Partitioning of airway and lung tissue properties: comparison of in situ and open-chest conditions.
Partitioning of airway and lung tissue properties: comparison of in situ and open-chest conditions.
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气道和肺组织特性的划分：原位和开胸条件的比较。
DOI：
10.1152/jappl.1995.79.3.861
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Lutchen,KR
中科院分区：
文献类型：
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作者：
Suki,B;Petak,F;Adamicza,A;Hantos,Z;Lutchen,KR
本研究的目的是调查在生理呼吸条件下，气道和肺组织特性是否在原位和开胸条件下不同。我们测量肺输入阻抗在狗从0.2至8 Hz的最佳呼吸机波形在四个潮气量（VT;从75至450毫升）在完整的动物使用食管球囊，以及打开胸部后。将两种情况下的肺阻抗分为气道和组织区室，分别以气道阻力和惯性（Iaw）以及组织阻尼（G）和弹性（H）参数为特征。除Iaw外，所有参数在一定程度上取决于VT。在开胸条件下，VT时，原位组织G和H略有下降; VT时，G略有下降，H略有增加。我们发现，在原位和开胸条件下，气道和肺组织的机械性能之间存在微小但显著的差异。在总人群中，G、气道阻力和Iaw参数分别比开胸条件下小13%（不显著）、35%（P < 0.001）和31%（P < 0.001）。然而，H在原位增大15%（P < 0.001）。虽然我们不能完全排除某些伪影，但这些差异很可能反映了肺部的真实的改变，这是由于两种情况下不同的配置和胸膜压力分布的可能差异。原位G值越小，E值越大，则G/H值减小36%（P < 0.001）。
The purpose of this study was to investigate under physiological breathing conditions whether airway and lung tissue properties are different in situ and in open-chest conditions. We measured lung input impedance in dogs from 0.2 to 8 Hz with an optimal ventilator waveform at four tidal volumes (VT; from 75 to 450 ml) in intact animals using an esophageal balloon as well as after opening the chest. The lung impedance from both conditions was partitioned into airway and tissue compartments as characterized by airway resistance and inertance (Iaw) and tissue damping (G) and elastance (H) parameters respectively. All parameters except Iaw depended to some extent on VT. The in situ tissue G and H slightly decreased with VT while in the open-chest condition; G decreased and H increased slightly with VT. We found small but significant differences between the mechanical properties of the airway and lung tissues in situ and in open-chest conditions. Over the total population, the G, airway resistance, and Iaw parameters were 13% (not significant), 35% (P < 0.001), and 31% (P < 0.001) smaller, respectively, in situ than in the open-chest condition. However, the H was 15% larger in situ (P < 0.001). Although we cannot completely rule out certain artifacts, these differences most likely reflect real alterations in the lung due to the different configurations and possible differences in the distribution of pleural pressures in the two conditions. The G being smaller and E being larger in situ resulted in hysteresivity (G/H) 36% smaller in situ (P < 0.001).