Physiological implications of the fractal distribution of ventilation and perfusion in the lung
Physiological implications of the fractal distribution of ventilation and perfusion in the lung
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DOI：
10.1114/1.1310215
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发表时间：
2000-08-01
影响因子：
3.8
通讯作者：
Glenny, RW
中科院分区：
文献类型：
--
作者：
Robertson, HT;Altemeier, WA;Glenny, RW
随着测量分辨率的提高，区域通气量和区域灌注量均显示出逐渐增加的异质性。由于肺气体交换的效率取决于局部通气量和局部灌注量的匹配，因此在一定范围内检验了这两个参数之间的相关性。我们用雾化1微米荧光微球(FMS)和注射15微米荧光微球(FMS)对三只麻醉猪的局部通风和灌流进行了标记。肺被干燥，充气，切成类似2厘米(3)的立方体，根据从每一块提取的荧光信号的测量来计算区域通气量和血流量。将相邻的碎片聚集成连续较大的聚集体积，并计算每个聚集大小的通气量和灌注量的平均值。虽然通气量和灌注量的变异系数都可以预测地随着集群大小的减小而增加，但集群内通气量和灌注量之间的相关性仍然很高，动物之间的平均相关性在0.82到0.92之间。因此，虽然通气量和灌注量的异质性都随着测量分辨率的提高而增加，但在正常俯卧肺中，这两个参数之间的强相关性几乎是样本大小不变的。这一发现解释了用高分辨率测量在正常肺中观察到的正常气体交换的效率，以及在正常肺中观察到的相当程度的通风和血流不均匀。(C)2000年生物医学工程学会。[S0090-6964(00)01708-2]。
Both regional ventilation and regional perfusion demonstrate progressive increases in heterogeneity as the resolution of measurement is improved. Because the efficiency of pulmonary gas exchange is dependent on the match between local ventilation and local perfusion, the correlation between these two parameters was examined over a range of scale. We marked regional ventilation and perfusion in three anesthetized pigs with aerosolized 1 mum fluorescent microspheres (FMS) and injected 15 mum FMS. The lungs were dried inflated, cut into similar to2 cm(3) cubes, and regional ventilation and blood flow were calculated from measurements of the fluorescence signals extracted from each piece. Adjacent pieces were clustered into successively larger aggregate volumes, and the averages of ventilation and of perfusion were calculated for each cluster size. While the coefficient of variation for both ventilation and perfusion increased predictably as the cluster size decreased, the correlation between ventilation and perfusion within clusters remained high, averaging between 0.82 and 0.92 among animals. Thus, while both ventilation and perfusion heterogeneity increase as the resolution of measurement improves, the strong correlation between these two parameters in a normal prone lung is nearly sample size invariant. This finding explains the observed efficiency of normal gas exchange in the face of the substantial degree of ventilation and perfusion heterogeneity observed in the normal lung with high-resolution measurement. (C) 2000 Biomedical Engineering Society. [S0090-6964(00)01708-2].