Rubin D Z, Lewis S M, Mittman C
J Appl Physiol Respir Environ Exerc Physiol. 1984 Mar;56(3):708-15. doi: 10.1152/jappl.1984.56.3.708.
We previously presented a method based on a computer lung model for determining the distribution of both specific ventilation and specific diffusing capacity. These argon and carbon monoxide (CO) washin and washout studies were obtained in 12 normal subjects and 24 patients with varying degrees of obstructive lung disease. In addition to end-tidal and mixed expired gas concentrations, the expired waveform for both gases was sampled. In patients we found that this method failed to adequately describe CO dynamics during the early part of expiration; predicted concentrations were higher than actual data. Modifications of the original model that satisfy all data are presented. This new model suggests that CO uptake occurs in spaces with ventilatory properties of dead space. The accuracy and reliability of these observations were established by computer simulation studies as well as by repeated testing in one subject. These proved to be highly reproducible over a period of 5 mo. Standard parameter sensitivity tests showed parameters to vary by less than 10% and to be stable even when realistic levels of noise were added to the data. We conclude that studies involving ventilation of insoluble gases are insufficient to describe gas exchange in the lung. The addition of an exchangeable gas adds significant understanding of lung function, particularly in disease.
我们之前提出了一种基于计算机肺模型的方法，用于确定比通气量和比弥散量的分布。对12名正常受试者和24名患有不同程度阻塞性肺疾病的患者进行了这些氩气和一氧化碳（CO）的吸入和呼出研究。除了潮气末和混合呼出气浓度外，还对两种气体的呼出波形进行了采样。在患者中，我们发现该方法未能充分描述呼气早期的CO动态；预测浓度高于实际数据。本文提出了满足所有数据的原始模型的修改方法。这个新模型表明，CO摄取发生在具有死腔通气特性的空间中。这些观察结果的准确性和可靠性通过计算机模拟研究以及在一名受试者中的重复测试得以确立。在5个月的时间里，这些结果被证明具有高度可重复性。标准参数敏感性测试表明，即使在数据中添加实际水平的噪声，参数变化也小于10%且保持稳定。我们得出结论，涉及不溶性气体通气的研究不足以描述肺内的气体交换。添加一种可交换气体能显著增进对肺功能的理解，尤其是在疾病状态下。
