血液在低压差下作管形定常层流流动其表观粘度与红细胞可逆性聚集的关系

目的　探讨血瘀症的流变学机理。方法　自制流变仪 ,在压差、管径、流态等方面接近人体静脉血流的仿生条件下 ,观察红细胞可逆性聚集与低压差粘度的关系。并与旋转式粘度计测量的结果相比较。结果　在管形定常层流流动中 ,当 τW<7.67× 1 0 -5N/cm2时 ,无论是红细胞本身硬化 ,还是血浆中缺乏使红细胞发生生理性聚集的有效成分 ,只要红细胞丧失了正常的聚集功能 ,低压差粘度均明显高于正常。此与旋转式粘度计测量的低切粘度相反。说明低压差粘度与低切粘度之间无正相关性。结论　流态不同 (片形、管形 ) ,血液的流变特性不同。在管形定常层流流动中 ,红细胞丧失了正常的聚集功能是低压差粘度增高的主要原因。它使静脉血回流阻力增大 ,微循环流出不畅 ,进而造成血液淤滞

The study of the relationship between apparent vislosity and the aggregation of erythrocytes when the blood performs a tubular steady laminal flow with small pressure difference

Objective To probe into the aggregation of blood extravastation.Methods Used self invented capillary viscometer,the study observed the relationship between the reversible aggregation of erythrocytes and lows shear rate viscosity under the condition that the diameter of the capillary tubes.Fluid states and Δ Ρ were close to those of human vein.Then analysized the results which was obtained through the rotational viscometer.Results When τ W<7.67 dyn/cm 2 ,no matter what the reason was,erythrocytes hardening or lack of constituents that were essential to the aggregation of erythrocytes, as long as erythrocytes lost the aggregation ability,the low shear rate viscosity was obviously higher than that of the normal in the tubular steady laminar flow, which was contrary to the results obtained with the rotational viscometer.The outcome revealed the absence of positive correlation between the viscosity of low shear rates and low Δ P.Conclusion Different fluid states (laminar or tubular)determine different rheological characteristics of blood.The rise of low Δ P viscosity in tubular steady laminar flow is mainly due to the erythrocytes that lacks normal aggegation ability, which increases the flow back resistance in vein, and deters the out flow of blood from microcirculation system, therefore, leads to the blood extravastation.