Baldwin J T, Tarbell J M, Deutsch S, Geselowitz D B
Bioengineering Program, Pennsylvania State University, University Park 16802.
ASAIO Trans. 1991 Jul-Sep;37(3):M348-9.
Fluid velocities were measured with a two-component laser Doppler anemometry system in the regurgitant jet regions of Bjork-Shiley Delrin monostrut tilting disc valves mounted within a Plexiglas model of the 70 cm3 Penn State electric left ventricular assist device. At each measurement location, 250 instantaneous velocity realizations were collected at times when regurgitation through the valves occurred. The maximum Reynolds shear and normal stresses were calculated after filtering the data. Results show that Reynolds shear and normal stresses proximal to the mitral valve were elevated to magnitudes of 9,000 dynes/cm2 and 20,000 dynes/cm2, respectively. The peak Reynolds stresses near the mitral valve occurred during early systole, when regurgitant jet velocities reached magnitudes as high as 440 cm/sec. The Reynolds shear and normal stresses proximal to the aortic valve reached magnitudes of 9,900 dynes/cm2 and 20,500 dynes/cm2, respectively. The peak Reynolds stresses near the aortic valve occurred during early diastole, when regurgitant jet velocities were as high as 280 cm/sec. These high Reynolds stresses created by turbulent regurgitant flow have the potential to cause significant blood damage.
使用双分量激光多普勒测速系统，在安装于70立方厘米宾夕法尼亚州立大学电动左心室辅助装置的有机玻璃模型内的 Bjork-Shiley 德尔林单支柱倾斜盘式瓣膜的反流喷射区域测量流体速度。在每个测量位置，当瓣膜发生反流时，采集250个瞬时速度数据。对数据进行滤波后，计算最大雷诺切应力和法向应力。结果表明，二尖瓣近端的雷诺切应力和法向应力分别升高到9000达因/平方厘米和20000达因/平方厘米。二尖瓣附近的雷诺应力峰值出现在收缩早期，此时反流喷射速度高达440厘米/秒。主动脉瓣近端的雷诺切应力和法向应力分别达到9900达因/平方厘米和20500达因/平方厘米。主动脉瓣附近的雷诺应力峰值出现在舒张早期，此时反流喷射速度高达280厘米/秒。由湍流反流产生的这些高雷诺应力有可能导致严重的血液损伤。
