1
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Donovan GM, Wang CJ, Noble PB, Wang KCW. Adipose tissue in the small airways: How much is enough to drive functional changes? J Theor Biol 2024; 588:111835. [PMID: 38643962 DOI: 10.1016/j.jtbi.2024.111835] [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: 10/17/2023] [Revised: 03/27/2024] [Accepted: 04/17/2024] [Indexed: 04/23/2024]
Abstract
Obesity is a contributing factor to asthma severity; while it has long been understood that obesity is related to greater asthma burden, the mechanisms though which this occurs have not been fully elucidated. One common explanation is that obesity mechanically reduces lung volume through accumulation of adipose tissue external to the thoracic cavity. However, it has been recently demonstrated that there is substantial adipose tissue within the airway wall itself, and that the presence of adipose tissue within the airway wall is related to body mass index. This suggests the possibility of an additional mechanism by which obesity may worsen asthma, namely by altering the behaviour of the airways themselves. To this end, we modify Anafi & Wilson's classic model of the bistable terminal airway to incorporate adipose tissue within the airway wall in order to answer the question of how much adipose tissue would be required in order to drive substantive functional changes. This analysis suggests that adipose tissue within the airway wall on the order of 1%-2% of total airway cross-sectional area could be sufficient to drive meaningful changes, and further that these changes may interact with volume effects to magnify the overall burden.
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Affiliation(s)
- Graham M Donovan
- Department of Mathematics, University of Auckland, Auckland, 1142, New Zealand.
| | - Carolyn J Wang
- School of Human Sciences, The University of Western Australia, Crawley, 6009, Western Australia, Australia
| | - Peter B Noble
- School of Human Sciences, The University of Western Australia, Crawley, 6009, Western Australia, Australia
| | - Kimberley C W Wang
- School of Human Sciences, The University of Western Australia, Crawley, 6009, Western Australia, Australia; Telethon Kids Institute, The University of Western Australia, Nedlands, 6009, Western Australia, Australia
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2
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Sharpe AL, Reibman J, Oppenheimer BW, Goldring RM, Liu M, Shao Y, Bohart I, Kwok B, Weinstein T, Addrizzo-Harris D, Sterman DH, Berger KI. Role of small airway dysfunction in unexplained exertional dyspnoea. ERJ Open Res 2023; 9:00603-2022. [PMID: 37284422 PMCID: PMC10240305 DOI: 10.1183/23120541.00603-2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 03/01/2023] [Indexed: 06/08/2023] Open
Abstract
Background Isolated small airway abnormalities may be demonstrable at rest in patients with normal spirometry; however, the relationship of these abnormalities to exertional symptoms remains uncertain. This study uses an augmented cardiopulmonary exercise test (CPET) to include evaluation of small airway function during and following exercise to unmask abnormalities not evident with standard testing in individuals with dyspnoea and normal spirometry. Methods Three groups of subjects were studied: 1) World Trade Center (WTC) dust exposure (n=20); 2) Clinical Referral (n=15); and Control (n=13). Baseline evaluation included respiratory oscillometry. Airway function during an incremental workload CPET was assessed by: 1) tidal flow versus volume curves during exercise to assess for dynamic hyperinflation and expiratory flow limitation; and 2) post-exercise spirometry and oscillometry to evaluate for airway hyperreactivity. Results All subjects demonstrated normal baseline forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC). Dyspnoea was reproduced during CPET in WTC and Clinical Referral groups versus Control without abnormality in respiratory pattern and minute ventilation. Tidal flow-volume curves uncovered expiratory flow limitation and/or dynamic hyperinflation with increased prevalence in WTC and Clinical Referral versus Control (55%, 87% versus 15%; p<0.001). Post-exercise oscillometry uncovered small airway hyperreactivity with increased prevalence in WTC and Clinical Referral versus Control (40%, 47% versus 0%, p<0.05). Conclusions We uncovered mechanisms for exertional dyspnoea in subject with normal spirometry that was attributable to either small airway dysfunction during exercise and/or small airway hyperreactivity following exercise. The similarity of findings in WTC environmentally exposed and clinically referred cohorts suggests broad relevance for these evaluations.
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Affiliation(s)
- Alexis L. Sharpe
- Department of Medicine, Division of Pulmonary Critical Care and Sleep Medicine, NYU Grossman School of Medicine, New York, NY, USA
- André Cournand Pulmonary Physiology Laboratory, Bellevue Hospital, New York, NY, USA
| | - Joan Reibman
- Department of Medicine, Division of Pulmonary Critical Care and Sleep Medicine, NYU Grossman School of Medicine, New York, NY, USA
- Department of Environmental Medicine, NYU Grossman School of Medicine, New York, NY, USA
| | - Beno W. Oppenheimer
- Department of Medicine, Division of Pulmonary Critical Care and Sleep Medicine, NYU Grossman School of Medicine, New York, NY, USA
- André Cournand Pulmonary Physiology Laboratory, Bellevue Hospital, New York, NY, USA
| | - Roberta M. Goldring
- Department of Medicine, Division of Pulmonary Critical Care and Sleep Medicine, NYU Grossman School of Medicine, New York, NY, USA
- André Cournand Pulmonary Physiology Laboratory, Bellevue Hospital, New York, NY, USA
| | - Mengling Liu
- Department of Population Health, NYU Grossman School of Medicine, New York, NY, USA
| | - Yongzhao Shao
- Department of Population Health, NYU Grossman School of Medicine, New York, NY, USA
| | - Isaac Bohart
- Department of Medicine, Division of Pulmonary Critical Care and Sleep Medicine, NYU Grossman School of Medicine, New York, NY, USA
- André Cournand Pulmonary Physiology Laboratory, Bellevue Hospital, New York, NY, USA
| | - Benjamin Kwok
- Department of Medicine, Division of Pulmonary Critical Care and Sleep Medicine, NYU Grossman School of Medicine, New York, NY, USA
- André Cournand Pulmonary Physiology Laboratory, Bellevue Hospital, New York, NY, USA
| | - Tatiana Weinstein
- Department of Medicine, Division of Pulmonary Critical Care and Sleep Medicine, NYU Grossman School of Medicine, New York, NY, USA
- André Cournand Pulmonary Physiology Laboratory, Bellevue Hospital, New York, NY, USA
| | - Doreen Addrizzo-Harris
- Department of Medicine, Division of Pulmonary Critical Care and Sleep Medicine, NYU Grossman School of Medicine, New York, NY, USA
| | - Daniel H. Sterman
- Department of Medicine, Division of Pulmonary Critical Care and Sleep Medicine, NYU Grossman School of Medicine, New York, NY, USA
| | - Kenneth I. Berger
- Department of Medicine, Division of Pulmonary Critical Care and Sleep Medicine, NYU Grossman School of Medicine, New York, NY, USA
- André Cournand Pulmonary Physiology Laboratory, Bellevue Hospital, New York, NY, USA
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3
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Wang X, Liang Q, Li Z, Li F. Body Composition and COPD: A New Perspective. Int J Chron Obstruct Pulmon Dis 2023; 18:79-97. [PMID: 36788999 PMCID: PMC9922509 DOI: 10.2147/copd.s394907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 02/02/2023] [Indexed: 02/10/2023] Open
Abstract
The proportion of obese or overweight patients in COPD patients is increasing. Although BMI, WC and other easy to measure indicators have been proven to be related to the risk of COPD, they cannot accurately reflect the distribution and changes of body composition, ignoring the body composition (such as fat distribution, muscle content, water content, etc.), the relationship between it and disease risk may be missed. By analyzing the correlation between different body composition indexes and COPD patients, we can provide new research ideas for the prognosis judgment or intervention of COPD disease.
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Affiliation(s)
- Xin Wang
- Department of Integrated Pulmonology, Fourth Clinical Medical College of Xinjiang Medical University, Urumqi, Xinjiang, People’s Republic of China,Xinjiang National Clinical Research Base of Traditional Chinese Medicine, Urumqi, Xinjiang, People’s Republic of China
| | - Qianqian Liang
- Department of Integrated Pulmonology, Fourth Clinical Medical College of Xinjiang Medical University, Urumqi, Xinjiang, People’s Republic of China,Xinjiang National Clinical Research Base of Traditional Chinese Medicine, Urumqi, Xinjiang, People’s Republic of China
| | - Zheng Li
- Department of Integrated Pulmonology, Fourth Clinical Medical College of Xinjiang Medical University, Urumqi, Xinjiang, People’s Republic of China,Xinjiang National Clinical Research Base of Traditional Chinese Medicine, Urumqi, Xinjiang, People’s Republic of China,Xinjiang Key Laboratory of Respiratory Disease Research, Urumqi, Xinjiang, People’s Republic of China,Xinjiang Clinical Medical Research Center of Respiratory Obstructive Diseases, Urumqi, Xinjiang, People’s Republic of China,Correspondence: Zheng Li; Fengsen Li, Tel +86-13999297797; +86-13999980996, Email ;
| | - Fengsen Li
- Department of Integrated Pulmonology, Fourth Clinical Medical College of Xinjiang Medical University, Urumqi, Xinjiang, People’s Republic of China,Xinjiang National Clinical Research Base of Traditional Chinese Medicine, Urumqi, Xinjiang, People’s Republic of China,Xinjiang Key Laboratory of Respiratory Disease Research, Urumqi, Xinjiang, People’s Republic of China,Xinjiang Clinical Medical Research Center of Respiratory Obstructive Diseases, Urumqi, Xinjiang, People’s Republic of China
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4
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Neder JA, O'Donnell DE. The severe asthma-obesity conundrum: Consequences for exertional dyspnoea and exercise tolerance in men and women. Respirology 2022; 27:1002-1005. [PMID: 35977722 DOI: 10.1111/resp.14346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 08/08/2022] [Indexed: 12/13/2022]
Affiliation(s)
- J Alberto Neder
- Laboratory of Clinical Exercise Physiology and Respiratory Investigation Unit, Queen's University & Kingston General Hospital, Kingston, Ontario, Canada
| | - Denis E O'Donnell
- Laboratory of Clinical Exercise Physiology and Respiratory Investigation Unit, Queen's University & Kingston General Hospital, Kingston, Ontario, Canada
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5
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Kaminsky DA, Simpson SJ, Berger KI, Calverley P, de Melo PL, Dandurand R, Dellacà RL, Farah CS, Farré R, Hall GL, Ioan I, Irvin CG, Kaczka DW, King GG, Kurosawa H, Lombardi E, Maksym GN, Marchal F, Oostveen E, Oppenheimer BW, Robinson PD, van den Berge M, Thamrin C. Clinical significance and applications of oscillometry. Eur Respir Rev 2022; 31:31/163/210208. [PMID: 35140105 PMCID: PMC9488764 DOI: 10.1183/16000617.0208-2021] [Citation(s) in RCA: 56] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Accepted: 10/29/2021] [Indexed: 12/28/2022] Open
Abstract
Recently, “Technical standards for respiratory oscillometry” was published, which reviewed the physiological basis of oscillometric measures and detailed the technical factors related to equipment and test performance, quality assurance and reporting of results. Here we present a review of the clinical significance and applications of oscillometry. We briefly review the physiological principles of oscillometry and the basics of oscillometry interpretation, and then describe what is currently known about oscillometry in its role as a sensitive measure of airway resistance, bronchodilator responsiveness and bronchial challenge testing, and response to medical therapy, particularly in asthma and COPD. The technique may have unique advantages in situations where spirometry and other lung function tests are not suitable, such as in infants, neuromuscular disease, sleep apnoea and critical care. Other potential applications include detection of bronchiolitis obliterans, vocal cord dysfunction and the effects of environmental exposures. However, despite great promise as a useful clinical tool, we identify a number of areas in which more evidence of clinical utility is needed before oscillometry becomes routinely used for diagnosing or monitoring respiratory disease. This paper provides a current review of the interpretation, clinical significance and application of oscillometry in respiratory medicine, with special emphasis on limitations of evidence and suggestions for future research.https://bit.ly/3GQPViA
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Affiliation(s)
- David A Kaminsky
- Dept of Medicine, Pulmonary and Critical Care Medicine, University of Vermont, Larner College of Medicine, Burlington, VT, USA.,These authors have contributed equally to this manuscript
| | - Shannon J Simpson
- Children's Lung Health, Telethon Kids Institute, School of Allied Health, Curtin University, Perth, Australia.,These authors have contributed equally to this manuscript
| | - Kenneth I Berger
- Division of Pulmonary, Critical Care, and Sleep Medicine, NYU School of Medicine and André Cournand Pulmonary Physiology Laboratory, Belleuve Hospital, New York, NY, USA
| | - Peter Calverley
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | - Pedro L de Melo
- Dept of Physiology, Biomedical Instrumentation Laboratory, Institute of Biology and Faculty of Engineering, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ronald Dandurand
- Lakeshore General Hospital, Pointe-Claire, QC, Canada.,Montreal Chest Institute, Meakins-Christie Labs, Oscillometry Unit of the Centre for Innovative Medicine, McGill University Health Centre and Research Institute, and McGill University, Montreal, QC, Canada
| | - Raffaele L Dellacà
- Dipartimento di Elettronica, Informazione e Bioingegneria - DEIB, Politecnico di Milano University, Milan, Italy
| | - Claude S Farah
- Dept of Respiratory Medicine, Concord Repatriation General Hospital, Sydney, Australia
| | - Ramon Farré
- Unitat de Biofísica i Bioenginyeria, Facultat de Medicina, Universitat de Barcelona-IDIBAPS, Barcelona, Spain.,CIBER de Enfermedades Respiratorias, Madrid, Spain
| | - Graham L Hall
- Children's Lung Health, Telethon Kids Institute, School of Allied Health, Curtin University, Perth, Australia
| | - Iulia Ioan
- Dept of Paediatric Lung Function Testing, Children's Hospital, Vandoeuvre-lès-Nancy, France.,EA 3450 DevAH - Laboratory of Physiology, Faculty of Medicine, University of Lorraine, Vandoeuvre-lès-Nancy, France
| | - Charles G Irvin
- Dept of Medicine, Pulmonary and Critical Care Medicine, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - David W Kaczka
- Depts of Anaesthesia, Biomedical Engineering and Radiology, University of Iowa, Iowa City, IA, USA
| | - Gregory G King
- Dept of Respiratory Medicine and Airway Physiology and Imaging Group, Royal North Shore Hospital, St Leonards, Australia.,Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia
| | - Hajime Kurosawa
- Dept of Occupational Health, Tohoku University School of Medicine, Sendai, Japan
| | - Enrico Lombardi
- Paediatric Pulmonary Unit, Meyer Paediatric University Hospital, Florence, Italy
| | - Geoffrey N Maksym
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada
| | - François Marchal
- Dept of Paediatric Lung Function Testing, Children's Hospital, Vandoeuvre-lès-Nancy, France.,EA 3450 DevAH - Laboratory of Physiology, Faculty of Medicine, University of Lorraine, Vandoeuvre-lès-Nancy, France
| | - Ellie Oostveen
- Dept of Respiratory Medicine, Antwerp University Hospital and University of Antwerp, Belgium
| | - Beno W Oppenheimer
- Division of Pulmonary, Critical Care, and Sleep Medicine, NYU School of Medicine and André Cournand Pulmonary Physiology Laboratory, Belleuve Hospital, New York, NY, USA
| | - Paul D Robinson
- Woolcock Institute of Medical Research, Children's Hospital at Westmead, Sydney, Australia
| | - Maarten van den Berge
- Dept of Pulmonary Diseases, University of Groningen, University Medical Centre Groningen, Groningen, The Netherlands
| | - Cindy Thamrin
- Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia
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6
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Skloot GS, O'Connor-Chapman KL, Schechter CB, Markley DJ, Bates JHT. Forced expiratory time: a composite of airway narrowing and airway closure. J Appl Physiol (1985) 2020; 130:80-86. [PMID: 33090909 DOI: 10.1152/japplphysiol.00556.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Forced expiratory time (FET) is a spirometrically derived variable thought to reflect lung function, but its physiological basis remains poorly understood. We developed a mathematical theory of FET assuming a linear forced expiratory flow-volume profile that terminates when expiratory flow falls below a defined detection threshold. FET is predicted to correlate negatively with both FEV1 and FVC if variations in the rate of lung emptying (relative to normal) among individuals in a population exceed variations in the amount of lung emptying. We retrospectively determined FET pre- and postmethacholine challenge in 1,241 patients (818 had normal lung function, 137 were obstructed, and 229 were restricted) and examined its relationships to spirometric and demographic variables in both hyperresponsive and normoresponsive individuals. Mean FET was 9.6 ± 2.2 s in the normal group, 12.3 ± 3.0 s in those with obstruction, and 8.8 ± 1.9 s in those with restriction. FET was inversely related to FEV1/FVC in all groups, negatively related to FEV1 in the obstructed patients, and positively related to FVC in both the normal and restricted patients. There was no relationship with methacholine responsiveness. Overall, our theory of the relationship between FET to the spirometric indices is supported by these findings and potentially explains how FET is affected by sex, age, smoking status, and possibly body mass index.NEW & NOTEWORTHY Forced expiratory time (FET) has long been felt to reflect important physiological information about lung function but exactly how has never been clear. Here, we use a model analysis to assess the contributions of airway narrowing versus airway closure to FET in a population of individuals and find support for the theory that FET correlates positively with FEV1 if the amounts of lung emptying over a forced expiration vary from predicted values more than variations in the rates of lung emptying, whereas the correlation is negative in the opposite case.
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Affiliation(s)
- Gwen S Skloot
- The Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Kieley L O'Connor-Chapman
- The Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Clyde B Schechter
- Department of Family and Social Medicine, Albert Einstein College of Medicine, Bronx, New York
| | - Daniel J Markley
- The Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Jason H T Bates
- Department of Medicine, Larner College of Medicine, University of Vermont, Burlington, Vermont
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7
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Oppenheimer BW, Goldring RM, Soghier I, Smith D, Parikh M, Berger KI. Small airway function in obese individuals with self-reported asthma. ERJ Open Res 2020; 6:00371-2019. [PMID: 32714957 PMCID: PMC7369433 DOI: 10.1183/23120541.00371-2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 04/22/2020] [Indexed: 11/05/2022] Open
Abstract
Diagnosis of asthma in obese individuals frequently relies on clinical history, as airflow by spirometry may remain normal. This study hypothesised that obese subjects with self-reported asthma and normal spirometry will demonstrate distinct clinical characteristics, metabolic comorbidities and enhanced small airway dysfunction as compared with healthy obese subjects. Spirometry, plethysmography and oscillometry data pre/post-bronchodilator were obtained in 357 obese subjects in three groups as follows: no asthma group (n=180), self-reported asthma normal spirometry group (n=126), and asthma obstructed spirometry group (n=51). To assess the effects of obesity related to reduced lung volume, oscillometry measurements were repeated during a voluntary inflation to predicted functional residual capacity (FRC). Dyspnoea was equally prevalent in all groups. In contrast, cough, wheeze and metabolic comorbidities were more frequent in the asthma normal spirometry and asthma obstructed spirometry groups versus the no asthma group (p<0.05). Despite similar body size, oscillometry measurements demonstrated elevated R 5-20 (difference between resistance at 5 and 20 Hz) in the no asthma and asthma normal spirometry groups (0.19±0.12; 0.23±0.13 kPa/(L·s-1), p<0.05) but to a lesser degree than the asthma obstructed spirometry group (0.34±0.20 kPa/(L·s-1), p<0.05). Differences between groups persisted post-bronchodilator (p<0.05). Following voluntary inflation to predicted FRC, R 5-20 in the no asthma and asthma normal spirometry groups fell to similar values, indicating a reversible process (0.11±0.07; 0.12±0.08 kPa/(L·s-1), p=NS). Persistently elevated R 5-20 was seen in the asthma obstructed spirometry group, suggesting chronic inflammation and/or remodelling (0.17±0.11 kPa/(L·s-1), p<0.05). Thus, small airway abnormalities of greater magnitude than observations in healthy obese people may be an early marker of asthma in obese subjects with self-reported disease despite normal airflow. Increased metabolic comorbidities in these subjects may have provided a milieu that impacted airway function.
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Affiliation(s)
- Beno W Oppenheimer
- André Cournand Pulmonary Physiology Laboratory, Division of Pulmonary, Critical Care and Sleep, Dept of Medicine, Bellevue Hospital/New York University School of Medicine, New York, NY, USA
| | - Roberta M Goldring
- André Cournand Pulmonary Physiology Laboratory, Division of Pulmonary, Critical Care and Sleep, Dept of Medicine, Bellevue Hospital/New York University School of Medicine, New York, NY, USA
| | - Israa Soghier
- Jacobi Medical Center, Dept of Medicine, Division of Pulmonary Medicine, Albert Einstein College of Medicine, New York, NY, USA
| | - David Smith
- André Cournand Pulmonary Physiology Laboratory, Division of Pulmonary, Critical Care and Sleep, Dept of Medicine, Bellevue Hospital/New York University School of Medicine, New York, NY, USA
| | - Manish Parikh
- Bellevue Hospital Bariatric Center, Dept of Surgery, New York University School of Medicine, New York, NY, USA
| | - Kenneth I Berger
- André Cournand Pulmonary Physiology Laboratory, Division of Pulmonary, Critical Care and Sleep, Dept of Medicine, Bellevue Hospital/New York University School of Medicine, New York, NY, USA
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8
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Abstract
This article will discuss in detail the pathophysiology of asthma from the point of view of lung mechanics. In particular, we will explain how asthma is more than just airflow limitation resulting from airway narrowing but in fact involves multiple consequences of airway narrowing, including ventilation heterogeneity, airway closure, and airway hyperresponsiveness. In addition, the relationship between the airway and surrounding lung parenchyma is thought to be critically important in asthma, especially as related to the response to deep inspiration. Furthermore, dynamic changes in lung mechanics over time may yield important information about asthma stability, as well as potentially provide a window into future disease control. All of these features of mechanical properties of the lung in asthma will be explained by providing evidence from multiple investigative methods, including not only traditional pulmonary function testing but also more sophisticated techniques such as forced oscillation, multiple breath nitrogen washout, and different imaging modalities. Throughout the article, we will link the lung mechanical features of asthma to clinical manifestations of asthma symptoms, severity, and control. © 2020 American Physiological Society. Compr Physiol 10:975-1007, 2020.
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Affiliation(s)
- David A Kaminsky
- University of Vermont Larner College of Medicine, Burlington, Vermont, USA
| | - David G Chapman
- University of Technology Sydney, Sydney, New South Wales, Australia
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9
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King GG, Bates J, Berger KI, Calverley P, de Melo PL, Dellacà RL, Farré R, Hall GL, Ioan I, Irvin CG, Kaczka DW, Kaminsky DA, Kurosawa H, Lombardi E, Maksym GN, Marchal F, Oppenheimer BW, Simpson SJ, Thamrin C, van den Berge M, Oostveen E. Technical standards for respiratory oscillometry. Eur Respir J 2020; 55:13993003.00753-2019. [PMID: 31772002 DOI: 10.1183/13993003.00753-2019] [Citation(s) in RCA: 265] [Impact Index Per Article: 66.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Accepted: 10/15/2019] [Indexed: 12/11/2022]
Abstract
Oscillometry (also known as the forced oscillation technique) measures the mechanical properties of the respiratory system (upper and intrathoracic airways, lung tissue and chest wall) during quiet tidal breathing, by the application of an oscillating pressure signal (input or forcing signal), most commonly at the mouth. With increased clinical and research use, it is critical that all technical details of the hardware design, signal processing and analyses, and testing protocols are transparent and clearly reported to allow standardisation, comparison and replication of clinical and research studies. Because of this need, an update of the 2003 European Respiratory Society (ERS) technical standards document was produced by an ERS task force of experts who are active in clinical oscillometry research.The aim of the task force was to provide technical recommendations regarding oscillometry measurement including hardware, software, testing protocols and quality control.The main changes in this update, compared with the 2003 ERS task force document are 1) new quality control procedures which reflect use of "within-breath" analysis, and methods of handling artefacts; 2) recommendation to disclose signal processing, quality control, artefact handling and breathing protocols (e.g. number and duration of acquisitions) in reports and publications to allow comparability and replication between devices and laboratories; 3) a summary review of new data to support threshold values for bronchodilator and bronchial challenge tests; and 4) updated list of predicted impedance values in adults and children.
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Affiliation(s)
- Gregory G King
- Dept of Respiratory Medicine and Airway Physiology and Imaging Group, Royal North Shore Hospital and The Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia
| | - Jason Bates
- Dept of Medicine, Pulmonary/Critical Care Division, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - Kenneth I Berger
- Division of Pulmonary, Critical Care, and Sleep Medicine, NYU School of Medicine and André Cournand Pulmonary Physiology Laboratory, Belleuve Hospital, New York, NY, USA
| | - Peter Calverley
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | - Pedro L de Melo
- Institute of Biology and Faculty of Engineering, Department of Physiology, Biomedical Instrumentation Laboratory, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Raffaele L Dellacà
- Dipartimento di Elettronica, Informazione e Bioingegneria - DEIB, Politecnico di Milano University, Milano, Italy
| | - Ramon Farré
- Unitat de Biofísica i Bioenginyeria, Facultat de Medicina, Universitat de Barcelona-IDIBAPS, Barcelona, Spain.,CIBER de Enfermedades Respiratorias, Madrid, Spain
| | - Graham L Hall
- Children's Lung Health, Telethon Kids Institute, School of Physiotherapy and Exercise Science, Curtin University, Perth, Australia
| | - Iulia Ioan
- Dept of Pediatric Lung Function Testing, Children's Hospital, Vandoeuvre-lès-Nancy, France.,EA 3450 DevAH - Laboratory of Physiology, Faculty of Medicine, University of Lorraine, Vandoeuvre-lès-Nancy, France
| | - Charles G Irvin
- Dept of Medicine, Pulmonary/Critical Care Division, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - David W Kaczka
- Depts of Anesthesia, Biomedical Engineering and Radiology, University of Iowa, Iowa City, IA, USA
| | - David A Kaminsky
- Dept of Medicine, Pulmonary/Critical Care Division, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - Hajime Kurosawa
- Dept of Occupational Health, Tohoku University School of Medicine, Sendai, Japan
| | - Enrico Lombardi
- Pediatric Pulmonary Unit, Meyer Pediatric University Hospital, Florence, Italy
| | - Geoffrey N Maksym
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada
| | - François Marchal
- Dept of Pediatric Lung Function Testing, Children's Hospital, Vandoeuvre-lès-Nancy, France.,EA 3450 DevAH - Laboratory of Physiology, Faculty of Medicine, University of Lorraine, Vandoeuvre-lès-Nancy, France
| | - Beno W Oppenheimer
- Division of Pulmonary, Critical Care, and Sleep Medicine, NYU School of Medicine and André Cournand Pulmonary Physiology Laboratory, Belleuve Hospital, New York, NY, USA
| | - Shannon J Simpson
- Children's Lung Health, Telethon Kids Institute, School of Physiotherapy and Exercise Science, Curtin University, Perth, Australia
| | - Cindy Thamrin
- Dept of Respiratory Medicine and Airway Physiology and Imaging Group, Royal North Shore Hospital and The Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia
| | - Maarten van den Berge
- University of Groningen, University Medical Center Groningen, Dept of Pulmonary Diseases, Groningen, The Netherlands
| | - Ellie Oostveen
- Dept of Respiratory Medicine, Antwerp University Hospital and University of Antwerp, Antwerp, Belgium
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10
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Elliot JG, Donovan GM, Wang KCW, Green FHY, James AL, Noble PB. Fatty airways: implications for obstructive disease. Eur Respir J 2019; 54:13993003.00857-2019. [PMID: 31624112 DOI: 10.1183/13993003.00857-2019] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 09/05/2019] [Indexed: 11/05/2022]
Abstract
Epidemiological studies report that overweight or obese asthmatic subjects have more severe disease than those of a healthy weight. We postulated that accumulation of adipose tissue within the airway wall may occur in overweight patients and contribute to airway pathology. Our aim was to determine the relationship between adipose tissue within the airway wall and body mass index (BMI) in individuals with and without asthma.Transverse airway sections were sampled in a stratified manner from post mortem lungs of control subjects (n=15) and cases of nonfatal (n=21) and fatal (n=16) asthma. The relationship between airway adipose tissue, remodelling and inflammation was assessed. The areas of the airway wall and adipose tissue were estimated by point count and expressed as area per mm of basement membrane perimeter (Pbm). The number of eosinophils and neutrophils were expressed as area densities.BMI ranged from 15 to 45 kg·m-2 and was greater in nonfatal asthma cases (p<0.05). Adipose tissue was identified in the outer wall of large airways (Pbm >6 mm), but was rarely seen in small airways (Pbm <6 mm). Adipose tissue area correlated positively with eosinophils and neutrophils in fatal asthma (Pbm >12 mm, p<0.01), and with neutrophils in control subjects (Pbm >6 mm, p=0.04).These data show that adipose tissue is present within the airway wall and is related to BMI, wall thickness and the number of inflammatory cells. Therefore, the accumulation of airway adipose tissue in overweight individuals may contribute to airway pathophysiology.
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Affiliation(s)
- John G Elliot
- West Australian Sleep Disorders Research Institute, Dept of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital, Nedlands, Australia .,School of Human Sciences, The University of Western Australia, Crawley, Australia
| | - Graham M Donovan
- Dept of Mathematics, University of Auckland, Auckland, New Zealand
| | - Kimberley C W Wang
- School of Human Sciences, The University of Western Australia, Crawley, Australia.,Telethon Kids Institute, University of Western Australia, Nedlands, Australia
| | - Francis H Y Green
- Dept of Pathology and Laboratory Medicine, University of Calgary, Calgary, AB, Canada
| | - Alan L James
- West Australian Sleep Disorders Research Institute, Dept of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital, Nedlands, Australia.,School of Medicine and Pharmacology, The University of Western Australia, Nedlands, Australia
| | - Peter B Noble
- School of Human Sciences, The University of Western Australia, Crawley, Australia
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11
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Gazzola M, Khadangi F, Clisson M, Beaudoin J, Clavel MA, Bossé Y. Shortening of airway smooth muscle is modulated by prolonging the time without simulated deep inspirations in ovine tracheal strips. J Appl Physiol (1985) 2019; 127:1528-1538. [PMID: 31545157 DOI: 10.1152/japplphysiol.00423.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The shortening of airway smooth muscle (ASM) is greatly affected by time. This is because stimuli affecting ASM shortening, such as bronchoactive molecules or the strain inflicted by breathing maneuvers, not only alter quick biochemical processes regulating contraction but also slower processes that allow ASM to adapt to an ever-changing length. Little attention has been given to the effect of time on ASM shortening. The present study investigates the effect of changing the time interval between simulated deep inspirations (DIs) on ASM shortening and its responsiveness to simulated DIs. Excised tracheal strips from sheep were mounted in organ baths and either activated with methacholine or relaxed with isoproterenol. They were then subjected to simulated DIs by imposing swings in distending stress, emulating a transmural pressure from 5 to 30 cmH2O. The simulated DIs were intercalated by 2, 5, 10, or 30 min. In between simulated DIs, the distending stress was either fixed or oscillating to simulate tidal breathing. The results show that although shortening was increased by prolonging the interval between simulated DIs, the bronchodilator effect of simulated DIs (i.e., the elongation of the strip post- vs. pre-DI) was not affected, and the rate of re-shortening post-simulated DIs was decreased. As the frequency with which DIs are taken increases upon bronchoconstriction, our results may be relevant to typical alterations observed in asthma, such as an increased rate of re-narrowing post-DI.NEW & NOTEWORTHY The frequency with which patients with asthma take deep inspirations (DIs) increases during bronchoconstriction. This in vitro study investigated the effect of changing the time interval between simulated DIs on airway smooth muscle shortening. The results demonstrated that decreasing the interval between simulated DIs not only decreases shortening, which may be protective against excessive airway narrowing, but also increases the rate of re-shortening post-simulated DIs, which may contribute to the increased rate of re-narrowing post-DI observed in asthma.
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12
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Bokov P, Delclaux C. [The impact of obesity on respiratory function]. Rev Mal Respir 2019; 36:1057-1063. [PMID: 31522948 DOI: 10.1016/j.rmr.2019.07.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 07/06/2019] [Indexed: 01/28/2023]
Abstract
The respiratory impact of obesity can be both symptomatic (resting and exertional breathlessness) and functional (pulmonary function at rest and on exercise). The prevalence of breathlessness is increased in adult obese individuals, ∼50% at rest and ∼75% on exertion (mMRC score>0). Pulmonary function abnormalities in obese adults include reduced functional residual capacity (FRC) and expiratory residual volume (ERV), and less frequently reduced total lung capacity (a restrictive defect, with TLC below the 5th percentile of predicted is present in around 15% in severe obese adults), with normal residual volume (RV). Airflows are barely affected by obesity, but bronchial hyperresponsiveness (BHR) is very prevalent, which may be due to the loss of bronchoprotective effect of deep inspiration in obesity (mechanical pathophysiology of BHR). In children, the modifications of lung volumes seen are quite different: TLC is normal while FRC and RV are reduced, explaining the increase in FVC. FEV1/FVC is therefore reduced by obesity, without true airflow obstruction (dysanaptic growth). Resting oxygen consumption (V'O2) is increased due to obesity and normally increases with exercise. Maximum V'O2 is normal or weakly reduced in obese patients; on the other hand, the increase in respiratory load increases the oxygen cost of ventilation, which tends to be rapid, both at rest and during exertion. Finally, it should be noted that there is only limited statistical correlation between exercise dyspnoea and respiratory function abnormalities in obesity.
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Affiliation(s)
- P Bokov
- Service de physiologie pédiatrique, centre pédiatrique des pathologies du sommeil, hôpital Robert-Debré, AP-HP, 48, boulevard Sérurier, 75019 Paris, France; Université Paris-Diderot, Sorbonne Paris Cité, faculté de médecine, 75018 Paris, France; Inserm, UMR1141, 75019 Paris, France
| | - C Delclaux
- Service de physiologie pédiatrique, centre pédiatrique des pathologies du sommeil, hôpital Robert-Debré, AP-HP, 48, boulevard Sérurier, 75019 Paris, France; Université Paris-Diderot, Sorbonne Paris Cité, faculté de médecine, 75018 Paris, France; Inserm, UMR1141, 75019 Paris, France.
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13
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Kaminsky DA, Chapman DG, Holbrook JT, Henderson RJ, Sugar EA, Mastronarde J, Teague WG, Busk M, Sumino K, Dixon AE, Wise RA, Irvin CG. Older age and obesity are associated with increased airway closure in response to methacholine in patients with asthma. Respirology 2019; 24:638-645. [PMID: 30838750 DOI: 10.1111/resp.13496] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 11/29/2018] [Accepted: 01/02/2019] [Indexed: 01/31/2023]
Abstract
BACKGROUND AND OBJECTIVE The reduction of forced expiratory volume in 1 s (FEV1 ) in response to methacholine challenge in asthma may reflect two components: airway narrowing, assessed by the change in FEV1 /forced vital capacity (FVC), and airway closure, assessed by the change in FVC. The purpose of this study was to determine the degree and determinants of airway closure in response to methacholine in a large group of asthmatic patients participating in studies conducted by the American Lung Association-Airways Clinical Research Centers (ALA-ACRC). METHODS We used the methacholine challenge data from participants in five studies of the ALA-ACRC to determine the closing index, defined as the contribution of airway closure to the decrease in FEV1 , and calculated as %ΔFVC/%ΔFEV1 . RESULTS There were a total of 936 participants with asthma, among whom the median closing index was 0.67 relative to that of a published healthy population of 0.54. A higher closing index was associated with increased age (10-year increments) (0.04, 95% CI = 0.02, 0.05, P < 0.005) and obesity (0.07, 95% CI = 0.03, 0.10, P < 0.001). There was no association between the closing index and asthma control. CONCLUSION Our findings confirm that airway closure in response to methacholine occurs in a large, diverse population of asthmatic participants, and that increased airway closure is associated with older age and obesity. These findings suggest that therapies targeting airway closure may be important in patients with a high closing index.
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Affiliation(s)
- David A Kaminsky
- Pulmonary and Critical Care, University of Vermont Larner College of Medicine, Burlington, VT, USA
| | - David G Chapman
- Pulmonary and Critical Care, University of Vermont Larner College of Medicine, Burlington, VT, USA.,Translational Airways Group, School of Life Sciences, University of Technology Sydney, Sydney, NSW, Australia.,Airway Physiology and Imaging Group, Woolcock Institute of Medical Research, Sydney, NSW, Australia
| | - Janet T Holbrook
- Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Robert J Henderson
- Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Elizabeth A Sugar
- Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - John Mastronarde
- Division of Pulmonary Medicine, Providence Portland Medical Center, Portland, OR, USA
| | - William G Teague
- Division of Pediatric Respiratory Medicine and Allergy, University of Virginia, Charlottesville, VA, USA
| | - Michael Busk
- Division of Pulmonary Medicine, St. Vincent Hospital and Health Care Center, Inc., Indianapolis, IN, USA
| | - Kaharu Sumino
- Division of Pulmonary and Critical Care Medicine, Washington University, St. Louis, MO, USA
| | - Anne E Dixon
- Pulmonary and Critical Care, University of Vermont Larner College of Medicine, Burlington, VT, USA
| | - Robert A Wise
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Charles G Irvin
- Pulmonary and Critical Care, University of Vermont Larner College of Medicine, Burlington, VT, USA
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14
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Bossé Y. The Strain on Airway Smooth Muscle During a Deep Inspiration to Total Lung Capacity. JOURNAL OF ENGINEERING AND SCIENCE IN MEDICAL DIAGNOSTICS AND THERAPY 2019; 2:0108021-1080221. [PMID: 32328568 PMCID: PMC7164505 DOI: 10.1115/1.4042309] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/06/2018] [Indexed: 02/05/2023]
Abstract
The deep inspiration (DI) maneuver entices a great deal of interest because of its ability to temporarily ease the flow of air into the lungs. This salutary effect of a DI is proposed to be mediated, at least partially, by momentarily increasing the operating length of airway smooth muscle (ASM). Concerningly, this premise is largely derived from a growing body of in vitro studies investigating the effect of stretching ASM by different magnitudes on its contractility. The relevance of these in vitro findings remains uncertain, as the real range of strains ASM undergoes in vivo during a DI is somewhat elusive. In order to understand the regulation of ASM contractility by a DI and to infer on its putative contribution to the bronchodilator effect of a DI, it is imperative that in vitro studies incorporate levels of strains that are physiologically relevant. This review summarizes the methods that may be used in vivo in humans to estimate the strain experienced by ASM during a DI from functional residual capacity (FRC) to total lung capacity (TLC). The strengths and limitations of each method, as well as the potential confounders, are also discussed. A rough estimated range of ASM strains is provided for the purpose of guiding future in vitro studies that aim at quantifying the regulatory effect of DI on ASM contractility. However, it is emphasized that, owing to the many limitations and confounders, more studies will be needed to reach conclusive statements.
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Affiliation(s)
- Ynuk Bossé
- Université Laval, Faculty of Medicine, Department of Medicine, IUCPQ, M2694, Pavillon Mallet, Chemin Sainte-Foy, Québec, QC G1V 4G5, Canada e-mail:
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15
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Peters U, Subramanian M, Chapman DG, Kaminsky DA, Irvin CG, Wise RA, Skloot GS, Bates JHT, Dixon AE. BMI but not central obesity predisposes to airway closure during bronchoconstriction. Respirology 2019; 24:543-550. [PMID: 30694011 DOI: 10.1111/resp.13478] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Revised: 12/04/2018] [Accepted: 12/12/2018] [Indexed: 01/03/2023]
Abstract
BACKGROUND AND OBJECTIVE Obesity produces restrictive effects on lung function. We previously reported that obese patients with asthma exhibit a propensity towards small airway closure during methacholine challenge which improved with weight loss. We hypothesized that increased abdominal adiposity, a key contributor to the restrictive effects of obesity on the lung, mediates this response. This study investigates the effect of body mass index (BMI) versus waist circumference (WC) on spirometric lung function, sensitivity to airway narrowing and closure, and airway closure during bronchoconstriction in patients with asthma. METHODS Participants underwent spirometry and methacholine challenge. Sensitivity to airway closure and narrowing was assessed from the dose-response slopes of the forced vital capacity (FVC) and the ratio of forced expiratory volume in 1 s (FEV1 ) to FVC, respectively. Airway closure during bronchoconstriction (closing index) was computed as the percent reduction in FVC divided by the percent reduction in FEV1 at maximal bronchoconstriction. RESULTS A total of 116 asthmatic patients (56 obese) underwent methacholine challenge. Spirometric lung function was inversely related to WC (P < 0.05), rather than BMI. Closing index increased significantly during bronchoconstriction in obese patients and was related to increasing BMI (P = 0.01), but not to WC. Sensitivity to airway closure and narrowing was not associated with BMI or WC. CONCLUSION Although WC is associated with restrictive effects on baseline lung function, increased BMI, rather than WC, predisposes to airway closure during bronchoconstriction. These findings suggest that obesity predisposes to airway closure during bronchoconstriction through mechanisms other than simple mass loading.
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Affiliation(s)
- Ubong Peters
- Division of Pulmonary and Critical Care Medicine, Vermont Lung Center, University of Vermont Larner College of Medicine, Burlington, VT, USA
| | - Meenakumari Subramanian
- Division of Pulmonary and Critical Care Medicine, Vermont Lung Center, University of Vermont Larner College of Medicine, Burlington, VT, USA
| | - David G Chapman
- Division of Pulmonary and Critical Care Medicine, Vermont Lung Center, University of Vermont Larner College of Medicine, Burlington, VT, USA.,Translational Airways Group, University of Technology, Sydney, NSW, Australia.,Airway Physiology and Imaging Group, Woolcock Institute of Medical Research, Sydney, NSW, Australia
| | - David A Kaminsky
- Division of Pulmonary and Critical Care Medicine, Vermont Lung Center, University of Vermont Larner College of Medicine, Burlington, VT, USA
| | - Charles G Irvin
- Division of Pulmonary and Critical Care Medicine, Vermont Lung Center, University of Vermont Larner College of Medicine, Burlington, VT, USA
| | - Robert A Wise
- Department of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Gwen S Skloot
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jason H T Bates
- Division of Pulmonary and Critical Care Medicine, Vermont Lung Center, University of Vermont Larner College of Medicine, Burlington, VT, USA
| | - Anne E Dixon
- Division of Pulmonary and Critical Care Medicine, Vermont Lung Center, University of Vermont Larner College of Medicine, Burlington, VT, USA
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16
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Mailhot-Larouche S, Bossé Y. Interval between simulated deep inspirations on the dynamics of airway smooth muscle contraction in guinea pig bronchi. Respir Physiol Neurobiol 2018; 259:136-142. [PMID: 30217723 DOI: 10.1016/j.resp.2018.09.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 09/06/2018] [Accepted: 09/10/2018] [Indexed: 11/26/2022]
Abstract
A certain amount of time is required to achieve a maximal contraction from airway smooth muscle (ASM) and stretches of substantial magnitude, such as the ones imparted by deep inspirations (DIs), interfere with contraction. The duration of ASM contraction without interference may thus affect its shortening, its mechanical response to DIs and the overall toll it exerts on the respiratory system. In this study, the effect of changing the interval between DIs on the dynamics of ASM was examined in vitro. Isolated bronchi derived from guinea pigs were held isotonically and stimulated to both contract and relax, in a randomized order, in response to 10-5 M of methacholine and 10-6 M of isoproterenol, respectively. Interference to ASM was inflicted after 2, 5, 10 and 30 min in a randomized order, by imposing a stretch that simulated a DI. The shortening before the stretch, the stiffness before and during the stretch, the post-stretch elongation of ASM and the ensuing re-shortening were measured. These experiments were also performed in the presence of simulated tidal breathing achieved through force fluctuations. The results demonstrate that, with or without force fluctuations, increasing the interval between simulated DIs increased shortening and post-stretch elongation, but not stiffness and re-shortening. These time-dependent effects were not observed when ASM was held in the relaxed state. These findings may help understand to which extent ASM shortening and the regulatory effect of DI are affected by changing the interval between DIs. The potential consequences of these findings on airway narrowing are also discussed.
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17
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Bates JHT, Rajendran V. Mitigation of airways responsiveness by deep inflation of the lung. J Appl Physiol (1985) 2018; 124:1447-1455. [PMID: 29446713 DOI: 10.1152/japplphysiol.00051.2018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Stretching activated strips of airway smooth muscle (ASM) significantly affects both active force and stiffness due to a temporary reduction of the proportion of cycling myosin cross bridges that are bound to their actin binding sites. For the same reason, stretch applied to ASM in situ by a deep inflation (DI) of the lungs is one of the most potent means of reversing bronchoconstriction. When the DI is sufficiently large, however, and is applied while bronchoconstriction is in the process of developing, the subsequent depression in airway resistance is more persistent than can be attributed simply to temporary detachment of ASM cross bridges. In the present study, we use a computational model to demonstrate that this DI-induced ablation of airway responsiveness can be explained by a dose-dependent reduction in the number of cross bridges available to bind to actin when the ASM in the airway wall is stretched above a critical threshold strain and that this disruption of the contractile apparatus recovers over an order of magnitude longer time scale than that of the simple reattachment of unbound cross bridges. NEW & NOTEWORTHY The mechanisms by which deep inflation of the lung reverse bronchoconstriction and affect subsequent airway responsiveness have important potential implications for asthma, yet remain controversial. This study uses computational modeling to posit a mechanism by which sufficiently vigorous inflations applied during active bronchoconstriction not only transiently reverse bronchoconstriction, but also reduce subsequent airways responsiveness for a period of time. Fitting the model to published data in mice supports this notion.
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Affiliation(s)
- Jason H T Bates
- Department of Medicine, Larner College of Medicine, University of Vermont , Burlington, Vermont
| | - Vignesh Rajendran
- Department of Medicine, Larner College of Medicine, University of Vermont , Burlington, Vermont
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18
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Wasilewski NV, Fisher T, Turcotte SE, Fisher JT, Lougheed MD. Bronchoprotective effect of deep inspirations in cough variant asthma: A distinguishing feature in the spectrum of airway disease? Respir Physiol Neurobiol 2017; 257:55-64. [PMID: 28917529 DOI: 10.1016/j.resp.2017.09.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 08/30/2017] [Accepted: 09/06/2017] [Indexed: 11/18/2022]
Abstract
PURPOSE To assess the effect of deep inspirations (DIs) on airway behaviour in individuals with classic asthma (CA), cough variant asthma (CVA), and methacholine (MCh)-induced cough but normal airway sensitivity (COUGH) during bronchoprovocation. METHODS Twenty-five adults (18 female; 44.8 ± 12.3 years (Mean ± SD); n = 9 CA, n = 9 CVA, and n = 7 COUGH) completed two single-dose MCh challenges, with and without DIs. Bronchoprotection was assessed by comparing changes in bronchoconstriction (FEV1, FVC, FEV1/FVC, FEF50, FEF25-75), gas trapping (RV, RV/TLC) and impulse oscillometry (IOS) measurements. RESULTS The% changes in FEV1 with and without DIs were not significantly different within any group. Decreases in FEF50 and FEF25-75 were greater in CA (p = 0.041 and p = 0.029), decreases in FVC (% predicted) and FEV1/FVC(%) were less in CVA (p = 0.048 and p = 0.010), and increases in RV (L) and RV/TLC (% predicted) were less in COUGH (p = 0.007 and p = 0.028), respectively. No differences in IOS measurements were noted. CONCLUSIONS DIs triggered bronchoconstriction in CA, bronchoprotection in CVA, and prevented gas trapping in COUGH.
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Affiliation(s)
- Nastasia V Wasilewski
- Department of Medicine, Kingston General Hospital and Queen's University, Kingston, ON, Canada; Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Thomas Fisher
- Department of Medicine, Kingston General Hospital and Queen's University, Kingston, ON, Canada
| | - Scott E Turcotte
- Department of Medicine, Kingston General Hospital and Queen's University, Kingston, ON, Canada; Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - John T Fisher
- Department of Medicine, Kingston General Hospital and Queen's University, Kingston, ON, Canada; Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - M Diane Lougheed
- Department of Medicine, Kingston General Hospital and Queen's University, Kingston, ON, Canada; Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada.
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Abstract
Growth of the segment of the population older than 65 years has led to intensified interest in understanding the biology of aging. This article is focused on age-related alterations in lung structure that produce predictable changes in physiologic function, both at rest and during exercise. Increased insight into the physiology of the healthy aging lung should ultimately lead to improved methods of lung function assessment in the elderly (defined as those older than 65 years) as well as better understanding of the manifestations and possibly even the treatment of geriatric lung disease.
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Affiliation(s)
- Gwen S Skloot
- Department of Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box #1232, New York, NY, USA.
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20
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V Wasilewski N, Fisher T, Turcotte SE, Fisher JT, Lougheed MD. Bronchodilating effect of deep inspirations in asthma and chronic cough. J Appl Physiol (1985) 2016; 120:1018-28. [PMID: 26940655 DOI: 10.1152/japplphysiol.00737.2015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 03/01/2016] [Indexed: 01/15/2023] Open
Abstract
The pathophysiologic processes distinguishing classic asthma (CA), cough-variant asthma (CVA), and methacholine (MCh)-induced cough but normal airway sensitivity (COUGH) are inadequately understood and may be a result of differences in the ability to bronchodilate following a deep inspiration (DI). The purpose of this study was to compare the bronchodilating effect of DIs in individuals with CA, CVA, and COUGH using high-dose MCh. Individuals aged 18-65 yr with CA or suspected CVA completed high-dose MCh testing to a maximum change in forced expiratory volume in 1 s (FEV1) of 50% from baseline (MAX). Impulse oscillometry (IOS) measurements and partial and maximal-flow volume curves (used to calculate a DI index) were recorded at baseline and at each dose of MCh. Body plethysmography was performed at baseline and MAX. Twenty-eight subjects [25 women, 39.8 ± 11.9 yr (means ± SD)] were studied (n = 11 CA, n = 10 CVA, and n = 7 COUGH). At MAX, the percent change in FEV1 was greater in subjects with CA compared with those with CVA (P < 0.001) and COUGH (P < 0.001), and the percent change in forced vital capacity was greater in those with CA than with COUGH (P = 0.017). Subjects with CA and CVA developed dynamic hyperinflation and gas trapping. In subjects with CA and CVA, all IOS parameters were significantly increased from baseline to MAX, except for central respiratory resistance (R20). In individuals with COUGH, total respiratory resistance, R20, and resonant frequency were significantly increased from baseline. At MAX, the DI index was positive in all groups, suggesting preserved bronchodilation (CA, 0.67 ± 0.97; CVA, 0.51 ± 0.73; COUGH, 0.01 ± 0.36; P = 0.211). We conclude that the bronchodilating effect of DIs is preserved in individuals with CA, CVA, and borderline with COUGH; however, hyperinflation and gas trapping are avoided in subjects with COUGH alone.
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Affiliation(s)
- Nastasia V Wasilewski
- Department of Medicine, Kingston General Hospital and Queen's University, Kingston, Ontario, Canada; and Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Thomas Fisher
- Department of Medicine, Kingston General Hospital and Queen's University, Kingston, Ontario, Canada; and
| | - Scott E Turcotte
- Department of Medicine, Kingston General Hospital and Queen's University, Kingston, Ontario, Canada; and Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - John T Fisher
- Department of Medicine, Kingston General Hospital and Queen's University, Kingston, Ontario, Canada; and Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - M Diane Lougheed
- Department of Medicine, Kingston General Hospital and Queen's University, Kingston, Ontario, Canada; and Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
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21
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Müller PDT, Domingos H, Patusco LAP, Rapello GVG. Lung function and left ventricular hypertrophy in morbidly obese candidates for bariatric surgery. J Bras Pneumol 2015; 41:427-32. [PMID: 26578134 PMCID: PMC4635089 DOI: 10.1590/s1806-37132015000000031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 07/05/2015] [Indexed: 11/28/2022] Open
Abstract
OBJECTIVE To look for correlations between lung function and cardiac dimension variables in morbidly obese patients, in order to test the hypothesis that the relative size of the small airways is independently correlated with left ventricular hypertrophy. METHODS This was a retrospective study involving 192 medical records containing a clinical protocol employed in candidates for bariatric surgery between January of 2006 and December of 2010. RESULTS Of the 192 patients evaluated, 39 (10 males and 29 females) met the inclusion criteria. The mean BMI of the patients was 49.2 ± 7.6 kg/m2, and the mean age was 35.5 ± 7.7 years. The FEF25-75/FVC, % correlated significantly with left ventricular posterior wall thickness and relative left ventricular posterior wall thickness, those correlations remaining statistically significant (r = -0.355 and r = -0.349, respectively) after adjustment for weight, gender, and history of systemic arterial hypertension. Stepwise multivariate linear regression analysis showed that FVC and FEV1 were the major determinants of left ventricular mass (in grams or indexed to body surface area). CONCLUSIONS A reduction in the relative size of the small airways appears to be independently correlated with obesity-related cardiac hypertrophy, regardless of factors affecting respiratory mechanics (BMI and weight), gender, or history of systemic arterial hypertension. However, FEV1 and FVC might be important predictors of left ventricular mass in morbidly obese individuals.
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Affiliation(s)
- Paulo de Tarso Müller
- Laboratório de Fisiopatologia Respiratória - LAFIR - Universidade Federal de Mato Grosso do Sul, Campo Grande, Brasil
- Disciplina de Pneumologia, Faculdade de Medicina, Universidade Federal de Mato Grosso do Sul, Campo Grande, Brasil
| | - Hamilton Domingos
- Disciplina de Cardiologia, Faculdade de Medicina, Universidade Federal de Mato Grosso do Sul, Campo Grande, Brasil
| | - Luiz Armando Pereira Patusco
- Laboratório de Fisiopatologia Respiratória - LAFIR - Universidade Federal de Mato Grosso do Sul, Campo Grande, Brasil
- Disciplina de Pneumologia, Faculdade de Medicina, Universidade Federal de Mato Grosso do Sul, Campo Grande, Brasil
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Brazzale DJ, Pretto JJ, Schachter LM. Optimizing respiratory function assessments to elucidate the impact of obesity on respiratory health. Respirology 2015; 20:715-21. [PMID: 26033636 DOI: 10.1111/resp.12563] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 11/09/2014] [Accepted: 11/23/2014] [Indexed: 01/15/2023]
Abstract
There is an increasing prevalence of obesity worldwide and its impact on respiratory health is of significant concern. Obesity affects the respiratory system by several mechanisms, including by direct mechanical changes due to fat deposition in the chest wall, abdomen and upper airway, as well as via systemic inflammation. The increased mechanical load in obese individuals leads to reduced chest wall and lung compliance and increased work of breathing. While there is generally minimal effect on spirometric values, as body mass index increases, the expiratory reserve volume, and hence functional residual capacity, reduces, often approaching residual volume in more severe obesity. The majority of evidence however suggests that obese individuals free from lung disease have relatively normal gas exchange. The link between asthma and obesity, while initially unclear, is now recognized as being a distinct asthma phenotype. While studies investigating objective markers of asthma have shown that there is no association between obesity and airway hyper-responsiveness, a recent working group identified obesity as a major risk factor for the development of asthma in all demographic groups. Although the temptation may be to attribute obesity as the cause of dyspnoea in symptomatic obese patients, accurate respiratory assessment of these individuals is necessary. Lung function tests can confirm that any altered physiology are the known respiratory consequences of obesity. However, given that obesity causes minimal changes in lung function, significant abnormalities warrant further investigation. An important consideration is the knowledge that many of the respiratory physiology consequences of obesity are reversible by weight loss.
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Affiliation(s)
- Danny J Brazzale
- Department of Respiratory and Sleep Medicine, Austin Hospital, Melbourne, Victoria, Australia.,Institute for Breathing and Sleep, Austin Hospital, Melbourne, Victoria, Australia
| | - Jeffrey J Pretto
- Institute for Breathing and Sleep, Austin Hospital, Melbourne, Victoria, Australia.,Department of Respiratory and Sleep Medicine, John Hunter Hospital, Newcastle, New South Wales, Australia
| | - Linda M Schachter
- Centre for Obesity Research and Education, Monash University, Melbourne, Victoria, Australia
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Noble PB, McFawn PK, Mitchell HW, Ansell TK, Bates JHT, Seow CY, Brusasco V, Pellegrino R, Skloot G, Togias A, Scichilone N. Commentaries on Viewpoint: Airway smooth muscle and airway hyperresponsiveness in human asthma: have we chased the wrong horse? J Appl Physiol (1985) 2015; 116:1116-8. [PMID: 24736833 DOI: 10.1152/japplphysiol.00025.2014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Peter B Noble
- School of Anatomy, Physiology and Human Biology The University of Western Australia
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24
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Cooper DM, Leu SY, Galassetti P, Radom-Aizik S. Dynamic interactions of gas exchange, body mass, and progressive exercise in children. Med Sci Sports Exerc 2014; 46:877-86. [PMID: 24091992 DOI: 10.1249/mss.0000000000000180] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE Cardiopulmonary exercise testing (CPET) is increasingly used as a biomarker of fitness in children. Maximal or peak values remain the most common variables obtained in CPET, but these physiologically challenging high-intensity work rates (WR) are often not achieved. We hypothesized that interactions of gas exchange, heart rate (HR), and WR CPET variables (slopes) could yield useful mechanistic and clinical insights that might enhance the clinical utility of CPET in children. We further hypothesized that the dependence of the slope on body mass could be predicted by the first-principle analysis of body size and physiological response. METHODS One hundred and sixty-nine healthy participants (8-18 yr old, body mass index <95th percentile, 82 females) underwent dual x-ray absorptiometry scan to estimate lean body mass (LBM) and performed a ramp-type progressive cycle ergometry exercise protocol with a breath-by-breath measurement of gas exchange. Linear regression was used to calculate the slopes among VO2, VCO2, VE, HR, and WR. RESULTS ΔWR/ΔHR (r = 0.87) and ΔVO2/ΔHR (r = 0.96) were strongly correlated with VO2peak, whereas ΔVO2/ΔWR (r = 0.42) and ΔVE/ΔVCO2 (r = -0.51) were mildly correlated with peak values. LBM was more highly correlated with those slopes predicted to be body size dependent (P < 0.0001) compared with total body mass. CONCLUSIONS The data largely supported our original hypotheses. Unlike peak or maximal values, which are derived from no more than a few data points at the end of a progressive exercise test, the CPET slopes were calculated from a much larger data set obtained throughout the test. An analysis of these slopes might ultimately prove useful clinically and in research studies when peak values are not achieved.
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Affiliation(s)
- Dan M Cooper
- Department of Pediatrics, Pediatric Exercise Research Center, University of California, Irvine, CA
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25
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Desai AG, Togias A, Schechter C, Fisher B, Parow A, Skloot G. Peripheral airways dysfunction in obesity reflects increased bronchomotor tone. J Allergy Clin Immunol 2014; 135:820-2. [PMID: 25441295 DOI: 10.1016/j.jaci.2014.09.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 09/10/2014] [Accepted: 09/15/2014] [Indexed: 01/25/2023]
Affiliation(s)
- Alpa G Desai
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, State University of New York at Stony Brook, Stony Brook, NY.
| | - Alkis Togias
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Md
| | - Clyde Schechter
- Department of Family and Social Medicine, Albert Einstein College of Medicine, Bronx, NY
| | - Beth Fisher
- Division of Pulmonary, Critical Care, Sleep Medicine, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Aimee Parow
- Division of Pulmonary, Critical Care, Sleep Medicine, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Gwen Skloot
- Division of Pulmonary, Critical Care, Sleep Medicine, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY
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26
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Tanimura K, Hirai T, Sato S, Hasegawa K, Muro S, Kurosawa H, Mishima M. Comparison of two devices for respiratory impedance measurement using a forced oscillation technique: basic study using phantom models. J Physiol Sci 2014; 64:377-82. [PMID: 25034109 PMCID: PMC10717423 DOI: 10.1007/s12576-014-0329-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Accepted: 06/30/2014] [Indexed: 12/22/2022]
Abstract
Since commercial forced oscillation technique (FOT) devices became available, they have been widely used for physiological assessments, mainly of obstructive lung diseases. However, it is not known whether the impedance values measured with different devices are identical. In this study, two FOT devices-the impulse oscillometry system (IOS) and the MostGraph (MG)-were compared using phantom models. The resistance values varied up to 10% from estimated values in both devices. Additionally, there was a difference in frequency dependence for the resistance between the devices. The reactance values measured with MG were higher than those measured with IOS. The effects of ventilation on the measured impedance values were higher for IOS than for MG, especially at lower frequencies. We concluded that the devices do not always generate identical impedance values. Thus, differences between the devices should be taken into consideration when evaluating clinical data.
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Affiliation(s)
- Kazuya Tanimura
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, Kawahara 54, Shogoin, Sakyo-ku, Kyoto, 606-8507 Japan
| | - Toyohiro Hirai
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, Kawahara 54, Shogoin, Sakyo-ku, Kyoto, 606-8507 Japan
| | - Susumu Sato
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, Kawahara 54, Shogoin, Sakyo-ku, Kyoto, 606-8507 Japan
| | - Koichi Hasegawa
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, Kawahara 54, Shogoin, Sakyo-ku, Kyoto, 606-8507 Japan
| | - Shigeo Muro
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, Kawahara 54, Shogoin, Sakyo-ku, Kyoto, 606-8507 Japan
| | - Hajime Kurosawa
- Center for Environmental Conservation and Research Safety, Tohoku University Department of Occupational Health, Tohoku University School of Medicine, Sendai, Japan
| | - Michiaki Mishima
- Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, Kawahara 54, Shogoin, Sakyo-ku, Kyoto, 606-8507 Japan
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Chapman DG, Irvin CG, Kaminsky DA, Forgione PM, Bates JHT, Dixon AE. Influence of distinct asthma phenotypes on lung function following weight loss in the obese. Respirology 2014; 19:1170-7. [PMID: 25138203 DOI: 10.1111/resp.12368] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 02/03/2014] [Accepted: 06/30/2014] [Indexed: 12/17/2022]
Abstract
BACKGROUND AND OBJECTIVE There appears to be two distinct clinical phenotypes of obese patients with asthma-those with early-onset asthma and high serum IgE (TH2-high), and those with late-onset asthma and low serum IgE (TH2-low). The aim of the present study was to determine in the two phenotypes of obese asthma the effect of weight loss on small airway function. METHODS TH2-low (n = 8) and TH2-high (n = 5) obese asthmatics underwent methacholine challenge before and 12 months following bariatric surgery. Dose-response slopes as measures of sensitivity to airway closure and narrowing were measured as maximum % fall forced vital capacity (FVC) and forced expiratory volume in 1 s/FVC, respectively, divided by dose. Resting airway mechanics were measured by forced oscillation technique. RESULTS Weight loss reduced sensitivity to airway closure in TH 2-low but not TH2-high obese asthmatics (pre-post mean change ± 95% confidence interval: 1.8 ± 0.8 doubling doses vs -0.3 ± 1.7 doubling doses, P = 0.04). However, there was no effect of weight loss on the sensitivity to airway narrowing in either group (P = 0.8, TH2-low: 0.8 ± 1.0 doubling doses, TH2-high: -1.1 ± 2.5 doubling doses). In contrast, respiratory resistance (20 Hz) improved in TH2-high but not in TH2-low obese asthmatics (pre-post change median interquartile range: 1.5 (1.3-2.8) cmH₂O/L/s vs 0.6 (-1.8-0.8) cmH₂O/L/s, P = 0.03). CONCLUSIONS TH2-low obese asthmatics appear to be characterized by increased small airway responsiveness and abnormalities in resting airway function that may persist following weight loss. However, this was not the case for TH2-high obese asthmatics, highlighting the complex interplay between IgE status and asthma pathophysiology in obesity.
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Affiliation(s)
- David G Chapman
- Department of Medicine, University of Vermont College of Medicine, Burlington, Vermont, USA
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Lee CK, Tefera E, Colice G. The effect of obesity on outcomes in mechanically ventilated patients in a medical intensive care unit. ACTA ACUST UNITED AC 2014; 87:219-26. [PMID: 24457313 DOI: 10.1159/000357317] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 11/05/2013] [Indexed: 11/19/2022]
Abstract
BACKGROUND The effect of obesity on outcomes in critically ill patients requiring invasive mechanical ventilation in a medical intensive care unit (ICU) is uncertain. OBJECTIVES This study was intended to further explore the relationship between outcomes and obesity in patients admitted to a medical ICU who required invasive mechanical ventilation. METHODS All adult patients admitted to the medical ICU at Washington Hospital Center requiring intubation and invasive mechanical ventilation for at least 24 h between January 1 and December 31, 2009, were retrospectively studied. Patients were categorized as nonobese (BMI <30) and obese (BMI ≥30). The primary outcome measure was 30-day mortality following intubation. Secondary outcomes included ICU length of stay (LOS), hospital LOS and duration of mechanical ventilation. RESULTS There were 504 eligible patients: 306 nonobese and 198 (39%) obese. Obese patients had significantly higher rates of diabetes (43 vs. 30%, p = 0.004), hyperlipidemia (32 vs. 24%, p = 0.04), asthma (16 vs. 8%, p = 0.004) and obstructive sleep apnea requiring continuous positive airway pressure treatment (12 vs. 1%, p < 0.001). Nonobese patients had a significantly higher rate of HIV infection (10 vs. 5%, p = 0.05) and malignancy (21 vs. 13%, p = 0.03). There were no significant differences in mortality up to 30 days following intubation and secondary outcomes between obese and nonobese patients. Multivariate analysis using logistic regression showed no significant relationship between mortality rate at 30 days following intubation and obesity. Outcomes were similar for the black obese (n = 153) and nonobese (n = 228) patients and the obese (n = 85) and very obese (n = 113) patients. CONCLUSIONS Obesity did not influence outcomes in critically ill patients requiring invasive mechanical ventilation in a medical ICU. Black obese patients had similar outcomes to black nonobese patients, and very obese patients also had similar outcomes to obese patients.
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Del Rio-Navarro BE, Blandon-Vijil V, Escalante-Domínguez AJ, Berber A, Castro-Rodriguez JA. Effect of obesity on bronchial hyperreactivity among Latino children. Pediatr Pulmonol 2013; 48:1201-5. [PMID: 23897755 DOI: 10.1002/ppul.22823] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 03/23/2013] [Indexed: 01/09/2023]
Abstract
BACKGROUND The association between obesity and bronchial hyperreactivity (BHR) in children has not been fully demonstrated in cross-sectional or longitudinal studies, and no study has specifically addressed Latino children. METHODS A cross-sectional study of 450 children (10-18 years) from public schools was conducted in Mexico city. Among this group, 260 met the study criteria (no chronic respiratory illnesses, including asthma and rhinitis; no acute respiratory infections; and no tobacco-exposure or endocrine or body dysmorphic disorders), and 229 performed reproducible pulmonary function and methacholine challenge tests and were fully analyzed. RESULTS According to BMI percentiles, 40 were normal weight, 116 were obese, and 73 morbidly obese. Children in the morbidly obese group had significantly higher % FVC than those in the normal-weight group, and obese children had higher % PEF those in the morbidly obese and normal-weight groups. In the BHR methacholine challenge test, baseline FEV1 values among obese children were significantly lower than in the morbidly obese group. Using adjusted percentages for FEV1 , values were significantly lower among obese compared to morbidly obese children at metacholine concentrations of 0.25, 1, and 4 mg/ml. The proportion of positive BHR (PC20 ≤ 16 mg/ml) was higher in these two groups compared to normal-weight children (28.4%, 17.8%, and 12.5%, respectively), although differences were not significant. CONCLUSION Our findings show that obesity by itself is not a sufficient condition to alter airway responsiveness to methacholine in a group of adolescents.
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30
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Badier M, Guillot C, Delpierre S. Increased asymptomatic airway hyper-responsiveness in obese individuals. J Asthma 2013; 50:573-8. [PMID: 23574027 DOI: 10.3109/02770903.2013.793705] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Asymptomatic airway hyper-responsiveness (AHR) represents a risk of further accelerated decline in lung function, and of asthma. Due to the fact that rare and contradictory results exist concerning the impact of obesity on BHR, we re-assessed the prevalence of bronchial hyper-responsiveness (BHR) in a large cohort of 60 lean, 84 overweight, and 360 class 1-3 obese non-asthmatic individuals, by coupled plethysmography and spirometry. METHODS Baseline-specific airway conductance (SGaw) and spirometric values were measured and then a methacholine challenge testing (MCT) was performed and considered as positive when a ≥200% increase in specific airway resistance (SRaw = 1/SGaw) was reached. RESULTS Compared to lean and overweight subjects, obese subjects of any class presented about a twice more frequent AHR (∼ 50% in obese vs. 17 and 26% in lean and overweight subjects, respectively). However, the bronchial sensitivity (methacholine dose doubling SRaw) and the shape of the relationship between SGaw and cumulative methacholine doses were the same in the five groups of individuals. CONCLUSION The present data show a more frequent AHR in obese subjects. The association of plethysmography with spirometry, by taking into account the bronchodilator effect of the lung inflation (preceding the expiratory flow measurement) in some individuals, permitted to include some MCT which would have been otherwise excluded.
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Affiliation(s)
- Monique Badier
- Explorations Fonctionnelles Respiratoires, Pôle thoracique et cardiovasculaire, Hôpital Nord. Chemin des Bourrely. 13915 Marseille Cedex 20, France
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Risk factors for airway hyperresponsiveness in severely obese women. Respir Physiol Neurobiol 2013; 186:137-45. [PMID: 23376152 DOI: 10.1016/j.resp.2013.01.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 01/07/2013] [Accepted: 01/11/2013] [Indexed: 12/12/2022]
Abstract
Obesity affects airway diameter and tidal ventilation pattern, which could perturb smooth muscle function. The objective was to assess the pathophysiology of airway hyperresponsiveness in obesity while controlling for gastro-oesophageal reflux disease. Obese women (n=118, mean±SD BMI 46.1±6.8kg/m(-2)) underwent pulmonary function testing (including tidal ventilation monitoring and methacholine challenge) and oesogastro-duodenal fibroscopy. Fifty-seven women (48%, 95% CI: 39-57%) exhibited hyperresponsiveness (dose-response slope ≥2.39% decrease/μmol) that was independently and positively correlated with predicted % FRC, Raw0.5 and negatively correlated with sigh frequency during tidal ventilation. Obese women had an increased breathing frequency but a similar sigh frequency than healthy lean women (n=30). Twenty-two obese women (19%, 95% CI: 12-26%) were classified as asthmatics (hyperresponsiveness and suggestive symptoms) without confounding effect of gastro-oesophageal reflux disease. In conclusion, in women referred for bariatric surgery, unloading of bronchial smooth muscle (reduced airway calibre and sigh frequency) is associated with hyperresponsiveness.
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Abstract
Noninvasive physiological measurements are reviewed that have been reported in the literature with the specific aim being to study the small airways in lung disease. This has mostly involved at-the-mouth noninvasive measurement of flow, pressure or inert gas concentration, with the intent of deriving one or more indices that are representative of small airway structure and function. While these measurements have remained relatively low-tech, the effort and sophistication increasingly reside with the interpretation of such indices. When aspiring to derive information at the mouth about structural and mechanical processes occurring several airway generations away in a complex cyclically changing cul-de-sac structure, conceptual or semi-quantitative lung models can be valuable. Two assumptions that are central to small airway structure-function measurement are that of an average airway change at a given peripheral lung generation and of a parallel heterogeneity in airway changes. While these are complementary pieces of information, they can affect certain small airways tests in confounding ways. We critically analyzed the various small airway tests under review, while contending that negative outcomes of these tests are probably a true reflection of the fact that no change occurred in the small airways. Utmost care has been taken to not favor one technique over another, given that most current small airways tests still have room for improvement in terms of rendering their content more specific to the small airways. One way to achieve this could consist of the coupling of signals collected at the mouth to spatial information gathered from imaging in the same patient.
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Affiliation(s)
- Sylvia Verbanck
- Respiratory Division, University Hospital UZ Brussel, Brussels, Belgium.
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Mahadev S, Farah CS, King GG, Salome CM. Obesity, expiratory flow limitation and asthma symptoms. Pulm Pharmacol Ther 2012; 26:438-43. [PMID: 22609068 DOI: 10.1016/j.pupt.2012.05.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 03/30/2012] [Accepted: 05/07/2012] [Indexed: 02/06/2023]
Abstract
Obesity is associated with poor asthma control, but the reason for this is unclear. Reduction in operating lung volume, as occurs in obesity, and bronchoconstriction, as occurs in asthma, can increase expiratory flow limitation during tidal breathing (EFLt), which may in turn increase respiratory symptoms. The aim of this study was to determine the effect of obesity on EFLt at baseline and after bronchoconstriction in non-asthmatic and asthmatic subjects, and to determine the association between EFLt, and respiratory symptoms. Data from previously published studies in non-asthmatic and asthmatic subjects were reanalyzed using an index of EFLt derived from respiratory system reactance measured by the forced oscillation technique. The analysis showed that during bronchoconstriction both non-asthmatic and asthmatic obese individuals were more likely to develop EFLt than non-obese subjects, despite similar changes in FEV1. Furthermore the index of EFLt was a significant determinant of the severity of breathlessness during challenge in non-asthmatic subjects, and of asthma symptom control in asthmatic subjects following anti-inflammatory treatment. These studies suggest that the combination of bronchoconstriction and low resting lung volume increase the risk of EFLt, and that this altered response to bronchoconstriction may increase the severity of symptoms and lead to worse asthma control.
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Affiliation(s)
- Sriram Mahadev
- Woolcock Institute of Medical Research, 431 Glebe Pt Rd., Glebe, NSW 2037, Australia.
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34
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Cockcroft DW, Davis BE. Deep inhalation bronchoprotection. Ann Allergy Asthma Immunol 2012; 109:74-5. [PMID: 22727163 DOI: 10.1016/j.anai.2012.04.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Revised: 04/23/2012] [Accepted: 04/23/2012] [Indexed: 10/28/2022]
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