An efficient computational fluid-particle dynamics method to predict deposition in a simplified approximation of the deep lung

Koullapis, Pantelis; Hofemeier, Philipp; Sznitman, Josué; Kassinos, Stavros C.

doi:10.1016/j.ejps.2017.09.016

Cited by 66 publications

(38 citation statements)

References 32 publications

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“…As recently highlighted [23,24], spatially and temporally resolving airflow and aerosol transport dynamics across a complete lung model with vast multiscale properties spanning over 20 airway bifurcations of the pulmonary tree requires high computational resources that are still typically beyond reach. In turn, our strategy revolves around in silico numerical simulations of ellipsoid-shaped fibers of varying equivalent diameters (d p ) and aspect ratios (AR) in an upper airways model and a bronchial tree, adopting a multiscale approach in the footsteps of Koullapis et al [23]. In particular, the upper airways domain (see Figure 1a) follows recent work [25] on the fate of inhaled spherical aerosols in upper airway models (i.e., from the mouth to the 6th generation of the tracheobronchial respiratory tree).…”

Section: Airway Geometry and Inhalation Conditionsmentioning

confidence: 99%

“…In parallel, following our multiscale approach, the bronchial model spanning generations 7 to 16 is simulated separately due to the different range of Re values across the airway tree, which decreases from approximately~10 3 at peak inhalation around the larynx constriction to~10 2 at the entrance of the lower bronchial tree [23,31,38]. Therefore, a viscous laminar model was implemented with a SIMPLE scheme of pressure-velocity coupling to describe the laminar flow that characterizes this region.…”

Section: Airflow Simulations and Boundary Conditionsmentioning

confidence: 99%

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In Silico Optimization of Fiber-Shaped Aerosols in Inhalation Therapy for Augmented Targeting and Deposition across the Respiratory Tract

et al. 2020

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Motivated by a desire to uncover new opportunities for designing the size and shape of fiber-shaped aerosols towards improved pulmonary drug delivery deposition outcomes, we explore the transport and deposition characteristics of fibers under physiologically inspired inhalation conditions in silico, mimicking a dry powder inhaler (DPI) maneuver in adult lung models. Here, using computational fluid dynamics (CFD) simulations, we resolve the transient translational and rotational motion of inhaled micron-sized ellipsoid particles under the influence of aerodynamic (i.e., drag, lift) and gravitational forces in a respiratory tract model spanning the first seven bifurcating generations (i.e., from the mouth to upper airways), coupled to a more distal airway model representing nine generations of the mid-bronchial tree. Aerosol deposition efficiencies are quantified as a function of the equivalent diameter (dp) and geometrical aspect ratio (AR), and these are compared to outcomes with traditional spherical particles of equivalent mass. Our results help elucidate how deposition patterns are intimately coupled to dp and AR, whereby high AR fibers in the narrow range of dp = 6–7 µm yield the highest deposition efficiency for targeting the upper- and mid-bronchi, whereas fibers in the range of dp= 4–6 µm are anticipated to cross through the conducting regions and reach the deeper lung regions. Our efforts underscore previously uncovered opportunities to design the shape and size of fiber-like aerosols towards targeted pulmonary drug delivery with increased deposition efficiencies, in particular by leveraging their large payloads for deep lung deposition.

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Section: Airway Geometry and Inhalation Conditionsmentioning

confidence: 99%

Section: Airflow Simulations and Boundary Conditionsmentioning

confidence: 99%

In Silico Optimization of Fiber-Shaped Aerosols in Inhalation Therapy for Augmented Targeting and Deposition across the Respiratory Tract

et al. 2020

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“…Recent advances in computed tomography (CT) scan imaging could lead to the development of individualized medicines for respiratory patients. This is of importance, as individual inhalation patterns are known to affect the transport and deposition of inhaled particles in the airways . For example, Longest et al .…”

Section: Introductionmentioning

confidence: 99%

“…This is of importance, as individual inhalation patterns are known to affect the transport and deposition of inhaled particles in the airways. [24] For example, Longest et al [25] compared aerosol deposition predictions of a new whole-airway CFD model with the available in vivo data for a dry powder inhaler evaluated across multiple inhalation waveforms. They demonstrated that considering the flow rate was identified as a potentially useful method for characterizing a DPI aerosol at a constant flow rate.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulations of particle behaviour in a realistic human airway model with varying inhalation patterns

et al. 2019

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Objectives For dry powder inhalers, the airflow properties in the airways could affect the deposition of inhaled particles; the flow patterns vary inherently between patients. This paper provides an evaluation of the effects of six airflow patterns on the behaviour of inhaled particles, as determined by using numerical simulations. Methods Constant‐velocity and unsteady inhalation flows were employed. The unsteady inhalation flow was set as an inhalation curve with a peak inspiratory flow rate. Under a constant flow of 28.3 l/min, the total flow rates were calculated to confirm the validity of the numerical simulation. The effects of different inhalation patterns on the particle behaviour in a realistic human airway model were revealed via numerical simulation. Key findings Different flow rates affected the behaviour and deposition of the inhaled particles. Under an inhalation flow pattern, different airflow tendencies were observed between the right and left bronchi. Particle deposition in the airways was promoted by a vortex following terminal‐velocity‐like breath‐holding. The inhalation flow pattern affected the behaviour and deposition of inhaled particles in the airway. Conclusions Our results indicated that particle deposition in a realistic human airway model was promoted by a vortex formation following the terminal‐velocity‐like breath‐holding. Moreover, the inhalation flow pattern significantly influenced the behaviour and deposition of inhaled particles in the airways. Additionally, the effect of flow patterns on the particle deposition in each airway position was quantitatively evaluated by numerical simulations for a realistic human airway model.

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“…Only a few recent works analysed the behaviour of nanometric and micrometric particles during a complete breath cycle (10,16,24,38)…”

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confidence: 99%

Computational Fluid Dynamic Models as Tools to Predict Aerosol Distribution in Tracheobronchial Airways

Atzeni

Lesma

Dubini

et al. 2020

Preprint

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Background: Aerosol and pollutants, in form of particulates 5 – 8 um in main size face every day our respiratory system as natural suspension in air or forced to be inhaled as a coadjutant in a medical therapy for respiratory diseases. This inhalation happens in children to elderly, women and men, healthy or sick and disable people. In this paper we analyzed the inhalation of aerosol in conditions assimilable to the thermal therapy, in a model of patient representing an adult man. Results: We use a computational fluid dynamic 3D model to compute and visualize the trajectories of aerosol (3-7-10-25 µm) down to the sixth generation of bronchi, in a steady and dynamic condition (7 µm) set as breath cycle at rest. Results, compared to a set of milestones experimental studies published in literature, allow the comprehension of particles behavior during the inhalation from mouth to bronchi sixth generation, the visualization of jet at larynx constriction and vortices, in a characteristic geometrical model including tracheal rings. Conclusions: Results on trajectories and deposition show the importance of the including transient physiological breath cycle on aerosol deposition analyses. Furthermore results indicate that vorticity in the glottides and trachea sections mix the trajectories on the transversal plane, excluding meaningful relation between position of the inhalation across the mouth and the deposition lobe. Numerical and graphical results, usable from researchers, technicians and medical doctors, may enable the design of medical devices and protocols to make the inhalations more effective in all the users’ population.

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An efficient computational fluid-particle dynamics method to predict deposition in a simplified approximation of the deep lung

Cited by 66 publications

References 32 publications

In Silico Optimization of Fiber-Shaped Aerosols in Inhalation Therapy for Augmented Targeting and Deposition across the Respiratory Tract

In Silico Optimization of Fiber-Shaped Aerosols in Inhalation Therapy for Augmented Targeting and Deposition across the Respiratory Tract

Numerical simulations of particle behaviour in a realistic human airway model with varying inhalation patterns

Computational Fluid Dynamic Models as Tools to Predict Aerosol Distribution in Tracheobronchial Airways

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