Aerosol transport throughout inspiration and expiration in the pulmonary airways. (24th February 2017)

• Record Type: Journal Article
• Authors: Oakes, Jessica M.; Shadden, Shawn C.; Grandmont, Céline; Vignon‐Clementel, Irene E.
• Is Part Of: International journal for numerical methods in biomedical engineering. Volume 33:Number 9(2017:Sep.)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-02-24
• Subjects: computational fluid dynamics (CFD) -- inhalation and exhalation -- particle deposition -- respiratory tract -- whole lung modeling; Biomedical engineering -- Periodicals; Imaging systems in medicine -- Periodicals; Numerical analysis -- Periodicals; Engineering mathematics -- Periodicals; 610.28
• DOI: 10.1002/cnm.2847
• Languages: English
• ISSNs: 2040-7939

Abstract

Abstract: Little is known about transport throughout the respiration cycle in the conducting airways. It is challenging to appropriately describe the time‐dependent number of particles entering back into the model during exhalation. Modeling the entire lung is not feasible; therefore, multidomain methods must be used. Here, we present a new framework that is designed to simulate particles throughout the respiration cycle, incorporating realistic airway geometry and respiration. This framework is applied for a healthy rat lung exposed to ∼ 1 μ m diameter particles, chosen to facilitate parameterization and validation. The flow field is calculated in the conducting airways (3D domain) by solving the incompressible Navier‐Stokes equations with experimentally derived boundary conditions. Particles are tracked throughout inspiration by solving a modified Maxey‐Riley equation. Next, we pass the time‐dependent particle concentrations exiting the 3D model to the 1D volume conservation and advection‐diffusion models (1D domain). Once the 1D models are solved, we prescribe the time‐dependent number of particles entering back into the 3D airways to again solve for 3D transport. The coupled simulations highlight that about twice as many particles deposit during inhalation compared to exhalation for the entire lung. In contrast to inhalation, where most particles deposit at the bifurcation zones, particles deposit relatively uniformly on the gravitationally dependent side of the 3D airways during exhalation. Strong agreement to previously collected regional experimental data is shown, as the 1D models account for lobe‐dependent morphology. This framework may be applied to investigate dosimetry in other species and pathological lungs. Abstract : Little is known about transport throughout the respiration cycle in the conducting airways. It is challenging to describe the time‐dependent number of particles entering back into the airways during exhalation. Modeling the full lung is not feasible; hence, multi‐domain methods must be employed. Here, we present a new framework that is designed to simulate particles throughout the respiration cycle. The in silico model was parametrized following rat exposure experiments and model predictions were compared to the experimental data.