Fisher T C, Van Der Waart F J, Meiselman H J
Department of Physiology and Biophysics, University of Southern California School of Medicine, Los Angeles 90033, USA.
Biorheology. 1996 Mar-Apr;33(2):153-68. doi: 10.1016/0006-355X(96)00013-3.
Much attention has been paid to the study of blood flow in long, narrow tubes. While the influence of tube diameter and driving pressure have been examined in detail, the influence of suspending phase viscosity has generally been assumed only to affect the blood viscosity in a linearly proportional manner, hence the practice of normalizing apparent blood viscosity values by the suspending phase viscosity to give a relative viscosity (e.g., Pries et al., 1992). While this assumption is probably valid for long tubes, it apparently does not hold for blood flow in short tubes (and by extension also for flow in short or branching capillary segments in vivo) in which RBC deformation plays a more significant role. In this paper we present a series of experiments using the Cell Transit Analyzer (CTA) in which the influence of driving pressure and suspending phase viscosity on RBC passage through short, narrow tubes has been systematically evaluated. Over the range studied (1 to 10 cm water), the influence of driving pressure was found to be unremarkable, in that RBC velocity scaled directly and linearly with pressure. This finding is consistent with previous studies. However, a distinct intercept was observed in the linear relationship between RBC pore transit time and suspending phase viscosity, which presumably arises as a consequence of RBC deformation either at the pore entrance or within the pore. Two simple mathematical models for the suspending phase-viscosity/transit-time relationship were considered. The results show that making CTA measurements over a range of suspending medium viscosities is a simple and practical way to obtain additional information about RBC mechanical properties.
人们对长而细的管道中的血流研究给予了极大关注。虽然已经详细研究了管道直径和驱动压力的影响，但悬浮相粘度的影响通常仅被认为以线性比例方式影响血液粘度，因此通过悬浮相粘度对表观血液粘度值进行归一化以得到相对粘度的做法很常见（例如，Pries等人，1992年）。虽然这个假设对于长管道可能是有效的，但对于短管道中的血流显然不成立（并且由此延伸到体内短或分支毛细血管段中的血流），在这些情况下红细胞变形起着更重要的作用。在本文中，我们展示了一系列使用细胞通过分析仪（CTA）进行的实验，其中系统地评估了驱动压力和悬浮相粘度对红细胞通过短而细的管道的影响。在所研究的范围内（1至10厘米水柱），发现驱动压力的影响不显著，因为红细胞速度与压力直接呈线性比例关系。这一发现与先前的研究一致。然而，在红细胞孔隙通过时间与悬浮相粘度之间的线性关系中观察到一个明显的截距，这可能是由于红细胞在孔隙入口处或孔隙内的变形所致。考虑了两个关于悬浮相粘度/通过时间关系的简单数学模型。结果表明，在一系列悬浮介质粘度范围内进行CTA测量是获取有关红细胞力学特性的额外信息的简单实用方法。
