Influence of Individualized Morphological Parameters on Aerosol Deposition Pattern: Analytical Simulation Results Compared With Experimental Data
MARINE PICHELIN, C Dubau, I Katz, S Montesantos, C Majoral, G Caillibotte
Air Liquide R&D
Abstract Number: 315
Working Group: Health Related Aerosols
Last modified: April 4, 2011
The aim of this work was twofold: (i) to introduce asymmetric features in the description of the human respiratory tract and (ii) to study the influence of individualized parameters of patientsí lung morphologies on aerosol deposition patterns within the lungs.
An analytical, mechanistic model was used to mimic aerosol inhalation experiments on healthy adult male subjects and simulate particle deposition within the lungs. The aerosol deposition is assumed to result from three mechanisms: inertial impaction, sedimentation, and diffusion. Simulations were performed using two different descriptions of the respiratory tract. The first one is a lung morphology based on the Soong model but scaled in terms of airway length and diameter, and alveolar volumes, according to subjectsí height and functional residual capacity (FRC). The second is an asymmetric lung morphology based on morphometric data extracted from High Resolution Computed Tomography images, such as length and diameter of the first airway generations, and lobar volumes (in terms of percentage of the FRC) completed for deeper generations by symmetric subtrees whose airway lengths and diameters are based on the Soong model morphometric data. In both cases, the gas ventilation distribution is based on downstream alveolar volume. When the simplest lung morphology is used, the flow rate repartition is symmetric between two daughters of any airway while, for the more advanced description of the lung tree, it is asymmetric and proportional to the alveolar volume available downstream the considered airway branch.
Comparisons with experimental measurements have been done for total and tracheo-bronchial deposition, highlighting the importance of addressing both asymmetric and individualized lung morphologies in analytical modeling of aerosol deposition. This work provides a scientifically sound foundation for designing patientís specific inhaled therapy treatments.