Schneditz D, Moser M, Smolle-Jüttner F M, Dörp E, Pogglitsch H, Kenner T
Department of Physiology, Karl Franzens University Graz.
Biorheology. 1990;27(6):895-902. doi: 10.3233/bir-1990-27610.
Both blood density and sound speed are closely related to total protein concentration in blood and, as a consequence, to rheologically important parameters of blood. Two methods that permit continuous measurement of these properties, the mechanical oscillator technique and the new ultrasonic technique, were used for measuring blood protein concentration over a continuous period of time in a group of hemodialysis patients and in volunteers. It was seen that the concentration of the components of blood varies considerably. This variability is related to transport phenomena within as well as to the flow of masses across the cardiovascular compartment. From the continuous measurement of concentrations during hemodialysis treatment, relative changes in blood volume can be recorded in order to control the fluid balance of the patient. Rapid fluctuations at the macroscopic scale with periods of 5 to 30 seconds are due to heterogeneities at the microscopic scale and to the particular rheological behaviour of the red blood cells at the level of the capillaries and the small blood vessels. The amplitude of rapid oscillations increased up to 1.2% in terms of hematocrit values when there was rhythmic, spontaneous breathing at various frequencies. The measurement of concentrations at an accessible measuring site may be used to investigate the rheology of blood in the human microvasculature.
血液密度和声速均与血液中的总蛋白浓度密切相关，因此也与血液的流变学重要参数密切相关。两种能够连续测量这些特性的方法，即机械振荡器技术和新的超声技术，被用于在一组血液透析患者和志愿者中连续一段时间测量血液蛋白浓度。可以看出，血液成分的浓度变化很大。这种变异性与心血管腔内的传输现象以及物质跨心血管腔的流动有关。通过在血液透析治疗期间对浓度进行连续测量，可以记录血容量的相对变化，以控制患者的液体平衡。宏观尺度上5至30秒周期的快速波动是由于微观尺度的不均匀性以及红细胞在毛细血管和小血管水平的特殊流变行为所致。当存在不同频率的有节奏的自发呼吸时，快速振荡的幅度以血细胞比容值计增加至1.2%。在可及测量部位测量浓度可用于研究人体微血管中的血液流变学。
