1
|
Stoelben E. [Idiopathic Subglottic Tracheal Stenosis]. Zentralbl Chir 2024; 149:308-314. [PMID: 38359868 DOI: 10.1055/a-2241-0616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
Idiopathic subglottic stenosis is a circular scarred narrowing of the airway at the transition from the cricoid cartilage to the trachea. The stenosis is found radiologically and endoscopically at the level of the cricoid cartilage without involvement of the cricoid or tracheal cartilage itself. The disease practically only affects women between the ages of 20 and 60. The same clinical picture occurs in granulomatosis with polyangiitis and less frequently in other autoimmune diseases, where it requires systemic treatment. The clinical picture usually begins insidiously with coughing and sputum production and leads to dyspnoea and a restricted cough. As the course is insidious and the patients are otherwise healthy, the symptoms are often misinterpreted and the diagnosis is delayed. Treatment consists of local measures, ranging from dilatation and laser surgical resection, sometimes with local application of medication to inhibit the proliferation of new scar tissue, to laryngotracheal resection of varying degrees. The disease is located in the border area between the trachea and larynx and the patients are therefore treated by ENT medicine, pneumology and thoracic surgery.
Collapse
Affiliation(s)
- Erich Stoelben
- Thoraxklinik, St. Hildegardiskrankenhaus, Köln, Deutschland
| |
Collapse
|
2
|
Stoelben E. [Functional, Radiological and Endoscopic Diagnostic of Tracheal Diseases]. Zentralbl Chir 2024; 149:253-259. [PMID: 38056500 DOI: 10.1055/a-2210-3636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2023]
Abstract
Diseases of the trachea are rare, while other diseases associated with shortness of breath and pulmonary symptoms are common, which is why the necessary diagnosis and therapy are regularly delayed. At the same time, diseases range from simple scarring stenosis to extensive tumour disease. Patients may be otherwise healthy, suffer from autoimmune disease, or have severe general illnesses, as in tracheotomised patients. Therefore, history and clinical examination provide very important clues to a disease of the trachea. Subsequent diagnostics should be ordered in a reasonable manner and lead to the correct diagnosis and subsequent therapy in a timely manner. Functional, radiological and endoscopic examinations, each with a special focus in experienced hands, avoid duplicate examinations or misinterpretations. Patients are grateful because diseases of the trachea - a central airway that cannot be bypassed - are experienced as life-threatening or at least as severely limiting the quality of life.
Collapse
Affiliation(s)
- Erich Stoelben
- Thoraxchirurgie, Thoraxklinik Köln, St. Hildegardis Krankenhaus, Köln, Deutschland
| |
Collapse
|
3
|
Chaddha U, Agrawal A, Kurman J, Ortiz-Comino R, Dutau H, Freitag L, Trisolini R, Dooms C, Zuccatosta L, Gasparini S, Herth F, Saka H, Lee P, Fielding D, Oki M, Rosell A, Murgu S. World Association for Bronchology and Interventional Pulmonology (WABIP) guidelines on airway stenting for malignant central airway obstruction. Respirology 2024. [PMID: 38812262 DOI: 10.1111/resp.14764] [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: 01/30/2024] [Accepted: 05/16/2024] [Indexed: 05/31/2024]
Abstract
Malignant Central Airway Obstruction (MCAO) encompasses significant and symptomatic narrowing of the central airways that can occur due to primary lung cancer or metastatic disease. Therapeutic bronchoscopy is associated with high technical success and symptomatic relief and includes a wide range of airway interventions including airway stents. Published literature suggests that stenting practices vary significantly across the world primarily due to lack of guidance. This document aims to address this knowledge gap by addressing relevant questions related to airway stenting in MCAO. An international group of 17 experts from 17 institutions across 11 countries with experience in using airway stenting for MCAO was convened as part of this guideline statement through the World Association for Bronchology and Interventional Pulmonology (WABIP). We performed a literature and internet search for reports addressing six clinically relevant questions. This guideline statement, consisting of recommendations addressing these six PICO questions, was formulated by a systematic and rigorous process involving the evaluation of published evidence, augmented with expert experience when necessary. Panel members participated in the development of the final recommendations using the modified Delphi technique.
Collapse
Affiliation(s)
- Udit Chaddha
- Division of Pulmonary, Critical Care & Sleep Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | | | | | - Rosamaria Ortiz-Comino
- Department of Respiratory Medicine, University Hospital Coventry and Warwickshire, Coventry, UK
| | - Herve Dutau
- Interventional Pulmonology Department, North University Hospital, Assistance Publique-Hôpitaux de Marseille, Marseille, France
| | - Lutz Freitag
- Ruhrlandklinik, University Hospital, University Duisburg Essen, Essen, Germany
| | - Rocco Trisolini
- Catholic University of the Sacred Hearth-Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Roma, Italy
| | - Christophe Dooms
- Department of Respiratory Diseases, University Hospital Leuven, Leuven, Belgium
| | - Lina Zuccatosta
- Azienda Ospedaliero-Universitaria delle Marche, Ancona, Italy
| | | | - Felix Herth
- Thoraxklinik and Translational Lung research Center Heidelberg, University of Heidelberg, Heidelberg, Germany
| | | | - Pyng Lee
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - David Fielding
- Royal Brisbane and Women's Hospital, Herston, Queensland, Australia
| | - Masahide Oki
- Department of Respiratory Medicine, National Hospital Organization Nagoya Medical Center, Nagoya, Japan
| | - Antoni Rosell
- Hospital Universitari Germans Trias I Pujol, Barcelona, Spain
| | - Septimiu Murgu
- Section of Pulmonary and Critical Care, The University of Chicago Pritzker School of Medicine, Chicago, Illinois, USA
| |
Collapse
|
4
|
Salguero BD, Agrawal A, Kaul V, Lo Cascio CM, Joy G, So M, Munagala R, Harkin T, Chaddha U. Airway stenting for liberation from positive pressure ventilation in patients with central airway obstruction presenting with acute respiratory failure. Respir Med 2024; 225:107599. [PMID: 38492817 DOI: 10.1016/j.rmed.2024.107599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 02/05/2024] [Accepted: 03/10/2024] [Indexed: 03/18/2024]
Abstract
BACKGROUND Central airway obstruction (CAO) can lead to acute respiratory failure (RF) necessitating positive pressure ventilation (PPV). The efficacy of airway stenting to aid liberation from PPV in patients with severe acute RF has been scarcely published. We present a systematic review and our recent experience. METHODS A systematic review of PubMed was performed, and a retrospective review of cases performed at our two institutions from 2018 to 2022 in adult patients who needed stent insertion for extrinsic or mixed CAO complicated by RF necessitating PPV. RESULTS Fifteen studies were identified with a total of 156 patients. The weighted mean of successful liberation from PPV post-stenting was 84.5% and the median survival was 127.9 days. Our retrospective series included a total of 24 patients. The most common etiology was malignant CAO (83%). The types of PPV used included high-flow nasal cannula (HFNC) (21%), non-invasive ventilation (NIV) (17%) and Invasive Mechanical Ventilation (62%). The overall rate of successful liberation from PPV was 79%, with 55% of HFNC and NIV cases being liberated immediately post-procedure. The median survival of the patients with MCAO that were successfully liberated from PPV was 74 days (n = 16, range 3-893 days), and for those with that failed to be liberated from PPV, it was 22 days (n = 4, range 9-26 days). CONCLUSION In patients presenting with acute RF from extrinsic or mixed morphology CAO requiring PPV, airway stenting can successfully liberate most from the PPV. This may allow patients to receive pathology-directed treatment and better end-of-life care.
Collapse
Affiliation(s)
- Bertin D Salguero
- Division of Pulmonary, Critical Care and Sleep Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Abhinav Agrawal
- Division of Pulmonary, Critical Care and Sleep Medicine, Zucker School of Medicine at Hofstra/Northwell, New Hyde Park, NY, USA
| | - Viren Kaul
- Division of Pulmonary and Critical Care Medicine, Crouse Health/SUNY Upstate Medical University, Syracuse, USA
| | - Christian M Lo Cascio
- Division of Pulmonary, Critical Care and Sleep Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Greta Joy
- Division of Pulmonary, Critical Care and Sleep Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Matsuo So
- Department of Medicine, Mount Sinai Beth Israel, New York, NY, USA
| | - Rohit Munagala
- Department of Medicine, Zucker School of Medicine at Hofstra/Northwell, New Hyde Park, NY, USA
| | - Timothy Harkin
- Division of Pulmonary, Critical Care and Sleep Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Udit Chaddha
- Division of Pulmonary, Critical Care and Sleep Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| |
Collapse
|
5
|
Emmerling J, Vahaji S, Morton DAV, Fletcher DF, Inthavong K. Scale resolving simulations of the effect of glottis motion and the laryngeal jet on flow dynamics during respiration. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2024; 247:108064. [PMID: 38382308 DOI: 10.1016/j.cmpb.2024.108064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 12/27/2023] [Accepted: 02/05/2024] [Indexed: 02/23/2024]
Abstract
BACKGROUND AND OBJECTIVE The movement of the respiratory walls has a significant impact on airflow through the respiratory tract. The majority of computational fluid dynamics (CFD) studies assume a static geometry which may not provide a realistic flow field. Furthermore, many studies use Reynolds Averaged Navier-Stokes (RANS) turbulence models that do not resolve turbulence structure. Combining the application of advanced scale-resolving turbulence models with moving respiratory walls using CFD will provide detailed insights into respiratory flow structures. METHODS This study simulated a complete breathing cycle involving inhalation and exhalation in a nasal cavity to trachea geometry that incorporated moving glottis walls. A second breathing cycle was simulated with static glottis walls for comparison. A recently developed hybrid RANS-LES turbulence model, the Stress-Blended Eddy Simulation (SBES), was incorporated to resolve turbulent flow structures in fine detail for both transient simulations. Transient results were compared with steady-state RANS simulations for the same respiratory geometry. RESULTS Glottis motion caused substantial effects on flow structure through the complete breathing cycle. Significant flow structure and velocity variations were observed due to glottal motion, primarily in the larynx and trachea. Resolved turbulence structures using SBES showed an intense mixing section in the glottis region during inhalation and in the nasopharynx during expiration, which was not present in the RANS simulations. CONCLUSION Transient simulations of a realistic breathing cycle uncovered flow structures absent in simulations with a constant flow rate. Furthermore, the incorporation of glottis motion impacted airflow characteristics that suggest rigid respiratory walls do not accurately describe respiratory flow. Future research in respiratory airflow should be conducted using transient scale-resolving models in conjunction with moving respiratory walls to capture flow structures in detail.
Collapse
Affiliation(s)
- Jake Emmerling
- School of Engineering, Deakin University, Waurn Ponds 3216, Australia
| | - Sara Vahaji
- Mechanical & Automotive Engineering, School of Engineering, RMIT University, Bundoora, Victoria 3083, Australia
| | - David A V Morton
- School of Engineering, Deakin University, Waurn Ponds 3216, Australia
| | - David F Fletcher
- School of Chemical and Biomolecular Engineering, University of Sydney, NSW 2006, Australia
| | - Kiao Inthavong
- Mechanical & Automotive Engineering, School of Engineering, RMIT University, Bundoora, Victoria 3083, Australia.
| |
Collapse
|
6
|
Michaud-Dorko J, Sundström E, de Luzan CF, Gutmark E, Oren L. The Effect of an Increasing Subglottal Stenosis Constriction That Extends From the Vocal Folds to the Inferior Border of the Cricoid Cartilage. J Biomech Eng 2024; 146:021002. [PMID: 37943109 PMCID: PMC11003117 DOI: 10.1115/1.4064029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 10/17/2023] [Accepted: 11/05/2023] [Indexed: 11/10/2023]
Abstract
Acquired subglottal stenosis is an unpredicted complication that can occur in some patients who have undergone prolonged endotracheal intubation. It is a narrowing of the airway at the level of the cricoid cartilage that can restrict airflow and cause breathing difficulty. Stenosis is typically treated with endoscopic airway dilation, with some patients experiencing multiple recurrences. The study highlights the potential of computational fluid dynamics as a noninvasive method for monitoring subglottic stenosis, which can aid in early diagnosis and surgical planning. An anatomically accurate human laryngeal airway model was constructed from computerized tomography (CT) scans. The subglottis cross-sectional area was narrowed systematically using ≈10% decrements. A quadratic profile was used to interpolate the transformation of the airway geometry from its modified shape to the baseline geometry. The numerical results were validated by static pressure measurements conducted in a physical model. The results show that airway resistance follows a squared ratio that is inversely proportional to the size of the subglottal opening (R∝A-2). The study found that critical constriction occurs in the subglottal region at 70% stenosis (upper end of grade 2). Moreover, removing airway tissue below 40% stenosis during surgical intervention does not significantly decrease airway resistance.
Collapse
Affiliation(s)
- Jacob Michaud-Dorko
- Department of Biomedical Engineering, University of Cincinnati, 665 Baldwin Hall, Cincinnati, OH 45221-0070
| | - Elias Sundström
- Department of Otolaryngology-Head and Neck Surgery, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH 45267-0528
| | - Charles Farbos de Luzan
- Department of Otolaryngology-Head and Neck Surgery, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH 45267-0528
| | - Ephraim Gutmark
- Department of Aerospace Engineering, University of Cincinnati, 799 Rhodes Hall, Cincinnati, OH 45221-0070
| | - Liran Oren
- Department of Otolaryngology-Head and Neck Surgery, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH 45267-0528
| |
Collapse
|
7
|
Ding M, Ning J, Liu X, Mi R, Cai Y. Stenotic geometry effects on airflow dynamics and respiration for central airway obstruction. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2023; 241:107760. [PMID: 37573642 DOI: 10.1016/j.cmpb.2023.107760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 08/08/2023] [Accepted: 08/09/2023] [Indexed: 08/15/2023]
Abstract
BACKGROUND AND OBJECTIVE The quantitative relationship between tracheal anatomy and ventilation function can be analyzed by using engineering-derived methods, including mathematical modeling and numerical simulations. In order to provide quantitative functional evaluation for patients with tracheobronchial stenosis, we here propose an aerodynamics-based assessment method by applying computational fluid dynamics analysis on synthetic and patient-specific airway models. METHODS By using 3D reconstruction of tracheobronchial tree and computational fluid dynamics simulations, the aerodynamic environment from the stenotic central airway down to the 4th-6th bifurcation of the tracheobronchial tree is examined in both synthetic and patient-derived models. The effects of stenotic anatomy (the degree of stenosis, stenotic length and location) on the aerodynamic parameters, including pressure drop, area-average velocity, volume flow rate, wall shear stress and airflow resistance, are investigated on three-dimensional models of tracheobronchial tree. RESULTS The results from 36 synthetic models demonstrate that 70% constriction marks the onset of a precipitous decrease in airflow relative to a normal airway. The analyses of simulation results of 8 patient-specific models indicate that the Myer-Cotton stenosis grading system can be interpreted in terms of aerodynamics-derived description, such as flow resistance. The tracheal stenosis significantly influences the resistance of peripheral bronchi, especially for patients with severe stenosis. CONCLUSIONS The present study forms a systematic framework for future development of more robust, bioengineering-informed evaluation methods for quantitative assessment of respiratory function of patients with central airway obstruction.
Collapse
Affiliation(s)
- Ming Ding
- Department of Respiratory Medicine, Southeast University Zhongda Hospital, Nanjing, Jiangsu, China
| | - Jing Ning
- School of Biological Sciences and Medical Engineering, Southeast University, Nanjing, Jiangsu, China
| | - Xiuyan Liu
- Department of Respiratory Medicine, Southeast University Zhongda Hospital, Nanjing, Jiangsu, China
| | - Runze Mi
- School of Biological Sciences and Medical Engineering, Southeast University, Nanjing, Jiangsu, China
| | - Yan Cai
- School of Biological Sciences and Medical Engineering, Southeast University, Nanjing, Jiangsu, China.
| |
Collapse
|
8
|
Döllinger M, Jakubaß B, Cheng H, Carter SJ, Kniesburges S, Aidoo B, Lee CH, Milstein C, Patel RR. Computational fluid dynamics of upper airway aerodynamics for exercise-induced laryngeal obstruction: A feasibility study. Laryngoscope Investig Otolaryngol 2023; 8:1294-1303. [PMID: 37899858 PMCID: PMC10601582 DOI: 10.1002/lio2.1140] [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: 06/23/2023] [Accepted: 07/31/2023] [Indexed: 10/31/2023] Open
Abstract
Objective Use of computational fluid dynamic (CFD) simulations to measure the changes in upper airway geometry and aerodynamics during (a) an episode of Exercise-Induced Laryngeal Obstruction (EILO) and (b) speech therapy exercises commonly employed for patients with EILO. Methods Magnetic resonance imaging stills of the upper airway including the nasal and oral cavities from an adult female were used to re-construct three-dimensional geometries of the upper airway. The CFD simulations were used to compute the maximum volume flow rate (l/s), pressure (Pa), airflow velocity (m/s) and area of cross-section opening in eight planes along the vocal tract, separately for inhalation and exhalation. Results Numerical predictions from three-dimensional geometrical modeling of the upper airway suggest that the technique of nose breathing for inhalation and pursed lip breathing for exhalation show most promising pressure conditions and cross-sectional diameters for rescue breathing exercises. Also, if EILO is due to the constriction at the vocal fold level, then a quick sniff may also be a proper rescue inhalation exercise. EILO affects both the inspiratory and the expiratory phases of breathing. Conclusions A prior knowledge of the supraglottal aerodynamics and the corresponding upper airway geometry from CFD analysis has the potential to assist the clinician in choosing the most effective rescue breathing technique for optimal functional outcome of speech therapy intervention in patients with EILO and in understanding the pathophysiology of EILO on a case-by-case basis with future studies. Level of Evidence 4.
Collapse
Affiliation(s)
- Michael Döllinger
- Division of Phoniatrics and Pediatric Audiology at the Department of Otorhinolaryngology Head & Neck SurgeryUniversity Hospital Erlangen, Friedrich‐Alexander‐Universität Erlangen‐NürnbergErlangenGermany
| | - Bernhard Jakubaß
- Division of Phoniatrics and Pediatric Audiology at the Department of Otorhinolaryngology Head & Neck SurgeryUniversity Hospital Erlangen, Friedrich‐Alexander‐Universität Erlangen‐NürnbergErlangenGermany
| | - Hu Cheng
- Department of Psychological and Brain Sciences, Program of NeuroscienceIndiana UniversityBloomingtonIndianaUSA
| | - Stephen J. Carter
- Department of KinesiologySchool of Public Health, Indiana UniversityBloomingtonIndianaUSA
| | - Stefan Kniesburges
- Division of Phoniatrics and Pediatric Audiology at the Department of Otorhinolaryngology Head & Neck SurgeryUniversity Hospital Erlangen, Friedrich‐Alexander‐Universität Erlangen‐NürnbergErlangenGermany
| | - Bea Aidoo
- Department of MedicineIndiana University School of MedicineBloomingtonIndianaUSA
| | - Chi Hwan Lee
- Department of Biomedical Engineering & Mechanical EngineeringPurdue UniversityWest LafayetteIndianaUSA
| | - Claudio Milstein
- Department of Otolaryngology‐Head & Neck Surgery, Cleveland Clinic Lerner and Case Western Reserve University Schools of MedicineHead and Neck Institute, Cleveland ClinicClevelandOhioUSA
| | - Rita R. Patel
- Department of Speech, Language, and Hearing Sciences and Department of Otolaryngology Head and Neck SurgeryIndiana UniversityBloomington/IndianapolisIndianaUSA
| |
Collapse
|
9
|
Zamora-Perarnau C, Malvè M, Fernández-Parra R. Computational fluid dynamics comparison of the upper airway velocity, pressure, and resistance in cats using an endotracheal tube or a supraglottic airway device. Front Vet Sci 2023; 10:1183223. [PMID: 37818391 PMCID: PMC10561303 DOI: 10.3389/fvets.2023.1183223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 09/04/2023] [Indexed: 10/12/2023] Open
Abstract
Intoduction In veterinary medicine, airway management of cats under general anesthesia is performed with an endotracheal tube (ETT) or supraglottic airway device (SGAD). This study aims to describe the use of computational fluid dynamics (CFD) to assess the velocities, pressures, and resistances of cats with ETT or SGAD. Methods A geometrical reconstruction model of the device, trachea, and lobar bronchi was carried out from computed tomography (CT) scans that include the head, neck, and thorax. Twenty CT scans of cats under general anesthesia using ETT (n = 10) and SGAD (n = 10) were modeled and analyzed. An inspiratory flow of 2.4 L/min was imposed in each model and velocity (m/s), general and regional pressures (cmH2O) were computed. General resistance (cmH2O/L/min) was calculated using differential pressure differences between the device inlet and lobar bronchi. Additionally, regional resistances were calculated at the device's connection with the breathing circuit (region A), at the glottis area for the SGAD, and the area of the ETT exit (bevel) (region B) and the device itself (region C). Results Recirculatory flow and high velocities were found at the ETT's bevel and at the glottis level in the SGAD group. The pressure gradient (Δp) was more enhanced in the ETT cases compared with the SGAD cases, where the pressure change was drastic. In region A, the Δp was higher in the ETT group, while in regions B and C, it was higher in the SGAD group. The general resistance was not statistically significant between groups (p = 0.48). Higher resistances were found at the region A (p = <0.001) in the ETT group. In contrast, the resistance was higher in the SGAD cases at the region B (p = 0.001). Discussion Overall, the provided CT-based CFD analysis demonstrated regional changes in airway pressure and resistance between ETT and SGAD during anesthetic flow conditions. Correct selection of the airway device size is recommended to avoid upper airway obstruction or changes in flow parameters.
Collapse
Affiliation(s)
- Carla Zamora-Perarnau
- Doctoral School, Catholic University of Valencia San Vicente Mártir, Valencia, Spain
- Department of Small Animal Medicine and Surgery, Faculty of Veterinary Medicine, Catholic University of Valencia San Vicente Mártir, Valencia, Spain
- Veterinary Referral Hospital UCV, Catholic University of Valencia San Vicente Mártir, Valencia, Spain
| | - Mauro Malvè
- Department of Engineering, Public University of Navarre (UPNA), Pamplona, Spain
- Biomedical Research Networking Center in Bioengineering, Biomaterials, and Nanomedicine (CIBER-BBN), Madrid, Spain
| | - Rocío Fernández-Parra
- Department of Small Animal Medicine and Surgery, Faculty of Veterinary Medicine, Catholic University of Valencia San Vicente Mártir, Valencia, Spain
- Veterinary Referral Hospital UCV, Catholic University of Valencia San Vicente Mártir, Valencia, Spain
| |
Collapse
|
10
|
Reid L, Hayatdavoodi M, Majumdar S. Airflow through the supraglottis during inspiration. Comput Methods Biomech Biomed Engin 2023; 26:1462-1477. [PMID: 36094796 DOI: 10.1080/10255842.2022.2121605] [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: 07/12/2022] [Revised: 08/22/2022] [Accepted: 08/29/2022] [Indexed: 11/03/2022]
Abstract
Exercise-induced laryngeal obstruction is a paradoxical laryngeal closure during inspiration at high-intensity exercise, with supraglottic closure being most common. This study develops a model based on the computational fluid dynamics to investigate airflow velocity and pressure and the air-induced loads on the supraglottis at various inspiratory flow rates. It is found that at high flow rates, positive wall pressure is formed in the hypopharynx localise towards its lower region, while posterior supraglottic wall pressures shift from positive to negative. These findings suggest that high inspiratory flow rates may increase supraglottic pressure differentials, ultimately contributing in the collapse.
Collapse
Affiliation(s)
- L Reid
- Centre for Anatomy and Human Identification, University of Dundee, Dundee, UK
| | - M Hayatdavoodi
- School of Science and Engineering, University of Dundee, Dundee, UK
| | - S Majumdar
- Ear, Nose, and Throat Department, Ninewells Hospital and Medical School, Dundee, UK
| |
Collapse
|
11
|
Bocanegra Evans H, Segnini JM, Doosttalab A, Cordero J, Castillo L. Effect of cartilaginous rings in tracheal flow with stenosis. BMC Biomed Eng 2023; 5:5. [PMID: 37259126 DOI: 10.1186/s42490-023-00068-4] [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: 03/14/2021] [Accepted: 02/24/2023] [Indexed: 06/02/2023] Open
Abstract
BACKGROUND In respiratory fluid dynamics research, it is typically assumed that the wall of the trachea is smooth. However, the trachea is structurally supported by a series of cartilaginous rings that create undulations on the wall surface, which introduce perturbations into the flow. Even though many studies use realistic Computer Tomography (CT) scan data to capture the complex geometry of the respiratory system, its limited spatial resolution does not resolve small features, including those introduced by the cartilaginous rings. RESULTS Here we present an experimental comparison of two simplified trachea models with Grade II stenosis (70% blockage), one with smooth walls and second with cartilaginous rings. The use a unique refractive index-matching method provides unprecedented optical access and allowed us to perform non-intrusive velocity field measurements close to the wall (e.g., Particle Image Velocimetry (PIV)). Measurements were performed in a flow regime comparable to a resting breathing state (Reynolds number ReD = 3350). The cartilaginous rings induce velocity fluctuations in the downstream flow, enhancing the near-wall transport of momentum flux and thus reducing flow separation in the downstream flow. The maximum upstream velocity in the recirculation region is reduced by 38%, resulting in a much weaker recirculation zone- a direct consequence of the cartilaginous rings. CONCLUSIONS These results highlight the importance of the cartilaginous rings in respiratory flow studies and the mechanism to reduce flow separation in trachea stenosis.
Collapse
Affiliation(s)
- Humberto Bocanegra Evans
- School of Mechanical Engineering, Purdue University, 1500 Kepner Dr Room 104, West Lafayette, IN, 47905, USA
| | - Jose Montoya Segnini
- School of Mechanical Engineering, Purdue University, 1500 Kepner Dr Room 104, West Lafayette, IN, 47905, USA
| | - Ali Doosttalab
- School of Mechanical Engineering, Purdue University, 1500 Kepner Dr Room 104, West Lafayette, IN, 47905, USA.
| | - Joehassin Cordero
- Department of Otolaryngology, Texas Tech University Health Sciences Center, Lubbock, TX, 79430, USA
| | - Luciano Castillo
- School of Mechanical Engineering, Purdue University, 1500 Kepner Dr Room 104, West Lafayette, IN, 47905, USA
| |
Collapse
|
12
|
Crosby T, Adkins L, McWhorter A, Kunduk M, Dunham M. Computational fluid dynamics model of laryngotracheal stenosis and correlation to pulmonary function measures. Respir Physiol Neurobiol 2023; 312:104037. [PMID: 36842729 DOI: 10.1016/j.resp.2023.104037] [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: 09/03/2022] [Revised: 02/16/2023] [Accepted: 02/21/2023] [Indexed: 02/28/2023]
Abstract
3D models of airway lumens were created from CT scans of 19 patients with laryngotracheal stenosis. Computational fluid dynamics (CFD) simulations were completed for each, and results were compared to measured peak inspiratory flow rate, grade of lumen constriction, and measures of airway geometry. Results demonstrate flow resistance and shear stress correlate with degree of lumen constriction and absolute cross-sectional area as well as flow rate. Flow recirculation depends on airway constriction but does not vary with flow rate. Resistance and wall shear stress did not correlate well with functional measures. Flow recirculation did differ between subjects with higher functional measures and subjects with lower functional measures. This analysis provides mathematical models to predict airway resistance, wall shear stress, and flow reversal according lumen constriction and inspiratory flow rate. It suggests aerodynamic factors such as flow recirculation play a role in differences in functional performance between patients with similar airway measures.
Collapse
Affiliation(s)
- Tyler Crosby
- Louisiana State University Health Science Center, New Orleans - Department of Otolaryngology, Head and Neck Surgery, 533 Bolivar Street, Suite 566, New Orleans, LA 70112, USA; Department of Otolaryngology-Head and Neck Surgery, NYU Langone Health, New York, New York.
| | - Lacey Adkins
- Louisiana State University Health Science Center, New Orleans - Department of Otolaryngology, Head and Neck Surgery, 533 Bolivar Street, Suite 566, New Orleans, LA 70112, USA; Our Lady of the Lake Regional Medical Center, Voice Center, 4950 Essen Ln Ste 401, Baton Rouge, LA 70809, USA
| | - Andrew McWhorter
- Louisiana State University Health Science Center, New Orleans - Department of Otolaryngology, Head and Neck Surgery, 533 Bolivar Street, Suite 566, New Orleans, LA 70112, USA; Our Lady of the Lake Regional Medical Center, Voice Center, 4950 Essen Ln Ste 401, Baton Rouge, LA 70809, USA
| | - Melda Kunduk
- Our Lady of the Lake Regional Medical Center, Voice Center, 4950 Essen Ln Ste 401, Baton Rouge, LA 70809, USA; Louisiana State University Department of Communication Sciences and Disorders, Louisiana State University, 68 Hatcher Hall, Field House Drive, Baton Rouge, LA 70803, USA
| | - Michael Dunham
- Louisiana State University Health Science Center, New Orleans - Department of Otolaryngology, Head and Neck Surgery, 533 Bolivar Street, Suite 566, New Orleans, LA 70112, USA; Our Lady of the Lake Children's Hospital, 8200 Constanin Blvd, Floor 3, Baton Rouge, LA 70809, USA
| |
Collapse
|
13
|
Analysis of Upper Airway Flow Dynamics in Robin Sequence Infants Using 4-D Computed Tomography and Computational Fluid Dynamics. Ann Biomed Eng 2023; 51:363-376. [PMID: 35951208 DOI: 10.1007/s10439-022-03036-6] [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: 04/01/2022] [Accepted: 07/20/2022] [Indexed: 01/25/2023]
Abstract
Robin Sequence (RS) is a potentially fatal craniofacial condition characterized by undersized jaw, posteriorly displaced tongue, and resultant upper airway obstruction (UAO). Accurate assessment of UAO severity is crucial for management and diagnosis of RS, yet current evaluation modalities have significant limitations and no quantitative measures of airway resistance exist. In this study, we combine 4-dimensional computed tomography and computational fluid dynamics (CFD) to assess, for the first time, UAO severity using fluid dynamic metrics in RS patients. Dramatic intrapopulation differences are found, with the ratio between most and least severe patients in breathing resistance, energy loss, and peak velocity equal to 40:1, 20:1, and 6:1, respectively. Analysis of local airflow dynamics characterized patients as presenting with primary obstructions either at the location of the tongue base, or at the larynx, with tongue base obstructions resulting in a more energetic stenotic jet and greater breathing resistance. Finally, CFD-derived flow metrics are found to correlate with the level of clinical respiratory support. Our results highlight the large intrapopulation variability, both in quantitative metrics of UAO severity (resistance, energy loss, velocity) and in the location and intensity of stenotic jets for RS patients. These results suggest that computed airflow metrics may significantly improve our understanding of UAO and its management in RS.
Collapse
|
14
|
Del Puppo M, Meister L, Médale M, Allary C, Nicollas R, Moreddu E. Heliox simulations for initial management of congenital laryngotracheal stenosis. Pediatr Pulmonol 2023; 58:230-238. [PMID: 36208011 PMCID: PMC10092700 DOI: 10.1002/ppul.26189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 09/22/2022] [Accepted: 09/26/2022] [Indexed: 01/11/2023]
Abstract
OBJECTIVES Congenital laryngotracheal stenosis is rare, potentially severe, and difficult to manage. Heliox is a medical gas effective in obstructive airway pathologies, given its physical properties. This study aims to model the interest of Heliox in reducing the respiratory work in congenital laryngotracheal stenosis, using numerical fluid flow simulations, before considering its clinical use. DESIGN This is a retrospective study, performing Computational Fluid Dynamics numerical simulations of the resistances to airflow and three types of Heliox, on 3D reconstructions from CT scans of children presenting with laryngotracheal stenosis. PATIENTS Infants and children who were managed in the Pediatric ENT department of a tertiary-care center and underwent CT scanning for laryngotracheal stenosis between 2008 and 2018 were included. RESULTS Fourteen models of congenital laryngotracheal stenosis were performed in children aged from 16 days to 5 years, and one model of the normal trachea in a 5-year-old child. Tightest stenosis obtained the highest airway resistances, ranging from 40 to 10 kPa/L/s (up to 800 times higher than in the normal case). Heliox enabled a decrease in pressure drops and airway resistances in all stenosis cases, correlated to increasing Helium concentration. CONCLUSIONS Heliox appears to reduce pressure drops and airway resistances in 3D models of laryngotracheal stenosis. It may represent a supportive treatment for laryngotracheal stenosis, while waiting for specialized care, thanks to the reduction of respiratory work.
Collapse
Affiliation(s)
- Marine Del Puppo
- Department of Pediatric Otolaryngology Head and Neck Surgery, La Timone Children's Hospital, AP-HM, Aix Marseille Université, Marseille, France.,Energetic Mechanics Department, Institut Universitaire des Systèmes Thermiques et Industriels, UMR 7343 CNRS, Aix Marseille Université, Marseille, France
| | - Lionel Meister
- Energetic Mechanics Department, Institut Universitaire des Systèmes Thermiques et Industriels, UMR 7343 CNRS, Aix Marseille Université, Marseille, France
| | - Marc Médale
- Energetic Mechanics Department, Institut Universitaire des Systèmes Thermiques et Industriels, UMR 7343 CNRS, Aix Marseille Université, Marseille, France
| | - Chloé Allary
- Department of Pediatric Anesthesia and Intensive Care, La Timone Children's Hospital, AP-HM, Aix Marseille Université, Marseille, France
| | - Richard Nicollas
- Department of Pediatric Otolaryngology Head and Neck Surgery, La Timone Children's Hospital, AP-HM, Aix Marseille Université, Marseille, France.,Energetic Mechanics Department, Institut Universitaire des Systèmes Thermiques et Industriels, UMR 7343 CNRS, Aix Marseille Université, Marseille, France
| | - Eric Moreddu
- Department of Pediatric Otolaryngology Head and Neck Surgery, La Timone Children's Hospital, AP-HM, Aix Marseille Université, Marseille, France.,Energetic Mechanics Department, Institut Universitaire des Systèmes Thermiques et Industriels, UMR 7343 CNRS, Aix Marseille Université, Marseille, France
| |
Collapse
|
15
|
Hilton BA, Thomson SL. Aerodynamic-induced Effects of Artificial Subglottic Stenosis on Vocal Fold Model Phonatory Response. J Voice 2022:S0892-1997(22)00374-5. [PMID: 36496305 PMCID: PMC10244482 DOI: 10.1016/j.jvoice.2022.11.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 11/16/2022] [Accepted: 11/17/2022] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Subglottic stenosis (SGS) is characterized by a narrowing of the trachea near the cricotracheal junction and impairs breathing. SGS may also adversely affect voice quality, but for reasons that are not fully understood. The purpose of this study is to provide experiment-based data concerning the effects on phonation of airway obstruction due to SGS. STUDY DESIGN Basic science METHODS: A device simulating a SGS of adjustable severity ranging from 36% to 99.8% obstruction was created. Self-oscillating synthetic VF models were mounted downstream of the device and data were acquired to evaluate the effects of the obstruction on phonatory response. RESULTS Onset pressures were relatively insensitive to obstructions of up to approximately 80% to 90% reductions in subglottic airway area and sharply increased thereafter. Flow rate (under conditions of constant pressure), flow resistance, and fundamental frequency all exhibited similar degrees of sensitivity to SGS obstruction as onset pressure. High-frequency noise became significant by 80% obstruction. Glottal area appeared to be less sensitive, not being affected until approximately 90% obstruction. CONCLUSIONS Consistent with previous computational studies, this study found that aerodynamic, acoustic, and vibratory responses of self-oscillating VF models were largely unaffected by SGS until approximately 80% to 90% obstruction, and significantly affected at higher obstructions. This suggests that Grades I and II stenoses are unlikely to introduce subglottic airway aerodynamic disturbances that are sufficient in and of themselves to significantly alter phonatory output. The SGS model introduces a framework for future benchtop studies involving subglottic and supraglottic airway constrictions.
Collapse
Affiliation(s)
- Benjamin A Hilton
- Department of Mechanical Engineering, Brigham Young University, Provo, Utah
| | - Scott L Thomson
- Department of Mechanical Engineering, Brigham Young University, Provo, Utah.
| |
Collapse
|
16
|
Computational fluid dynamics assessment of congenital tracheal stenosis. Pediatr Surg Int 2022; 38:1769-1776. [PMID: 36104600 DOI: 10.1007/s00383-022-05228-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/05/2022] [Indexed: 10/14/2022]
Abstract
PURPOSE The severity of congenital tracheal stenosis (CTS) is commonly evaluated based on the degree of stenosis. However, it does not always reflect the clinical respiratory status. We applied computational fluid dynamics (CFD) to the assessment of CTS. The aim of this study was to evaluate its validity. METHODS CFD models were constructed on 15 patients (12 preoperative models and 15 postoperative models) with CTS before and after surgery, using the computed tomographic data. Energy flux, needed to drive airflow, measured by CFD and the minimum cross-sectional area of the trachea (MCAT) were quantified and evaluated retrospectively. RESULTS The energy flux correlated positively with the clinical respiratory status before and after surgery (rs = 0.611, p = 0.035 and rs = 0.591, p = 0.020, respectively). Although MCAT correlated negatively with the clinical respiratory status before surgery (rs = -0.578, p = 0.044), there was not significant correlation between the two after surgery (p = 0.572). CONCLUSIONS The energy flux measured by CFD assessment reflects the respiratory status in CTS before and after surgery. CFD can be an additional objective and quantitative evaluation tool for CTS.
Collapse
|
17
|
Kageyama S, Takeishi N, Taenaka H, Yoshida T, Wada S. Fluid dynamic assessment of positive end-expiratory pressure in a tracheostomy tube connector during respiration. Med Biol Eng Comput 2022; 60:2981-2993. [PMID: 36002620 PMCID: PMC9402408 DOI: 10.1007/s11517-022-02649-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 08/19/2022] [Indexed: 11/24/2022]
Abstract
High-flow oxygen therapy using a tracheostomy tube is a promising clinical approach to reduce the work of breathing in tracheostomized patients. Positive end-expiratory pressure (PEEP) is usually applied during oxygen inflow to improve oxygenation by preventing end-expiratory lung collapse. However, much is still unknown about the geometrical effects of PEEP, especially regarding tracheostomy tube connectors (or adapters). Quantifying the degree of end-expiratory pressure (EEP) that takes patient-specific spirometry into account would be useful in this regard, but no such framework has been established yet. Thus, a platform to assess PEEP under respiration was developed, wherein three-dimensional simulation of airflow in a tracheostomy tube connector is coupled with a lumped lung model. The numerical model successfully reflected the magnitude of EEP measured experimentally using a lung phantom. Numerical simulations were further performed to quantify the effects of geometrical parameters on PEEP, such as inlet angles and rate of stenosis in the connector. Although sharp inlet angles increased the magnitude of EEP, they cannot be expected to achieve clinically reasonable PEEP. On the other hand, geometrical constriction in the connector can potentially result in PEEP as obtained with conventional nasal cannulae.
Collapse
|
18
|
Kageyama S, Takeishi N, Harada N, Taniguchi K, Morita K, Wada S. Airway performance in infants with congenital tracheal stenosis associated with unilateral pulmonary agenesis: effect of tracheal shape on energy flux. Med Biol Eng Comput 2022; 60:2335-2348. [DOI: 10.1007/s11517-022-02601-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 06/07/2022] [Indexed: 12/01/2022]
|
19
|
Ayten O, Iscanli IGE, Canoglu K, Ozdemir C, Saylan B, Caliskan T, Akin H, Tezel C. Tracheal Stenosis After Prolonged Intubation Due to COVID-19. J Cardiothorac Vasc Anesth 2022; 36:2948-2953. [PMID: 35283040 PMCID: PMC8832874 DOI: 10.1053/j.jvca.2022.02.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 02/04/2022] [Accepted: 02/06/2022] [Indexed: 01/01/2023]
Abstract
Objectives The authors aimed to evaluate the characteristics and management outcomes of patients who developed tracheal stenosis after invasive mechanical ventilation (IMV) due to COVID-19. Design, Setting, and Participants The data of 7 patients with tracheal stenosis and 201 patients without tracheal stenosis after IMV due to COVID-19 between March 2020 and October 2021 were retrospectively analyzed. Interventions Flexible bronchoscopy was performed for the diagnosis of tracheal stenosis and the evaluation of the treatment's effectiveness, and rigid bronchoscopy was applied for the dilatation of tracheal stenosis. Measurements and Main Results In the follow-up period, tracheal stenosis was observed in 7 of 208 patients (2 women, 5 men; 3.3%). The patients were divided into 2 groups as patients with tracheal stenosis (n = 7) and patients without tracheal stenosis (n = 201). There were no statistically significant differences between the 2 groups in terms of age, sex, body mass index, and comorbidities (p > 0.05). The mean duration of IMV of the patients with tracheal stenosis was longer than patients without tracheal stenosis (27.9 ± 13 v 11.2 ± 9 days, p < 0.0001, respectively). Three (43%) of the stenoses were web-like and 4 (57%) of them were complex-type stenosis. The mean length of the stenoses was 1.81 ± 0.82 cm. Three of the patients were treated successfully with bronchoscopic dilatation, and 4 of them were treated with tracheal resection. Conclusions Tracheal stenosis developed in 7 of 208 (3.3%) patients with COVID-19 who were treated with IMV. The most important characteristic of patients with tracheal stenosis was prolonged IMV support.
Collapse
Affiliation(s)
- Omer Ayten
- Department of Pulmonary Medicine, Sultan Abdulhamid Han Teaching Hospital, Istanbul, Turkey.
| | - Insa Gul Ekiz Iscanli
- Department of Intensive Care Unit, Sultan Abdulhamid Han Teaching Hospital, Istanbul, Turkey
| | - Kadir Canoglu
- Department of Pulmonary Medicine, Sultan Abdulhamid Han Teaching Hospital, Istanbul, Turkey
| | - Cengiz Ozdemir
- Department of Pulmonary Medicine, Yedikule Teaching Hospital for Pulmonology and Thoracic Surgery, Istanbul, Turkey
| | - Bengü Saylan
- Department of Pulmonary Medicine, Sultan Abdulhamid Han Teaching Hospital, Istanbul, Turkey
| | - Tayfun Caliskan
- Department of Pulmonary Medicine, Sultan Abdulhamid Han Teaching Hospital, Istanbul, Turkey
| | - Hasan Akin
- Department of Thoracic Surgery, Yedikule Teaching Hospital for Pulmonology and Thoracic Surgery, Istanbul, Turkey
| | - Cağatay Tezel
- Department of Thoracic Surgery, Sultan Abdulhamid Han Teaching Hospital, Istanbul, Turkey
| |
Collapse
|
20
|
Investigation and Analysis of the Influence of Vegetative Tracheobronchial Foreign Body on Airflow Field. Appl Bionics Biomech 2022; 2022:8930283. [PMID: 35528537 PMCID: PMC9071906 DOI: 10.1155/2022/8930283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 03/30/2022] [Accepted: 04/08/2022] [Indexed: 11/17/2022] Open
Abstract
The BSL k-ω turbulence model was used to numerically simulate the inspiratory airflow of the airway with foreign bodies using a real CT scan human airway model. The paper selects three foreign bodies with different diameters, three different foreign body positions, and three different breathing intensities, and the FLUENT software is used to perform numerical simulation. This study has found that the increase in the diameter of the foreign body and flow velocity will make the flow structure in the airway more complicated. The airway pressure will increase so that the resistance of breathing will increase, and the shear force will also increase, which hurt the airway. The impact of the foreign body on the left side on the flow structure in the airway is less than that of the foreign body on the right side. The foreign body on the left side causes the pressure drop in the airway to be higher than that on the right side. Moreover, sharp changes in pressure driving force and airway curvature will affect the airflow pattern of the central airway. We concluded that foreign matter has a great influence on the characteristics of the airflow structure, and more research is needed to increase the understanding of the airflow pattern under the condition of foreign matter in the airway, and the research helps doctors avoid the influence of airflow when removing foreign bodies in the airway.
Collapse
|
21
|
Functional analysis of the airways after pulmonary lobectomy through computational fluid dynamics. Sci Rep 2022; 12:3321. [PMID: 35228582 PMCID: PMC8885819 DOI: 10.1038/s41598-022-06852-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 12/14/2021] [Indexed: 12/25/2022] Open
Abstract
Pulmonary lobectomy, which consists of the partial or complete resection of a lung lobe, is the gold standard intervention for lung cancer removal. The removal of functional tissue during the surgery and the re-adaptation of the remaining thoracic structures decrease the patient's post-operative pulmonary function. Residual functionality is evaluated through pulmonary function tests, which account for the number of resected segments without considering local structural alterations and provide an average at-the-mouth estimation. Computational Fluid Dynamics (CFD) has been demonstrated to provide patient-specific, quantitative, and local information about airways airflow dynamics. A CFD investigation was performed on image-based airway trees reconstructed before and after the surgery for twelve patients who underwent lobectomy at different lobes. The geometrical alterations and the variations in fluid dynamics parameters and in lobar ventilation between the pre and post-operative conditions were evaluated. The post-operative function was estimated and compared with current clinical algorithms and with actual clinical data. The post-operative configuration revealed a high intersubject variability: regardless of the lobectomy site, an increment of global velocity, wall pressure, and wall shear stress was observed. Local flow disturbances also emerged at, and downstream of, the resection site. The analysis of lobar ventilation showed severe variations in the volume flow rate distribution, highlighting the compensatory effects in the contralateral lung with an increment of inflow. The estimation of post-operative function through CFD was comparable with the current clinical algorithm and the actual spirometric measurements. The results confirmed that CFD could provide additional information to support the current clinical approaches both in the operability assessment and in the prescription of personalized respiratory rehabilitation.
Collapse
|
22
|
Molecular Mechanisms and Physiological Changes behind Benign Tracheal and Subglottic Stenosis in Adults. Int J Mol Sci 2022; 23:ijms23052421. [PMID: 35269565 PMCID: PMC8910114 DOI: 10.3390/ijms23052421] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 02/16/2022] [Accepted: 02/21/2022] [Indexed: 02/06/2023] Open
Abstract
Laryngotracheal stenosis (LTS) is a complex and heterogeneous disease whose pathogenesis remains unclear. LTS is considered to be the result of aberrant wound-healing process that leads to fibrotic scarring, originating from different aetiology. Although iatrogenic aetiology is the main cause of subglottic or tracheal stenosis, also autoimmune and infectious diseases may be involved in causing LTS. Furthermore, fibrotic obstruction in the anatomic region under the glottis can also be diagnosed without apparent aetiology after a comprehensive workup; in this case, the pathological process is called idiopathic subglottic stenosis (iSGS). So far, the laryngotracheal scar resulting from airway injury due to different diseases was considered as inert tissue requiring surgical removal to restore airway patency. However, this assumption has recently been revised by regarding the tracheal scarring process as a fibroinflammatory event due to immunological alteration, similar to other fibrotic diseases. Recent acquisitions suggest that different factors, such as growth factors, cytokines, altered fibroblast function and genetic susceptibility, can all interact in a complex way leading to aberrant and fibrotic wound healing after an insult that acts as a trigger. However, also physiological derangement due to LTS could play a role in promoting dysregulated response to laryngo-tracheal mucosal injury, through biomechanical stress and mechanotransduction activation. The aim of this narrative review is to present the state-of-the-art knowledge regarding molecular mechanisms, as well as mechanical and physio-pathological features behind LTS.
Collapse
|
23
|
Guedes F, Branquinho MV, Sousa AC, Alvites RD, Bugalho A, Maurício AC. Central airway obstruction: is it time to move forward? BMC Pulm Med 2022; 22:68. [PMID: 35183132 PMCID: PMC8858525 DOI: 10.1186/s12890-022-01862-x] [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: 10/01/2021] [Accepted: 02/14/2022] [Indexed: 12/18/2022] Open
Abstract
Abstract
Introduction
Central airway obstruction (CAO) represents a pathological condition that can lead to airflow limitation of the trachea, main stem bronchi, bronchus intermedius or lobar bronchus.
Main body
It is a common clinical situation consensually considered under-diagnosed. Management of patients with CAO can be difficult and deciding on the best treatment approach represents a medical challenge. This work intends to review CAO classifications, causes, treatments and its therapeutic limitations, approaching benign and malign presentations. Three illustrative cases are further presented, supporting the clinical problem under review.
Conclusion
Management of CAO still remains a challenge. The available options are not always effective nor free from complications. A new generation of costume-tailored airway stents, associated with stem cell-based therapy, could be an option in specific clinical situations.
Collapse
|
24
|
Wang L, Ge H, Chen L, Hajipour A, Feng Y, Cui X. LES study on the impact of airway deformation on the airflow structures in the idealized mouth–throat model. JOURNAL OF THE BRAZILIAN SOCIETY OF MECHANICAL SCIENCES AND ENGINEERING 2022; 44:23. [PMCID: PMC8696248 DOI: 10.1007/s40430-021-03324-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
To investigate the impacts of upper airway deformation on the airflow structures, the airflow fields in the trachea are simulated using three geometrical models considering three different levels of airway deformations. Structured grids are used to create the high-quality grids. Large eddy simulation with the Smagorinsky sub-grid model is adopted to solve the three-dimensional in-compressible Navier–Stokes equations using the solver pisoFoam in the open-source CFD software OpenFOAM. The numerical results demonstrate that the airway deformation influences the main airflow structures depending on the deformation level. Particularly, it slightly impacts on the laryngeal jet such as the profile and the strength of laryngeal jet. The strength of the laryngeal jet increases slightly for the heavy deformation. In contrast, it impacts on the recirculation zone, secondary vortices, and turbulent kinetic energy more obviously. The increasing airway deformation will produce stronger secondary flow, smaller recirculation zone, and weaker turbulent kinetic energy. The turbulence intensity distribution varies as well. The obviously impacted flow region is mainly within the region of one to six tracheal diameters downstream the glottis.
Collapse
Affiliation(s)
- Li Wang
- HangZhou Long Beach Technology Ltd. Co, Hangzhou, China
| | - Haiwen Ge
- Department of Mechanical Engineering, Texas Tech University, Lubbock, TX USA
| | - Liang Chen
- First Affiliated Hospital of Zhejiang University, Zhejiang University, Hangzhou, China
| | - Alireza Hajipour
- Department of Mechanical Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran
| | - Yaning Feng
- School of Aerospace Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Xinguang Cui
- School of Aerospace Engineering, Huazhong University of Science and Technology, Wuhan, China
| |
Collapse
|
25
|
Shen X, Tan W, Jia B, Ye M. Relationship between a Tracheal and Left Pulmonary Artery Stenosis Index and the Prognosis of Pulmonary Artery Sling with Tracheal Stenosis. Pediatr Cardiol 2021; 42:1585-1593. [PMID: 34046721 DOI: 10.1007/s00246-021-02643-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 05/19/2021] [Indexed: 11/26/2022]
Abstract
Pulmonary artery sling is a rare congenital pulmonary vascular malformation, often associated with tracheal or bronchial stenosis. Surgical treatment of pulmonary artery sling with tracheal stenosis (T) has a high risk of death and a relatively poor prognosis. This study explored the relationship between the T and left pulmonary artery stenosis (P) ratio and the effects of surgery for pulmonary artery sling with tracheal stenosis. Patients undergoing surgery for pulmonary artery sling in our center from January 2010 to December 2018 were retrospectively analyzed. Routine cardiac-enhanced computed tomography (CT) was performed preoperatively, and the P and T diameters were measured on the CT image. The T/P ratio was then calculated and analyzed. Thirty cases of pulmonary artery sling combined with tracheal stenosis were operated under cardiopulmonary bypass. The mean age at operation was 13.8 ± 13.6 months (1.2-57.1 months, Q1-Q3: 5-17 months), and the mean body weight was 8.8 ± 3.5 kg (3.8-17.3 kg, Q1-Q3: 5.8-11.5 kg). Twenty-three patients survived, and seven died, with an overall survival rate of 76.7%. Twenty-four patients underwent left pulmonary artery re-implantation, six patients underwent simultaneous left pulmonary artery re-implantation and slide tracheoplasty, and patients with intracardiac malformations (ventricular septal defect (n = 6) and atrial septal defect (n = 4)) underwent concurrent repair of the intracardiac defect. All cases had different degrees of tracheal stenosis, and the most narrowed trachea occurred with compression by the left pulmonary artery sling. The T/P ratio in the tracheoplasty group was significantly higher than that in the non-tracheoplasty group. The mortality rate in the T/P ≤ 1.15 group was significantly lower than that in the T/P > 1.15 group. Pulmonary artery sling treatment has a high risk of death. Left pulmonary artery re-implantation is an effective and safe surgical method for treating pulmonary artery sling, and slide tracheoplasty is an effective surgical method to correct tracheal stenosis. Children with T > 78.4% should receive active intervention for the tracheal stenosis, and these children have a considerable postoperative survival rate. The T/P ratio can be used to compare the relative superiority of the two compressions. A T/P ratio > 1.15 can be used as a reference index for intervention in tracheal stenosis and is a risk factor for postoperative death.
Collapse
Affiliation(s)
- Xiao Shen
- Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - WeiQiang Tan
- Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - Bing Jia
- Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - Ming Ye
- Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China.
| |
Collapse
|
26
|
Agrawal A, Baird BJ, Madariaga MLL, Blair EA, Murgu S. Multi-disciplinary management of patients with benign airway strictures: A review. Respir Med 2021; 187:106582. [PMID: 34481304 DOI: 10.1016/j.rmed.2021.106582] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Accepted: 08/18/2021] [Indexed: 11/29/2022]
Abstract
Histologically benign airway strictures are frequently misdiagnosed as asthma or COPD and may present with severe symptoms including respiratory failure. A clear understanding of pathophysiology and existing classification systems is needed to determine the appropriate treatment options and predict clinical course. Clinically significant airway strictures can involve the upper and central airways extending from the subglottis to the lobar airways. Optimal evaluation includes a proper history and physical examination, neck and chest computed tomography, pulmonary function testing, endoscopy and serology. Available treatments include medical therapy, endoscopic procedures and open surgery which are based on the stricture's extent, location, etiology, morphology, severity of airway narrowing and patient's functional status. The acuity of the process, patient's co-morbidities and operability at the time of evaluation determine the need for open surgical or endoscopic interventions. The optimal management of patients with benign airway strictures requires the availability, expertise and collaboration of otolaryngologists, thoracic surgeons and interventional pulmonologists. Multidisciplinary airway teams can facilitate accurate diagnosis, guide management and avoid unnecessary procedures that could potentially worsen the extent of the disease or clinical course. Implementation of a complex airway program including multidisciplinary clinics and conferences ensures that such collaboration leads to timely, patient-centered and evidence-based interventions. In this article we outline algorithms of care and illustrate therapeutic techniques based on published evidence.
Collapse
Affiliation(s)
- Abhinav Agrawal
- Interventional Pulmonology & Bronchoscopy, Division of Pulmonary, Critical Care & Sleep Medicine, Zucker School of Medicine at Hofstra/Northwell, New Hyde Park, NY, USA.
| | - Brandon J Baird
- Section of Otolaryngology - Head and Neck Surgery, Department of Surgery, University of Chicago, Chicago, IL, USA.
| | - Maria Lucia L Madariaga
- Section of Thoracic Surgery, Department of Surgery, University of Chicago, Chicago, IL, USA.
| | - Elizabeth A Blair
- Section of Otolaryngology - Head and Neck Surgery, Department of Surgery, University of Chicago, Chicago, IL, USA.
| | - Septimiu Murgu
- Interventional Pulmonology, Section of Pulmonary and Critical Care, Department of Medicine, University of Chicago, Chicago, IL, USA.
| |
Collapse
|
27
|
Kimura K, Du L, Berry LD, Huang LC, Chen SC, Francis DO, Gelbard A. Modeling Recurrence in Idiopathic Subglottic Stenosis With Mobile Peak Expiratory Flow. Laryngoscope 2021; 131:E2841-E2848. [PMID: 34309022 DOI: 10.1002/lary.29760] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 07/05/2021] [Accepted: 07/09/2021] [Indexed: 01/20/2023]
Abstract
OBJECTIVES/HYPOTHESIS We sought to establish normative peak expiratory flow (PEF) data for patients with idiopathic subglottic stenosis (iSGS), evaluate whether immediate changes in PEF after a procedure predict long-term treatment response, and test if a decline in longitudinal PEF is associated with disease recurrence. STUDY DESIGN International, prospective, 3-year multicenter cohort study of 810 patients with untreated, newly diagnosed, or previously treated iSGS. METHODS iSGS patients consented and enrolled in the North American Airway Collaborative (NoAAC) iSGS1000 cohort recorded PEF data on a mobile smartphone app. Cox regression tested the associations between the magnitude of postoperative PEF improvement and longitudinal 90-day PEF decline with the risk of disease recurrence. RESULTS Within the NoAAC iSGS1000 cohort, 810 patients participated in a 3-year prospective study comparing surgical treatment efficacy and 385 had appropriate PEF measurements and follow-up data. Of those patients, 42% (161/385) required at least one operation during study follow-up. The mean PEF preceding operative intervention was 241 L/min (95% confidence interval [CI]: 120-380) corresponding to a predicted PEF of 52%. The mean increase in PEF following a procedure was 111 L/min (95% CI: 96-125 L/min). Interestingly, the magnitude of immediate PEF improvement was not predictive of disease recurrence (hazard ratio [HR] for 100 L/min increase = 0.90, 95% CI: 0.60-1.00). However, recurrence was associated with the magnitude of PEF decline over 90 days (30% vs. 10% decline, HR = 2.2, 95% CI: 1.5-3.0). CONCLUSIONS We provide normative PEF data on a large iSGS patient cohort. The degree of PEF improvement immediately after surgery was not associated with a longer procedure-free interval. However, a 30% decline in PEF over 90 days was associated with elevated risk of disease recurrence. LEVEL OF EVIDENCE 2 Laryngoscope, 2021.
Collapse
Affiliation(s)
- Kyle Kimura
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, U.S.A
| | - Liping Du
- Vanderbilt Center for Quantitative Sciences, Vanderbilt-Ingram Cancer Center, Nashville, Tennessee, U.S.A
| | - Lynn D Berry
- Vanderbilt Center for Quantitative Sciences, Vanderbilt-Ingram Cancer Center, Nashville, Tennessee, U.S.A
| | - Li-Ching Huang
- Vanderbilt Center for Quantitative Sciences, Vanderbilt-Ingram Cancer Center, Nashville, Tennessee, U.S.A
| | - Sheau-Chiann Chen
- Vanderbilt Center for Quantitative Sciences, Vanderbilt-Ingram Cancer Center, Nashville, Tennessee, U.S.A
| | - David O Francis
- Division of Otolaryngology-Head and Neck Surgery, University of Wisconsin-Madison, Madison, Wisconsin, U.S.A
| | - Alexander Gelbard
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, U.S.A
| |
Collapse
|
28
|
Tullio M, Aliboni L, Pennati F, Carrinola R, Palleschi A, Aliverti A. Computational fluid dynamics of the airways after left-upper pulmonary lobectomy: A case study. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2021; 37:e3462. [PMID: 33826242 PMCID: PMC8365666 DOI: 10.1002/cnm.3462] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 03/17/2021] [Accepted: 04/04/2021] [Indexed: 06/12/2023]
Abstract
Pulmonary lobectomy is the gold standard intervention for lung cancer removal and consists of the complete resection of the affected lung lobe, which, coupled with the re-adaptation of the remaining thoracic structures, decreases the postoperative pulmonary function of the patient. Current clinical practice, based on spirometry and cardiopulmonary exercise tests, does not consider local changes, providing an average at-the-mouth estimation of residual functionality. Computational Fluid Dynamics (CFD) has proved a valuable solution to obtain quantitative and local information about airways airflow dynamics. A CFD investigation was performed on the airway tree of a left-upper pulmonary lobectomy patient, to quantify the effects of the postoperative alterations. The patient-specific bronchial models were reconstructed from pre- and postoperative CT scans. A parametric laryngeal model was merged to the geometries to account for physiological-like inlet conditions. Numerical simulations were performed in Fluent. The postoperative configuration revealed fluid dynamic variations in terms of global velocity (+23%), wall pressure (+48%), and wall shear stress (+39%). Local flow disturbances emerged at the resection site: a high-velocity peak of 4.92 m/s was found at the left-lower lobe entrance, with a local increase of pressure at the suture zone (18 Pa). The magnitude of pressure and secondary flows increased in the trachea and flow dynamics variations were observed also in the contralateral lung, causing altered lobar ventilation. The results confirmed that CFD is a patient-specific approach for a quantitative evaluation of fluid dynamics parameters and local ventilation providing additional information with respect to current clinical approaches.
Collapse
Affiliation(s)
- Marta Tullio
- Dipartimento di ElettronicaInformazione e Bioingegneria, Politecnico di MilanoMilanItaly
| | - Lorenzo Aliboni
- Dipartimento di ElettronicaInformazione e Bioingegneria, Politecnico di MilanoMilanItaly
| | - Francesca Pennati
- Dipartimento di ElettronicaInformazione e Bioingegneria, Politecnico di MilanoMilanItaly
| | - Rosaria Carrinola
- Thoracic Surgery and Lung Transplantation UnitFondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico of MilanMilanItaly
| | - Alessandro Palleschi
- Thoracic Surgery and Lung Transplantation UnitFondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico of MilanMilanItaly
- Department of Pathophysiology and TransplantationUniversity of MilanMilanItaly
| | - Andrea Aliverti
- Dipartimento di ElettronicaInformazione e Bioingegneria, Politecnico di MilanoMilanItaly
| |
Collapse
|
29
|
Zobaer T, Sutradhar A. Modeling the effect of tumor compression on airflow dynamics in trachea using contact simulation and CFD analysis. Comput Biol Med 2021; 135:104574. [PMID: 34175532 DOI: 10.1016/j.compbiomed.2021.104574] [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: 12/17/2020] [Revised: 06/08/2021] [Accepted: 06/10/2021] [Indexed: 10/21/2022]
Abstract
Malignant central airway obstruction can cause severe breathing difficulty in a patient that requires surgical intervention or stent implantation to alleviate it. A predictive model to identify the onset of this event as the central airway is progressively compressed by tumor growth will be helpful for clinicians to plan for medical intervention. We present such a model to simulate tumor compression of the trachea and the resulting change in airflow dynamics to estimate the level of stenosis that will cause severe breathing difficulties. A patient-specific model of trachea was generated from acquired Computed Tomography (CT) scans for the simulations. The compression of this trachea due to tumor growth is modeled using nonlinear contact simulations of ellipsoidal tumors with the trachea. Computational fluid dynamics (CFD) is employed to simulate the turbulent airflow during inhalation in the stenosed trachea. From the CFD simulated flow fields, the power loss due to airflow through the domain is calculated. The results show that when the obstruction in the trachea reaches 50%, compared to the undeformed model, the power loss can rise to more than 66%. A measure of breathing difficulty can be derived by correlating it with the power loss. Thus, medical intervention can be predicted based on the degree of stenosis if the induced power loss exceeds a threshold that causes severe breathing discomfort.
Collapse
Affiliation(s)
- Tareq Zobaer
- Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH, USA.
| | - Alok Sutradhar
- Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH, USA.
| |
Collapse
|
30
|
Frank-Ito DO, Cohen SM. Orally Inhaled Drug Particle Transport in Computerized Models of Laryngotracheal Stenosis. Otolaryngol Head Neck Surg 2021; 164:829-840. [PMID: 33045904 PMCID: PMC8294408 DOI: 10.1177/0194599820959674] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 08/25/2020] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Adjuvant management for laryngotracheal stenosis (LTS) may involve inhaled corticosteroids, but metered dose inhalers are designed for pulmonary drug delivery. Comprehensive analyses of drug particle deposition efficiency for orally inhaled corticosteroids in the stenosis of LTS subjects are lacking. STUDY DESIGN Descriptive research. SETTING Academic medical center. METHODS Anatomically realistic 3-dimensional reconstructions of the upper airway were created from computed tomography images of 4 LTS subjects-2 subglottic stenosis and 2 tracheal stenosis subjects. Computational fluid dynamics modeling was used to simulate airflow and drug particle transport in each airway. Three inhalation pressures were simulated, 10 Pa, 25 Pa, and 40 Pa. Drug particle transport was simulated for 100 to 950 nanoparticles and 1 to 50 micron-particles. Particles were released into the airway to mimic varying inhaler conditions with and without a spacer chamber. RESULTS Based on smallest to largest cross-sectional area ratio, the laryngotracheal stenotic segment shrunk by 57% and 47%, respectively, for subglottic stenosis models and by 53% for both tracheal stenosis models. Airflow resistance at the stenotic segment was lower in subglottic stenosis models than in tracheal stenosis models: 0.001 to 0.011 Pa.s/mL vs 0.024 to 0.082 Pa.s/mL. Drug depositions for micron-particles and nanoparticles at stenosis were 0.06% to 2.48% and 0.10% to 2.60% for subglottic stenosis and tracheal stenosis models, respectively. Particle sizes with highest stenotic deposition were 6 to 20 µm for subglottic stenosis models and 1 to 10 µm for tracheal stenosis models. CONCLUSION This study suggests that at most, 2.60% of inhaled drug particles deposit at the stenosis. Particle size ranges with highest stenotic deposition may not represent typical sizes emitted by inhalers.
Collapse
Affiliation(s)
- Dennis Onyeka Frank-Ito
- Department of Head and Neck Surgery & Communication Sciences, Duke University Medical Center, Durham, North Carolina, USA
- Computational Biology & Bioinformatics PhD Program, Duke University, Durham, North Carolina, USA
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina, USA
| | - Seth Morris Cohen
- Department of Head and Neck Surgery & Communication Sciences, Duke University Medical Center, Durham, North Carolina, USA
| |
Collapse
|
31
|
Gunatilaka CC, Schuh A, Higano NS, Woods JC, Bates AJ. The effect of airway motion and breathing phase during imaging on CFD simulations of respiratory airflow. Comput Biol Med 2020; 127:104099. [PMID: 33152667 PMCID: PMC7770091 DOI: 10.1016/j.compbiomed.2020.104099] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 10/07/2020] [Accepted: 10/26/2020] [Indexed: 01/21/2023]
Abstract
RATIONALE Computational fluid dynamics (CFD) simulations of respiratory airflow can quantify clinically useful information that cannot be obtained directly, such as the work of breathing (WOB), resistance to airflow, and pressure loss. However, patient-specific CFD simulations are often based on medical imaging that does not capture airway motion and thus may not represent true physiology, directly affecting those measurements. OBJECTIVES To quantify the variation of respiratory airflow metrics obtained from static models of airway anatomy at several respiratory phases, temporally averaged airway anatomies, and dynamic models that incorporate physiological motion. METHODS Neonatal airway images were acquired during free-breathing using 3D high-resolution MRI and reconstructed at several respiratory phases in two healthy subjects and two with airway disease (tracheomalacia). For each subject, five static (end expiration, peak inspiration, end inspiration, peak expiration, averaged) and one dynamic CFD simulations were performed. WOB, airway resistance, and pressure loss across the trachea were obtained for each static simulation and compared with the dynamic simulation results. RESULTS Large differences were found in the airflow variables between the static simulations at various respiratory phases and the dynamic simulation. Depending on the static airway model used, WOB, resistance, and pressure loss varied up to 237%, 200%, and 94% compared to the dynamic simulation respectively. CONCLUSIONS Changes in tracheal size and shape throughout the breathing cycle directly affect respiratory airflow dynamics and breathing effort. Simulations incorporating realistic airway wall dynamics most closely represent airway physiology; if limited to static simulations, the airway geometry must be obtained during the respiratory phase of interest for a given pathology.
Collapse
Affiliation(s)
- Chamindu C Gunatilaka
- Center for Pulmonary Imaging Research, Cincinnati Children's Hospital Medical Center, Cincinnati, USA; Department of Physics, University of Cincinnati, Cincinnati, USA
| | - Andreas Schuh
- Department of Computing, Imperial College London, London, UK
| | - Nara S Higano
- Center for Pulmonary Imaging Research, Cincinnati Children's Hospital Medical Center, Cincinnati, USA; Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, USA
| | - Jason C Woods
- Center for Pulmonary Imaging Research, Cincinnati Children's Hospital Medical Center, Cincinnati, USA; Department of Physics, University of Cincinnati, Cincinnati, USA; Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, USA; Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, USA
| | - Alister J Bates
- Center for Pulmonary Imaging Research, Cincinnati Children's Hospital Medical Center, Cincinnati, USA; Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, USA.
| |
Collapse
|
32
|
Yang MM, Higano NS, Gunatilaka CC, Hysinger EB, Amin RS, Woods JC, Bates AJ. Subglottic Stenosis Position Affects Work of Breathing. Laryngoscope 2020; 131:E1220-E1226. [PMID: 33280109 DOI: 10.1002/lary.29169] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 08/30/2020] [Accepted: 09/22/2020] [Indexed: 12/12/2022]
Abstract
OBJECTIVES Subglottic stenosis (SGS) is the most common type of laryngeal stenosis in neonates. SGS severity is currently graded based on percent area of obstruction (%AO) via the Myer-Cotton grading scale. However, patients with similar %AO can have widely different clinical courses. Computational fluid dynamics (CFD) based on patient-specific imaging can quantify the relationship between airway geometry and flow dynamics. We investigated the effect of %AO and axial position of SGS on work of breathing (WOB) in neonates using magnetic resonance imaging. METHODS High-resolution ultrashort echo-time MRI of the chest and airway was obtained in three neonatal patients with no suspected airway abnormalities; images were segmented to construct three-dimensional (3D) models of the neonatal airways. These models were then modified with virtual SGSs of varying %AO and axial positioning. CFD simulations of peak inspiratory flow were used to calculate patient-specific WOB in nonstenotic and artificially stenosed airway models. RESULTS CFD simulations demonstrated a relationship between stenosis geometry and WOB increase. WOB rapidly increased with %AO greater than about 70%. Changes in axial position could also increase WOB by approximately the same amount as a 10% increase in %AO. Increased WOB was particularly pronounced when the SGS lumen was misaligned with the glottic jet. CONCLUSION The results indicate a strong, predictable relationship between WOB and axial position of the stenotic lumen relative to the glottis, which has not been previously reported. These findings may lead to precision diagnosis and treatment prediction tools in individual patients. LEVEL OF EVIDENCE 4 Laryngoscope, 131:E1220-E1226, 2021.
Collapse
Affiliation(s)
- Max M Yang
- University of Cincinnati College of Medicine, Cincinnati, Ohio, U.S.A
| | - Nara S Higano
- Center for Pulmonary Imaging Research, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, U.S.A.,Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, U.S.A
| | - Chamindu C Gunatilaka
- Center for Pulmonary Imaging Research, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, U.S.A.,Department of Physics, University of Cincinnati, Cincinnati, Ohio, U.S.A
| | - Erik B Hysinger
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, U.S.A.,Department of Pediatrics, University of Cincinnati, Cincinnati, Ohio, U.S.A
| | - Raouf S Amin
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, U.S.A.,Department of Pediatrics, University of Cincinnati, Cincinnati, Ohio, U.S.A
| | - Jason C Woods
- Center for Pulmonary Imaging Research, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, U.S.A.,Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, U.S.A.,Department of Physics, University of Cincinnati, Cincinnati, Ohio, U.S.A.,Department of Pediatrics, University of Cincinnati, Cincinnati, Ohio, U.S.A.,Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, U.S.A
| | - Alister J Bates
- Center for Pulmonary Imaging Research, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, U.S.A.,Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, U.S.A.,Department of Pediatrics, University of Cincinnati, Cincinnati, Ohio, U.S.A
| |
Collapse
|
33
|
Gunatilaka CC, Higano NS, Hysinger EB, Gandhi DB, Fleck RJ, Hahn AD, Fain SB, Woods JC, Bates AJ. Increased Work of Breathing due to Tracheomalacia in Neonates. Ann Am Thorac Soc 2020; 17:1247-1256. [PMID: 32579852 PMCID: PMC7640633 DOI: 10.1513/annalsats.202002-162oc] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 06/24/2020] [Indexed: 11/20/2022] Open
Abstract
Rationale: Dynamic collapse of the tracheal lumen (tracheomalacia) occurs frequently in premature neonates, particularly in those with common comorbidities such as bronchopulmonary dysplasia. The tracheal collapse increases the effort necessary to breathe (work of breathing [WOB]). However, quantifying the increased WOB related to tracheomalacia has previously not been possible. Therefore, it is also not currently possible to separate the impact of tracheomalacia on patient symptoms from parenchymal abnormalities.Objectives: To measure the increase in WOB due to airway motion in individual subjects with and without tracheomalacia and with different types of respiratory support.Methods: Fourteen neonatal intensive care unit subjects not using invasive mechanical ventilation were recruited. In eight, tracheomalacia was diagnosed via clinical bronchoscopy, and six did not have tracheomalacia. Self-gated three-dimensional ultrashort-echo-time magnetic resonance imaging (MRI) was performed on each subject with clinically indicated respiratory support to obtain cine images of tracheal anatomy and motion during the respiratory cycle. The component of WOB due to resistance within the trachea was then calculated via computational fluid dynamics (CFD) simulations of airflow on the basis of the subject's anatomy, motion, and respiratory airflow rates. A second CFD simulation was performed for each subject with the airway held static at its largest (i.e., most open) position to determine the increase in WOB due to airway motion and collapse.Results: The tracheal-resistive component of WOB was increased because of airway motion by an average of 337% ± 295% in subjects with tracheomalacia and 24% ± 14% in subjects without tracheomalacia (P < 0.02). In the tracheomalacia group, subjects who were treated with continuous positive airway pressure (CPAP) using a RAM cannula expended less energy for breathing compared with the subjects who were breathing room air or on a high-flow nasal cannula.Conclusions: Neonatal subjects with tracheomalacia have increased energy expenditure compared with neonates with normal airways, and CPAP may be able to attenuate the increase in respiratory work. Subjects with tracheomalacia expend more energy on the tracheal-resistive component of WOB alone than nontracheomalacia patients expend on the resistive WOB for the entire respiratory system, according to previously reported values. CFD may be able to provide an objective measure of treatment response for children with tracheomalacia.
Collapse
Affiliation(s)
| | - Nara S. Higano
- Center for Pulmonary Imaging Research
- Division of Pulmonary Medicine, and
| | - Erik B. Hysinger
- Division of Pulmonary Medicine, and
- Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, Ohio; and
| | - Deep B. Gandhi
- Center for Pulmonary Imaging Research
- Department of Radiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio
| | - Robert J. Fleck
- Department of Radiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio
- Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, Ohio; and
| | | | - Sean B. Fain
- Department of Medical Physics
- Department of Radiology, and
- Department of Biomedical Engineering, University of Wisconsin–Madison, Madison, Wisconsin
| | - Jason C. Woods
- Center for Pulmonary Imaging Research
- Division of Pulmonary Medicine, and
- Department of Radiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio
- Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, Ohio; and
| | - Alister J. Bates
- Center for Pulmonary Imaging Research
- Division of Pulmonary Medicine, and
- Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, Ohio; and
| |
Collapse
|
34
|
Criner GJ, Eberhardt R, Fernandez-Bussy S, Gompelmann D, Maldonado F, Patel N, Shah PL, Slebos DJ, Valipour A, Wahidi MM, Weir M, Herth FJ. Interventional Bronchoscopy. Am J Respir Crit Care Med 2020; 202:29-50. [PMID: 32023078 DOI: 10.1164/rccm.201907-1292so] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
For over 150 years, bronchoscopy, especially flexible bronchoscopy, has been a mainstay for airway inspection, the diagnosis of airway lesions, therapeutic aspiration of airway secretions, and transbronchial biopsy to diagnose parenchymal lung disorders. Its utility for the diagnosis of peripheral pulmonary nodules and therapeutic treatments besides aspiration of airway secretions, however, has been limited. Challenges to the wider use of flexible bronchoscopy have included difficulty in navigating to the lung periphery, the avoidance of vasculature structures when performing diagnostic biopsies, and the ability to biopsy a lesion under direct visualization. The last 10-15 years have seen major advances in thoracic imaging, navigational platforms to direct the bronchoscopist to lung lesions, and the ability to visualize lesions during biopsy. Moreover, multiple new techniques have either become recently available or are currently being investigated to treat a broad range of airway and lung parenchymal diseases, such as asthma, emphysema, and chronic bronchitis, or to alleviate recurrent exacerbations. New bronchoscopic therapies are also being investigated to not only diagnose, but possibly treat, malignant peripheral lung nodules. As a result, flexible bronchoscopy is now able to provide a new and expanding armamentarium of diagnostic and therapeutic tools to treat patients with a variety of lung diseases. This State-of-the-Art review succinctly reviews these techniques and provides clinicians an organized approach to their role in the diagnosis and treatment of a range of lung diseases.
Collapse
Affiliation(s)
- Gerard J Criner
- Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania
| | - Ralf Eberhardt
- Pneumology and Critical Care Medicine, Thoraxklinik, University of Heidelberg, Heidelberg, Germany
| | | | - Daniela Gompelmann
- Pneumology and Critical Care Medicine, Thoraxklinik, University of Heidelberg, Heidelberg, Germany
| | - Fabien Maldonado
- Department of Medicine and Department of Thoracic Surgery, Vanderbilt University, Nashville, Tennessee
| | - Neal Patel
- Division of Pulmonary Medicine, Mayo Clinic, Jacksonville, Florida
| | - Pallav L Shah
- Respiratory Medicine at the Royal Brompton Hospital and National Heart & Lung Institute, Imperial College, London, United Kingdom
| | - Dirk-Jan Slebos
- Department of Pulmonary Diseases, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Arschang Valipour
- Department of Respiratory and Critical Care Medicine, Krankenhaus Nord, Vienna, Austria; and
| | - Momen M Wahidi
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, Duke University School of Medicine, Durham, North Carolina
| | - Mark Weir
- Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania
| | - Felix J Herth
- Pneumology and Critical Care Medicine, Thoraxklinik, University of Heidelberg, Heidelberg, Germany
| |
Collapse
|
35
|
Naunheim MR, Puka E, Choksawad K, Franco RA. Voice-Related Quality of Life in Idiopathic Subglottic Stenosis: Effect of Serial Intralesional Steroid Injections. Laryngoscope 2020; 131:366-369. [PMID: 32902886 DOI: 10.1002/lary.29059] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 08/04/2020] [Accepted: 08/10/2020] [Indexed: 11/08/2022]
Abstract
OBJECTIVES Serial intralesional steroid injection (SILSI) is an emerging treatment for idiopathic subglottic stenosis (ISGS), providing improvement in both subjective symptoms and objective airflow parameters. Little is known about how this airway remodeling affects the voice. This project analyzes subjective voice changes after SILSI and correlates these with airflow parameters. METHODS An ISGS database containing voice-related quality of life (V-RQOL) and spirometry (peak expiratory flow percentage [%PEF]) was retrospectively queried. Included were ISGS patients from 2009 to 2019 who had at least one SILSI treatment. Encounters without complete data were excluded. Differences between preprocedure and postprocedure metrics were calculated. Correlations and nonparametric bivariate analysis were performed. RESULTS Six hundred and seventeen steroid injections were performed in 55 patients, with an average of 3.5 years of follow-up. The average V-RQOL for all patient encounters, both pre- and postprocedure, showed little subjective dysphonia (83.5 of 100, 95% confidence interval [CI] 81.6 to 85.4). Considering SILSI-only treatments, there were 143 encounters with full data; of these, V-RQOL improved in 70 (49.0%), did not change in 40 (28.0%), and worsened in 33 (23.0%). Average V-RQOL improvement for the entire cohort was 1.9 points (95% CI: 0.7 to 3.2), which was small but significant (P = .0003). Across all data, there was a weak but significant correlation between PEF% and V-RQOL (ρ = 0.22, P = .0043). CONCLUSION SILSI was associated with improvement in subjective voice ratings in about half of patients, and the improvement correlated with improved airflow measurements. This research adds to the growing body of data regarding SILSI and suggests that further work on functional changes to the larynx with airway remodeling is imperative. LEVEL OF EVIDENCE 4 Laryngoscope, 131:366-369, 2021.
Collapse
Affiliation(s)
- Matthew R Naunheim
- Department of Otolaryngology - Head and Neck Surgery, Massachusetts Eye and Ear Infirmary; Department of Otolaryngology Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts, U.S.A
| | - Elefteria Puka
- Department of Otolaryngology - Head and Neck Surgery, Massachusetts Eye and Ear Infirmary; Department of Otolaryngology Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts, U.S.A
| | - Kanittha Choksawad
- Department of Otolaryngology - Head and Neck Surgery, Massachusetts Eye and Ear Infirmary; Department of Otolaryngology Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts, U.S.A
| | - Ramon A Franco
- Department of Otolaryngology - Head and Neck Surgery, Massachusetts Eye and Ear Infirmary; Department of Otolaryngology Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts, U.S.A
| |
Collapse
|
36
|
Fernández-Tena A, Barrio-Perotti R, Blanco-Marigorta E, Pandal-Blanco A. In silico prototype of a human lung with a single airway to predict particle deposition. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2020; 36:e3339. [PMID: 32237044 DOI: 10.1002/cnm.3339] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 02/13/2020] [Accepted: 03/14/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Experimental analyses of the flow of drug particles inside the human lung usually require that the patient be exposed to radiation and also of expensive equipment that often lack of enough accuracy. Numerical calculations based on CFD (computational fluid dynamics) have been proven to be a valuable tool to analyze flows in diverse applications. METHODS The complexity of the human lung disallows running calculations on complete lung models due to the large number of cells that would be required. In this work, using a proprietary methodology, particle deposition in the lung is simulated by reducing its multiple branches to a single path. RESULTS The tested flow rates were 18, 30, and 75 L min-1 , which are equivalent to different respiratory rates varying from light activity to heavy exercise. Most of the particles are accumulated in the upper airways, mainly at the mouth and also at the confluence of the larynx and the trachea (epiglottis), while the remaining particles travel across the lung. The reported procedure allowed simulating the operation of the entire lung by means of a single individual path. CONCLUSIONS The obtained calculations are in good agreement with the experimental results found in the technical literature, thus showing that the model can provide a realistic description of the lung operation, while avoiding high computational costs. Moreover, the calculations suggest that particle sizes above 15 μm and inspiratory flows higher than 30 L min-1 must be avoided in order to allow drug particles to reach the lower airways.
Collapse
Affiliation(s)
- Ana Fernández-Tena
- Facultad de Enfermería, Universidad de Oviedo. Instituto Nacional de Silicosis and GRUBIPU-ISPA, Asturias, Spain
| | - Raúl Barrio-Perotti
- Departamento de Energía, Universidad de Oviedo and GRUBIPU-ISPA, Asturias, Spain
| | | | - Adrián Pandal-Blanco
- Departamento de Energía, Universidad de Oviedo and GRUBIPU-ISPA, Asturias, Spain
| |
Collapse
|
37
|
Computational Evaluation of Surgical Design for Multisegmental Complex Congenital Tracheal Stenosis. BIOMED RESEARCH INTERNATIONAL 2020; 2020:3509814. [PMID: 32382545 PMCID: PMC7191439 DOI: 10.1155/2020/3509814] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 04/03/2020] [Accepted: 04/09/2020] [Indexed: 11/25/2022]
Abstract
Multisegmental complex congenital tracheal stenosis (CTS) is an uncommon but potentially life-threatening malformation of the airway. Staged surgery is indicated for the complex pathophysiology of the abnormal trachea. Surgical intervention to fix the stenotic segments may result in different postoperative outcomes. However, only few studies reported the design of surgical correction for multisegmental CTS. We used computer-aided design (CAD) to simulate surgical correction under different schemes to develop a patient-specific tracheal model with two segmental stenoses. Computational fluid dynamics (CFD) was used to compare the outcomes of different designs. Aerodynamic parameters of the trachea were evaluated. An obvious interaction was found between the two segments of stenosis in different surgical designs. The surgical corrective order of stenotic segments greatly affected the aerodynamic parameters and turbulence flows downstream of tracheal stenosis and upstream of the bronchus. Patient-specific studies using CAD and CFD minimize the risk of staged surgical correction and facilitate quantitative evaluation of surgical design for multiple segments of complex CTS.
Collapse
|
38
|
Poynot WJ, Gonthier KA, Dunham ME, Crosby TW. Classification of tracheal stenosis in children based on computational aerodynamics. J Biomech 2020; 104:109752. [PMID: 32224051 DOI: 10.1016/j.jbiomech.2020.109752] [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: 09/03/2019] [Revised: 02/12/2020] [Accepted: 03/13/2020] [Indexed: 10/24/2022]
Abstract
Tracheal stenosis is a health condition in which local narrowing of the upper trachea can cause breathing difficulties and increased incidence of infection, among other symptoms. Occurring most commonly due to intubation of infants, tracheal stenosis often requires corrective surgery. It is challenging to determine the most effective surgical strategy for a given patient as current clinical methods used to assess tracheal stenosis are simplistic and subjective, and are not rigorously based on aerodynamic considerations. This paper summarizes a non-invasive approach based on computational fluid dynamics (CFD) and medical imaging to establish relationships between trachea anatomy and inspiration performance. Though patient-specific CFD analysis has gained recent popularity, an objective of this study is to computationally formulate dimensionless analytical correlations between anatomy and performance that are applicable to any member of a class of patients and that can be interpreted within the context of the Myer-Cotton stenotic airway classification system. These correlations can provide aerodynamics-based insight for the development of more robust stenosis evaluation methods and may allow for time-efficient assessment of corrective surgical strategies.
Collapse
Affiliation(s)
- William J Poynot
- Department of Mechanical and Industrial Engineering, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Keith A Gonthier
- Department of Mechanical and Industrial Engineering, Louisiana State University, Baton Rouge, LA 70803, USA.
| | - Michael E Dunham
- Department of Otolaryngology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Tyler W Crosby
- Department of Otolaryngology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| |
Collapse
|
39
|
Xiao Q, Cetto R, Doorly DJ, Bates AJ, Rose JN, McIntyre C, Comerford A, Madani G, Tolley NS, Schroter R. Assessing Changes in Airflow and Energy Loss in a Progressive Tracheal Compression Before and After Surgical Correction. Ann Biomed Eng 2019; 48:822-833. [PMID: 31792705 PMCID: PMC6949211 DOI: 10.1007/s10439-019-02410-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 11/09/2019] [Indexed: 12/19/2022]
Abstract
The energy needed to drive airflow through the trachea normally constitutes a minor component of the work of breathing. However, with progressive tracheal compression, patient subjective symptoms can include severe breathing difficulties. Many patients suffer multiple respiratory co-morbidities and so it is important to assess compression effects when evaluating the need for surgery. This work describes the use of computational prediction to determine airflow resistance in compressed tracheal geometries reconstructed from a series of CT scans. Using energy flux analysis, the regions that contribute the most to airway resistance during inhalation are identified. The principal such region is where flow emerging from the zone of maximum constriction undergoes breakup and turbulent mixing. Secondary regions are also found below the tongue base and around the glottis, with overall airway resistance scaling nearly quadratically with flow rate. Since the anatomical extent of the imaged airway varied between scans-as commonly occurs with clinical data and when assessing reported differences between research studies-the effect of sub-glottic inflow truncation is considered. Analysis shows truncation alters the location of jet breakup and weakly influences the pattern of pressure recovery. Tests also show that placing a simple artificial glottis in the inflow to a truncated model can replicate patterns of energy loss in more extensive models, suggesting a means to assess sensitivity to domain truncation in tracheal airflow simulations.
Collapse
Affiliation(s)
- Qiwei Xiao
- Department of Aeronautics, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK
| | - Raul Cetto
- Department of Aeronautics, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK.,Department of Otolaryngology and Head and Neck Surgery, Imperial College Healthcare, St. Mary's Hospital, Praed St, London, W2 1NY, UK
| | - Denis J Doorly
- Department of Aeronautics, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK.
| | - Alister J Bates
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave, Cincinnati, OH, USA
| | - Jan N Rose
- Department of Aeronautics, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK
| | - Charlotte McIntyre
- Department of Aeronautics, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK.,Department of Otolaryngology and Head and Neck Surgery, Imperial College Healthcare, St. Mary's Hospital, Praed St, London, W2 1NY, UK
| | - Andrew Comerford
- Department of Aeronautics, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK
| | - Gitta Madani
- Department of Clinical Radiology, Imperial College Healthcare, St. Mary's Hospital, Praed St, London, W2 1NY, UK
| | - Neil S Tolley
- Department of Otolaryngology and Head and Neck Surgery, Imperial College Healthcare, St. Mary's Hospital, Praed St, London, W2 1NY, UK
| | - Robert Schroter
- Department of Bioengineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK
| |
Collapse
|
40
|
Harada A, Shimojima N, Shimotakahara A, Azuma S, Ishizuka Y, Tomita H, Hirobe S. Surgical indication for congenital tracheal stenosis complicated by pulmonary artery sling. J Thorac Dis 2019; 11:5474-5479. [PMID: 32030266 DOI: 10.21037/jtd.2019.11.31] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background Congenital tracheal stenosis (CTS) is a rare and life-threatening disease in children. Although pulmonary artery sling (PA sling) complicated by CTS sometimes occurs, there are few reports detailing the management of CTS with PA sling. The purpose of this retrospective study was to determine the appropriate indications for surgical intervention for CTS complicated by PA sling. Methods We evaluated 42 patients (19 males and 23 females) with the median age of 9.9±3.3 months (range, 5-34 months) with CTS complicated by PA sling who were treated at our hospital between 2005 and 2018. Twenty-eight patients received both a slide tracheoplasty and PA re-implantation, and 14 patients were managed conservatively for CTS. Among the latter, nine patients received PA re-implantation only, and five were managed conservatively without any surgery. We determined the surgical indications by retrospectively comparing the DLR value [tracheal diameter (mm)/stenotic length ratio], history of ventilator respiration, mortality rate, and post-operative course of patients at a single institution. Results The cut-off value for the DLR was determined to be 5.9 (sensitivity: 0.929, specificity: 0.714) by using the ROC curve (AUC 0.89, P<0.05). Conclusions A DLR value under 5.9 may serve as a new surgical indication for CTS complicated by PA sling.
Collapse
Affiliation(s)
- Atsushi Harada
- Department of Surgery, Tokyo Metropolitan Children's Medical Center, Tokyo, Japan
| | - Naoki Shimojima
- Department of Surgery, Tokyo Metropolitan Children's Medical Center, Tokyo, Japan
| | | | - Saya Azuma
- Department of Surgery, Tokyo Metropolitan Children's Medical Center, Tokyo, Japan
| | - Yoshiaki Ishizuka
- Department of Surgery, Tokyo Metropolitan Children's Medical Center, Tokyo, Japan
| | - Hirofumi Tomita
- Department of Surgery, Tokyo Metropolitan Children's Medical Center, Tokyo, Japan
| | - Seiichi Hirobe
- Department of Surgery, Tokyo Metropolitan Children's Medical Center, Tokyo, Japan
| |
Collapse
|
41
|
Yamoto M, Fukumoto K, Sekioka A, Iwazaki T, Sano K, Takahashi T, Nakaya K, Nomura A, Yamada Y, Urushihara N. Non-operative management of congenital tracheal stenosis: criteria by computed tomography. Pediatr Surg Int 2019; 35:1123-1130. [PMID: 31410561 DOI: 10.1007/s00383-019-04532-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/01/2019] [Indexed: 11/28/2022]
Abstract
OBJECTIVES Whether to perform surgical or conservative treatment for congenital tracheal stenosis (CTS) is controversial. Thus, the computed tomography (CT) criteria for conservative treatment of CTS were investigated. METHODS From 2005 to 2017, 28 CTS cases were included. The operative cases and preoperative death cases constituted the required intervention group (group I), and the non-operative surviving cases constituted the observation group (group O). The diameter of the tracheal narrowest part (DTNP) on CT was evaluated as a criterion for non-operative follow-up. RESULTS Chest CT was performed 19 times in 19 group I cases and 18 times in 9 group O cases. The median age of the patients that underwent CT scan examinations was 3.4 months (range 0-25 months) in group I and 22 months (range 0-60 months) in group O. The cut-off values of the non-operative criteria were 40.8% (AUC: 0.82, p < .01) normal for age of the trachea's narrowest part, and 41.6% normal for body weight (AUC: 0.92, p < .01), respectively. CONCLUSIONS DTNP is 40% and more of the normal diameter appears necessary for non-surgical management. The present study suggests that the criteria for conservative management of CTS are that the DTNP is not less than 40% of the normal tracheal diameter, with a few symptoms.
Collapse
Affiliation(s)
- Masaya Yamoto
- Department of Pediatric Surgery, Shizuoka Children's Hospital, 860 Urushiyama, Aoi-ku, Shizuoka, 420-8660, Japan.
| | - Koji Fukumoto
- Department of Pediatric Surgery, Shizuoka Children's Hospital, 860 Urushiyama, Aoi-ku, Shizuoka, 420-8660, Japan
| | - Akinori Sekioka
- Department of Pediatric Surgery, Shizuoka Children's Hospital, 860 Urushiyama, Aoi-ku, Shizuoka, 420-8660, Japan
| | - Teruo Iwazaki
- Department of Radiology, Shizuoka Children's Hospital, 860 Urushiyama, Aoi-ku, Shizuoka, 420-8660, Japan
| | - Kyouhei Sano
- Department of Radiology, Shizuoka Children's Hospital, 860 Urushiyama, Aoi-ku, Shizuoka, 420-8660, Japan
| | - Toshiaki Takahashi
- Department of Pediatric Surgery, Shizuoka Children's Hospital, 860 Urushiyama, Aoi-ku, Shizuoka, 420-8660, Japan
| | - Kengo Nakaya
- Department of Pediatric Surgery, Shizuoka Children's Hospital, 860 Urushiyama, Aoi-ku, Shizuoka, 420-8660, Japan
| | - Akiyoshi Nomura
- Department of Pediatric Surgery, Shizuoka Children's Hospital, 860 Urushiyama, Aoi-ku, Shizuoka, 420-8660, Japan
| | - Yutaka Yamada
- Department of Pediatric Surgery, Shizuoka Children's Hospital, 860 Urushiyama, Aoi-ku, Shizuoka, 420-8660, Japan
| | - Naoto Urushihara
- Department of Pediatric Surgery, Shizuoka Children's Hospital, 860 Urushiyama, Aoi-ku, Shizuoka, 420-8660, Japan
| |
Collapse
|
42
|
Fernández-Parra R, Pey P, Zilberstein L, Malvè M. Use of computational fluid dynamics to compare upper airway pressures and airflow resistance in brachycephalic, mesocephalic, and dolichocephalic dogs. Vet J 2019; 253:105392. [PMID: 31685131 DOI: 10.1016/j.tvjl.2019.105392] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 09/22/2019] [Accepted: 09/23/2019] [Indexed: 10/25/2022]
Abstract
Brachycephalic dog breeds are prone to breathing difficulties because of their upper airway anatomy. Several surgical techniques exist to correct anatomical pathologies and common surgical approaches aim to correct functional abnormalities in the nares and/or the soft palate. However, further research is needed to improve clinical outcomes. This study evaluated air pressure and airflow resistance in the upper airways and trachea in nine sedated, sternally recumbent dogs of different skull types (dolichocephalic, n=3; mesocephalic, n=3; brachycephalic, n=3). CT images were acquired from the nostrils to the caudal border of the lungs and geometrical reconstruction of the upper airway and trachea was performed. Analysis of computational fluid dynamics was performed using inspiratory flow adapted to bodyweight for each dog. Flow (L/min) and pressure (cmH2O) were computed for the entire upper airway and trachea. Resistance (cmH2O/L/min) was calculated using pressure differences between the nose, larynx, and trachea. In this pilot study, statistical comparisons were not performed. Pressure maps, airflow, and resistance were similar in dolichocephalic and mesocephalic breeds. Median pressure difference (3.76cmH2O) and resistance (0.154cmH2O/L/min) between the nose and larynx were numerically higher in brachycephalic dogs than in other breeds (0.45cmH2O and 0.016cmH2O/L/min, respectively). Median pressure difference (0.205cmH2O) and resistance (0.009cmH2O/L/min) between the larynx and trachea was numerically similar in all dogs, except for the English bulldog. The methodology used in this preliminary study to quantify airflow characteristics such as pressure and resistance could improve the understanding of brachycephalic obstruction airway syndrome.
Collapse
Affiliation(s)
- R Fernández-Parra
- Ecole Nationale Vétérinaire d'Alfort, 7 Avenue du General de Gaulle, Maisons-Alfort, Paris, 94704, France; Department of Small Animal Clinical Science, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive Saskatoon, SK S7N 5B4, Canada; Institut national de la santé et de la recherche médicale (INSERM), U955, Equipe 03, 51 avenue du Maréchal de Lattre de Tassigny, 94010, Créteil cedex, France.
| | - P Pey
- Antech Imaging Services, Fountain Valley, CA, 92708, USA; Department of Veterinary Medical Science, University of Bologna, Ozzano dell'Emilia, Italy
| | - L Zilberstein
- Ecole Nationale Vétérinaire d'Alfort, 7 Avenue du General de Gaulle, Maisons-Alfort, Paris, 94704, France
| | - M Malvè
- Department of Engineering, Public University of Navarre, Campus Arrosadía s/n, 31006, Pamplona, Spain; Aragon Institute of Engineering Research, University of Zaragoza, C/María de Luna s/n, 50018, Zaragoza, Spain; Centro de Investigación Biomédica en Red - Bioingeniería, Biomateriales y Nanomedicina, CIBER-BBN, C/Poeta Mariano Esquillor s/n, 50018, Zaragoza, Spain
| |
Collapse
|
43
|
Bates AJ, Schuh A, Amine-Eddine G, McConnell K, Loew W, Fleck RJ, Woods JC, Dumoulin CL, Amin RS. Assessing the relationship between movement and airflow in the upper airway using computational fluid dynamics with motion determined from magnetic resonance imaging. Clin Biomech (Bristol, Avon) 2019; 66:88-96. [PMID: 29079097 DOI: 10.1016/j.clinbiomech.2017.10.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 10/05/2017] [Accepted: 10/10/2017] [Indexed: 02/07/2023]
Abstract
BACKGROUND Computational fluid dynamics simulations of respiratory airflow in the upper airway reveal clinically relevant information, including sites of local resistance, inhaled particle deposition, and the effect of pathological constrictions. Unlike previous simulations, which have been performed on rigid anatomical models from static medical imaging, this work utilises ciné imaging during respiration to create dynamic models and more closely represent airway physiology. METHODS Airway movement maps were obtained from non-rigid image registration of fast-cine MRI and applied to high-spatial-resolution airway surface models. Breathing flowrates were recorded simultaneously with imaging. These data formed the boundary conditions for large eddy simulation computations of the airflow from exterior mask to bronchi. Simulations with rigid geometries were performed to demonstrate the resulting airflow differences between airflow simulations in rigid and dynamic airways. FINDINGS In the analysed rapid breathing manoeuvre, incorporating airway movement significantly changed the findings of the CFD simulations. Peak resistance increased by 19.8% and occurred earlier in the breath. Overall pressure loss decreased by 19.2%, and the proportion of flow in the mouth increased by 13.0%. Airway wall motion was out-of-phase with the air pressure force, demonstrating the presence of neuromuscular motion. In total, the anatomy did 25.2% more work on the air than vice versa. INTERPRETATIONS Realistic movement of the airway is incorporated into CFD simulations of airflow in the upper airway for the first time. This motion is vital to producing clinically relevant computational models of respiratory airflow and will allow novel analysis of dynamic conditions, such as sleep apnoea.
Collapse
Affiliation(s)
- Alister J Bates
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; Department of Bioengineering, Imperial College London, UK.
| | - Andreas Schuh
- Department of Computing, Imperial College London, UK
| | | | - Keith McConnell
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Wolfgang Loew
- Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Robert J Fleck
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Jason C Woods
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Charles L Dumoulin
- Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Raouf S Amin
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| |
Collapse
|
44
|
Abstract
The present study sought to assess the feasibility and effectiveness of double stent insertion as a means of managing combined malignant airway and superior vena cava (SVC) obstruction (CMASO).From July 2010 to January 2018, twelve consecutive patients with CMASO were treated by double stent insertion (airway and SVC stents) in our centers. We assessed data pertaining to both technical and clinical success rates, as well as to long-term patient outcomes.The use of double stents (12 airway stents and 19 SVC stents) was technically successful in all study subjects, with a 0 to 92 days period between the 2 stent insertions (mean 27.8 days). Patients did not show evidence of any procedure-related complications. Mean patient Hugh-Jones grades improved from 4.4 ± 0.5 before inserting the airway stent down to 1.2 ± 0.4 following this insertion (P < .001). Mean SVC pressure was reduced from 17.5 ± 2.8 mm Hg before the stent insertion down to 6.7 ± 1.4 mm Hg following this insertion (P < .001). Fifty-six days after insertion, a single patient experienced re-obstruction of their SVC stent. All patients died within the follow-up period, with a median survival time of 113 days for these 12 patients.This double stent insertion protocol is both effective and safe as a means of offering palliative care to those with CMASO.
Collapse
Affiliation(s)
- Jing-Yan Ren
- Department of Intensive Care Unit, Zaozhuang Hospital of Beijing Traditional Chinese Medical University, Zaozhuang
| | - Chi Cao
- Department of Radiology, Xuzhou Central Hospital, Xuzhou, China
| | - Yu-Fei Fu
- Department of Radiology, Xuzhou Central Hospital, Xuzhou, China
| | - Hong-Tao Du
- Department of Radiology, Xuzhou Central Hospital, Xuzhou, China
| |
Collapse
|
45
|
Rios G, Morrison RJ, Song Y, Fernando SJ, Wootten C, Gelbard A, Luo H. Computational Fluid Dynamics Analysis of Surgical Approaches to Bilateral Vocal Fold Immobility. Laryngoscope 2019; 130:E57-E64. [PMID: 30883777 DOI: 10.1002/lary.27925] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 01/04/2019] [Accepted: 02/20/2019] [Indexed: 11/06/2022]
Abstract
OBJECTIVES Bilateral vocal fold immobility (BVFI) is a rare and life-threatening condition in which both vocal folds are fixed, resulting in airway obstruction associated with life-threatening respiratory compromise. Treatment of BVFI is largely surgical and remains an unsatisfactory compromise between voice, breathing, and swallowing. No comparisons between currently employed techniques currently exist. We sought to employ computational fluid dynamics (CFD) modeling to delineate the optimal surgical approach for BVFI. METHODS Utilizing clinical computed tomography of BVFI subjects, coupled with image analytics employing CFD models and subject pulmonary function data, we compared the airflow features in the baseline pathologic states and changes seen between endoscopic cordotomy, endoscopic suture lateralization, and posterior cricoid expansion. RESULTS CFD modeling demonstrated that the greatest airflow velocity occurs through the posterior glottis on inspiration and anterior glottis on expiration in both the normal condition and in BVFI. Glottic airflow velocity and resistance were significantly higher in the BVFI condition compared to normal. Geometric indices (cross-sectional area of airway) were lower in posterior cricoid expansion surgery when compared to alternate surgical approaches. CFD measures (airflow velocity and resistance) improved with all surgical approaches but were superior with posterior cricoid expansion. CONCLUSION CFD modeling can provide discrete, quantitative assessment of the airflow through the laryngeal inlet, and offers insights into the pathophysiology and changes that occur after surgery for BVFI. LEVEL OF EVIDENCE NA. Laryngoscope, 130:E57-E64, 2020.
Collapse
Affiliation(s)
- Gabriel Rios
- Department of Mechanical Engineering, School of Engineering, Vanderbilt University, Nashville, Tennessee
| | - Robert J Morrison
- Department of Otolaryngology, School of Medicine, Vanderbilt University, Nashville, Tennessee.,Department of Otolaryngology-Head & Neck Surgery, Michigan Medicine, University of Michigan, Ann Arbor, Michigan, U.S.A
| | - Yi Song
- Department of Mechanical Engineering, School of Engineering, Vanderbilt University, Nashville, Tennessee
| | - Shanik J Fernando
- Department of Otolaryngology, School of Medicine, Vanderbilt University, Nashville, Tennessee
| | - Christopher Wootten
- Department of Otolaryngology, School of Medicine, Vanderbilt University, Nashville, Tennessee
| | - Alexander Gelbard
- Department of Otolaryngology, School of Medicine, Vanderbilt University, Nashville, Tennessee
| | - Haoxiang Luo
- Department of Mechanical Engineering, School of Engineering, Vanderbilt University, Nashville, Tennessee
| |
Collapse
|
46
|
Bates AJ, Schuh A, McConnell K, Williams BM, Lanier JM, Willmering MM, Woods JC, Fleck RJ, Dumoulin CL, Amin RS. A novel method to generate dynamic boundary conditions for airway CFD by mapping upper airway movement with non-rigid registration of dynamic and static MRI. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2018; 34:e3144. [PMID: 30133165 DOI: 10.1002/cnm.3144] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 06/21/2018] [Accepted: 08/12/2018] [Indexed: 06/08/2023]
Abstract
Computational fluid dynamics (CFD) simulations of airflow in the human airways have the potential to provide a great deal of information that can aid clinicians in case management and surgical decision making, such as airway resistance, energy expenditure, airflow distribution, heat and moisture transfer, and particle deposition, as well as the change in each of these due to surgical interventions. However, the clinical relevance of CFD simulations has been limited to date, as previous models either did not incorporate neuromuscular motion or any motion at all. Many common airway pathologies, such as obstructive sleep apnea (OSA) and tracheomalacia, involve large movements of the structures surrounding the airway, such as the tongue and soft palate. Airway wall motion may be due to many factors including neuromuscular motion, internal aerodynamic forces, and external forces such as gravity. Therefore, to realistically model these airway diseases, a method is required to derive the airway wall motion, whatever the cause, and apply it as a boundary condition to CFD simulations. This paper presents and validates a novel method of capturing in vivo motion of airway walls from magnetic resonance images with high spatiotemporal resolution, through a novel combination of non-rigid image, surface, and surface-normal-vector registration. Coupled with image-synchronous pneumotachography, this technique provides the necessary boundary conditions for dynamic CFD simulations of breathing, allowing the effect of the airway's complex motion to be calculated for the first time, in both normal subjects and those with conditions such as OSA.
Collapse
Affiliation(s)
- Alister J Bates
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Bioengineering, Imperial College London, UK
| | - Andreas Schuh
- Department of Computing, Imperial College London, UK
| | - Keith McConnell
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Brynne M Williams
- Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - J Matthew Lanier
- Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Matthew M Willmering
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Jason C Woods
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati, Cincinnati, OH, USA
- Departments of Radiology and Physics, University of Cincinnati, Cincinnati, OH, USA
| | - Robert J Fleck
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Radiology, University of Cincinnati, Cincinnati, OH, USA
| | - Charles L Dumoulin
- Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati, Cincinnati, OH, USA
| | - Raouf S Amin
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati, Cincinnati, OH, USA
| |
Collapse
|
47
|
Fluid dynamic assessment of tracheal flow in infants with congenital tracheal stenosis before and after surgery. Med Biol Eng Comput 2018; 57:837-847. [PMID: 30421262 DOI: 10.1007/s11517-018-1928-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 10/31/2018] [Indexed: 10/27/2022]
Abstract
Tracheal flow in infants with congenital tracheal stenosis (CTS) was numerically investigated using subject-specific airway models before and after reconstructive surgery. We quantified tracheal flow based on airway resistance during inhalation, and compared it between controls and patients before and after surgery. The airway resistance in each subject was assessed using geometrical parameters of the trachea: the minimum cross-sectional area Amin, the minimum cross-sectional area normalized by the standard deviation of the cross-sectional area Amin/σA, the area ratio of the minimum and maximum cross-sectional area Amin/Amax, and ratio of the normalized standard deviation of cross-sectional area to the mean cross-sectional area σA/Amean. Our numerical results demonstrated that such geometrical parameters could be used to assess the severity of CTS. Since subjects can be more clearly categorized as controls and most preoperative patients in terms of the airway resistance, a simulation using subject-specific airway models can lead us to a precise understanding of tracheal flow, and also provide knowledge about therapeutic decision. Our numerical results also demonstrated that significant surgical expansion of cross-sectional area did not help recover tracheal flow because of expansion loss. These results will be helpful not only when making therapeutic decisions about surgery but also when assessing quality of life in postoperative patients. Graphical abstract.
Collapse
|
48
|
Bourinet V, Thiam K, Guinde J, Laroumagne S, Dutau H, Astoul P. [Trans-vocal cord prostheses - preliminary experience treating benign laryngotracheal stenosis in adults]. Rev Mal Respir 2018; 36:49-56. [PMID: 30337136 DOI: 10.1016/j.rmr.2018.01.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 01/25/2018] [Indexed: 01/01/2023]
Abstract
INTRODUCTION Benign laryngotracheal stenosis is a rare pathology with multiple etiologies, the management of which is complex. This is because of the configuration and proximity of the larynx and the difficulty with surgical approaches, which are potentially mutilating, especially for the management of a benign disease. When surgery is challenging, iterative dilatations of the stricture or the fashioning of a definitive tracheotomy are therapeutic alternatives. Advances in rigid bronchoscopy and the evolution of prosthetic silicone material allow a new approach in the management of benign laryngotracheal stenosis, by placing flexible silicone prostheses which cover all the stenosis from the arytenoids to the trachea. This preliminary work aims to evaluate the feasibility, effectiveness, tolerance and complications of the implementation of this type of prosthesis. PATIENTS AND METHODS This is a retrospective single-centre study which analyzed the records of patients with symptomatic benign laryngotracheal stenosis who underwent placement of a transcordial prosthesis over a period of three years. The prosthesis used, inserted under general anesthesia during a rigid tube interventional bronchoscopy, was either a straight silicone prosthesis or a Montgomery T-tube for those with a pre-existing tracheotomy. RESULTS Six patients were included. Five are still alive, one patient died from a cause unrelated to the placement of the prosthesis. Four have no tracheostomy and two now have no transcordal prosthesis. The data collected on tolerance found, for three patients, two cases of minor aspiration and one case of transient cough. All patients had whispered voice dysphonia. We did not observe prosthesis migration or obstruction. CONCLUSION These preliminary results are encouraging. Transcordal prostheses in benign laryngotracheal stenosis have a complementary or alternative role compared to surgery with a palliative or even curative objective.
Collapse
Affiliation(s)
- V Bourinet
- Service d'oncologie thoracique, maladies de la Plèvre, pneumologie interventionnelle, hôpital Nord Aix-Marseille université, 13000 Marseille, France
| | - K Thiam
- Service d'oncologie thoracique, maladies de la Plèvre, pneumologie interventionnelle, hôpital Nord Aix-Marseille université, 13000 Marseille, France; Service de pneumo-oncologie, université Cheikh-Anta-Diop, CHU Fann, Dakar, Sénégal
| | - J Guinde
- Service d'oncologie thoracique, maladies de la Plèvre, pneumologie interventionnelle, hôpital Nord Aix-Marseille université, 13000 Marseille, France
| | - S Laroumagne
- Service d'oncologie thoracique, maladies de la Plèvre, pneumologie interventionnelle, hôpital Nord Aix-Marseille université, 13000 Marseille, France
| | - H Dutau
- Service d'oncologie thoracique, maladies de la Plèvre, pneumologie interventionnelle, hôpital Nord Aix-Marseille université, 13000 Marseille, France.
| | - P Astoul
- Service d'oncologie thoracique, maladies de la Plèvre, pneumologie interventionnelle, hôpital Nord Aix-Marseille université, 13000 Marseille, France; Aix-Marseille université, 13000 Marseille, France
| |
Collapse
|
49
|
Linhas R, Lima F, Coutinho D, Almeida J, Neves S, Oliveira A, Ladeira I, Lima R, Campainha S, Guimarães M. Role of the impulse oscillometry in the evaluation of tracheal stenosis. Pulmonology 2018; 24:224-230. [PMID: 29627402 DOI: 10.1016/j.pulmoe.2017.12.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 11/26/2017] [Accepted: 12/11/2017] [Indexed: 10/17/2022] Open
Abstract
INTRODUCTION AND OBJECTIVES Tracheal stenosis is a rare and challenging disease. Bronchoscopy is the gold standard for diagnosis and assessment but brings inherent risks. Spirometry is commonly used to access obstructions but is not always feasible due to patient related factors. We therefore considered impulse oscillometry (IOS) as a non-invasive method to quantify airway obstruction and its potential use for diagnosis and follow-up of tracheal stenosis. MATERIALS AND METHODS Patients with confirmed tracheal stenosis were recruited between January 1st, 2015 and December 31st, 2016. Before bronchoscopy, all subjects underwent IOS and spirometry; for patients submitted to interventional bronchoscopy the same techniques were also performed after the procedure. We assessed the correlation between IOS measurements and airway narrowing as well as between IOS and spirometry values. RESULTS Twenty-one patients were included. Tracheal narrowing was inversely correlated with X5% (r -0.442, p 0.045) and positively correlated with FEV1/PEF (r 0.467, p 0.033). The stenosis length was inversely correlated with PEF and PEF% (r -0.729, p=0.001 and r -0.707, p=0.002, respectively). There was a strong correlation between spirometric and IOS values. We did not find any significant differences between pre- and post-intervention IOS values for patients assessed after interventional bronchoscopy. CONCLUSIONS Our study showed a weak correlation between X5% and tracheal narrowing making it unclear whether IOS can be used for physiological assessment of patients with tracheal stenosis. Stenosis length correlated with PEF making it a potential predictor of successful surgical approach. The correlation between IOS and spirometric values makes IOS a potential alternative in patients with suspected tracheal stenosis who are not able to perform spirometry. Larger scale studies should clarify the role of IOS in this pathology.
Collapse
Affiliation(s)
- R Linhas
- Department of Pulmonology, Centro Hospitalar Vila Nova de Gaia/Espinho, EPE, Portugal.
| | - F Lima
- Department of Pulmonology, Centro Hospitalar Vila Nova de Gaia/Espinho, EPE, Portugal
| | - D Coutinho
- Bronchoscopy Unit, Centro Hospitalar de Vila Nova de Gaia/Espinho, EPE, Portugal
| | - J Almeida
- Bronchoscopy Unit, Centro Hospitalar de Vila Nova de Gaia/Espinho, EPE, Portugal
| | - S Neves
- Bronchoscopy Unit, Centro Hospitalar de Vila Nova de Gaia/Espinho, EPE, Portugal
| | - A Oliveira
- Bronchoscopy Unit, Centro Hospitalar de Vila Nova de Gaia/Espinho, EPE, Portugal
| | - I Ladeira
- Respiratory Physiopathology Laboratory, Centro Hospitalar de Vila Nova de Gaia/Espinho, EPE, Portugal
| | - R Lima
- Respiratory Physiopathology Laboratory, Centro Hospitalar de Vila Nova de Gaia/Espinho, EPE, Portugal
| | - S Campainha
- Bronchoscopy Unit, Centro Hospitalar de Vila Nova de Gaia/Espinho, EPE, Portugal
| | - M Guimarães
- Respiratory Physiopathology Laboratory, Centro Hospitalar de Vila Nova de Gaia/Espinho, EPE, Portugal
| |
Collapse
|
50
|
Regeneration of Tracheal Tissue in Partial Defects Using Porcine Small Intestinal Submucosa. Stem Cells Int 2018; 2018:5102630. [PMID: 29681948 PMCID: PMC5846444 DOI: 10.1155/2018/5102630] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 10/12/2017] [Accepted: 10/26/2017] [Indexed: 02/03/2023] Open
Abstract
Background Surgical correction of tracheal defects is a complex procedure when the gold standard treatment with primary end-to-end anastomosis is not possible. An alternative treatment may be the use of porcine small intestinal submucosa (SIS). It has been used as graft material for bioengineering applications and to promote tissue regeneration. The aim of this study was to evaluate whether SIS grafts improved tracheal tissue regeneration in a rabbit model of experimental tracheostomy. Methods Sixteen rabbits were randomized into two groups. Animals in the control group underwent only surgical tracheostomy, while animals in the SIS group underwent surgical tracheostomy with an SIS graft covering the defect. We examined tissues at the site of tracheostomy 60 days after surgery using histological analysis with hematoxylin and eosin (H&E) staining and analyzed the perimeter and area of the defect with Image-Pro® PLUS 4.5 (Media Cybernetics). Results The average perimeter and area of the defects were smaller by 15.3% (p = 0.034) and 21.8% (p = 0.151), respectively, in the SIS group than in the control group. Histological analysis revealed immature cartilage, pseudostratified ciliated epithelium, and connective tissue in 54.5% (p = 0.018) of the SIS group, while no cartilaginous regeneration was observed in the control group. Conclusions Although tracheal SIS engraftment could not prevent stenosis in a rabbit model of tracheal injury, it produced some remarkable changes, efficiently facilitating neovascularization, reepithelialization, and neoformation of immature cartilage.
Collapse
|