Investigating the effects of laryngotracheal stenosis on upper airway aerodynamics

Cheng, Tracy; Carpenter, David; Witsell, David L.; Frank‐Ito, Dennis O.

doi:10.1002/lary.26954

Cited by 24 publications

(26 citation statements)

References 65 publications

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“…Nonetheless, a few CFD studies have investigated the effects of LTS on airflow dynamics in the laryngotracheal airway. 40-45…”

Section: Discussionmentioning

confidence: 99%

Orally Inhaled Drug Particle Transport in Computerized Models of Laryngotracheal Stenosis

Frank‐Ito

2020

Otolaryngol.--head neck surg.

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Objective Adjuvant management for laryngotracheal stenosis (LTS) may involve inhaled corticosteroids, but metered dose inhalers are designed for pulmonary drug delivery. Comprehensive analyses of drug particle deposition efficiency for orally inhaled corticosteroids in the stenosis of LTS subjects are lacking. Study Design Descriptive research. Setting Academic medical center. Methods Anatomically realistic 3-dimensional reconstructions of the upper airway were created from computed tomography images of 4 LTS subjects—2 subglottic stenosis and 2 tracheal stenosis subjects. Computational fluid dynamics modeling was used to simulate airflow and drug particle transport in each airway. Three inhalation pressures were simulated, 10 Pa, 25 Pa, and 40 Pa. Drug particle transport was simulated for 100 to 950 nanoparticles and 1 to 50 micron-particles. Particles were released into the airway to mimic varying inhaler conditions with and without a spacer chamber. Results Based on smallest to largest cross-sectional area ratio, the laryngotracheal stenotic segment shrunk by 57% and 47%, respectively, for subglottic stenosis models and by 53% for both tracheal stenosis models. Airflow resistance at the stenotic segment was lower in subglottic stenosis models than in tracheal stenosis models: 0.001 to 0.011 Pa.s/mL vs 0.024 to 0.082 Pa.s/mL. Drug depositions for micron-particles and nanoparticles at stenosis were 0.06% to 2.48% and 0.10% to 2.60% for subglottic stenosis and tracheal stenosis models, respectively. Particle sizes with highest stenotic deposition were 6 to 20 µm for subglottic stenosis models and 1 to 10 µm for tracheal stenosis models. Conclusion This study suggests that at most, 2.60% of inhaled drug particles deposit at the stenosis. Particle size ranges with highest stenotic deposition may not represent typical sizes emitted by inhalers.

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“…Nonetheless, a few CFD studies have investigated the effects of LTS on airflow dynamics in the laryngotracheal airway. 40-45…”

Section: Discussionmentioning

confidence: 99%

Orally Inhaled Drug Particle Transport in Computerized Models of Laryngotracheal Stenosis

Frank‐Ito

2020

Otolaryngol.--head neck surg.

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“…This introduces the possibility of generating objective parameters of CFD metrics to help guide treatment. In another study, Cheng et al 16 examined inspiratory airflow and resistance in LTS using CFD. Their modeling demonstrated increases in resistance and decreases in airflow in this disease.…”

Section: Discussionmentioning

confidence: 99%

The Application of Computational Fluid Dynamics in the Evaluation of Laryngotracheal Pathology

Mason

McGhee

Zhao

et al. 2019

Ann Otol Rhinol Laryngol

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Objectives: Laryngotracheal stenosis and obstruction can be challenging to manage. Traditional assessment tools are limited in clinical correlation. Three-dimensional computational fluid dynamics (CFD) modeling is a novel technique used to analyze airflow dynamics. The objective of this study was to apply CFD to the human upper airway to explore its utility. Methods: CFD models were constructed on an adult patient with an obstructive tracheal lesion before and after intervention and on an adult with normal airway anatomy, using computed tomographic imaging obtained retrospectively. Key airflow metrics were calculated. Results: CFD provided detailed airway geometry. The normal airway had a peak flow velocity of 3.12 m/s, wall shear stress of 0.30 Pa, and resistance of 0.02 Pa/mL/s. The pathologic patient showed an elevated peak flow velocity of 12.25 m/s, wall shear stress of 3.90 Pa, and resistance of 0.22 Pa/mL/s. This was reflected clinically with dyspnea, stridor, and obstructive impairment via pulmonary function testing. Following treatment, peak flow velocity corrected to 3.95 m/s, wall shear stress to 0.72Pa, and resistance to 0.01 Pa/mL/s. Cross-sectional area improved to 190 mm 2 from a minimum of 53 mm 2 at the same segment. Stridor and dyspnea resolved. Conclusions: CFD metrics were calculated on the normal, diseased, and posttreatment upper airway. Variations were reflected in clinical symptoms. These methods could model surgical outcomes and anticipate disease severity. Article reuse guidelines: sagepub.com/journals-permissions

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“…[40,41] and experimental models [42][43][44] have been considered to analyse the airflow pattern in the extrathoracic region. A commonly used model for airflow characterization in the extrathoracic airways are either non-realistic idealized model [23,[45][46][47] or realistic CT-based models [15,23,39,[48][49][50][51]. Some of the published literature considered laminar flow in this region [40,52,53] whereas, most of the studies are based on turbulent flow [42,45,46,54].…”

Section: Extrathoracic Regionmentioning

confidence: 99%

A Review of Respiratory Anatomical Development, Air Flow Characterization and Particle Deposition

Islam

Paul

Ong

et al. 2020

IJERPH

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The understanding of complex inhalation and transport processes of pollutant particles through the human respiratory system is important for investigations into dosimetry and respiratory health effects in various settings, such as environmental or occupational health. The studies over the last few decades for micro- and nanoparticle transport and deposition have advanced the understanding of drug-aerosol impacts in the mouth-throat and the upper airways. However, most of the Lagrangian and Eulerian studies have utilized the non-realistic symmetric anatomical model for airflow and particle deposition predictions. Recent improvements to visualization techniques using high-resolution computed tomography (CT) data and the resultant development of three dimensional (3-D) anatomical models support the realistic representation of lung geometry. Yet, the selection of different modelling approaches to analyze the transitional flow behavior and the use of different inlet and outlet conditions provide a dissimilar prediction of particle deposition in the human lung. Moreover, incorporation of relevant physical and appropriate boundary conditions are important factors to consider for the more accurate prediction of transitional flow and particle transport in human lung. This review critically appraises currently available literature on airflow and particle transport mechanism in the lungs, as well as numerical simulations with the aim to explore processes involved. Numerical studies found that both the Euler–Lagrange (E-L) and Euler–Euler methods do not influence nanoparticle (particle diameter ≤50 nm) deposition patterns at a flow rate ≤25 L/min. Furthermore, numerical studies demonstrated that turbulence dispersion does not significantly affect nanoparticle deposition patterns. This critical review aims to develop the field and increase the state-of-the-art in human lung modelling.

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Investigating the effects of laryngotracheal stenosis on upper airway aerodynamics

Abstract: NA. Laryngoscope, 128:E141-E149, 2018.

Cited by 24 publications

References 65 publications

Orally Inhaled Drug Particle Transport in Computerized Models of Laryngotracheal Stenosis

Orally Inhaled Drug Particle Transport in Computerized Models of Laryngotracheal Stenosis

The Application of Computational Fluid Dynamics in the Evaluation of Laryngotracheal Pathology

A Review of Respiratory Anatomical Development, Air Flow Characterization and Particle Deposition

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