Lutchen K R, Saidel G M, Primiano F P, Horowitz J G, Deal E C
Am Rev Respir Dis. 1984 Dec;130(6):974-9. doi: 10.1164/arrd.1984.130.6.974.
Quantitative characteristics of the dynamic mechanical and gas distribution behavior in 6 normal subjects and 5 subjects with COPD were compared during tidal breathing. Transpulmonary pressure, total lung volume, flow, and N2 fraction at the mouth were measured while N2 was washed out from the lung. The washouts were performed at several frequencies and lung volumes. As an index of nonuniform mechanical behavior, we calculated the frequency variation in dynamic pulmonary compliance (CLdyn). Based on a moment analysis of the multibreath N2 washout, we calculated a mean dilution number (MDN) as an index of the inhomogeneity of alveolar gas distribution and mixing. At FRC or above FRC the CLdyn decreased much more with frequency for the COPD subjects than for the normal subjects. The MDN was also much greater in the presence of COPD. However, the frequency dependence of the MDN was small for both the normal and COPD subjects and uncorrelated with the frequency dependence of CLdyn. Because the multibreath N2 washout and the frequency dependence of CLdyn reflect different aspects of ventilation inhomogeneity, these two responses are unique.
在潮式呼吸过程中，比较了6名正常受试者和5名慢性阻塞性肺疾病（COPD）受试者动态力学和气体分布行为的定量特征。在从肺中冲洗出氮气时，测量了跨肺压、肺总量、流量和口腔处的氮气分数。冲洗在几个频率和肺容积下进行。作为非均匀力学行为的指标，我们计算了动态肺顺应性（CLdyn）的频率变化。基于多次呼吸氮气冲洗的矩分析，我们计算了平均稀释数（MDN）作为肺泡气体分布和混合不均匀性的指标。在功能残气量（FRC）或高于FRC时，COPD受试者的CLdyn随频率的下降比正常受试者大得多。COPD患者的MDN也大得多。然而，正常受试者和COPD受试者的MDN频率依赖性都很小，且与CLdyn的频率依赖性无关。由于多次呼吸氮气冲洗和CLdyn的频率依赖性反映了通气不均匀性的不同方面，这两种反应是独特的。
