D'Angelo Edgardo, Calderini Edoardo, Tavola Mario, Pecchiari Matteo
Department of Physiopathology and Transplantations, Università degli Studi di Milano, Milan, Italy.
Division of Anesthesia and Intensive Care, Ospedale di Lecco, Lecco, Italy.
Respir Physiol Neurobiol. 2019 Mar;261:31-39. doi: 10.1016/j.resp.2018.12.003. Epub 2018 Dec 13.
In 9 anesthetized, paralyzed dogs lung and chest-wall standard (viscous resistance, Rint, and quasi-static elastance, Est) and viscoelastic parameters (resistance, Rvel, and time constant, τvel) were measured in the supine posture before and after rib-cage block, after application of an expiratory threshold load, and after 75° head-up tilting before and after wide chest opening. Lung and chest-wall τvel were the same under all conditions. Rvel was independent of volume and posture, and greater for the lung. Chest-wall Rint was independent of flow, volume, and posture. Lung Rint decreased with increasing volume. Chest-wall Rint, Est and Rvel increased with rib-cage block, allowing the assessment of both abdominal-wall and rib-cage characteristics. When chest opening did not elicit bronchoconstriction, the decrease of Rvel was ∼6%. Main conclusions: lung and chest-wall exhibit linear tissue viscoelasticity within the range studied; rib-cage and abdomen characteristics are similar, and asynchronous motion is not expected at physiological respiratory rates; in normal lungs, heterogeneity of parallel time constants plays a marginal role.
在9只麻醉、麻痹的狗身上，于仰卧位测量了胸廓阻滞前后、施加呼气阈值负荷后以及胸廓广泛打开前后75°头高位倾斜时肺和胸壁的标准参数（粘性阻力，Rint，和准静态弹性，Est）以及粘弹性参数（阻力，Rvel，和时间常数，τvel）。在所有条件下，肺和胸壁的τvel相同。Rvel与容积和体位无关，且肺的Rvel更大。胸壁Rint与流量、容积和体位无关。肺Rint随容积增加而降低。胸廓阻滞时胸壁Rint、Est和Rvel增加，从而能够评估腹壁和胸廓的特征。当胸廓打开未引发支气管收缩时，Rvel下降约6%。主要结论：在所研究的范围内，肺和胸壁呈现线性组织粘弹性；胸廓和腹部特征相似，在生理呼吸频率下预计不会出现异步运动；在正常肺中，平行时间常数的异质性作用较小。
