AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
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Simulation of Particle Deposition in Laryngotracheal Stenosis Using Computational Fluid Dynamics
TRACY CHENG, David Carpenter, David Witsell, Seth Cohen, Dennis Frank-Ito, Duke University School of Medicine
Abstract Number: 380 Working Group: Health Related Aerosols
Abstract Laryngotracheal stenosis (LTS) is a compression or narrowing of the endolaryngeal/endotracheal airway often caused by intubation during surgery. LTS patients experience significant respiratory morbidity which may progress to acute airway compromise if not properly managed. One common medical therapy for LTS is inhaled corticosteroids to prevent granulation tissue formation after surgery. However, these corticosteroids inhalers were designed to target lower airway deposition in asthma treatment rather than the endolaryngeal/endotracheal airway. In this study, computational fluid dynamics modeling was used to investigate drug particle transport in endolaryngeal/endotracheal airway three-dimensional models of 10 LTS subjects with glottic stenosis (3 subjects), subglottic stenosis (3 subjects), and tracheal stenosis (4 subjects). Airflow and particle transport were simulated through these LTS models with particles sizes ranging from 1-50µm at a velocity of 1m/s. Airflow simulations were conducted with an inspiratory pressure of 25Pascals through both nostrils and mouth for all subjects. Glottic stenosis subjects had the highest total particle deposition fraction across all particle sizes in the stenotic region (6.6-34.8%) compared to subglottic (0.5-3.4%) and tracheal (0.1-1.1%) stenosis subjects. In addition, particle sizes with the most deposition fraction (DF) in the stenotic region for glottic stenosis subjects were 8µm (DF=84.9%), 17µm (DF=28.2%), and 19µm (DF=82.7%); for subglottic stenosis subjects, 1µm (DF=6.8%), 10µm (DF=15.6%), and 11µm (DF=3.3%); and for tracheal stenosis subjects, 4µm & 5µm (DF=2.8%), 7µm (DF=0.6% & 7.7%), and 10µm (DF=4.3%). Furthermore, the number of different particle sizes (and largest particle size; LPS) depositing into the stenotic region for glottic stenosis subjects was between 46 and 50 different particle sizes (LPS=50µm); between 8 and 29 different particle sizes (LPS=33µm) for subglottic stenosis subjects, and between 14 and 30 different sizes (LPS=37µm) for tracheal stenosis subjects. These results suggest that particle deposition may differ in LTS depending on the anatomic location of stenosis.