Experimental methods for flow and aerosol measurements in human airways and their replicas

Lízal, František; Jedelský, Jan; Morgan, Kaye S.; Bauer, K.; Llop, Jordi; Cossío, Unai; Kassinos, Stavros C.; Verbanck, Sylvia; Ruíz-Cabello, Jesús; Santos, Arnoldo; Koch, Edmund; Schnabel, Christian

doi:10.1016/j.ejps.2017.08.021

Cited by 50 publications

(30 citation statements)

References 273 publications

(343 reference statements)

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“…A wide range of in silico [3][4][5][6][7][8][9][10] and experimental [11,12] studies have been performed on airflow and particle transport characterization in idealized and realistic models of the lung. Almost all the available literature, however, considers healthy airways for airflow and particle transport modelling.…”

Section: Introductionmentioning

confidence: 99%

Airflow and Particle Transport Prediction through Stenosis Airways

Singh

Raghav

Padhmashali

et al. 2020

IJERPH

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Airflow and particle transport in the human lung system is influenced by biological and other factors such as breathing pattern, particle properties, and deposition mechanisms. Most of the studies to date have analyzed airflow characterization and aerosol transport in idealized and realistic models. Precise airflow characterization for airway stenosis in a digital reference model is lacking in the literature. This study presents a numerical simulation of airflow and particle transport through a stenosis section of the airway. A realistic CT-scan-based mouth-throat and upper airway model was used for the numerical calculations. Three different models of a healthy lung and of airway stenosis of the left and right lung were used for the calculations. The ANSYS FLUENT solver, based on the finite volume discretization technique, was used as a numerical tool. Proper grid refinement and validation were performed. The numerical results show a complex-velocity flow field for airway stenosis, where airflow velocity magnitude at the stenosis section was found to be higher than that in healthy airways. Pressure drops at the mouth-throat and in the upper airways show a nonlinear trend. Comprehensive pressure analysis of stenosis airways would increase our knowledge of the safe mechanical ventilation of the lung. The turbulence intensities at the stenosis sections of the right and left lung were found to be different. Deposition efficiency (DE) increased with flow rate and particle size. The findings of the present study increase our understanding of airflow patterns in airway stenosis under various disease conditions. More comprehensive stenosis analysis is required to further improve knowledge of the field.

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Section: Introductionmentioning

confidence: 99%

Airflow and Particle Transport Prediction through Stenosis Airways

Singh

Raghav

Padhmashali

et al. 2020

IJERPH

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“…Additionally, quantification of the images is extremely challenging. An alternative to overcome these drawbacks consists of labelling the drug or the aerosol with a positron emitter (Lizal et al 2018). The disintegration of the positron emitter leads ultimately to the generation of high energy gamma rays, which have virtually no penetration limits and can be externally detected and processed to generate three dimensional (3D)-images.…”

Section: Introductionmentioning

confidence: 99%

Preclinical evaluation of aerosol administration systems using Positron Emission Tomography

Cossío¹,

Gómez‐Vallejo²,

Flores³

et al. 2018

European Journal of Pharmaceutics and Biopharmaceutics

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Pulmonary administration of drugs has recently gained attention because it exhibits numerous advantages compared to oral or intravenous administration. The administration of aerosols for inhalation to animals, however, remains a critical challenge and only a few methods of administration have been developed. Herein, we compare the regional distribution of aerosols in the lungs of wild type rats after pulmonary administration using three different methods: (a) The Penn-Century MicroSprayer® Aerosolizer; (b) an in-house designed aerosol generation system; and (c) the Aeroneb® Lab Micropump Nebulizer. Both the regional distribution and the fraction of aerosol deposited in the lungs were determined by means of radiolabelling of the aerosol followed by in vivo and ex vivo Positron Emission Tomography (PET) imaging and dissection and gamma counting. Endotracheal insufflation using the PennCentury MicroSprayer resulted in >85% of the administered dose accumulated in the lungs, with a non-uniform distribution of the radioactivity in different lobes and a low animal-to-animal reproducibility. Administration using the in-house designed and the Aeroneb nebulizers resulted in a uniform distribution over the lungs, but only a small fraction of the nebulized activity (ca. 0.1%) was deposited in the lungs.

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“…These can be described using two non-dimensional particle numbers, namely the Stokes and gravity numbers [10]. We note that a detailed discussion of ensuing air flow patterns in the modeled respiratory tract is omitted here for brevity; flow topologies qualitatively resemble extensive works on the topic [39, 40]. However, for an intubated patient the abrupt diameter change from the tip of the intubation tube to the trachea (Fig.…”

Section: Resultsmentioning

confidence: 99%

Targeted Drug Delivery to Upper Airways Using a Pulsed Aerosol Bolus and Inhaled Volume Tracking Method

Ostrovski

Dorfman

Mezhericher

et al. 2018

Flow Turbulence Combust

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The pulmonary route presents an attractive delivery pathway for topical treatment of lung diseases. While significant progress has been achieved in understanding the physical underpinnings of aerosol deposition in the lungs, our ability to target or confine the deposition of inhalation aerosols to specific lung regions remains meagre. Here, we present a novel inhalation proof-of-concept in silico for regional targeting in the upper airways, quantitatively supported by computational fluid dynamics (CFD) simulations of inhaled micron-sized particles (i.e. 1-10 μm) using an intubated, anatomically-realistic, multi-generation airway tree model. Our targeting strategy relies on selecting the particle release time, whereby a short-pulsed bolus of aerosols is injected into the airways and the inhaled volume of clean air behind the bolus is tracked to reach a desired inhalation depth (i.e. airway generations). A breath hold maneuver then follows to facilitate deposition, via sedimentation, before exhalation resumes and remaining airborne particles are expelled. Our numerical findings showcase how particles in the range 5-10 μm combined with such inhalation methodology are best suited to deposit in the upper airways, with deposition fractions between 0.68 and unity. In contrast, smaller (< 2 μm) particles are less than optimal due to their slow sedimentation rates. We illustrate further how modulating the volume inhaled behind the pulsed bolus, prior to breath hold, may be leveraged to vary the targeted airway sites. We discuss the feasibility of the proposed inhalation framework and how it may help pave the way for specialized topical lung treatments.

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Experimental methods for flow and aerosol measurements in human airways and their replicas

Cited by 50 publications

References 273 publications

Airflow and Particle Transport Prediction through Stenosis Airways

Airflow and Particle Transport Prediction through Stenosis Airways

Preclinical evaluation of aerosol administration systems using Positron Emission Tomography

Targeted Drug Delivery to Upper Airways Using a Pulsed Aerosol Bolus and Inhaled Volume Tracking Method

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