Optimal frequency range to analyze respiratory transfer impedance with six-element model.
Optimal frequency range to analyze respiratory transfer impedance with six-element model.
复制标题
用六元模型分析呼吸转移阻抗的最佳频率范围。
DOI：
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发表时间：
1993
影响因子：
3.3
通讯作者：
C. Gallina
中科院分区：
文献类型：
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作者：
W. Tomalak;R. Peslin;C. Duvivier;C. Gallina
本研究的目的是使用 DuBois 等人的六元模型评估组织和气道机械特性方面分析呼吸转移阻抗 (Ztr) 的最佳频率范围。 (J.Appl.Physiol.8:587-594, 1956)。通过研究气道流量与胸部周围施加的伪随机压力振荡之间的关系，在 9 名健康受试者中测量了 2 至 64 Hz 的 Ztr。测量是在嘴部放置和不放置两种机械负载的情况下进行的：1.4 Pa.s2.l-1 的附加惯性和 1.65 hPa.s.l-1 的附加阻力。针对上气道壁的分流效应对数据进行了校正。负载引起的 Ztr 变化在高达 56 Hz 的频率下与 DuBois 模型中假设的 T 网络拓扑非常一致；一致性在较高频率下恶化，可能是由于难以在胸部周围获得均匀的压力场。模型与数据的拟合度在 56 Hz 以上时也急剧恶化。在 2 至 56 Hz 频率范围内，在有负载和无负载的情况下获得了相似的组织和气道系数值。在该频率范围内，系数的置信区间优于 10%。我们得出的结论是，DuBois 的模型在健康受试者中在 2 至 56 Hz 范围内有效，并且可以准确划分气道和组织特性。此外，我们提供的证据表明，上气道分流对 Ztr 数据的影响可以忽略不计，并且只要用低阻抗呼吸速度描记器测量气道流量即可得出导出系数。
The aim of this investigation was to assess the optimal frequency range for analyzing respiratory transfer impedance (Ztr) in terms of tissue and airway mechanical properties using the six-element model of DuBois et al. (J. Appl. Physiol. 8:587-594, 1956). Ztr was measured in nine healthy subjects from 2 to 64 Hz by studying the relationship between airway flow and pseudorandom pressure oscillations applied around the chest. The measurements were performed with and without two mechanical loads placed at the mouth: an added inertance of 1.4 Pa.s2.l-1 and an added resistance of 1.65 hPa.s.l-1. The data were corrected for the shunt effect of upper airway walls. The changes in Ztr induced by the loads were very consistent up to 56 Hz with the T-network topology assumed in DuBois's model; the agreement deteriorated at higher frequencies, presumably due to the difficulty of obtaining a homogeneous pressure field around the chest. The fit of the model to the data also worsened sharply at above 56 Hz. In the 2- to 56-Hz frequency range, similar values of the tissue and airway coefficients were obtained with and without the loads. In that frequency range the confidence intervals of the coefficients were better than 10%. We conclude that DuBois's model is valid from 2 to 56 Hz in healthy subjects and allows accurate partitioning of airways and tissue properties. In addition, we present evidence that the upper airway shunt negligibly influences Ztr data and the derived coefficients provided airway flow is measured with a low-impedance pneumotachograph.