Haselton F R, Parker R E, Roselli R J, Harris T R
J Appl Physiol Respir Environ Exerc Physiol. 1984 Jul;57(1):98-109. doi: 10.1152/jappl.1984.57.1.98.
In this study, we have compared an effective diffusivity model with several models previously used to describe lung microvascular exchange of small molecules (multiple indicator curves): the Crone integral extraction model, the Sangren-Sheppard model, and the Rowlett-Harris model. The parameters of each model were adjusted to achieve a best fit of multiple-tracer data from six isolated dog lung preparations perfused under zone III conditions at three flows and from five awake sheep before and after histamine infusion. The effective diffusivity model was the best at matching the data and the unique falling extraction pattern observed in the lung. When the isolated lung data was analyzed, the permeability-surface area products (PS) of three models were all significantly lower at lower flows. However, the effective diffusivity model parameter (D 1/2 S, an effective diffusivity-surface area product) was not significantly affected by flow reduction. Lung lymph flow and lymph-to-plasma protein ratios from the awake sheep indicated that PS and D 1/2 S should have increased, and except for the Sangren-Sheppard model, all models predicted significantly increased values. By use of sensitivity analysis, the parameters of the effective diffusivity model were found to be more independently determined than those of the Sangren-Sheppard model, but data collected at longer times were necessary to reliably identify the extravascular volume parameter (LS, diffusing distance-surface area product) of the effective diffusivity model. We conclude that the effective diffusivity model is a better descriptor of multiple tracer data from the lung, that its parameters are more reliably and independently determined, and that it more reliably describes the effects of flow and histamine infusion on capillary-tissue exchange.
在本研究中，我们将一种有效扩散率模型与先前用于描述小分子肺微血管交换的几种模型（多指示剂曲线）进行了比较：克朗积分提取模型、桑格伦-谢泼德模型和罗利特-哈里斯模型。对每个模型的参数进行了调整，以实现对来自6个在三区条件下以三种流量灌注的离体犬肺制剂以及5只清醒绵羊在组胺输注前后的多示踪剂数据的最佳拟合。有效扩散率模型在匹配数据和肺中观察到的独特下降提取模式方面表现最佳。分析离体肺数据时，三种模型的通透面积乘积（PS）在较低流量下均显著降低。然而，有效扩散率模型参数（D 1/2 S，有效扩散率-面积乘积）不受流量降低的显著影响。清醒绵羊的肺淋巴流量和淋巴-血浆蛋白比表明PS和D 1/2 S应该增加，除了桑格伦-谢泼德模型外，所有模型预测的值均显著增加。通过敏感性分析发现，有效扩散率模型的参数比桑格伦-谢泼德模型的参数更能独立确定，但需要收集更长时间的数据才能可靠地识别有效扩散率模型的血管外容积参数（LS，扩散距离-面积乘积）。我们得出结论，有效扩散率模型能更好地描述来自肺的多示踪剂数据，其参数能更可靠、独立地确定，并且能更可靠地描述流量和组胺输注对毛细血管-组织交换的影响。
