title: A micromechanical model for estimating alveolar wall strain in mechanically ventilated edematous lungs.
abstract: To elucidate the micromechanics of pulmonary edema has been a significant medical concern, which is beneficial to better guide ventilator settings in clinical practice. In this paper, we present an adjoining two-alveoli model to quantitatively estimate strain and stress of alveolar walls in mechanically ventilated edematous lungs. The model takes into account the geometry of the alveolus, the effect of surface tension, the length-tension properties of parenchyma tissue, and the change in thickness of the alveolar wall. On the one hand, our model supports experimental findings (Perlman CE, Lederer DJ, Bhattacharya J. Am J Respir Cell Mol Biol 44: 34-39, 2011) that the presence of a liquid-filled alveolus protrudes into the neighboring air-filled alveolus with the shared septal strain amounting to a maximum value of 1.374 (corresponding to the maximum stress of 5.12 kPa) even at functional residual capacity; on the other hand, it further shows that the pattern of alveolar expansion appears heterogeneous or homogeneous, strongly depending on differences in air-liquid interface tension on alveolar segments. The proposed model is a preliminary step toward picturing a global topographical distribution of stress and strain on the scale of the lung as a whole to prevent ventilator-induced lung injury.
authors.affiliation: Biomedical Instrument Institute, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China; and Department of Precise Medical Device, Shanghai Medical Instrumentation College, Shanghai, China chenzl@smic.edu.cn.
authors.forename: Zheng-long
authors.initials: ZL
authors.lastname: Chen
authors.affiliation: Biomedical Instrument Institute, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China; and.
authors.forename: Ya-zhu
authors.initials: YZ
authors.lastname: Chen
authors.affiliation: Department of Precise Medical Device, Shanghai Medical Instrumentation College, Shanghai, China.
authors.forename: Zhao-yan
authors.initials: ZY
authors.lastname: Hu
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D006801:Humans; D008953:Models, Anatomic; D011650:Pulmonary Alveoli / Q000503:physiopathology*; D011654:Pulmonary Edema / Q000503:physiopathology*; D012121:Respiration, Artificial / Q000009:adverse effects*; D013312:Stress, Physiological; D013500:Surface Tension; D055397:Ventilator-Induced Lung Injury / Q000503:physiopathology*
keywords: alveolar wall; pulmonary edema; stress and strain; surface tension; ventilator-induced lung injury