Effects of turbulent stresses upon mechanical hemolysis: Experimental and computational analysis
Effects of turbulent stresses upon mechanical hemolysis: Experimental and computational analysis
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DOI：
10.1097/01.mat.0000136512.36370.b5
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发表时间：
2004-09-01
期刊：
影响因子：
4.2
通讯作者：
Umezu, M
中科院分区：
文献类型：
--
作者：
Kameneva, MV;Burgreen, GW;Umezu, M
进行了实验和计算研究，以阐明湍流应力在机械性血液损伤（溶血）中的作用。用离心泵将牛红细胞（RBC）悬液驱动通过封闭循环回路。通过锥形连接器将小毛细管（内径1 mm和长度70 mm）结合到循环回路中。用盐水稀释RBC悬浮液，以在23 ℃下达到2.0 +/- 0.1 cP的渐近表观粘度，从而在标称流速和压力下产生湍流。为了研究在相同毛细管中相同壁剪切应力下的层流，通过加入右旋糖酐-40将RBC悬浮液的表观粘度增加至6.3 +/- 0.1 cP（23 ℃）。使用驱动压力和右旋糖酐介导的动态粘度调节的各种组合，产生范围为300- 5，000的雷诺数，并测量溶血速率。进行了初步研究，以验证悬浮培养基不会影响RBC的机械脆性。这些实验室研究的结果表明，在毛细管中相同的壁剪切应力下，与层流相比，湍流的溶血水平显著更高（p < 0.05）。这证实了湍流应力对血液机械创伤有很大的影响。通过计算流体动力学模型得到的溶血的数值预测与这些实验数据吻合良好。
Experimental and computational studies were performed to elucidate the role of turbulent stresses in mechanical blood damage (hemolysis). A suspension of bovine red blood cells (RBC) was driven through a closed circulating loop by a centrifugal pump. A small capillary tube (inner diameter 1 mm and length 70 mm) was incorporated into the circulating loop via tapered connectors. The suspension of RBCs was diluted with saline to achieve an asymptotic apparent viscosity of 2.0 +/- 0.1 cP at 23degreesC to produce turbulent flow at nominal flow rate and pressure. To study laminar flow at the identical wall shear stresses in the same capillary tube, the apparent viscosity of the RBC suspension was increased to 6.3 +/- 0.1 cP (at 23degreesC) by addition of Dextran-40. Using various combinations of driving pressure and Dextran mediated adjustments in dynamic viscosity Reynolds numbers ranging from 300-5,000 were generated, and rates of hemolysis were measured. Pilot studies were performed to verify that the suspension media did not affect mechanical fragility of the RBCs. The results of these bench studies demonstrated that, at the same wall shear stress in a capillary tube, the level of hemolysis was significantly greater (p < 0.05) for turbulent flow as compared with laminar flow. This confirmed that turbulent stresses contribute strongly to blood mechanical trauma. Numerical predictions of hemolysis obtained by computational fluid dynamic modeling were in good agreement with these experimental data.