J Appl Physiol (1985). 2023 Jul 13. doi: 10.1152/japplphysiol.00631.2022. Online ahead of print.
ABSTRACT
Sliding between lung lobes along lobar fissures is a poorly understood aspect of lung mechanics. The objective of this study was to test the hypothesis that lobar sliding helps reduce distortion in the lung parenchyma during breathing. Finite element models of left lungs with geometries and boundary conditions derived from medical images of human subjects were developed. Effect of lobar sliding was studied by comparing nonlinear finite elastic contact mechanics simulations that allowed and disallowed lobar sliding. Lung parenchymal distortion during simulated breath holds and tidal breathing was quantified with the model’s spatial mean anisotropic deformation index (ADI), a measure of directional preference in volume change that varies spatially in the lung. Models that allowed lobar sliding had significantly lower mean ADI (i.e. lesser parenchymal distortion) than models that disallowed lobar sliding under both simulations of tidal breathing (5.3% median difference, p = 0.008, n = 8) and simulations of lung deformation between breath holds at total lung capacity and functional residual capacity (3.2% median difference, p = 0.03, n = 6). This effect was most pronounced in the lower lobe where lobar sliding reduced parenchymal distortion with statistical significance, but not in the upper. Additionally, more lobar sliding was correlated with greater reduction in distortion between sliding and non-sliding models in our study cohorts (Pearson’s correlation coefficient of 0.95 for tidal breathing, 0.87 for breath holds, and 0.91 for the combined data set). These findings are consistent with the hypothesis that lung lobar sliding reduces parenchymal distortion during breathing.
PMID:37439240 | DOI:10.1152/japplphysiol.00631.2022
