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Fluid dynamics of the upper airway in pediatric patients with severe laryngomalacia. Phys Eng Sci Med 2022; 45:1083-1091. [PMID: 36326986 DOI: 10.1007/s13246-022-01174-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 08/11/2022] [Indexed: 11/06/2022]
Abstract
Laryngomalacia is the top cause of pediatric laryngeal wheeze. We used computational fluid dynamics to study the inspiratory airflow dynamics in severe pediatric laryngomalacia. Computed tomography was performed on the upper airways of two infants, one with severe laryngomalacia and one with normal airway, and 3D models were reconstructed. ANSYS CFD-POST software was used to simulate airflow in these models to compare the volumetric flow rate, flow velocity, pressure, wall shear, and vortex. The volume flow rate in the laryngomalacia model was significantly reduced compared with the control model. Under inspiratory pressures, the peak flow velocity, pressure, and shear force in the control model appeared at the soft palate stenosis, while that in the laryngomalacia model appeared at the supraglottis stenosis. In both models, the maximum flow velocity and shear force increased with decreasing inspiratory pressure, while the minimum pressure decreased with decreasing inspiratory pressure. In the control model, the airflow vortex appeared anteriorly below the posterior section of the soft palate. In the laryngomalacia model, the vortex appeared anteriorly below the posterior section of the soft palate and anteriorly below the vocal folds. Our methodology provides a new mechanistic understanding of pediatric laryngomalacia.
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Particle inhalability of a standing mannequin with large airways in a ventilated room. Comput Biol Med 2021; 138:104858. [PMID: 34560501 DOI: 10.1016/j.compbiomed.2021.104858] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 09/06/2021] [Accepted: 09/07/2021] [Indexed: 11/23/2022]
Abstract
This study presents a series of numerical simulations for airflow field and particle dispersion and deposition around a mannequin inside a ventilated room. A 3-D airway system of a volunteer subject with a large respiratory system was reconstructed from the nostril inlet to the end of the tracheobronchial tree 4th generation and was integrated into a standing mannequin at the center of a room. The room ventilation system supplied air through a diffuser and expelled air via a damper in three modes. The airflow field was first evaluated by solving the governing equations and the k-ω SST transitional turbulence model using the Ansys-Fluent software. Then spherical particles with various diameters were released into the room, and their trajectories were evaluated using the Lagrangian approach. Aspiration fraction and particle deposition for inhalation flow rates of 15 and 30 L/min were analyzed using a modified discrete random walk (DRW) stochastic model using a user-defined function (UDF) coupled to the Ansys-Fluent discrete phase model. For the first ventilation mode, a recirculation flow region formed behind the mannequin that led the airflow streamlines to the breathing zone. A recirculation flow formed in front of the face for the second ventilation mode that led the airflow streamlines out of the mannequin breathing zone. For the third mode, however, there was no strong recirculation flow zone around the mannequin. Simulation results showed that the aspiration fraction in the first ventilation mode was higher than the other modes. In addition, the regional deposition rates and deposition patterns of particles inside the respiratory system were presented for each region. Accordingly, most large particles were trapped in the nasal passage; however, some large particles penetrated deeper into the airway due to the large airway size. For the higher breathing rate, the percentage of large escaped particles from the lobe branches dropped by a factor of 7 compared to the lower breathing rate.
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Chen WH, Chang CM, Mutuku JK, Lam SS, Lee WJ. Aerosol deposition and airflow dynamics in healthy and asthmatic human airways during inhalation. JOURNAL OF HAZARDOUS MATERIALS 2021; 416:125856. [PMID: 34492805 DOI: 10.1016/j.jhazmat.2021.125856] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 03/13/2021] [Accepted: 04/06/2021] [Indexed: 05/07/2023]
Abstract
Inhalation of aerosols such as pharmaceutical aerosols or virus aerosol uptake is of great concern to the human population. To elucidate the underlying aerosol dynamics, the deposition fractions (DFs) of aerosols in healthy and asthmatic human airways of generations 13-15 are predicted. The Navier-stokes equations governing the gaseous phase and the discrete phase model for particles' motion are solved using numerical methods. The main forces responsible for deposition are inertial impaction forces and complex secondary flow velocities. The curvatures and sinusoidal folds in the asthmatic geometry lead to the formation of complex secondary flows and hence higher DFs. The intensities of complex secondary flows are strongest at the generations affected by asthma. The DF in the healthy airways is 0%, and it ranges from 1.69% to 52.93% in the asthmatic ones. From this study, the effects of the pharmaceutical aerosol particle diameters in the treatment of asthma patients can be established, which is conducive to inhibiting the inflammation of asthma airways. Furthermore, with the recent development of COVID-19 which causes pneumonia, the predicted physics and effective simulation methods of bioaerosols delivery to asthma patients are vital to prevent the exacerbation of the chronic ailment and the epidemic.
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Affiliation(s)
- Wei-Hsin Chen
- Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan 701, Taiwan; Research Center for Smart Sustainable Circular Economy, Tunghai University, Taichung 407, Taiwan; Department of Mechanical Engineering, National Chin-Yi University of Technology, Taichung 411, Taiwan.
| | - Che-Ming Chang
- Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan 701, Taiwan; International Master Degree Program on Energy Engineering, National Cheng Kung University, Tainan 701, Taiwan
| | - Justus Kavita Mutuku
- Department of Environmental Engineering, National Cheng Kung University, Tainan 701, Taiwan; Center for Environmental Toxin and Emerging-Contaminant Research, Cheng Shiu University, Kaohsiung 833, Taiwan; Super micro mass research and technology center, Cheng Shiu University, Kaohsiung 833, Taiwan
| | - Su Shiung Lam
- Pyrolysis Technology Research Group, Higher Institution Centre of Excellence (HICoE), Institute of Tropical Aquaculture and Fisheries (AKUATROP), Universiti Malaysia Terengganu, Kuala Nerus 21030, Terengganu, Malaysia; Henan Province Engineering Research Center for Biomass Value-Added Products, Henan Agricultural University, Zhengzhou 450002, Henan, China
| | - Wen-Jhy Lee
- Department of Environmental Engineering, National Cheng Kung University, Tainan 701, Taiwan
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Malvè M, Sánchez-Matás C, López-Villalobos JL. Modelling Particle Transport and Deposition in the Human Healthy and Stented Tracheobronchial Airways. Ann Biomed Eng 2020; 48:1805-1820. [PMID: 32215754 DOI: 10.1007/s10439-020-02493-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 03/15/2020] [Indexed: 12/27/2022]
Abstract
The main goal of this study is the quantification of the particle transport and deposition within the human airways during light, normal and exercise breathing conditions using the computational fluid dynamics. In particular we presented a comparison between healthy and stented airways. The considered tracheobronchial model is based on the Weibel symmetric model in which we have inserted the Dumon prosthesis at different locations and on the CT-based geometries of a healthy and a stented airway. The results indicate an important redistribution of the particle deposition locations. Local overdoses can be found in the proximal regions of the prostheses, independently of the breathing conditions, of the particle size and of the considered geometry. The presented work is aimed to contribute to the understanding of the particle deposition in the human lung and to improve drug-aerosol therapies. For patients that underwent airways reconstructive surgery, it can give detailed information about the deposition efficiency and it may help targeting specific airways regions.
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Affiliation(s)
- M Malvè
- Departamento de Ingeniería, Universidad Pública de Navarra, Campus Arrosadía s/n, E-31006, Pamplona, Spain. .,CIBER-BBN, Centro de Investigación Biomédica en Red - Bioingeniería, Biomateriales y Nanomedicina, C/Poeta Mariano Esquillor s/n, 50018, Zaragoza, Spain. .,Aragón Institute of Engineering Research, Universidad de Zaragoza, C/María de Luna s/n, 50018, Zaragoza, Spain.
| | - C Sánchez-Matás
- Department of Thoracic Surgery, University Hospital Virgen del Rocío, Avenida Manuel Siurot s/n, 41013, Sevilla, Spain
| | - J L López-Villalobos
- Department of Thoracic Surgery, University Hospital Virgen del Rocío, Avenida Manuel Siurot s/n, 41013, Sevilla, Spain
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Ganguly K, Carlander U, Garessus EDG, Fridén M, Eriksson UG, Tehler U, Johanson G. Computational modeling of lung deposition of inhaled particles in chronic obstructive pulmonary disease (COPD) patients: identification of gaps in knowledge and data. Crit Rev Toxicol 2019; 49:160-173. [DOI: 10.1080/10408444.2019.1584153] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Koustav Ganguly
- Integrative Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Ulrika Carlander
- Integrative Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Estella DG Garessus
- Integrative Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Markus Fridén
- Respiratory, Inflammation and Autoimmunity IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
- Translational PKPD, Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Ulf G Eriksson
- Early Clinical Development, IMED Biotech Unit, Quantitative Clinical Pharmacology, AstraZeneca, Gothenburg, Sweden
| | - Ulrika Tehler
- Pharmaceutical Sciences, IMED Biotech Unit, Early Product Development, AstraZeneca, Gothenburg, Sweden
| | - Gunnar Johanson
- Integrative Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
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Zhang B, Qi S, Yue Y, Shen J, Li C, Qian W, Wu J. Particle Disposition in the Realistic Airway Tree Models of Subjects with Tracheal Bronchus and COPD. BIOMED RESEARCH INTERNATIONAL 2018; 2018:7428609. [PMID: 30155481 PMCID: PMC6098871 DOI: 10.1155/2018/7428609] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 07/02/2018] [Accepted: 07/18/2018] [Indexed: 12/31/2022]
Abstract
Dispositions of inhalable particles in the human respiratory tract trigger and exacerbate airway inflammatory diseases. However, the particle deposition (PD) in airway of subjects with tracheal bronchus (TB) and chronic obstructive pulmonary diseases (COPD) is unknown. We therefore propose to clarify the disrupted PD associated with TB and COPD using the computational fluid dynamics (CFD) simulation. Totally nine airway tree models are included. Six are extracted from CT images of different individuals (two with TB, two with COPD, and two healthy controls (HC)). The others are the artificially modified models (AMMs) generated by the virtual lesion. Specifically, they are constructed through artificially adding a tracheal bronchus or a stenosis on one HC model. The deposition efficiency (DE) and deposition fraction (DF) in these models are obtained by the Euler-Lagrange approach, analyzed, and compared across models, locations, and particle sizes (0.1-10.0 micrometers). It is found that the PD in models with TB and COPD has been disrupted by the geometrical changes and followed airflow alternations. DE of the tracheal bronchus is higher for TB models. For COPD, the stenosis location determines the effects on DE and DF. Higher DF at the trachea is observed in TB1, TB2, and COPD2 models. DE increases with the particle size, and DE of the terminal bronchi is higher than that of central regions. Combined with AMMs, the CFD simulation using realistic airway models demonstrates disruptions of DP. The methods and findings might help understand the etiology of pulmonary diseases and improve the efficacy of inhaled medicines.
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Affiliation(s)
- Baihua Zhang
- Sino-Dutch Biomedical and Information Engineering School, Northeastern University, Shenyang, China
- Key Laboratory of Medical Image Computing of Northeastern University (Ministry of Education), Shenyang, China
| | - Shouliang Qi
- Sino-Dutch Biomedical and Information Engineering School, Northeastern University, Shenyang, China
- Key Laboratory of Medical Image Computing of Northeastern University (Ministry of Education), Shenyang, China
| | - Yong Yue
- Department of Radiology, ShengJing Hospital of China Medical University, Shenyang, China
| | - Jing Shen
- Department of Radiology, Affiliated Zhongshan Hospital of Dalian University, Dalian, China
| | - Chen Li
- Sino-Dutch Biomedical and Information Engineering School, Northeastern University, Shenyang, China
| | - Wei Qian
- Sino-Dutch Biomedical and Information Engineering School, Northeastern University, Shenyang, China
- College of Engineering, University of Texas at El Paso, El Paso, USA
| | - Jianlin Wu
- Department of Radiology, Affiliated Zhongshan Hospital of Dalian University, Dalian, China
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An In Silico Subject-Variability Study of Upper Airway Morphological Influence on the Airflow Regime in a Tracheobronchial Tree. Bioengineering (Basel) 2017; 4:bioengineering4040090. [PMID: 29144436 PMCID: PMC5746757 DOI: 10.3390/bioengineering4040090] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 11/13/2017] [Accepted: 11/14/2017] [Indexed: 11/16/2022] Open
Abstract
Determining the impact of inter-subject variability on airflow pattern and nanoparticle deposition in the human respiratory system is necessary to generate population-representative models, useful for several biomedical engineering applications. Thus, the overall research objective is to quantitatively correlate geometric parameters and coupled transport characteristics of air, vapor, and nanoparticles. Focusing on identifying morphological parameters that significantly influence airflow field and nanoparticle transport, an experimentally validated computational fluid-particle dynamics (CFPD) model was employed to simulate airflow pattern in three human lung-airway configurations. The numerical results will be used to generate guidelines to construct a representative geometry of the human respiratory system.
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