Berkeley Fluids Seminar

September 24, 2014

Dr. Jessica Oakes (Mechanical Eng., UC Berkeley)

Airflow and Aerosol Deposition in Healthy and Emphysematous Lungs:
Findings from Numerical Simulations and In-Vivo Experiments

Aerosol particles are commonly used for therapeutic drug delivery as they can be delivered to the body systemically (e.g. insulin for diabetic patients) or be used to treat lung diseases (asthma, cystic fibrosis, lung cancer). While there have been significant advancements in computational and experimental models of particle deposition in the lung, relatively few studies have compared their predictions of deposition to experimental data. Additionally, little work has been done to study the influence of emphysema on particle deposition in the lung. Emphysema is an irreversible disease that results in oxygen impairment that influences 4.1 million people in the United States. Motivated by recently available in-vivo experimental data of particle deposition in healthy and emphysematous rat lungs (Oakes et al. Journal of Applied Physiology, DOI: 10.1152/japplphysiol.01165.2013), we performed multi-scale numerical simulations in healthy and emphysema-like rat lungs following methods described in our recent work (Oakes et al. (2014) Annals of Biomedical Engineering, 42: 899-914). Areas of the lung destroyed by emphysema were defined in the numerical models to match those found in the experiments. Once the airflow was determined, particles with mass median aerodynamic diameter (MMAD) of 1.2 μm were tracked throughout inspiration. In the healthy lungs, good agreement was found between the numerical predictions of aerosol delivery to the different lobes and experimental data of lobar deposition. However, similar agreement was not found for the emphysematous lungs. It is likely that the deposition rate downstream of our 3D geometry is not proportional to the delivery of particles in emphysematous lungs. Including small airway collapse, variations in downstream airway size and tissue properties, deposition in the acinus region of the lung and tracking particles throughout expiration may result in a more favorable match between the numerical and experimental data.

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Acknowledgments

Prof. Graham Fleming (Vice Chancellor for Research, UC Berkeley)

Prof. Eliot Quataert on behalf of The Theoretical Astrophysics Center and the Astronomy Department (UC Berkeley)

Prof. Philip S. Marcus on behalf of the Mechanical Engineering Department (UC Berkeley)

Prof. Michael Manga (Earth and Planetary Science, UC Berkeley)

Prof. Evan Variano (Civil and Environmental Engineering, UC Berkeley)