Lee J S, Lee L P
Department of Biomedical Engineering, University of Virginia, Charlottesville 22908.
J Appl Physiol (1985). 1988 Dec;65(6):2571-8. doi: 10.1152/jappl.1988.65.6.2571.
By diluting the hematocrit (Ha) in the rabbit's circulation without changing its blood volume, we found that the ventilatory-induced fluctuation (delta rho) in the density of aortic blood and Ha (which was in the range of 8-39%) are related by this linear regression: delta rho = 0.63 g/l (-0.009 + Ha). In this hemodilution experiment, the rabbits were ventilated by an intermittent positive pressure of 6 mmHg at a frequency of 30-35 cycles/min. Based on the Fahraeus effect for capillary blood flows and the dispersion of the density indicator in the rabbit's central circulation, we computed from the fluctuation of the measured density within a ventilation cycle the fluctuation of pulmonary capillary blood volume and found it to be 4.1 +/- 0.4% of the capillary blood volume for all hematocrits. Since the same fluctuation in the airway pressure was used to induce the volumetric fluctuation, its independence of Ha indicates that the hemodilution has no effect on the viscoelasticity of pulmonary capillaries.
通过在不改变家兔循环血量的情况下稀释血细胞比容（Ha），我们发现，主动脉血密度和Ha（范围为8% - 39%）中通气诱导的波动（δρ）通过以下线性回归相关：δρ = 0.63 g/l（-0.009 + Ha）。在该血液稀释实验中，家兔通过6 mmHg的间歇正压以30 - 35次/分钟的频率进行通气。基于法赫瑞效应（Fahraeus effect）对毛细血管血流的影响以及密度指示剂在兔体中心循环中的分散情况，我们根据通气周期内测量密度的波动计算出肺毛细血管血容量的波动，发现对于所有血细胞比容而言，其为毛细血管血容量的4.1±0.4%。由于使用相同的气道压力波动来诱导体积波动，其对Ha的独立性表明血液稀释对肺毛细血管的粘弹性没有影响。
