A multi-scale model of gas transport in the lung to study heterogeneous lung ventilation during the multiple-breath washout test
Fig 4
Overview of different simulation results for baseline model configuration and modified compliance.
Results of the simulated N2 gas washout for the baseline configuration (uniform and constant lung model parameter, black) and for altered trumpet lobule compliance using ϕ = 0.5, 1.5 in two different regions, respectively, each accounting for 25% of all trumpet lobules (purple color). Normalized phase III slopes sIII are shown for the first (a) and last (b) breath. The washout profile (N2 concentration at the entrance of the trachea) in (c) linear scale and (d) logarithmic scale for 50 simulated breaths with a uniform concentration decay for the baseline model, and a non-uniform decay for the regionally modified model (slow-fast washout profile). Panels (e) and (f) illustrate further the model with modified lobular compliance at the end of the fifth breath: (e) spatial N2 concentration distribution where the trumpet lobules parametrized with lower and higher compliance are located on the left and right side of the airway tree, respectively. In (f) the mean lobular N2 concentration is shown for each trumpet lobule.