000/sec) for mixtures of oxygenated and deoxygenated SS and AA RBCs were evaluated in sickle plasma at 37 degrees C.RESULTS: RBC suspension viscosity was shear-dependent (i.e., viscosity decreased with increasing shear rate) and increased with Hct and proportion of SS RBCs. An "optimal" Hct level (defined as a maximal of the Hct-to-viscosity ratio) was seen only at shear rates above 50/sec. At lower shear rates (e.g., 5/sec), where plasma-mediated RBC-RBC interactions predominate, any increment in Hct was offset by a proportionally greater increase in viscosity, thus leading to a lower Hct-to-viscosity ratio.CONCLUSION: These results indicate the importance of plasma-mediated RBC interactions and suggest that the benefits of transfusion may vary depending on local flow rates (i.e., shear rates) and organ-specific hemodynamics.