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Zhang Y, Hu Z, Wang Y, Lou M, Ma R, Gong M, Dong J, Zheng G, Wang B. Numerical investigation of nanoparticle deposition in the olfactory region among pediatric nasal airways with adenoid hypertrophy. Comput Biol Med 2023; 167:107587. [PMID: 37890422 DOI: 10.1016/j.compbiomed.2023.107587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Revised: 09/28/2023] [Accepted: 10/15/2023] [Indexed: 10/29/2023]
Abstract
To understand inhaled nanoparticle transport and deposition characteristics in pediatric nasal airways with adenoid hypertrophy (AH), with a specific emphasis on the olfactory region, virtual nanoparticle inhalation studies were conducted on anatomically accurate child nasal airway models. The computational fluid-particle dynamics (CFPD) method was employed, and numerical simulations were performed to compare the airflow and nanoparticle deposition patterns between nasal airways with nasopharyngeal obstruction before adenoidectomy and healthy nasal airways after virtual adenoidectomy. The influence of different inhalation rates and exhalation phase on olfactory regional nanoparticle deposition features was systematically analyzed. We found that nasopharyngeal obstruction resulted in significant uneven airflow distribution in the nasal cavity. The deposited nanoparticles were concentrated in the middle meatus, septum, inferior meatus and nasal vestibule. The deposition efficiency (DE) in the olfactory region decreases with increasing nanoparticle size (1-10 nm) during inhalation. After adenoidectomy, the pediatric olfactory region DE increased significantly while nasopharynx DE dramatically decreased. When the inhalation rate decreased, the deposition pattern in the olfactory region significantly altered, exhibiting an initial rise followed by a subsequent decline, reaching peak deposition at 2 nm. During exhalation, the pediatric olfactory region DE was substantially lower than during inhalation, and the olfactory region DE in the pre-operative models were found to be significantly higher than that of the post-operative models. In conclusions, ventilation and particle deposition in the olfactory region were significantly improved in post-operative models. Inhalation rate and exhalation process can significantly affect nanoparticle deposition in the olfactory region.
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Affiliation(s)
- Ya Zhang
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, 710004, China
| | - Zhenzhen Hu
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, 710004, China; School of Engineering, RMIT University, Bundoora, VIC, 3083, Australia
| | - Yusheng Wang
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, 710004, China
| | - Miao Lou
- Department of Otorhinolaryngology Head and Neck Surgery, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi, 710068, China
| | - Ruiping Ma
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, 710004, China
| | - Minjie Gong
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, 710004, China
| | - Jingliang Dong
- Institute for Sustainable Industries & Liveable Cities, Victoria University, PO Box 14428, Melbourne, VIC, 8001, Australia; First Year College, Victoria University, Footscray Park Campus, Footscray, VIC, 3011, Australia.
| | - Guoxi Zheng
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, 710004, China.
| | - Botao Wang
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, 710004, China.
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Hu Z, Dong J, Lou M, Zhang J, Ma R, Wang Y, Gong M, Wang B, Tong Z, Ren H, Zheng G, Zhang Y. Effect of different degrees of adenoid hypertrophy on pediatric upper airway aerodynamics: a computational fluid dynamics study. Biomech Model Mechanobiol 2023; 22:1163-1175. [PMID: 37256522 DOI: 10.1007/s10237-023-01707-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 02/22/2023] [Indexed: 06/01/2023]
Abstract
To improve the diagnostic accuracy of adenoid hypertrophy (AH) in children and prevent further complications in time, it is important to study and quantify the effects of different degrees of AH on pediatric upper airway (UA) aerodynamics. In this study, based on computed tomography (CT) scans of a child with AH, UA models with different degrees of obstruction (adenoidal-nasopharyngeal (AN) ratio of 0.9, 0.8, 0.7, and 0.6) and no obstruction (AN ratio of 0.5) were constructed through virtual surgery to quantitatively analyze the aerodynamic characteristics of UA with different degrees of obstruction in terms of the peak velocity, pressure drop (△P), and maximum wall shear stress (WSS). We found that two obvious whirlpools are formed in the anterior upper part of the pediatric nasal cavity and in the oropharynx, which is caused by the sudden increase in the nasal cross-section area, resulting in local flow separation and counterflow. In addition, when the AN ratio was ≥ 0.7, the airflow velocity peaked at the protruding area in the nasopharynx, with an increase 1.1-2.7 times greater than that in the nasal valve area; the △P in the nasopharynx was significantly increased, with an increase 1.1-6.8 times greater than that in the nasal cavity; and the maximum WSS of the posterior wall of the nasopharynx was 1.1-4.4 times larger than that of the nasal cavity. The results showed that the size of the adenoid plays an important role in the patency of the pediatric UA.
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Affiliation(s)
- Zhenzhen Hu
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, 157 Xiwu Road, Xi'an, 710004, Shaanxi, China
| | - Jingliang Dong
- Institute for Sustainable Industries & Liveable Cities, Victoria University, PO Box 14428, Melbourne, VIC, 8001, Australia
- First Year College, Victoria University, Footscray Park Campus, Footscray, VIC, 3011, Australia
- School of Engineering, RMIT University, Bundoora, VIC, 3083, Australia
| | - Miao Lou
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, 157 Xiwu Road, Xi'an, 710004, Shaanxi, China
| | - Jingbin Zhang
- Department of Imaging, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Ruiping Ma
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, 157 Xiwu Road, Xi'an, 710004, Shaanxi, China
| | - Yusheng Wang
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, 157 Xiwu Road, Xi'an, 710004, Shaanxi, China
| | - Minjie Gong
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, 157 Xiwu Road, Xi'an, 710004, Shaanxi, China
| | - Botao Wang
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, 157 Xiwu Road, Xi'an, 710004, Shaanxi, China
| | - Zhenbo Tong
- School of Energy and Environment, Southeast University, Nanjing, China
| | - Hongxian Ren
- School of Energy and Environment, Southeast University, Nanjing, China
| | - Guoxi Zheng
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, 157 Xiwu Road, Xi'an, 710004, Shaanxi, China.
| | - Ya Zhang
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, 157 Xiwu Road, Xi'an, 710004, Shaanxi, China.
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Targeted drug delivery with polydisperse particle transport and deposition in patient-specific upper airway during inhalation and exhalation. Respir Physiol Neurobiol 2023; 308:103986. [PMID: 36396028 DOI: 10.1016/j.resp.2022.103986] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 10/16/2022] [Accepted: 11/07/2022] [Indexed: 11/16/2022]
Abstract
Identifying the deposition pattern of inhaled pharmaceutical aerosols in the human respiratory system and understanding the effective parameters in this process is vital for more efficient drug delivery to this region. This study investigated aerosol deposition in a patient-specific upper respiratory airway and determined the deposition fraction (DF) and pressure drop across the airway. An experimental setup was developed to measure the pressure drop in the same realistic geometry printed from the patient-specific geometry. The unsteady simulations were performed with a flow rate of 15 L/min and different particle diameters ranging from 2 to 30 µm. The results revealed significant flow circulation after the nasal valve in the upper and oropharynx regions, and a maximum local velocity observed in the nasopharynx. Transient cumulative deposition fraction showed that after 2 s of the simulation, all particles deposit or escape the computational domain. About 30 % of the injected large particles (dp ≥ 20 µm) deposited in the first 1 cm away from the nostril and more than 95 % deposited in the nasal airway before entering the oropharynx region. While almost 94 % deposition in trachea was composed of particles smaller than 5 µm. Approximately 20 % of inhaled fine particles (2-5 µm) deposited in the upper airway and the rest deposited in oropharynx, larynx and trachea.
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Melzow F, Mertens S, Todorov H, Groneberg DA, Paris S, Gerber A. Aerosol exposure of staff during dental treatments: a model study. BMC Oral Health 2022; 22:128. [PMID: 35428223 PMCID: PMC9012061 DOI: 10.1186/s12903-022-02155-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 04/05/2022] [Indexed: 12/20/2022] Open
Abstract
Background Due to exposure to potentially infectious aerosols during treatments, the dental personnel is considered being at high risk for aerosol transmitted diseases like COVID-19. The aim of this study was to evaluate aerosol exposure during different dental treatments as well as the efficacy of dental suction to reduce aerosol spreading.
Methods Dental powder-jet (PJ; Air-Flow®), a water-cooled dental handpiece with a diamond bur (HP) and water-cooled ultrasonic scaling (US) were used in a simulation head, mounted on a dental unit in various treatment settings. The influence of the use of a small saliva ejector (SE) and high-volume suction (HVS) was evaluated. As a proxy of aerosols, air-born particles (PM10) were detected using a Laser Spectrometer in 30 cm distance from the mouth. As control, background particle counts (BC) were measured before and after experiments. Results With only SE, integrated aerosol levels [median (Q25/Q75) µg/m3 s] for PJ [91,246 (58,213/118,386) µg/m3 s, p < 0.001, ANOVA] were significantly increased compared to BC [7243 (6501/8407) µg/m3 s], whilst HP [11,119 (7190/17,234) µg/m3 s, p > 0.05] and US [6558 (6002/7066) µg/m3 s; p > 0.05] did not increase aerosol levels significantly. The use of HVS significantly decreased aerosol exposure for PJ [37,170 (29,634/51,719) µg/m3 s; p < 0.01] and HP [5476 (5066/5638) µg/m3 s; p < 0.001] compared to SE only, even reaching lower particle counts than BC levels for HP usage (p < 0.001). Conclusions To reduce the exposure to potentially infectious aerosols, HVS should be used during aerosol-forming dental treatments.
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Comparison of Sinus Deposition from an Aqueous Nasal Spray and Pressurised MDI in a Post-Endoscopic Sinus Surgery Nasal Replica. Pharm Res 2022; 39:317-327. [PMID: 35137359 PMCID: PMC8881262 DOI: 10.1007/s11095-021-03129-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 10/17/2021] [Indexed: 11/16/2022]
Abstract
Background Optimising intranasal distribution and retention of topical therapy is essential for effectively managing patients with chronic rhinosinusitis, including those that have had functional endoscopic sinus surgery (FESS). This study presents a new technique for quantifying in vitro experiments of fluticasone propionate deposition within the sinuses of a 3D-printed model from a post-FESS patient. Methods Circular filter papers were placed on the sinus surfaces of the model. Deposition of fluticasone on the filter paper was quantified using high-performance liquid chromatography (HPLC) assay-based techniques. The deposition patterns of two nasal drug delivery devices, an aqueous nasal spray (Flixonase) and metered dose inhaler (Flixotide), were compared. The effects of airflow (0 L/min vs. 12 L/min) and administration angle (30° vs. and 45°) were evaluated. Results Inhaled airflow made little difference to sinus deposition for either device. A 45° administration angle improved frontal sinus deposition with the nasal spray and both ethmoidal and sphenoidal deposition with the inhaler. The inhaler provided significantly better deposition within the ethmoid sinuses (8.5x) and within the maxillary sinuses (3.9x) compared with the nasal spray under the same conditions. Conclusion In the post-FESS model analysed, the inhaler produced better sinus deposition overall compared with the nasal spray. The techniques described can be used and adapted for in vitro performance testing of different drug formulations and intranasal devices under different experimental conditions. They can also help validate computational fluid dynamics modelling and in vivo studies.
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Tian L, Dong J, Shang Y, Tu J. Detailed comparison of anatomy and airflow dynamics in human and cynomolgus monkey nasal cavity. Comput Biol Med 2021; 141:105150. [PMID: 34942396 DOI: 10.1016/j.compbiomed.2021.105150] [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: 09/01/2021] [Revised: 12/14/2021] [Accepted: 12/14/2021] [Indexed: 11/26/2022]
Abstract
Nonhuman primates are occasionally used as laboratory models for sophisticated medical research as they bear the closest resemblance to humans in morphometry and physiological functions. A range of nonhuman primate species have been employed in the inhalation toxicity, nasal drug delivery and respiratory viral infection studies, and they provided valuable insight to disease pathogenesis while other laboratory animals such as rodents cannot recapitulate due to the lesser degree of similarity in metabolism, anatomy and cellular response to that of humans. It is anticipated that nonhuman primate models of respiratory diseases will continue to be instrumental for translating biomedical research for improvement of human health, and the confidence in laboratory data extrapolation between species will play a pivotal role. From the morphometry and flow dynamics point of view, this study performed a detailed comparative analysis between human and a cynomolgus monkey nasal airway, with intention to provide high-fidelity qualitative and quantitative linkage between the two species for more effective laboratory data extrapolation. The study revealed that cynomolgus monkey could be a good human surrogate in nasal inhalation studies; however, care should be given for interspecies data extrapolation as subtle differences in anatomy and airflow dynamics were present between the two species.
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Affiliation(s)
- Lin Tian
- School of Engineering, Mechanical and Automative, RMIT University, Bundoora, VIC, Australia.
| | - Jingliang Dong
- School of Engineering, Mechanical and Automative, RMIT University, Bundoora, VIC, Australia
| | - Yidan Shang
- School of Engineering, Mechanical and Automative, RMIT University, Bundoora, VIC, Australia
| | - Jiyuan Tu
- School of Engineering, Mechanical and Automative, RMIT University, Bundoora, VIC, Australia.
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Salati H, Khamooshi M, Vahaji S, Christo FC, Fletcher DF, Inthavong K. N95 respirator mask breathing leads to excessive carbon dioxide inhalation and reduced heat transfer in a human nasal cavity. PHYSICS OF FLUIDS (WOODBURY, N.Y. : 1994) 2021; 33:081913. [PMID: 34552313 PMCID: PMC8450908 DOI: 10.1063/5.0061574] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 08/06/2021] [Indexed: 05/16/2023]
Abstract
Face masks and respirators are used to filter inhaled air, which may contain airborne droplets and high particulate matter (PM) concentrations. The respirators act as a barrier to the inhaled and exhaled air, which may change the nasal airflow characteristics and air-conditioning function of the nose. This study aims to investigate the nasal airflow dynamics during respiration with and without an N95 respirator driven by airflow through the nasal cavity to assess the effect of the respirator on breathing conditions during respiration. To achieve the objective of this study, transient computational fluid dynamics simulations have been utilized. The nasal geometry was reconstructed from high-resolution Computed Tomography scans of a healthy 25-year-old female subject. The species transport method was used to analyze the airflow, temperature, carbon dioxide (CO2), moisture content (H2O), and temperature distribution within the nasal cavity with and without an N95 respirator during eight consecutive respiration cycles with a tidal volume of 500 ml. The results demonstrated that a respirator caused excessive CO2 inhalation by approximately 7 × greater per breath compared with normal breathing. Furthermore, heat and mass transfer in the nasal cavity was reduced, which influences the perception of nasal patency. It is suggested that wearers of high-efficiency masks that have minimal porosity and low air exchange for CO2 regulation should consider the amount of time they wear the mask.
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Affiliation(s)
| | - Mehrdad Khamooshi
- Mechanical and Automotive Engineering, School of Engineering, RMIT University, Bundoora, Australia
| | - Sara Vahaji
- School of Engineering, Faculty of Science Engineering and Built Environment, Deakin University, Victoria, Australia
| | - Farid C. Christo
- School of Engineering, Faculty of Science Engineering and Built Environment, Deakin University, Victoria, Australia
| | - David F. Fletcher
- School of Chemical and Biomolecular Engineering, The University of Sydney, NSW 2006 Australia
| | - Kiao Inthavong
- Mechanical and Automotive Engineering, School of Engineering, RMIT University, Bundoora, Australia
- Author to whom correspondence should be addressed:
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Senanayake P, Salati H, Wong E, Bradshaw K, Shang Y, Singh N, Inthavong K. The impact of nasal adhesions on airflow and mucosal cooling - A computational fluid dynamics analysis. Respir Physiol Neurobiol 2021; 293:103719. [PMID: 34147672 DOI: 10.1016/j.resp.2021.103719] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 06/01/2021] [Accepted: 06/10/2021] [Indexed: 10/21/2022]
Abstract
Nasal adhesions are a known postoperative complication following surgical procedures for nasal airway obstruction (NAO); and are a common cause of surgical failure, with patients often reporting significant NAO, despite relatively minor adhesion size. Division of such nasal adhesions often provides much greater relief than anticipated, based on the minimal reduction in cross-sectional area associated with the adhesion. The available literature regarding nasal adhesions provides little evidence examining their quantitative and qualitative effects on nasal airflow using objective measures. This study examined the impact of nasal adhesions at various anatomical sites on nasal airflow and mucosal cooling using computational fluid dynamics (CFD). A high-resolution CT scan of the paranasal sinuses of a 25-year-old, healthy female patient was segmented to create a three-dimensional nasal airway model. Virtual nasal adhesions of 2.5 mm diameter were added to various locations within the nasal cavity, representing common sites seen following NAO surgery. A series of models with single adhesions were created. CFD analysis was performed on each model and compared with a baseline no-adhesion model, comparing airflow and heat and mass transfer. The nasal adhesions resulted in no significant change in bulk airflow patterns through the nasal cavity. However, significant changes were observed in local airflow and mucosal cooling around and immediately downstream to the nasal adhesions. These were most evident with anterior nasal adhesions at the internal valve and anterior inferior turbinate. Postoperative nasal adhesions create local airflow disruption, resulting in reduced local mucosal cooling on critical surfaces, explaining the exaggerated perception of nasal obstruction. In particular, anteriorly located adhesions created greater disruption to local airflow and mucosal cooling, explaining their associated greater subjective sensation of obstruction.
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Affiliation(s)
- Praween Senanayake
- Department of Otolaryngology, Head and Neck Surgery, Westmead Hospital, Sydney, NSW, Australia
| | - Hana Salati
- Mechanical & Automotive Engineering, School of Engineering, RMIT University, Bundoora, Victoria 3083, Australia
| | - Eugene Wong
- Mechanical & Automotive Engineering, School of Engineering, RMIT University, Bundoora, Victoria 3083, Australia
| | - Kimberley Bradshaw
- Department of Otolaryngology, Head and Neck Surgery, Westmead Hospital, Sydney, NSW, Australia
| | - Yidan Shang
- Mechanical & Automotive Engineering, School of Engineering, RMIT University, Bundoora, Victoria 3083, Australia
| | - Narinder Singh
- Department of Otolaryngology, Head and Neck Surgery, Westmead Hospital, Sydney, NSW, Australia; Faculty of Medicine & Health, The University of Sydney, NSW 2006, Australia
| | - Kiao Inthavong
- Mechanical & Automotive Engineering, School of Engineering, RMIT University, Bundoora, Victoria 3083, Australia.
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Can computational fluid dynamic models help us in the treatment of chronic rhinosinusitis. Curr Opin Otolaryngol Head Neck Surg 2020; 29:21-26. [PMID: 33315616 DOI: 10.1097/moo.0000000000000682] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW The aim of this study was to review the recent literature (January 2017-July 2020) on computational fluid dynamics (CFD) studies relating to chronic rhinosinusitis (CRS), including airflow within the pre and postoperative sinonasal cavity, virtual surgery, topical drug and saline delivery (sprays, nebulizers and rinses) and olfaction. RECENT FINDINGS Novel CFD-specific parameters (heat flux and wall shear stress) are highly correlated with patient perception of nasal patency. Increased ostial size markedly improves sinus ventilation and drug delivery. New virtual surgery tools allow surgeons to optimize interventions. Sinus deposition of nasal sprays is more effective with smaller, low-inertia particles, outside of the range produced by many commercially available products. Saline irrigation effectiveness is improved using greater volume, with liquid entering sinuses via 'flooding' of ostia rather than direct jet entry. SUMMARY CFD has provided new insights into sinonasal airflow, air-conditioning function, the nasal cycle, novel measures of nasal patency and the impact of polyps and sinus surgery on olfaction. The deposition efficiency of topical medications on sinus mucosa can be markedly improved through parametric CFD experiments by optimising nasal spray particle size and velocity, nozzle angle and insertion location, while saline irrigation effectiveness can be optimized by modelling squeeze bottle volume and head position. More sophisticated CFD models (inhalation and exhalation, spray particle and saline irrigation) will increasingly provide translational benefits in the clinical management of CRS.
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Füri P, Groma V, Török S, Farkas Á, Dian C. Ultrafine urban particle measurements in Budapest and their airway deposition distribution calculation. Inhal Toxicol 2020; 32:494-502. [PMID: 33283557 DOI: 10.1080/08958378.2020.1850937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
OBJECTIVES The aim of this study was to provide particle number and mass deposition rates of submicron particles in the human airways as inputs for toxicology and other areas of aerosol science. METHODS Scanning Mobility Particle Spectrometer was used to measure the number concentrations and size distributions of the ultrafine urban particles during summer and winter in Budapest. The Stochastic Lung Model (SLM) was applied to calculate number and mass deposition rates of the inhaled particles in different anatomical regions of the airways. RESULTS Our calculations revealed that for the selected days in summer and winter with PM10 values below the health limit 4.7 and 18.4 billion particles deposited in the bronchial region of the lungs. The deposition in the acinar region of the lung was even higher, 8.3 billion particles for the summer day, and 33.8 billion particles for winter day. CONCLUSIONS Our results clearly demonstrate that large daily numbers of urban UFPs are deposited in the respiratory tract, which may play a key role in the health effects of particulate matter (PM) inhalation. Present results, connecting the ambient exposure parameters with the local burden of the airway epithelium, can be useful inputs of in vitro cell culture experiments. By the combination of urban UFP monitoring and numerical modeling of particle deposition with toxicological studies, the health risks of urban aerosols could be better assessed. The use of UFP data in addition to PM10 and PM2.5 in the epidemiological studies would also be indicated.
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Affiliation(s)
- Péter Füri
- Centre for Energy Research, Budapest, Hungary
| | | | | | | | - Csenge Dian
- Centre for Energy Research, Budapest, Hungary
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Talebizadehsardari P, Rahimzadeh H, Ahmadi G, Inthavong K, Keshtkar MM, Moghimi M. Nano-particle deposition in laminar annular pipe flows. ADV POWDER TECHNOL 2020. [DOI: 10.1016/j.apt.2020.06.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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12
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Dang Khoa N, Phuong NL, Ito K. Numerical modeling of nanoparticle deposition in realistic monkey airway and human airway models: a comparative study. Inhal Toxicol 2020; 32:311-325. [DOI: 10.1080/08958378.2020.1800148] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Nguyen Dang Khoa
- Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Fukuoka, Japan
| | - Nguyen Lu Phuong
- Faculty of Environment, University of Natural resources and Environment, Ho Chi Minh City, Vietnam
| | - Kazuhide Ito
- Faculty of Engineering Sciences, Kyushu University, Fukuoka, Japan
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Particle deposition in the paranasal sinuses following endoscopic sinus surgery. Comput Biol Med 2019; 116:103573. [PMID: 31999554 DOI: 10.1016/j.compbiomed.2019.103573] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 12/02/2019] [Accepted: 12/02/2019] [Indexed: 11/21/2022]
Abstract
Optimizing intranasal distribution and retention of topical therapy is essential in the management of patients with chronic rhinosinusitis, including those that have had functional endoscopic sinus surgery (FESS). Computational fluid dynamics analysis has not previously been used to investigate sinus nasal spray delivery in the complete post-operative sinonasal geometries of patients who have undergone FESS. Models of sinonasal cavities were created from postoperative magnetic resonance imaging scans in four patients, three of whom underwent a comprehensive FESS, the other a modified endoscopic Lothrop procedure. Spray simulations were conducted at different flow rates (5 L/min, 10 L/min and 15 L/min) using sixteen particle sizes ranging from 4 μm to 70μm, spray velocity of 10 m/s and plume angle of 15°. Two different spray insertion angles were compared. Airflow distribution in the sinuses was closely related to the patient's nasal geometry and surgical intervention, in particular a unique crossflow between nasal chambers was present for the Lothrop patient. Sinus deposition was generally more effective with inhalational transport of low-inertia particles outside of the range produced by many standard nasal sprays or nebulizer. This was true except in the Lothrop patient, since previous surgery had been performed removing most of the septum where high-inertia particles would normally deposit. For sinuses receiving minimal airflow, particle penetration was diminished and successful deposition in the region became more restricted by device parameters. Further research is needed to validate these findings and explore other spray variables in a wider spectrum of patients to ascertain a multi-level approach to optimizing drug delivery in the sinuses.
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Inthavong K, Das P, Singh N, Sznitman J. In silico approaches to respiratory nasal flows: A review. J Biomech 2019; 97:109434. [PMID: 31711609 DOI: 10.1016/j.jbiomech.2019.109434] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 09/15/2019] [Accepted: 10/17/2019] [Indexed: 12/20/2022]
Abstract
The engineering discipline of in silico fluid dynamics delivers quantitative information on airflow behaviour in the nasal regions with unprecedented detail, often beyond the reach of traditional experiments. The ability to provide visualisation and analysis of flow properties such as velocity and pressure fields, as well as wall shear stress, dynamically during the respiratory cycle may give significant insight to clinicians. Yet, there remains ongoing challenges to advance the state-of-the-art further, including for example the lack of comprehensive CFD modelling on varied cohorts of patients. The present article embodies a review of previous and current in silico approaches to simulating nasal airflows. The review discusses specific modelling techniques required to accommodate physiologically- and clinically-relevant findings. It also provides a critical summary of the reported results in the literature followed by an outlook on the challenges and topics anticipated to drive research into the future.
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Affiliation(s)
| | - Prashant Das
- Department of Mechanical Engineering, University of Alberta, Edmonton, Canada
| | - Narinder Singh
- Dept of Otolaryngology, Head & Neck Surgery, Westmead Hospital Clinical School, Faculty of Medicine, University of Sydney, Australia
| | - Josué Sznitman
- Department of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa, Israel
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15
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Inthavong K. From indoor exposure to inhaled particle deposition: A multiphase journey of inhaled particles. ACTA ACUST UNITED AC 2019. [DOI: 10.1007/s42757-019-0046-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
AbstractIndoor air quality and its effect on respiratory health are reliant on understanding the level of inhalation exposure, particle inhalability, and particle deposition in the respiratory airway. In the indoor environment, controlling airflow through different ventilation systems can reduce inhalation exposure. This produces a wide variety of complex flow phenomena, such as recirculation, coanda flow, separation, and reattachment. Airborne particles drifting through the air, that move within the breathing region become inhaled into nasal cavity the nostrils. Studies have developed the aspiration efficiency to assist in predicting the fraction of inhaled particles. Inside the nasal cavity, micron and submicron particle deposition occurs in very different ways (inertial impaction, sedimentation, diffusion) and different locations. In addition, fibrous particles such as asbestos are influenced by tumbling effects and its deposition mechanism can include interception. Indoor fluid-particle dynamics related to inhalation exposure and eventual deposition in the respiratory airway is presented. This study involves multi-disciplinary fields involving building science, fluid dynamics, computer science, and medical imaging disciplines. In the future, an integrated approach can lead to digital/in-silico representations of the human respiratory airway able to predict the inhaled particle exposure and its toxicology effect.
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16
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Zhang Y, Shang Y, Inthavong K, Tong Z, Sun B, Zhu K, Yu A, Zheng G. Computational investigation of dust mite allergens in a realistic human nasal cavity. Inhal Toxicol 2019; 31:224-235. [PMID: 31431101 DOI: 10.1080/08958378.2019.1647315] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Aim: Inhaled allergens from house dust mite (HDM) are a major source of allergic disease such as allergic rhinitis and asthma. It has been a challenge to properly evaluate health risks caused by HDM related allergens including mite bodies, eggs and fecal pellets. This paper presents a numerical study on particle deposition of dust mite allergens in a human nasal cavity. Materials and methods: A realistic nasal cavity model was reconstructed from CT scans and a Computational Fluid Dynamics analysis of steady airflow was simulated. The discrete phase model was used to trace particle trajectories of three dust mite related particles. Results: The flow and particle model were validated by comparing with nasal resistance measurement and previous literature respectively. Aerodynamic characteristics and deposition of dust mite allergens in the nasal cavity were analyzed under different breathing conditions including rest and exercising conditions. Conclusions: The numerical results revealed the roles of different nasal cavity regions in filtering various types of dust mite allergens with consideration of breathing conditions.
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Affiliation(s)
- Ya Zhang
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University , Xi'an , China
| | - Yidan Shang
- College of Air Transportation, Shanghai University of Engineering Science , Shanghai , China.,School of Engineering, RMIT University , Bundoora , Australia
| | - Kiao Inthavong
- School of Engineering, RMIT University , Bundoora , Australia
| | - Zhenbo Tong
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University , Nanjing , China
| | - Bin Sun
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University , Xi'an , China
| | - Kang Zhu
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University , Xi'an , China
| | - Aibing Yu
- Laboratory for Simulation and Modelling of Particulate Systems, Department of Chemical Engineering, Monash University , Clayton , Australia
| | - Guoxi Zheng
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University , Xi'an , China
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Dong J, Shang Y, Tian L, Inthavong K, Qiu D, Tu J. Ultrafine particle deposition in a realistic human airway at multiple inhalation scenarios. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2019; 35:e3215. [PMID: 31077567 DOI: 10.1002/cnm.3215] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 04/03/2019] [Accepted: 05/06/2019] [Indexed: 05/13/2023]
Abstract
The scarcity of regional deposition data in distal respiratory airways represents an important challenge for current toxicology and pharmacology research. To bridge this gap, a realistic airway model extending from nasal and oral openings to distal bronchial airways with varying pathway length was built in this study. Transport and deposition characteristics of naturally inhaled ultrafine particles (UFPs) ranging from 1 to 100 nm were numerically investigated, and effects of different inhalation scenarios were considered. To enable intercase particle deposition comparison, an adjusted parameter, unified deposition enhancement factor (UDEF), was proposed for quantifying the localised deposition concentration. Results show that compartment particle deposition peaked around the ultrafine end of the considered size range, and it dropped rapidly with the increase of particle size. Different inhalation modes caused notable deposition changes in the extrathoracic region, while its effects in the TB airway are much less. For UFPs larger than 10 nm, predicted deposition efficiencies in all compartments are all at lowest levels among considered particle size range, implying UFPs ranging from 10 to 100 nm can travel through the whole respiratory airway model and escape to the alveolar region. Furthermore, high enhancement factors were observed at the vicinity of most bifurcation apexes, and more even UDEF distribution was observed from 1-nm particle cases. While for 100-nm cases, the deposited particles tend to concentrate at few "hot spots" (areas of high deposition concentration in relation to surrounding surfaces) with greater UDEF in the tracheobronchial airway.
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Affiliation(s)
- Jingliang Dong
- Indoor Environment Engineering Research Center of Fujian Province, Fujian University of Technology, Fuzhou, Fujian, 350118, China
- School of Engineering, RMIT University, PO Box 71, Bundoora, VIC, 3083, Australia
| | - Yidan Shang
- School of Engineering, RMIT University, PO Box 71, Bundoora, VIC, 3083, Australia
| | - Lin Tian
- School of Engineering, RMIT University, PO Box 71, Bundoora, VIC, 3083, Australia
| | - Kiao Inthavong
- School of Engineering, RMIT University, PO Box 71, Bundoora, VIC, 3083, Australia
| | - Dasheng Qiu
- Department of Nuclear medicine (Positron Emission Tomography/Computed Tomography), Hubei Cancer Hospital, Wuhan, Hubei, 430079, China
| | - Jiyuan Tu
- School of Engineering, RMIT University, PO Box 71, Bundoora, VIC, 3083, Australia
- Key Laboratory of Ministry of Education for Advanced Reactor Engineering and Safety, Institute of Nuclear and New Energy Technology, Tsinghua University, PO Box 1021, Beijing, 100086, China
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18
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Geometry and airflow dynamics analysis in the nasal cavity during inhalation. Clin Biomech (Bristol, Avon) 2019; 66:97-106. [PMID: 29074148 DOI: 10.1016/j.clinbiomech.2017.10.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 10/02/2017] [Accepted: 10/03/2017] [Indexed: 02/07/2023]
Abstract
BACKGROUND A major issue among computational respiratory studies is the wide variety of nasal morphologies being studied, caused by both inter-population and inter-subject variations. METHOD Six nasal cavity geometries exhibiting diverse geometry variations were subjected to steady inhalation flow rate of 15L/min. to determine if any consistent flow behaviour could be found. FINDINGS Despite vastly different geometries we were able to identify consistent flow patterns including relatively high velocity in the nasal valve region, followed by flow continuing predominantly in the inferior half of the airway. We also found conformity among models where the inhaled air reached a near-conditioned state by the middle of the nasal cavity. Air from the front of the face reached the olfactory regions while air from the lateral sides of the face moved through the inferior half of the nasal cavity. INTERPRETATION The ability to predict gross flow features provides a baseline flow field to compare against. This contributes towards establishing well defined flow predictions and be used as a comparison for future larger studies.
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Talebizadehsardari P, Rahimzadeh H, Ahmadi G, Moghimi MA, Inthavong K, Esapour M. Nano-particle deposition in axisymmetric annular pipes with thread. PARTICULATE SCIENCE AND TECHNOLOGY 2019. [DOI: 10.1080/02726351.2019.1613705] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Pouyan Talebizadehsardari
- Department for Management of Science and Technology Development, Ton Duc Thang University, Ho Chi Minh City, Vietnam
- Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City, Vietnam
| | - Hassan Rahimzadeh
- Department of Mechanical Engineering, Amirkabir University of Technology, Tehran, Tehran, Iran
| | - Goodarz Ahmadi
- Department of Mechanical and Aeronautical Engineering, Clarkson University, New York, New York, USA
| | - Mohammad A. Moghimi
- Department of Mechanical and Aeronautical Engineering, University of Pretoria, Pretoria, Gauteng, South Africa
| | - Kiao Inthavong
- School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, Melbourne, Victoria, Australia
| | - Mehdi Esapour
- School of Mechanical Engineering, Mazandaran University of Science and Technology, Babol, Mazandaran, Iran
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20
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Numerical assessment of respiratory airway exposure risks to diesel exhaust particles. ACTA ACUST UNITED AC 2019. [DOI: 10.1007/s42757-019-0005-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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21
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Tian L, Shang Y, Chen R, Bai R, Chen C, Inthavong K, Tu J. Correlation of regional deposition dosage for inhaled nanoparticles in human and rat olfactory. Part Fibre Toxicol 2019; 16:6. [PMID: 30683122 PMCID: PMC6346518 DOI: 10.1186/s12989-019-0290-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 01/15/2019] [Indexed: 12/18/2022] Open
Abstract
Background Nose-to-brain transport of airborne ultrafine particles (UFPs) via the olfactory pathway has been verified as a possible route for particle translocation into the brain. The exact relationship between increased airborne toxicant exposure and neurological deterioration in the human central nervous system, is still unclear. However, the nasal olfactory is undoubtedly a critical junction where the time course and toxicant dose dependency might be inferred. Method Computational fluid-particle dynamics modeling of inhaled nanoparticles (1 to 100 nm) under low to moderate breathing conditions (5 to 14 L/min – human; and 0.14 to 0.40 L/min – rat) were performed in physiologically realistic human and rat nasal airways. The simulation emphasized olfactory deposition, and variations in airflow and particle flux caused by the inter-species airway geometry differences. Empirical equations were developed to predict regional deposition rates of inhaled nanoparticles on human and rat olfactory mucosa in sedentary breathing. Considering, breathing and geometric differences, quantified correlations between human and the rat olfactory deposition dose against a variety of metrics were proposed. Results Regional deposition of nanoparticles in human and the rat olfactory was extremely low, with the highest deposition (< 3.5 and 8.1%) occurring for high diffusivity particles of 1.5 nm and 5 nm, respectively. Due to significant filtering of extremely small particles (< 2 nm) by abrupt sharp turns at front of the rat nose, only small fractions of the inhaled nanoparticles (in this range) reached rat olfactory than that in human (1.25 to 45%); however, for larger sizes (> 3 nm), significantly higher percentage of the inhaled nanoparticles reached rat nasal olfactory than that in human (2 to 32 folds). Taking into account the physical and geometric features between human and rat, the total deposition rate (#/min) and deposition rate per unit surface area (#/min/mm2) were comparable for particles> 3 nm. However, when body mass was considered, the normalized deposition rate (#/min/kg) in the rat olfactory region exceeded that in the human. Nanoparticles < 1.5 nm were filtered out by rat anterior nasal cavity, and therefore deposition in human olfactory region exceeded that in the rat model. Conclusion Regional deposition dose of inhaled nanoparticles in a human and rat olfactory region was governed by particle size and the breathing rate. Interspecies correlation was determined by combining the effect of deposition dosage, physical\geometric features, and genetic differences. Developed empirical equations provided a tool to quantify inhaled nanoparticle dose in human and rat nasal olfactory regions, which lay the ground work for comprehensive interspecies correlation between the two species. Furthermore, this study contributes to the fields in toxicology, i.e., neurotoxicity evaluation and risk assessment of UFPs, in long-term and low-dose inhalation exposure scenarios.
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Affiliation(s)
- Lin Tian
- School of Engineering - Mechanical and Automotive, RMIT University, Bundoora, VIC, Australia
| | - Yidan Shang
- School of Engineering - Mechanical and Automotive, RMIT University, Bundoora, VIC, Australia
| | - Rui Chen
- CAS Key Lab for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Ambient Particles Health Effects and Prevention Techniques, National Center for Nanoscience and Technology of China, Beijing, China
| | - Ru Bai
- CAS Key Lab for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Ambient Particles Health Effects and Prevention Techniques, National Center for Nanoscience and Technology of China, Beijing, China
| | - Chunying Chen
- CAS Key Lab for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Ambient Particles Health Effects and Prevention Techniques, National Center for Nanoscience and Technology of China, Beijing, China.
| | - Kiao Inthavong
- School of Engineering - Mechanical and Automotive, RMIT University, Bundoora, VIC, Australia
| | - Jiyuan Tu
- School of Engineering - Mechanical and Automotive, RMIT University, Bundoora, VIC, Australia. .,Key Laboratory of Ministry of Education for Advanced Reactor Engineering and Safety, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, China.
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22
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Shang Y, Inthavong K, Tu J. Development of a computational fluid dynamics model for mucociliary clearance in the nasal cavity. J Biomech 2019; 85:74-83. [PMID: 30685195 DOI: 10.1016/j.jbiomech.2019.01.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 12/09/2018] [Accepted: 01/04/2019] [Indexed: 12/22/2022]
Abstract
Intranasal drug delivery has attracted significant attention because of the opportunity to deliver systemic drugs directly to the blood stream. However, the mucociliary clearance poses a challenge in gaining high efficacy of intranasal drug delivery because cilia continuously carry the mucus blanket towards the laryngeal region. To better understand mucus flow behaviour on the human nasal cavity wall, we present computational model development, and evaluation of mucus motion on a realistic nasal cavity model reconstructed from CT-scans. The model development involved two approaches based on the actual nasal cavity geometry namely: (i) unwrapped-surface model in 2D domain and (ii) 3D-shell model. Conservation equations of fluid motion were applied to the domains, where a mucus production source term was used to initiate the mucus motion. The analysis included mucus flow patterns, virtual saccharin tests and quantitative velocity magnitude analysis, which demonstrated that the 3D-shell model results provided better agreement with experimental data. The unwrapped-surface model also suffered from mesh-deformations during the unwrapping stage and this led to higher mucus velocity compared to experimental data. Therefore, the 3D-shell model was recommended for future mucus flow simulations. As a first step towards mucus motion modelling this study provides important information that accurately simulates a mucus velocity field on a human nasal cavity wall, for assessment of toxicology and efficacy of intranasal drug delivery.
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Affiliation(s)
- Yidan Shang
- College of Air Transportation, Shanghai University of Engineering Science, Shanghai 201620, China; School of Engineering, RMIT University, PO Box 71, Bundoora, VIC 3083, Australia
| | - Kiao Inthavong
- School of Engineering, RMIT University, PO Box 71, Bundoora, VIC 3083, Australia.
| | - Jiyuan Tu
- School of Engineering, RMIT University, PO Box 71, Bundoora, VIC 3083, Australia; Key Laboratory of Ministry of Education for Advanced Reactor Engineering and Safety, Institute of Nuclear and New Energy Technology, Tsinghua University, PO Box 1021, Beijing 100086, China
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23
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Lu Phuong N, Dang Khoa N, Inthavong K, Ito K. Particle and inhalation exposure in human and monkey computational airway models. Inhal Toxicol 2019; 30:416-428. [DOI: 10.1080/08958378.2018.1545810] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Nguyen Lu Phuong
- Department of Energy and Environmental Engineering, Faculty of Engineering Sciences, Kyushu University, Kasuga, Japan
- Department of Environmental Management, Faculty of Environment, University of Natural Resources and Environment, Ho Chi Minh City, Vietnam
| | - Nguyen Dang Khoa
- Department of Environmental Management, Faculty of Environment, University of Natural Resources and Environment, Ho Chi Minh City, Vietnam
| | - Kiao Inthavong
- Department of Mechanical and Automotive Engineering, School of Engineering, RMIT University, Melbourne, Australia
| | - Kazuhide Ito
- Department of Energy and Environmental Engineering, Faculty of Engineering Sciences, Kyushu University, Kasuga, Japan
- Department of Mechanical and Automotive Engineering, School of Engineering, RMIT University, Melbourne, Australia
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Abstract
PURPOSE OF REVIEW The current article reviews the literature on the distribution of nasal irrigation in the treatment of chronic sinusitis, especially in how sinus surgery and irrigation techniques affect its delivery to the nasal cavity and paranasal sinuses. RECENT FINDINGS Nasal irrigation has become a useful tool in the treatment of chronic sinusitis. Used after endoscopic surgery of the paranasal sinuses, irrigation has shown to be effective in improving edema and removing crusts and secretions in that place. However, some relevant points have been considered in the surgical technique and in the postoperative period to improve irrigation access to the paranasal sinuses such as the amplitude of the sinus ostial opening, irrigation volume and device used, as well as head position during irrigation. SUMMARY Postoperative lavage of the paranasal sinus is a recognized adjuvant in the treatment of chronic rhinosinusitis, reducing morbidity and improving local healing, besides allowing the association of topical medications that can be carried to the paranasal sinuses along with the saline increasing the reach of these drugs. Detailed attention to the techniques described in this review improves the distribution of irrigation in the paranasal sinuses after sinus surgery and considerably increases the efficacy of this therapy.
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Covello V, Pipolo C, Saibene A, Felisati G, Quadrio M. Numerical simulation of thermal water delivery in the human nasal cavity. Comput Biol Med 2018; 100:62-73. [PMID: 29975856 DOI: 10.1016/j.compbiomed.2018.06.029] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 06/24/2018] [Accepted: 06/25/2018] [Indexed: 11/29/2022]
Abstract
This work describes an extensive numerical investigation of thermal water delivery for the treatment of inflammatory disorders in the human nasal cavity. The numerical simulation of the multiphase air-droplets flow is based upon the Large Eddy Simulation (LES) technique, with droplets of thermal water described via a Lagrangian approach. Droplet deposition is studied for different sizes of water droplets, corresponding to two different thermal treatments, i.e. aerosol and inhalation. Numerical simulations are conducted on a patient-specific anatomy, employing two different grid sizes, under steady inspiration at two breathing intensities. The results are compared with published in vivo and in vitro data. The effectiveness of the various thermal treatments is then assessed qualitatively and quantitatively, by a detailed analysis of the deposition patterns of the droplets. Discretization effects on the deposition dynamics are addressed. The level of detail of the present work, together with the accuracy afforded by the LES approach, leads to an improved understanding of how the mixture of air-water droplets is distributed within the nose and the paranasal sinuses.
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Affiliation(s)
- V Covello
- Department of Aerospace Science and Technology, Politecnico di Milano, Via La Masa 34, 20156, Milano, Italy
| | - C Pipolo
- Otorhinolaryngology Unit, Head and Neck Department, San Paolo Hospital, Università degli Studi di Milano, Via di Rudini 8, 20142, Milano, Italy
| | - A Saibene
- Otorhinolaryngology Unit, Head and Neck Department, San Paolo Hospital, Università degli Studi di Milano, Via di Rudini 8, 20142, Milano, Italy
| | - G Felisati
- Otorhinolaryngology Unit, Head and Neck Department, San Paolo Hospital, Università degli Studi di Milano, Via di Rudini 8, 20142, Milano, Italy
| | - M Quadrio
- Department of Aerospace Science and Technology, Politecnico di Milano, Via La Masa 34, 20156, Milano, Italy.
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Tian L, Shang Y, Chen R, Bai R, Chen C, Inthavong K, Tu J. A combined experimental and numerical study on upper airway dosimetry of inhaled nanoparticles from an electrical discharge machine shop. Part Fibre Toxicol 2017; 14:24. [PMID: 28701167 PMCID: PMC5508797 DOI: 10.1186/s12989-017-0203-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 06/26/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUNDS Exposure to nanoparticles in the workplace is a health concern to occupational workers with increased risk of developing respiratory, cardiovascular, and neurological disorders. Based on animal inhalation study and human lung tumor risk extrapolation, current authoritative recommendations on exposure limits are either on total mass or number concentrations. Effects of particle size distribution and the implication to regional airway dosages are not elaborated. METHODS Real time production of particle concentration and size distribution in the range from 5.52 to 98.2 nm were recorded in a wire-cut electrical discharge machine shop (WEDM) during a typical working day. Under the realistic exposure condition, human inhalation simulations were performed in a physiologically realistic nasal and upper airway replica. The combined experimental and numerical study is the first to establish a realistic exposure condition, and under which, detailed dose metric studies can be performed. In addition to mass concentration guided exposure limit, inhalation risks to nano-pollutant were reexamined accounting for the actual particle size distribution and deposition statistics. Detailed dosimetries of the inhaled nano-pollutants in human nasal and upper airways with respect to particle number, mass and surface area were discussed, and empirical equations were developed. RESULTS An astonishing enhancement of human airway dosages were detected by current combined experimental and numerical study in the WEDM machine shop. Up to 33 folds in mass, 27 folds in surface area and 8 folds in number dosages were detected during working hours in comparison to the background dosimetry measured at midnight. The real time particle concentration measurement showed substantial emission of nano-pollutants by WEDM machining activity, and the combined experimental and numerical study provided extraordinary details on human inhalation dosimetry. It was found out that human inhalation dosimetry was extremely sensitive to real time particle concentration and size distribution. Averaged particle concentration over 24-h period will inevitably misrepresent the sensible information critical for realistic inhalation risk assessment. CONCLUSIONS Particle size distribution carries very important information in determining human airway dosimetry. A pure number or mass concentration recommendation on the exposure limit at workplace is insufficient. A particle size distribution, together with the deposition equations, is critical to recognize the actual exposure risks. In addition, human airway dosimetry in number, mass and surface area varies significantly. A complete inhalation risk assessment requires the knowledge of toxicity mechanisms in response to each individual metric. Further improvements in these areas are needed.
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Affiliation(s)
- Lin Tian
- School of Engineering - Mechanical and Automotive, RMIT University, Bundoora, VIC, Australia
| | - Yidan Shang
- School of Engineering - Mechanical and Automotive, RMIT University, Bundoora, VIC, Australia
| | - Rui Chen
- CAS Key Lab for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Ambient Particles Health Effects and Prevention Techniques, National Center for Nanoscience and Technology of China, Beijing, China
| | - Ru Bai
- CAS Key Lab for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Ambient Particles Health Effects and Prevention Techniques, National Center for Nanoscience and Technology of China, Beijing, China
| | - Chunying Chen
- CAS Key Lab for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Ambient Particles Health Effects and Prevention Techniques, National Center for Nanoscience and Technology of China, Beijing, China.
| | - Kiao Inthavong
- School of Engineering - Mechanical and Automotive, RMIT University, Bundoora, VIC, Australia
| | - Jiyuan Tu
- School of Engineering - Mechanical and Automotive, RMIT University, Bundoora, VIC, Australia. .,Key Laboratory of Ministry of Education for Advanced Reactor Engineering and Safety, Institute of Nuclear and New Energy Technology Tsinghua University, PO Box 1021, Beijing, 100086, China.
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Xi J, Si XA, Peters S, Nevorski D, Wen T, Lehman M. Understanding the mechanisms underlying pulsating aerosol delivery to the maxillary sinus: In vitro tests and computational simulations. Int J Pharm 2017; 520:254-266. [PMID: 28189854 DOI: 10.1016/j.ijpharm.2017.02.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Revised: 01/15/2017] [Accepted: 02/05/2017] [Indexed: 01/05/2023]
Abstract
BACKGROUND Pulsating aerosol delivery has been demonstrated in depositing medications into paranasal sinuses. However, its mechanisms are not fully understood. Influences of the nasal anatomy and sound frequency on intrasinus delivery are not yet clear. OBJECTIVES This study aimed to gain a better understanding of the mechanisms for enhanced intrasinus delivery with pulsating sound. Specifically, effects of the pulsation frequency, ostium size, and sinus shape on the intrasinus dosage and resonance frequency would be examined. METHODS AND MATERIALS Both experiments and computational modeling were conducted to understand the pulsating aerosol delivery in both idealized (two-bottle) and realistic nose-sinus models. A computational model of intrasinus pulsation delivery was developed using COMSOL and was cross-validated with both experimental and theoretical results. RESULTS In contrast to previous studies, seemingly erratic relations between the intrasinus dosage and ostium diameter were observed in experiments, which suggested a more complicated particle transport mechanism. Improved agreement was achieved when grouping the ostium size and sinus volume into the resonance frequency, and therefore, validated the hypothesis that intrasinus deposition strongly depends on the resonance frequency. Extensive computational simulations revealed that the deposition was highest at the resonance frequency and decreased gradually at off-resonance frequencies. The resonance frequency depended on the ostium and sinus morphology, but was independent of the nasal cavity. CONCLUSION Results of this study verified the hypothesis of resonance being the mechanism for enhanced particle deposition in the maxillary sinus. A better knowledge of the relationship between sinus dosages, pulsating frequency, and nasal morphometry is essential for improving the design of intrasinus delivery devices.
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Affiliation(s)
- Jinxiang Xi
- School of Engineering and Technology, Central Michigan University, Mount Pleasant, MI, USA.
| | - Xiuhua April Si
- Department of Mechanical Engineering, California Baptist University, Riverside, CA, USA
| | - Shannon Peters
- School of Engineering and Technology, Central Michigan University, Mount Pleasant, MI, USA
| | - Dannielle Nevorski
- School of Engineering and Technology, Central Michigan University, Mount Pleasant, MI, USA
| | - Tianshu Wen
- School of Engineering and Technology, Central Michigan University, Mount Pleasant, MI, USA
| | - Mark Lehman
- Department of Speech-Language Pathology, Central Michigan University, Mount Pleasant, MI, USA
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Kumar H, Jain R, Douglas RG, Tawhai MH. Airflow in the Human Nasal Passage and Sinuses of Chronic Rhinosinusitis Subjects. PLoS One 2016; 11:e0156379. [PMID: 27249219 PMCID: PMC4889048 DOI: 10.1371/journal.pone.0156379] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 05/13/2016] [Indexed: 11/18/2022] Open
Abstract
Endoscopic surgery is performed on patients with chronic inflammatory disease of the paranasal sinuses to improve sinus ventilation. Little is known about how sinus surgery affects sinonasal airflow. In this study nasal passage geometry was reconstructed from computed tomographic imaging from healthy normal, pre-operative, and post-operative subjects. Transient air flow through the nasal passage during calm breathing was simulated. Subject-specific differences in ventilation of the nasal passage were observed. Velocity magnitude at ostium was different between left and right airway. In FESS, airflow in post-surgical subjects, airflow at the maxillary sinus ostium was upto ten times higher during inspiration. In a Lothrop procedure, airflow at the frontal sinus ostium can be upto four times higher during inspiration. In both post-operative subjects, airflow at ostium was not quasi-steady. The subject-specific effect (of surgery) on sinonasal interaction evaluated through airflow simulations may have important consequences for pre- and post-surgical assessment and surgical planning, and design for improvement of the delivery efficiency of nasal therapeutics.
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Affiliation(s)
- Haribalan Kumar
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
- * E-mail:
| | - Ravi Jain
- Department of surgery, The University of Auckland, Auckland, New Zealand
| | - Richard G. Douglas
- Department of surgery, The University of Auckland, Auckland, New Zealand
| | - Merryn H. Tawhai
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
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Dong J, Shang Y, Inthavong K, Tu J, Chen R, Bai R, Wang D, Chen C. From the Cover: Comparative Numerical Modeling of Inhaled Nanoparticle Deposition in Human and Rat Nasal Cavities. Toxicol Sci 2016; 152:284-96. [PMID: 27208081 DOI: 10.1093/toxsci/kfw087] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
To gain a better understanding of nanoparticle exposure in human nasal cavities, laboratory animals (e.g. rat) are used for in vivo studies. However, due to anatomical differences between human and rodent nasal cavities, direct particle deposition comparisons between species are difficult. This paper presents a comparative nanoparticle (1 nm, 10 nm, and 100 nm) deposition study using anatomically realistic models of a human and rat nasal cavity. The particle deposition fraction was highest consistently in the main nasal passage, for all nanoparticles tested, in the human model; whereas this was only the case for 10 nm, and 100 nm particles for the rodent model, where greater deposition was found in the anterior nose for 1 nm particles. A deposition intensity (DI) term was introduced to represent the accumulated deposition fraction on cross-sectional slices. A common and preferential deposition site in the human model was found for all nanoparticles occurring at a distance of 3.5 cm inside the nasal passage. For the rodent model maximum DI occurred in the vestibule region at a distance of 0.3 cm, indicating that the rodent vestibule produces exceptionally high particle filtration capability. We also introduced a deposition flux which was a ratio of the regional deposition fraction relative to the region's surface area fraction. This value allowed direct comparison of deposition flux between species, and a regional extrapolation scaling factor was found (e.g. 1/10 scale for vestibule region for rat to human comparison). This study bridges the in vitro exposure experiments and in vivo nanomaterials toxicity studies, and can contribute towards improving inter-species exposure extrapolation studies in the future.
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Affiliation(s)
- Jingliang Dong
- *School of Engineering, RMIT University, PO Box 71, Bundoora, VIC 3083, Australia and
| | - Yidan Shang
- *School of Engineering, RMIT University, PO Box 71, Bundoora, VIC 3083, Australia and
| | - Kiao Inthavong
- *School of Engineering, RMIT University, PO Box 71, Bundoora, VIC 3083, Australia and
| | - Jiyuan Tu
- *School of Engineering, RMIT University, PO Box 71, Bundoora, VIC 3083, Australia and
| | - Rui Chen
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Ambient Particles Health Effects and Prevention Techniques, National Center for Nanoscience & Technology of China, Beijing 100090, China
| | - Ru Bai
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Ambient Particles Health Effects and Prevention Techniques, National Center for Nanoscience & Technology of China, Beijing 100090, China
| | - Dongliang Wang
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Ambient Particles Health Effects and Prevention Techniques, National Center for Nanoscience & Technology of China, Beijing 100090, China
| | - Chunying Chen
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Ambient Particles Health Effects and Prevention Techniques, National Center for Nanoscience & Technology of China, Beijing 100090, China
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30
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Tian L, Inthavong K, Lidén G, Shang Y, Tu J. Transport and Deposition of Welding Fume Agglomerates in a Realistic Human Nasal Airway. ANNALS OF OCCUPATIONAL HYGIENE 2016; 60:731-47. [PMID: 27074799 DOI: 10.1093/annhyg/mew018] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 02/22/2016] [Indexed: 12/30/2022]
Abstract
Welding fume is a complex mixture containing ultra-fine particles in the nanometer range. Rather than being in the form of a singular sphere, due to the high particle concentration, welding fume particles agglomerate into long straight chains, branches, or other forms of compact shapes. Understanding the transport and deposition of these nano-agglomerates in human respiratory systems is of great interest as welding fumes are a known health hazard. The neurotoxin manganese (Mn) is a common element in welding fumes. Particulate Mn, either as soluble salts or oxides, that has deposited on the olfactory mucosa in human nasal airway is transported along the olfactory nerve to the olfactory bulb within the brain. If this Mn is further transported to the basal ganglia of the brain, it could accumulate at the part of the brain that is the focal point of its neurotoxicity. Accounting for various dynamic shape factors due to particle agglomeration, the current computational study is focused on the exposure route, the deposition pattern, and the deposition efficiency of the inhaled welding fume particles in a realistic human nasal cavity. Particular attention is given to the deposition pattern and deposition efficiency of inhaled welding fume agglomerates in the nasal olfactory region. For particles in the nanoscale, molecular diffusion is the dominant transport mechanism. Therefore, Brownian diffusion, hydrodynamic drag, Saffman lift force, and gravitational force are included in the model study. The deposition efficiencies for single spherical particles, two kinds of agglomerates of primary particles, two-dimensional planar and straight chains, are investigated for a range of primary particle sizes and a range of number of primary particles per agglomerate. A small fraction of the inhaled welding fume agglomerates is deposited on the olfactory mucosa, approximately in the range 0.1-1%, and depends on particle size and morphology. The strong size dependence of the deposition in olfactory mucosa on particle size implies that the occupation deposition of welding fume manganese can be expected to vary with welding method.
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Affiliation(s)
- Lin Tian
- 1Department of Mechanical and Automotive Engineering, School of Engineering, RMIT University, Building 251.3, Plenty Road, Bundoora, Victoria 3083, Australia
| | - Kiao Inthavong
- 1Department of Mechanical and Automotive Engineering, School of Engineering, RMIT University, Building 251.3, Plenty Road, Bundoora, Victoria 3083, Australia
| | - Göran Lidén
- 2Department of Environmental Science and Analytical Chemistry, Stockholm University, Svante Arrhenius väg 8, SE-11418 Stockholm, Sweden
| | - Yidan Shang
- 1Department of Mechanical and Automotive Engineering, School of Engineering, RMIT University, Building 251.3, Plenty Road, Bundoora, Victoria 3083, Australia
| | - Jiyuan Tu
- 1Department of Mechanical and Automotive Engineering, School of Engineering, RMIT University, Building 251.3, Plenty Road, Bundoora, Victoria 3083, Australia;
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Cisonni J, Lucey AD, King AJC, Islam SMS, Lewis R, Goonewardene MS. Numerical simulation of pharyngeal airflow applied to obstructive sleep apnea: effect of the nasal cavity in anatomically accurate airway models. Med Biol Eng Comput 2015; 53:1129-39. [PMID: 26429351 DOI: 10.1007/s11517-015-1399-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Accepted: 09/19/2015] [Indexed: 11/26/2022]
Abstract
Repetitive brief episodes of soft-tissue collapse within the upper airway during sleep characterize obstructive sleep apnea (OSA), an extremely common and disabling disorder. Failure to maintain the patency of the upper airway is caused by the combination of sleep-related loss of compensatory dilator muscle activity and aerodynamic forces promoting closure. The prediction of soft-tissue movement in patient-specific airway 3D mechanical models is emerging as a useful contribution to clinical understanding and decision making. Such modeling requires reliable estimations of the pharyngeal wall pressure forces. While nasal obstruction has been recognized as a risk factor for OSA, the need to include the nasal cavity in upper-airway models for OSA studies requires consideration, as it is most often omitted because of its complex shape. A quantitative analysis of the flow conditions generated by the nasal cavity and the sinuses during inspiration upstream of the pharynx is presented. Results show that adequate velocity boundary conditions and simple artificial extensions of the flow domain can reproduce the essential effects of the nasal cavity on the pharyngeal flow field. Therefore, the overall complexity and computational cost of accurate flow predictions can be reduced.
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Affiliation(s)
- Julien Cisonni
- Fluid Dynamics Research Group, Department of Mechanical Engineering, Curtin University, Perth, WA, Australia.
| | - Anthony D Lucey
- Fluid Dynamics Research Group, Department of Mechanical Engineering, Curtin University, Perth, WA, Australia
| | - Andrew J C King
- Fluid Dynamics Research Group, Department of Mechanical Engineering, Curtin University, Perth, WA, Australia
| | - Syed Mohammed Shamsul Islam
- Fluid Dynamics Research Group, Department of Mechanical Engineering, Curtin University, Perth, WA, Australia
- School of Dentistry/Oral Health Centre of Western Australia, University of Western Australia, Crawley, WA, Australia
| | - Richard Lewis
- Perth Head and Neck Surgery, Nedlands, WA, Australia
| | - Mithran S Goonewardene
- School of Dentistry/Oral Health Centre of Western Australia, University of Western Australia, Crawley, WA, Australia
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Abstract
CONTEXT Inhaled nanoparticles can migrate to the brain via the olfactory bulb, as demonstrated in experiments in several animal species. This route of exposure may be the mechanism behind the correlation between air pollution and human neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease. OBJECTIVES This article aims to (i) estimate the dose of inhaled nanoparticles that deposit in the human olfactory epithelium during nasal breathing at rest and (ii) compare the olfactory dose in humans with our earlier dose estimates for rats. MATERIALS AND METHODS An anatomically-accurate model of the human nasal cavity was developed based on computed tomography scans. The deposition of 1-100 nm particles in the whole nasal cavity and its olfactory region were estimated via computational fluid dynamics (CFD) simulations. Our CFD methods were validated by comparing our numerical predictions for whole-nose deposition with experimental data and previous CFD studies in the literature. RESULTS In humans, olfactory dose of inhaled nanoparticles is highest for 1-2 nm particles with ∼1% of inhaled particles depositing in the olfactory region. As particle size grows to 100 nm, olfactory deposition decreases to 0.01% of inhaled particles. DISCUSSION AND CONCLUSION Our results suggest that the percentage of inhaled particles that deposit in the olfactory region is lower in humans than in rats. However, olfactory dose per unit surface area is estimated to be higher in humans in the 1--7 nm size range due to the larger inhalation rate in humans. These dose estimates are important for risk assessment and dose-response studies investigating the neurotoxicity of inhaled nanoparticles.
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Affiliation(s)
- Guilherme J M Garcia
- Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin , Milwaukee, WI , USA
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33
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Frank-Ito DO, Wofford M, Schroeter JD, Kimbell JS. Influence of Mesh Density on Airflow and Particle Deposition in Sinonasal Airway Modeling. J Aerosol Med Pulm Drug Deliv 2015; 29:46-56. [PMID: 26066089 DOI: 10.1089/jamp.2014.1188] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND There are methodological ambiguities in the literature on mesh refinement analysis for computational fluid dynamics (CFD) modeling of physiologically realistic airflow dynamics and particle transport in the human sinonasal cavity. To investigate grid independence in discretization of the (sino)nasal geometry, researchers have considered CFD variables such as pressure drop, velocity profile, wall shear, airflow, and particle deposition fractions. Standardization in nasal geometry is also lacking: unilateral or bilateral nasal cavities with and without paranasal sinuses have been used. These methodological variants have led to inconsistencies in establishing grid-independent mesh densities. The aim of this study is to provide important insight in the role of mesh refinement analysis on airflow and particle deposition in sinonasal airway modeling. METHODS A three-dimensional reconstruction of the complete sinonasal cavity was created from computed tomography images of a subject who had functional endoscopic sinus surgery. To investigate airflow grid independence, nine different tetrahedral mesh densities were generated. For particle transport mesh refinement analysis, hybrid tetrahedral-prism elements with near-wall prisms ranging from 1 to 6 layers were implemented. Steady-state, laminar inspiratory airflow simulations under physiologic pressure-driven conditions and nebulized particle transport simulations were performed with particle sizes ranging from 1-20 μm. RESULTS Mesh independence for sinonasal airflow was achieved with approximately 4 million unstructured tetrahedral elements. The hybrid mesh containing 4 million tetrahedral cells with three prism layers demonstrated asymptotic behavior for sinonasal particle deposition. Inclusion of boundary prism layers reduced deposition fractions relative to tetrahedral-only meshes. CONCLUSIONS To ensure numerically accurate simulation results, mesh refinement analyses should be performed for both airflow and particle transport simulations. Tetrahedral-only meshes overpredict particle deposition and are less accurate than hybrid tetrahedral-prism meshes.
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Affiliation(s)
- Dennis O Frank-Ito
- 1 Division of Otolaryngology, Head and Neck Surgery, Duke University Medical Center , Durham, North Carolina
| | - Matthew Wofford
- 2 Department of Otolaryngology, Head and Neck Surgery, University of North Carolina , Chapel Hill, North Carolina
| | | | - Julia S Kimbell
- 2 Department of Otolaryngology, Head and Neck Surgery, University of North Carolina , Chapel Hill, North Carolina
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34
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High resolution visualization and analysis of nasal spray drug delivery. Pharm Res 2014; 31:1930-7. [PMID: 24549819 DOI: 10.1007/s11095-013-1294-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 12/31/2013] [Indexed: 10/25/2022]
Abstract
PURPOSE Effective nasal drug delivery of new-generation systemic drugs requires efficient devices that can achieve targeted drug delivery. It has been established that droplet size, spray plume, and droplet velocity are major contributors to drug deposition. Continual effort is needed to better understand and characterise the physical mechanisms underpinning droplet formation from nasal spray devices. METHODS High speed laser photography combined with an in-house designed automated actuation system, and a highly precise traversing unit, measurements and images magnified in small field-of-view regions within the spray was performed. RESULTS The qualitative results showed a swirling liquid sheet at the near-nozzle region as the liquid is discharged before ligaments of fluid are separated off the liquid sheet. Droplets are formed and continue to deform as they travel downstream at velocities of up to 20 m/s. Increase in actuation pressure produces more rapid atomization and discharge time where finer droplets are produced. CONCLUSIONS The results suggest that device designs should consider reducing droplet inertia to penetrate the nasal valve region, but find a way to deposit in the main nasal passage and not escape through to the lungs.
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Inthavong K, Shang Y, Tu J. Surface mapping for visualization of wall stresses during inhalation in a human nasal cavity. Respir Physiol Neurobiol 2013; 190:54-61. [PMID: 24051139 DOI: 10.1016/j.resp.2013.09.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 09/09/2013] [Accepted: 09/10/2013] [Indexed: 11/25/2022]
Abstract
Airflow analysis can assist in better understanding the physiology however the human nasal cavity is an extremely complicated geometry that is difficult to visualize in 3D space, let alone in 2D space. In this paper, an anatomically accurate 3D surface of the nasal passages derived from CT data was unwrapped and transformed into a 2D space, into a UV-domain (where u and v are the coordinates) to allow a complete view of the entire wrapped surface. This visualization technique allows surface flow parameters to be analyzed with greater precision. A UV-unwrapping tool is developed and a strategy is presented to allow deeper analysis to be performed. This includes (i) the ability to present instant comparisons of geometry and flow variables between any number of different nasal cavity models through normalization of the 2D unwrapped surface; (ii) visualization of an entire surface in one view and; (iii) a planar surface that allows direct 1D and 2D analytical solutions of diffusion of inhaled vapors and particles through the nasal walls. This work lays a foundation for future investigations that correlates adverse and therapeutic health responses to local inhalation of gases and particles.
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Affiliation(s)
- Kiao Inthavong
- School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, Australia
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Asgharian B, Price O, McClellan G, Corley R, Einstein DR, Jacob RE, Harkema J, Carey SA, Schelegle E, Hyde D, Kimbell JS, Miller FJ. Development of a rhesus monkey lung geometry model and application to particle deposition in comparison to humans. Inhal Toxicol 2012; 24:869-99. [PMID: 23121298 PMCID: PMC5119470 DOI: 10.3109/08958378.2012.725782] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The exposure-dose-response characterization of an inhalation hazard established in an animal species needs to be translated to an equivalent characterization in humans relative to comparable doses or exposure scenarios. Here, the first geometry model of the conducting airways for rhesus monkeys is developed based upon CT images of the conducting airways of a 6-month-old male, rhesus monkey. An algorithm was developed for adding the alveolar region airways using published rhesus morphometric data. The resultant lung geometry model can be used in mechanistic particle or gaseous dosimetry models. Such dosimetry models require estimates of the upper respiratory tract volume of the animal and the functional residual capacity, as well as of the tidal volume and breathing frequency of the animal. The relationship of these variables to rhesus monkeys of differing body weights was established by synthesizing and modeling published data as well as modeling pulmonary function measurements on 121 rhesus control animals. Deposition patterns of particles up to 10 µm in size were examined for endotracheal and and up to 5 µm for spontaneous breathing in infant and young adult monkeys and compared to those for humans. Deposition fraction of respirable size particles was found to be higher in the conducting airways of infant and young adult rhesus monkeys compared to humans. Due to the filtering effect of the conducting airways, pulmonary deposition in rhesus monkeys was lower than that in humans. Future research areas are identified that would either allow replacing assumptions or improving the newly developed lung model.
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Affiliation(s)
- Bahman Asgharian
- Applied Research Associates, Inc., 8537 Six Forks Road, Suite 600, Raleigh, NC 27615-2963, USA.
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