Glenny R W, Lamm W J, Albert R K, Robertson H T
Department of Medicine, University of Washington, Seattle 98195.
J Appl Physiol (1985). 1991 Aug;71(2):620-9. doi: 10.1152/jappl.1991.71.2.620.
Regional pulmonary blood flow in dogs under zone 3 conditions was measured in supine and prone postures to evaluate the linear gravitational model of perfusion distribution. Flow to regions of lung that were 1.9 cm3 in volume was determined by injection of radiolabeled microspheres in both postures. There was marked perfusion heterogeneity within isogravitational planes (coefficient of variation = 42.5%) as well as within gravitational planes (coefficient of variation = 44.2 and 39.2% in supine and prone postures, respectively; P = 0.02). On average, vertical height explained only 5.8 and 2.4% of the flow variability in the supine and prone postures, respectively. Whereas the gravitational model predicts that regional flows should be negatively correlated when measured in supine and prone postures, flows in the two postures were positively correlated, with an r2 of 0.708 +/- 0.050. Regional perfusion as a function of distance from the center of a lung explained 13.4 and 10.8% of the flow variability in the supine and prone postures, respectively. A linear combination of vertical height and radial distance from the centers of each lung provided a better-fitting model but still explained only 20.0 and 12.0% of the flow variability in the supine and prone postures, respectively. The entire lung was searched for a region of contiguous lung pieces (22.8 cm3) with high flow. Such a region was found in the dorsal area of the lower lobes in six of seven animals, and flow to this region was independent of posture. Under zone 3 conditions, neither gravity nor radial location is the principal determinant of regional perfusion distribution in supine and prone dogs.
在区域3条件下，对处于仰卧位和俯卧位的犬的局部肺血流量进行了测量，以评估灌注分布的线性重力模型。通过在两种体位下注射放射性标记微球，确定了体积为1.9 cm³的肺区域的血流量。在等重力平面内存在明显的灌注异质性（变异系数=42.5%），在重力平面内也存在明显的灌注异质性（仰卧位和俯卧位的变异系数分别为44.2%和39.2%；P=0.02）。平均而言，垂直高度分别仅解释了仰卧位和俯卧位血流量变异性的5.8%和2.4%。虽然重力模型预测，在仰卧位和俯卧位测量时局部血流量应呈负相关，但两种体位下的血流量呈正相关，r²为0.708±0.050。作为距肺中心距离的函数的局部灌注分别解释了仰卧位和俯卧位血流量变异性的13.4%和10.8%。垂直高度和距每个肺中心的径向距离的线性组合提供了一个拟合更好的模型，但仍分别仅解释了仰卧位和俯卧位血流量变异性的20.0%和12.0%。在整个肺中寻找具有高血流量的连续肺组织区域（22.8 cm³）。在7只动物中的6只动物的下叶背侧区域发现了这样一个区域，该区域的血流量与体位无关。在区域3条件下，重力和径向位置都不是仰卧位和俯卧位犬局部灌注分布的主要决定因素。
