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Oueslati F, Saey D, Vézina FA, Nadreau É, Martin M, Maltais F. Acute Cardiopulmonary and Muscle Oxygenation Responses to Normocapnic Hyperpnea Exercise in COPD. Med Sci Sports Exerc 2022; 54:47-56. [PMID: 34334721 DOI: 10.1249/mss.0000000000002760] [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: 11/21/2022]
Abstract
PURPOSE This study aimed to investigate cardiorespiratory responses and intercostal muscle oxygenation during normocapnic hyperpnea exercise in chronic obstructive pulmonary disease (COPD). METHODS Twenty-two patients with COPD performed a cardiopulmonary cycling exercise test to assess peak oxygen consumption (V˙O2peak) and minute ventilation (V˙Epeak). They also performed a normocapnic hyperpnea exercise alone, at 50%-60% of V˙Epeak to exhaustion, using a respiratory device (Spirotiger) connected to a gas analyzer to monitor V˙O2, V˙E, and end-tidal CO2 partial pressure. Cardiac output, and intercostal and vastus lateralis muscle oxygenation were continuously measured during exercise using finger photoplethysmography and near-infrared spectroscopy, respectively. Arterial blood gases (arterial PCO2) and inspiratory capacity were obtained at rest and at the end of hyperpnea exercise. RESULTS The hyperpnea exercise lasted 576 ± 277 s at a V˙E of 34.5 ± 12.1 L·min-1 (58% ± 6% of V˙Epeak), a respiratory rate of 22 ± 4 breaths per minute, and a tidal volume of 1.43 ± 0.43 L. From rest to the end of hyperpnea exercise, V˙O2 increased by 0.35 ± 0.16 L·min-1 (P < 0.001), whereas end-tidal CO2 partial pressure and arterial PCO2 decreased by ~2 mm Hg (P = 0.031) and ~5 mm Hg (P = 0.002, n = 13), respectively. Moreover, inspiratory capacity fell from 2.44 ± 0.84 L at rest to 1.96 ± 0.59 L (P = 0.002). During the same period, heart rate and cardiac output increased from 69 ± 12 bpm and 4.94 ± 1.15 L·min-1 at rest to 87 ± 17 bpm (P = 0.002) and 5.92 ± 1.58 L·min-1 (P = 0.007), respectively. During hyperpnea exercise, intercostal deoxyhemoglobin and total hemoglobin increased by 14.26% ± 13.72% (P = 0.001) and 8.69% ± 12.49% (P = 0.003) compared with their resting value. However, during the same period, vastus lateralis oxygenation remained stable (P > 0.05). CONCLUSIONS In patients with COPD, normocapnic hyperpnea exercise provided a potent cardiorespiratory physiological stimulus, including dynamic hyperinflation, and increased intercostal deoxyhemoglobin consistent with enhanced requirement for muscle O2 extraction.
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Affiliation(s)
- Ferid Oueslati
- Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Québec, CANADA
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Ramsook AH, Molgat-Seon Y, Boyle KG, Mitchell RA, Puyat JH, Koehle MS, Sheel AW, Guenette JA. Reliability of diaphragm voluntary activation measurements in healthy adults. Appl Physiol Nutr Metab 2020; 46:247-256. [PMID: 32910865 DOI: 10.1139/apnm-2020-0221] [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] [Indexed: 11/22/2022]
Abstract
Voluntary activation can be used to assess central fatigue of the diaphragm after tasks such as exercise or inspiratory muscle loading. Cervical magnetic stimulation (CMS) of the phrenic nerves elicits an involuntary contraction, or twitch, of the diaphragm. This twitch is quantified based on a measure of transdiaphragmatic pressure and can be used to evaluate diaphragm contractile function and diaphragm voluntary activation (diaphragm-VA). The test-retest reliability of diaphragm-VA using CMS is currently unknown. Thirteen participants (4 male, 9 female; aged 25 ± 3 years) performed a series of interpolated twitch manoeuvres, which included a maximal inspiratory effort against a semi-occluded mouthpiece and 2 CMS-stimuli, 1 during the inspiratory manoeuvre and 1 after when the participant returned to functional residual capacity to quantify diaphragm-VA. Intraclass correlation coefficients (ICCs) and standard error of measurement (SEM) measured between-day and within-session reliability of diaphragm-VA, respectively. Maximal diaphragm-VA values were 91% (SD: 6; SEM: 3.9) and 92% (SD: 5; SEM: 2.2) during visits 1 and 2 (p = 0.68), respectively, and displayed "good" between-day reliability (ICC: 0.88; 95% confidence interval: 0.67-0.95; SEM: 2.7). Our results suggest that assessing diaphragm-VA using CMS is reliable in young healthy adults. Measuring diaphragm-VA may provide additional insight into the consequences and mechanisms of diaphragm fatigue. Novelty: Magnetic stimulation of the phrenic nerves can reliably measure voluntary activation of the diaphragm. Diaphragm voluntary activation can be used to provide additional insight into fatigability of the diaphragm.
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Affiliation(s)
- Andrew H Ramsook
- Department of Physical Therapy, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada.,Centre for Heart Lung Innovation, The University of British Columbia and St. Paul's Hospital, Vancouver, British Columbia, Canada
| | - Yannick Molgat-Seon
- Department of Physical Therapy, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada.,Centre for Heart Lung Innovation, The University of British Columbia and St. Paul's Hospital, Vancouver, British Columbia, Canada.,Department of Kinesiology and Applied Health, Faculty of Kinesiology and Applied Health, The University of Winnipeg, Winnipeg, Manitoba, Canada
| | - Kyle G Boyle
- Department of Physical Therapy, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada.,Centre for Heart Lung Innovation, The University of British Columbia and St. Paul's Hospital, Vancouver, British Columbia, Canada
| | - Reid A Mitchell
- Department of Physical Therapy, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada.,Centre for Heart Lung Innovation, The University of British Columbia and St. Paul's Hospital, Vancouver, British Columbia, Canada
| | - Joseph H Puyat
- Centre for Health Evaluation and Outcome Services, Providence Health Care Research Institute, The University of British Columbia and St. Paul's Hospital, Vancouver, British Columbia, Canada
| | - Michael S Koehle
- School of Kinesiology, Faculty of Education, The University of British Columbia, Vancouver, British Columbia, Canada.,Department of Family Practice, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada
| | - A William Sheel
- Centre for Heart Lung Innovation, The University of British Columbia and St. Paul's Hospital, Vancouver, British Columbia, Canada.,School of Kinesiology, Faculty of Education, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Jordan A Guenette
- Department of Physical Therapy, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada.,Centre for Heart Lung Innovation, The University of British Columbia and St. Paul's Hospital, Vancouver, British Columbia, Canada.,School of Kinesiology, Faculty of Education, The University of British Columbia, Vancouver, British Columbia, Canada
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Neder JA, Marillier M, Bernard AC, James MD, Milne KM, O’Donnell DE. The Integrative Physiology of Exercise Training in Patients with COPD. COPD 2019; 16:182-195. [DOI: 10.1080/15412555.2019.1606189] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- J. Alberto Neder
- Respiratory Investigation Unit and Laboratory of Clinical Exercise Physiology, Division of Respirology, Department of Medicine, Kingston Health Science Center and Queen’s University, Kingston, Ontario, Canada
| | - Mathieu Marillier
- Respiratory Investigation Unit and Laboratory of Clinical Exercise Physiology, Division of Respirology, Department of Medicine, Kingston Health Science Center and Queen’s University, Kingston, Ontario, Canada
| | - Anne-Catherine Bernard
- Respiratory Investigation Unit and Laboratory of Clinical Exercise Physiology, Division of Respirology, Department of Medicine, Kingston Health Science Center and Queen’s University, Kingston, Ontario, Canada
| | - Matthew D. James
- Respiratory Investigation Unit and Laboratory of Clinical Exercise Physiology, Division of Respirology, Department of Medicine, Kingston Health Science Center and Queen’s University, Kingston, Ontario, Canada
| | - Kathryn M. Milne
- Respiratory Investigation Unit and Laboratory of Clinical Exercise Physiology, Division of Respirology, Department of Medicine, Kingston Health Science Center and Queen’s University, Kingston, Ontario, Canada
- Clinician Investigator Program, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Denis E. O’Donnell
- Respiratory Investigation Unit and Laboratory of Clinical Exercise Physiology, Division of Respirology, Department of Medicine, Kingston Health Science Center and Queen’s University, Kingston, Ontario, Canada
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Laveneziana P, Niérat MC, LoMauro A, Aliverti A. A case of unexplained dyspnoea: when lung function testing matters! Breathe (Sheff) 2018; 14:325-332. [PMID: 30519301 PMCID: PMC6269186 DOI: 10.1183/20734735.025018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
“Lung function corner” articles in Breathe present the results of a lung function test and the authors then debate the interpretation, including potential controversies and background from the literature. As section editors of this newly created section of Breathe, we felt it was important to write the first article, which highlights the usefulness of lung function testing in guiding clinical diagnosis especially in difficult cases such the one we discuss here. Diverse methods are available for assessment of the respiratory muscles; the technique used should be tailored to the question posed.http://ow.ly/ChbX30m91bt
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Affiliation(s)
- Pierantonio Laveneziana
- Sorbonne Université, INSERM, UMRS1158 Neurophysiologie respiratoire expérimentale et clinique, Paris, France.,AP-HP, Groupe Hospitalier Pitié-Salpêtrière Charles Foix, Service des Explorations Fonctionnelles de la Respiration, de l'Exercice et de la Dyspnée du Département R3S, Paris, France
| | - Marie-Cécile Niérat
- Sorbonne Université, INSERM, UMRS1158 Neurophysiologie respiratoire expérimentale et clinique, Paris, France
| | - Antonella LoMauro
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy
| | - Andrea Aliverti
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy
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Wang L, Gu W, Shi Y, Chen Y, Tan Y. Protective effects of astragaloside IV on IL-8-treated diaphragmatic muscle cells. Exp Ther Med 2018; 17:519-524. [PMID: 30651831 DOI: 10.3892/etm.2018.6940] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 09/12/2018] [Indexed: 12/13/2022] Open
Abstract
The diaphragmatic fatigue that results from airflow obstruction is associated with the severe morbidity of patients with chronic obstructive pulmonary disease. Astragaloside IV (AS-IV) has antioxidant, anti-apoptotic and anti-inflammatory activities in various cell types. The present study aimed to evaluate the protective effects of AS-IV in diaphragmatic muscle cells. Diaphragmatic muscle cells extracted from neonatal rats were treated with a series of AS-IV concentrations (5, 10 or 20 mg/l) and the AKT inhibitor GSK690693 in the presence of interleukin-8 (IL-8). Cell proliferation and AKT phosphorylation were measured using Cell Counting Kit-8 and western blot assays, respectively. Cell apoptosis and reactive oxygen species (ROS) production were evaluated using flow cytometric analysis. Caspase activity and concentrations of proinflammatory factors (tumor necrosis factor-α, IL-6 and IL-8) were assessed using a caspase colorimetric assay and ELISA, respectively. IL-8 treatment resulted in decreased rates of cell proliferation and increased rates of AKT phosphorylation, cell apoptosis, caspase 3/9 activity, ROS production and proinflammatory factor production. AS-IV and GSK690693 treatment reversed the effects of IL-8. The effects of AS-IV were dose-dependent. The present results suggested that AS-IV is a candidate for the treatment of diaphragmatic fatigue due to its antioxidant, anti-apoptotic and anti-inflammatory activity.
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Affiliation(s)
- Li Wang
- Department of Respiratory Medicine, Nanjing First Hospital, Nanjing Medical University, Nanjing, Jiangsu 210006, P.R. China
| | - Wei Gu
- Department of Respiratory Medicine, Nanjing First Hospital, Nanjing Medical University, Nanjing, Jiangsu 210006, P.R. China
| | - Ying Shi
- Department of Respiratory Medicine, Nanjing First Hospital, Nanjing Medical University, Nanjing, Jiangsu 210006, P.R. China
| | - Yubao Chen
- Department of Respiratory Medicine, Nanjing First Hospital, Nanjing Medical University, Nanjing, Jiangsu 210006, P.R. China
| | - Yan Tan
- Department of Respiratory Medicine, Nanjing First Hospital, Nanjing Medical University, Nanjing, Jiangsu 210006, P.R. China
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Sheel AW, Boushel R, Dempsey JA. Competition for blood flow distribution between respiratory and locomotor muscles: implications for muscle fatigue. J Appl Physiol (1985) 2018; 125:820-831. [PMID: 29878876 DOI: 10.1152/japplphysiol.00189.2018] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Sympathetically induced vasoconstrictor modulation of local vasodilation occurs in contracting skeletal muscle during exercise to ensure appropriate perfusion of a large active muscle mass and to maintain also arterial blood pressure. In this synthesis, we discuss the contribution of group III-IV muscle afferents to the sympathetic modulation of blood flow distribution to locomotor and respiratory muscles during exercise. This is followed by an examination of the conditions under which diaphragm and locomotor muscle fatigue occur. Emphasis is given to those studies in humans and animal models that experimentally changed respiratory muscle work to evaluate blood flow redistribution and its effects on locomotor muscle fatigue, and conversely, those that evaluated the influence of coincident limb muscle contraction on respiratory muscle blood flow and fatigue. We propose the concept of a "two-way street of sympathetic vasoconstrictor activity" emanating from both limb and respiratory muscle metaboreceptors during exercise, which constrains blood flow and O2 transport thereby promoting fatigue of both sets of muscles. We end with considerations of a hierarchy of blood flow distribution during exercise between respiratory versus locomotor musculatures and the clinical implications of muscle afferent feedback influences on muscle perfusion, fatigue, and exercise tolerance.
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Affiliation(s)
- A William Sheel
- School of Kinesiology, University of British Columbia , Vancouver, British Columbia , Canada
| | - Robert Boushel
- School of Kinesiology, University of British Columbia , Vancouver, British Columbia , Canada
| | - Jerome A Dempsey
- Department of Population Health Sciences, John Rankin Laboratory of Pulmonary Medicine, School of Medicine and Public Health, University of Wisconsin , Madison, Wisconsin
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7
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The Link between Reduced Inspiratory Capacity and Exercise Intolerance in Chronic Obstructive Pulmonary Disease. Ann Am Thorac Soc 2018; 14:S30-S39. [PMID: 28398073 DOI: 10.1513/annalsats.201610-834fr] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Low inspiratory capacity (IC), chronic dyspnea, and reduced exercise capacity are inextricably linked and are independent predictors of increased mortality in chronic obstructive pulmonary disease. It is no surprise, therefore, that a major goal of management is to improve IC by reducing lung hyperinflation to improve respiratory symptoms and health-related quality of life. The negative effects of lung hyperinflation on respiratory muscle and cardiocirculatory function during exercise are now well established. Moreover, there is growing appreciation that a key mechanism of exertional dyspnea in chronic obstructive pulmonary disease is critical mechanical constraints on tidal volume expansion during exercise when resting IC is reduced. Further evidence for the importance of lung hyperinflation comes from multiple studies, which have reported the clinical benefits of therapeutic interventions that reduce lung hyperinflation and increase IC. A reduced IC in obstructive pulmonary disease is further eroded by exercise and contributes to ventilatory limitation and dyspnea. It is an important outcome for both clinical and research studies.
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8
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Behnia M, Wheatley C, Avolio A, Johnson B. Influence of resting lung diffusion on exercise capacity in patients with COPD. BMC Pulm Med 2017; 17:117. [PMID: 28841877 PMCID: PMC5571500 DOI: 10.1186/s12890-017-0454-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 08/02/2017] [Indexed: 11/16/2022] Open
Abstract
Background Lung diffusing capacity for carbon monoxide (DLCO) gives an overall assessment of functional lung surface area for gas exchange and can be assessed using various methods. DLCO is an important factor in exercise intolerance in patients with chronic obstructive pulmonary disease (COPD). We investigated if the intra-breath (IBDLCO) method may give a more sensitive measure of available gas exchange surface area than the more typical single breath (SBDLCO) method and if COPD subjects with the largest resting DLCO relative to pulmonary blood flow (Qc) would have a more preserved exercise capacity. Methods Informed consent, hemoglobin, spirometry, SBDLCO, IBDLCO, and Qc during IBDLCO were performed in moderate to severe COPD patients, followed by progressive cycle ergometry to exhaustion with measures of oxygen saturation (SaO2) and expired gases. Results Thirty two subjects (47% female, age 66 ± 9 yrs., BMI 30.4 ± 6.3 kg/m2, smoking hx 35 ± 29 pkyrs, 2.3 ± 0.8 on the 0-4 GOLD classification scale) participated. The majority used multiple inhaled medications and 20% were on oral steroids. Averages were: FEV1/FVC 58 ± 10%Pred, peak VO2 11.4 ± 3.1 ml/kg/min, and IBDLCO 72% of the SBDLCO (r = 0.88, SB vs IB methods). Using univariate regression, both the SB and IBDLCO (% predicted but not absolute) were predictive of VO2peak in ml/kg/min; SBDLCO/Qc (r = 0.63, p < 0.001) was the best predictor of VO2peak; maximal expiratory flows over the mid to lower lung volumes were the most significantly predictive spirometric measure (r = 0.49, p < 0.01). However, in multivariate models only BMI added additional predictive value to the SBDLCO/Qc for predicting aerobic capacity (r = 0.73). Adjusting for current smoking status and gender did not significantly change the primary results. Conclusion In patients with moderate to severe COPD, preservation of lung gas exchange surface area as assessed using the resting SBDLCO/Qc appears to be a better predictor of exercise capacity than more classic measures of lung mechanics.
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Affiliation(s)
- Mehrdad Behnia
- University of Central Florida School of Medicine and Division of Critical Care, Florida Hospital, Orlando, FL, USA. .,, PO Box 953814, Lake Mary, FL, 32795, USA.
| | - Courtney Wheatley
- Division of Cardiovascular Diseases, Mayo Clinic, Scottsdale, AZ, USA
| | - Alberto Avolio
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Bruce Johnson
- Division of Cardiovascular Diseases, Mayo Clinic, Scottsdale, AZ, USA
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9
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Lewis P, Sheehan D, Soares R, Coelho AV, O'Halloran KD. Redox Remodeling Is Pivotal in Murine Diaphragm Muscle Adaptation to Chronic Sustained Hypoxia. Am J Respir Cell Mol Biol 2017; 55:12-23. [PMID: 26681636 DOI: 10.1165/rcmb.2015-0272oc] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Mechanisms underpinning chronic sustained hypoxia (CH)-induced structural and functional adaptations in respiratory muscles are unclear despite the clinical relevance to respiratory diseases. The objectives of the present study were to thoroughly assess the putative role of CH-induced redox remodeling in murine diaphragm muscle over time and the subsequent effects on metabolic enzyme activities, catabolic signaling and catabolic processes, and diaphragm muscle contractile function. C57Bl6/J mice were exposed to normoxia or normobaric CH (fraction of inspired oxygen = 0.1) for 1, 3, or 6 weeks. A second cohort was exposed to CH for 6 weeks with and without antioxidant supplementation (tempol or N-acetyl cysteine). After CH exposure, we performed two-dimensional redox proteomics with mass spectrometry, enzyme activity assays, and cell-signaling assays on diaphragm homogenates. We also assessed diaphragm isotonic contractile and endurance properties ex vivo. Global protein redox changes in the diaphragm after CH are indicative of oxidation. Remodeling of proteins key to contractile, metabolic, and homeostatic functions was observed. Several oxidative and glycolytic enzyme activities were decreased by CH. Redox-sensitive chymotrypsin-like proteasome activity of the diaphragm was increased. CH decreased phospho-forkhead box O3a (FOXO3a) and phospho-mammalian target of rapamycin content. Hypoxia-inducible factor-1α and phospho-p38 mitogen-activated protein kinase content was increased in CH diaphragm, and this was attenuated by antioxidant treatment. CH exposure decreased force- and power-generating capacity of the diaphragm, and this was prevented by antioxidant supplementation with N-acetyl cysteine but not tempol. Redox remodeling is pivotal for diaphragm adaptation to CH, affecting metabolic activity, atrophy signaling, and functional performance. Antioxidant supplementation may be useful as an adjunctive therapy in respiratory-related diseases characterized by hypoxic stress.
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Affiliation(s)
| | - David Sheehan
- 2 School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland; and
| | - Renata Soares
- 3 Instituto de Tecnologia Quimica e Biologica António Xavier, Universidade Novade Lisboa, Lisbon, Portugal
| | - Ana Varela Coelho
- 3 Instituto de Tecnologia Quimica e Biologica António Xavier, Universidade Novade Lisboa, Lisbon, Portugal
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O'Donnell DE, Elbehairy AF, Berton DC, Domnik NJ, Neder JA. Advances in the Evaluation of Respiratory Pathophysiology during Exercise in Chronic Lung Diseases. Front Physiol 2017; 8:82. [PMID: 28275353 PMCID: PMC5319975 DOI: 10.3389/fphys.2017.00082] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 01/30/2017] [Indexed: 11/13/2022] Open
Abstract
Dyspnea and exercise limitation are among the most common symptoms experienced by patients with various chronic lung diseases and are linked to poor quality of life. Our understanding of the source and nature of perceived respiratory discomfort and exercise intolerance in chronic lung diseases has increased substantially in recent years. These new mechanistic insights are the primary focus of the current review. Cardiopulmonary exercise testing (CPET) provides a unique opportunity to objectively evaluate the ability of the respiratory system to respond to imposed incremental physiological stress. In addition to measuring aerobic capacity and quantifying an individual's cardiac and ventilatory reserves, we have expanded the role of CPET to include evaluation of symptom intensity, together with a simple "non-invasive" assessment of relevant ventilatory control parameters and dynamic respiratory mechanics during standardized incremental tests to tolerance. This review explores the application of the new advances in the clinical evaluation of the pathophysiology of exercise intolerance in chronic obstructive pulmonary disease (COPD), chronic asthma, interstitial lung disease (ILD) and pulmonary arterial hypertension (PAH). We hope to demonstrate how this novel approach to CPET interpretation, which includes a quantification of activity-related dyspnea and evaluation of its underlying mechanisms, enhances our ability to meaningfully intervene to improve quality of life in these pathologically-distinct conditions.
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Affiliation(s)
- Denis E. O'Donnell
- Division of Respiratory Medicine, Department of Medicine, Queen's University and Kingston General HospitalKingston, ON, Canada
| | - Amany F. Elbehairy
- Division of Respiratory Medicine, Department of Medicine, Queen's University and Kingston General HospitalKingston, ON, Canada
- Department of Chest Diseases, Faculty of Medicine, Alexandria UniversityAlexandria, Egypt
| | - Danilo C. Berton
- Division of Respiratory Medicine, Department of Medicine, Queen's University and Kingston General HospitalKingston, ON, Canada
| | - Nicolle J. Domnik
- Division of Respiratory Medicine, Department of Medicine, Queen's University and Kingston General HospitalKingston, ON, Canada
| | - J. Alberto Neder
- Division of Respiratory Medicine, Department of Medicine, Queen's University and Kingston General HospitalKingston, ON, Canada
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11
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Ju S, Lee SJ, Park MJ, Cho YJ, Jeong YY, Jeon KN, Bae K, Lee JD, Kim HC. Clinical importance of cross-sectional area of intercostal muscles in patients with chronic obstructive pulmonary disease. CLINICAL RESPIRATORY JOURNAL 2017; 12:939-947. [PMID: 28054460 DOI: 10.1111/crj.12609] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Revised: 11/26/2016] [Accepted: 12/21/2016] [Indexed: 01/06/2023]
Abstract
INTRODUCTION Limb muscle wasting is one of main systemic manifestation of chronic obstructive pulmonary disease (COPD). However, the change of respiratory muscle is unclear. OBJECTIVES This study assessed the cross-sectional area (CSA) of the intercostal muscles (ICMs) in patients with COPD, using chest computed tomography (CT) and determined its association with the clinical characteristics of COPD. METHODS They retrospectively reviewed 60 patients with stable COPD and compared them with 30 controls. CSA (mm2 ) of the ICM on chest CT was measured at the midline level of the lateral arch of the bilateral first rib with a 3-mm slice thickness by using CT histogram software. The association with the clinical characteristics of COPD and with the control groups was assessed. RESULTS CSA of the ICM and the CSA/body mass index (BMI) were lower in the COPD group than in the control group. Patients with Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage 4 had a significantly lower CSA of the ICM than patients with stage 1, 2, and 3. CSA of the ICM was positively associated with FEV1 , %FEV1 predicted, FEV1 /FVC ratio, and BMI and negatively associated with age. However, there were no associations with PaO2 , PaCO2 , smoking status, 6-minute walk test, frequency of acute exacerbation of COPD, and serum C-reactive protein level. CONCLUSION Intercostal muscle atrophy occurs in COPD patients and is associated with severity of airway obstruction, BMI, and increasing age.
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Affiliation(s)
- Sunmi Ju
- Division Pulmonology and Allergy, Department of Internal Medicine, Gyeongsang National University Hospital, Gyeongsang National University School of Medicine, Jinju, Korea
| | - Seung Jun Lee
- Division Pulmonology and Allergy, Department of Internal Medicine, Gyeongsang National University Hospital, Gyeongsang National University School of Medicine, Jinju, Korea
| | - Mi Jung Park
- Department of Diagnostic Radiology, College of Medicine, Gyeongsang National University Hospital, Gyeongsang National University School of Medicine, Jinju, Korea
| | - Yu Ji Cho
- Division Pulmonology and Allergy, Department of Internal Medicine, Gyeongsang National University Hospital, Gyeongsang National University School of Medicine, Jinju, Korea
| | - Yi Yeong Jeong
- Division Pulmonology and Allergy, Department of Internal Medicine, Gyeongsang National University Hospital, Gyeongsang National University School of Medicine, Jinju, Korea
| | - Kyung Nyeo Jeon
- Department of Diagnostic Radiology, College of Medicine, Gyeongsang National University Hospital, Gyeongsang National University School of Medicine, Jinju, Korea
| | - Kyungsoo Bae
- Department of Diagnostic Radiology, College of Medicine, Gyeongsang National University Hospital, Gyeongsang National University School of Medicine, Jinju, Korea
| | - Jong Deog Lee
- Division Pulmonology and Allergy, Department of Internal Medicine, Gyeongsang National University Hospital, Gyeongsang National University School of Medicine, Jinju, Korea
| | - Ho Cheol Kim
- Division Pulmonology and Allergy, Department of Internal Medicine, Gyeongsang National University Hospital, Gyeongsang National University School of Medicine, Jinju, Korea
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12
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Gea J, Casadevall C, Pascual S, Orozco-Levi M, Barreiro E. Clinical management of chronic obstructive pulmonary disease patients with muscle dysfunction. J Thorac Dis 2016; 8:3379-3400. [PMID: 28066619 DOI: 10.21037/jtd.2016.11.105] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Muscle dysfunction is frequently observed in chronic obstructive pulmonary disease (COPD) patients, contributing to their exercise limitation and a worsening prognosis. The main factor leading to limb muscle dysfunction is deconditioning, whereas respiratory muscle dysfunction is mostly the result of pulmonary hyperinflation. However, both limb and respiratory muscles are also influenced by other negative factors, including smoking, systemic inflammation, nutritional abnormalities, exacerbations and some drugs. Limb muscle weakness is generally diagnosed through voluntary isometric maneuvers such as handgrip or quadriceps muscle contraction (dynamometry); while respiratory muscle loss of strength is usually recognized through a decrease in maximal static pressures measured at the mouth. Both types of measurements have validated reference values. Respiratory muscle strength can also be evaluated determining esophageal, gastric and transdiaphragmatic maximal pressures although there is a lack of widely accepted reference equations. Non-volitional maneuvers, obtained through electrical or magnetic stimulation, can be employed in patients unable to cooperate. Muscle endurance can also be assessed, generally using repeated submaximal maneuvers until exhaustion, but no validated reference values are available yet. The treatment of muscle dysfunction is multidimensional and includes improvement in lifestyle habits (smoking abstinence, healthy diet and a good level of physical activity, preferably outside), nutritional measures (diet supplements and occasionally, anabolic drugs), and different modalities of general and muscle training.
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Affiliation(s)
- Joaquim Gea
- Servei de Pneumologia, Hospital del Mar - IMIM, Experimental Sciences and Health Department (DCEXS), Universitat Pompeu Fabra, CIBERES, ISC III, Barcelona, Catalonia, Spain
| | - Carme Casadevall
- Servei de Pneumologia, Hospital del Mar - IMIM, Experimental Sciences and Health Department (DCEXS), Universitat Pompeu Fabra, CIBERES, ISC III, Barcelona, Catalonia, Spain
| | - Sergi Pascual
- Servei de Pneumologia, Hospital del Mar - IMIM, Experimental Sciences and Health Department (DCEXS), Universitat Pompeu Fabra, CIBERES, ISC III, Barcelona, Catalonia, Spain
| | - Mauricio Orozco-Levi
- Department of Respiratory, Cardiovascular Foundation from Colombia Floridablanca, Santander, Colombia, CIBERES, ISC III, Barcelona, Catalonia, Spain
| | - Esther Barreiro
- Servei de Pneumologia, Hospital del Mar - IMIM, Experimental Sciences and Health Department (DCEXS), Universitat Pompeu Fabra, CIBERES, ISC III, Barcelona, Catalonia, Spain
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13
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Lewis P, McMorrow C, Bradford A, O'Halloran KD. Improved tolerance of acute severe hypoxic stress in chronic hypoxic diaphragm is nitric oxide-dependent. J Physiol Sci 2015; 65:427-33. [PMID: 26001629 PMCID: PMC10717054 DOI: 10.1007/s12576-015-0381-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 05/02/2015] [Indexed: 10/23/2022]
Abstract
The effects of chronic hypoxia (CH) on respiratory muscle performance have hardly been investigated, despite clinical relevance. Results from recent studies are indicative of unique adaptive strategies in hypoxic diaphragm. Respiratory muscle tolerance of acute severe hypoxic stress was examined in normoxic and CH diaphragm in the presence and absence of a nitric oxide (NO) synthase inhibitor. We tested the hypothesis that improved tolerance of severe hypoxic stress in CH diaphragm is NO-dependent. Wistar rats were exposed to normoxia (sea-level, n = 6) or CH (ambient pressure = 380 mmHg, n = 6) for 6 weeks. Diaphragm muscle functional properties were determined ex vivo under severe hypoxic conditions (gassed with 95%N2/5% CO2) with and without 1 mM L-N(G)-nitroarginine (L-NNA, nNOS inhibitor). Fatigue tolerance, but not force, was significantly improved in CH diaphragm (p = 0.008). CH exposure did not affect diaphragm muscle fibre oxidative capacity determined from cluster analysis of area-density plots of muscle fibre succinate dehydrogenase activity. Acute NOS inhibition reduced diaphragm peak tetanic force (p = 0.018), irrespective of gas treatment, and completely reversed improved fatigue tolerance of the CH diaphragm. We conclude that CH exposure improves fatigue tolerance during acute severe hypoxic stress in an NO-dependent manner, independent of muscle fibre oxidative capacity.
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Affiliation(s)
- Philip Lewis
- Department of Physiology, School of Medicine, Western Gateway Building, University College Cork, Western Road, Cork, Ireland,
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14
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Radiologic manifestations of bronchoscopic lung volume reduction in severe chronic obstructive pulmonary disease. AJR Am J Roentgenol 2015; 204:475-86. [PMID: 25714276 DOI: 10.2214/ajr.14.13185] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE. Bronchoscopic lung volume reduction promises to become an effective treatment option in severe chronic obstructive pulmonary disease. Several techniques are currently being investigated, including implantation of devices into the lung and instillation of hot water vapor or polymer. This article reviews the spectrum of radiologic manifestations on chest radiography and CT that occur after the intervention. CONCLUSION. Familiarity with the intended effects and adverse events will aid the radiologist in supporting bronchoscopic lung volume reduction.
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15
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Langer D, Ciavaglia CE, Neder JA, Webb KA, O'Donnell DE. Lung hyperinflation in chronic obstructive pulmonary disease: mechanisms, clinical implications and treatment. Expert Rev Respir Med 2014; 8:731-49. [PMID: 25159007 DOI: 10.1586/17476348.2014.949676] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Lung hyperinflation is highly prevalent in patients with chronic obstructive pulmonary disease and occurs across the continuum of the disease. A growing body of evidence suggests that lung hyperinflation contributes to dyspnea and activity limitation in chronic obstructive pulmonary disease and is an important independent risk factor for mortality. In this review, we will summarize the recent literature on pathogenesis and clinical implications of lung hyperinflation. We will outline the contribution of lung hyperinflation to exercise limitation and discuss its impact on symptoms and physical activity. Finally, we will examine the physiological rationale and efficacy of selected pharmacological and non-pharmacological 'lung deflating' interventions aimed at improving symptoms and physical functioning.
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Affiliation(s)
- Daniel Langer
- Respiratory Investigation Unit, Queen's University & Kingston General Hospital, 102 Stuart Street, Kingston, ON K7L 2V6, Canada
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16
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Does expiratory muscle activity influence dynamic hyperinflation and exertional dyspnea in COPD? Respir Physiol Neurobiol 2014; 199:24-33. [DOI: 10.1016/j.resp.2014.04.005] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 04/15/2014] [Accepted: 04/18/2014] [Indexed: 11/24/2022]
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17
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Wüthrich TU, Eberle EC, Spengler CM. Locomotor and diaphragm muscle fatigue in endurance athletes performing time-trials of different durations. Eur J Appl Physiol 2014; 114:1619-33. [DOI: 10.1007/s00421-014-2889-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 04/06/2014] [Indexed: 01/19/2023]
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18
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Abstract
The systemic effects and comorbidities of chronic respiratory disease such as COPD contribute substantially to its burden. Symptoms in COPD do not solely arise from the degree of airflow obstruction as exercise limitation is compounded by the specific secondary manifestations of the disease including skeletal muscle impairment, osteoporosis, mood disturbance, anemia, and hormonal imbalance. Pulmonary rehabilitation targets the systemic manifestations of COPD, the causes of which include inactivity, systemic inflammation, hypoxia and corticosteroid treatment. Comorbidities are common, including cardiac disease, obesity, and metabolic syndrome and should not preclude pulmonary rehabilitation as they may also benefit from similar approaches.
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Affiliation(s)
- Rachael A Evans
- Department of Respiratory Medicine, Glenfield Hospital, Groby Road, Leicester LE3 9QP, UK
| | - Michael D L Morgan
- Department of Respiratory Medicine, Glenfield Hospital, Groby Road, Leicester LE3 9QP, UK.
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19
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Gagnon P, Guenette JA, Langer D, Laviolette L, Mainguy V, Maltais F, Ribeiro F, Saey D. Pathogenesis of hyperinflation in chronic obstructive pulmonary disease. Int J Chron Obstruct Pulmon Dis 2014; 9:187-201. [PMID: 24600216 PMCID: PMC3933347 DOI: 10.2147/copd.s38934] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Chronic obstructive pulmonary disease (COPD) is a preventable and treatable lung disease characterized by airflow limitation that is not fully reversible. In a significant proportion of patients with COPD, reduced lung elastic recoil combined with expiratory flow limitation leads to lung hyperinflation during the course of the disease. Development of hyperinflation during the course of COPD is insidious. Dynamic hyperinflation is highly prevalent in the advanced stages of COPD, and new evidence suggests that it also occurs in many patients with mild disease, independently of the presence of resting hyperinflation. Hyperinflation is clinically relevant for patients with COPD mainly because it contributes to dyspnea, exercise intolerance, skeletal muscle limitations, morbidity, and reduced physical activity levels associated with the disease. Various pharmacological and nonpharmacological interventions have been shown to reduce hyperinflation and delay the onset of ventilatory limitation in patients with COPD. The aim of this review is to address the more recent literature regarding the pathogenesis, assessment, and management of both static and dynamic lung hyperinflation in patients with COPD. We also address the influence of biological sex and obesity and new developments in our understanding of hyperinflation in patients with mild COPD and its evolution during progression of the disease.
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Affiliation(s)
- Philippe Gagnon
- Faculté de Médecine, Université Laval, Québec, QC, Canada ; Centre de Recherche, Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, QC, Canada
| | - Jordan A Guenette
- Centre for Heart Lung Innovation, University of British Columbia, St Paul's Hospital, Vancouver, BC, Canada ; Department of Physical Therapy, University of British Columbia, Vancouver, BC, Canada
| | - Daniel Langer
- Department of Kinesiology and Rehabilitation Sciences, KU Leuven, Leuven, Belgium
| | - Louis Laviolette
- Centre de Recherche, Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, QC, Canada
| | | | - François Maltais
- Faculté de Médecine, Université Laval, Québec, QC, Canada ; Centre de Recherche, Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, QC, Canada
| | - Fernanda Ribeiro
- Faculté de Médecine, Université Laval, Québec, QC, Canada ; Centre de Recherche, Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, QC, Canada
| | - Didier Saey
- Faculté de Médecine, Université Laval, Québec, QC, Canada ; Centre de Recherche, Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, QC, Canada
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20
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Laveneziana P, Guenette JA, Webb KA, O’Donnell DE. New physiological insights into dyspnea and exercise intolerance in chronic obstructive pulmonary disease patients. Expert Rev Respir Med 2014; 6:651-62. [DOI: 10.1586/ers.12.70] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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21
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Vogiatzis I, Zakynthinos S. Factors limiting exercise tolerance in chronic lung diseases. Compr Physiol 2013; 2:1779-817. [PMID: 23723024 DOI: 10.1002/cphy.c110015] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The major limitation to exercise performance in patients with chronic lung diseases is an issue of great importance since identifying the factors that prevent these patients from carrying out activities of daily living provides an important perspective for the choice of the appropriate therapeutic strategy. The factors that limit exercise capacity may be different in patients with different disease entities (i.e., chronic obstructive, restrictive or pulmonary vascular lung disease) or disease severity and ultimately depend on the degree of malfunction or miss coordination between the different physiological systems (i.e., respiratory, cardiovascular and peripheral muscles). This review focuses on patients with chronic obstructive pulmonary disease (COPD), interstitial lung disease (ILD) and pulmonary vascular disease (PVD). ILD and PVD are included because there is sufficient experimental evidence for the factors that limit exercise capacity and because these disorders are representative of restrictive and pulmonary vascular disorders, respectively. A great deal of emphasis is given, however, to causes of exercise intolerance in COPD mainly because of the plethora of research findings that have been published in this area and also because exercise intolerance in COPD has been used as a model for understanding the interactions of different pathophysiologic mechanisms in exercise limitation. As exercise intolerance in COPD is recognized as being multifactorial, the impacts of the following factors on patients' exercise capacity are explored from an integrative physiological perspective: (i) imbalance between the ventilatory capacity and requirement; (ii) imbalance between energy demands and supplies to working respiratory and peripheral muscles; and (iii) peripheral muscle intrinsic dysfunction/weakness.
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Affiliation(s)
- Ioannis Vogiatzis
- Department of Physical Education and Sport Sciences, National and Kapodistrian University of Athens, Greece.
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22
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O'Donnell DE, Laveneziana P, Webb K, Neder JA. Chronic obstructive pulmonary disease: clinical integrative physiology. Clin Chest Med 2013; 35:51-69. [PMID: 24507837 DOI: 10.1016/j.ccm.2013.09.008] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Peripheral airway dysfunction, inhomogeneous ventilation distribution, gas trapping, and impaired pulmonary gas exchange are variably present in all stages of chronic obstructive pulmonary disease (COPD). This article provides a cogent physiologic explanation for the relentless progression of activity-related dyspnea and exercise intolerance that all too commonly characterizes COPD. The spectrum of physiologic derangements that exist in smokers with mild airway obstruction and a history compatible with COPD is examined. Also explored are the perceptual and physiologic consequences of progressive erosion of the resting inspiratory capacity. Finally, emerging information on the role of cardiocirculatory impairment in contributing to exercise intolerance in patients with varying degrees of airway obstruction is reviewed.
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Affiliation(s)
- Denis E O'Donnell
- Division of Respiratory and Critical Care Medicine, Department of Medicine, Queen's University, 102 Stuart Street, Kingston, Ontario K7L 2V6, Canada.
| | - Pierantonio Laveneziana
- Service d'Explorations Fonctionnelles de la Respiration, de l'Exercice et de la Dyspnée Hôpital Universitaire Pitié-Salpêtrière (AP-HP), Laboratoire de Physio-Pathologie Respiratoire, Faculty of Medicine, Pierre et Marie Curie University (Paris VI), 47-83 Boulevard de l'Hôpital,75013 Paris, France
| | - Katherine Webb
- Division of Respiratory and Critical Care Medicine, Department of Medicine, Queen's University, 102 Stuart Street, Kingston, Ontario K7L 2V6, Canada
| | - J Alberto Neder
- Division of Respiratory and Critical Care Medicine, Department of Medicine, Queen's University, 102 Stuart Street, Kingston, Ontario K7L 2V6, Canada
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23
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Bachasson D, Wuyam B, Pepin JL, Tamisier R, Levy P, Verges S. Quadriceps and respiratory muscle fatigue following high-intensity cycling in COPD patients. PLoS One 2013; 8:e83432. [PMID: 24324843 PMCID: PMC3855800 DOI: 10.1371/journal.pone.0083432] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 11/05/2013] [Indexed: 11/24/2022] Open
Abstract
Exercise intolerance in COPD seems to combine abnormal ventilatory mechanics, impaired O2 transport and skeletal muscle dysfunction. However their relatie contribution and their influence on symptoms reported by patients remain to be clarified. In order to clarify the complex interaction between ventilatory and neuromuscular exercise limiting factors and symptoms, we evaluated respiratory muscles and quadriceps contractile fatigue, dynamic hyperinflation and symptoms induced by exhaustive high-intensity cycling in COPD patients. Fifteen gold II-III COPD patients (age = 67±6 yr; BMI = 26.6±4.2 kg.m-2) performed constant-load cycling test at 80% of their peak workload until exhaustion (9.3±2.4 min). Before exercise and at exhaustion, potentiated twitch quadriceps strength (Qtw), transdiaphragmatic (Pdi,tw) and gastric (Pga,tw) pressures were evoked by femoral nerve, cervical and thoracic magnetic stimulation, respectively. Changes in operational lung volumes during exercise were assessed via repetitive inspiratory capacity (IC) measurements. Dyspnoea and leg discomfort were measured on visual analog scale. At exhaustion, Qtw (-33±15%, >15% reduction observed in all patients but two) and Pdi,tw (-20±15%, >15% reduction in 6 patients) were significantly reduced (P<0.05) but not Pga,tw (-6±10%, >15% reduction in 3 patients). Percentage reduction in Qtw correlated with the percentage reduction in Pdi,tw (r=0.66; P<0.05). Percentage reductions in Pdi,tw and Pga,tw negatively correlated with the reduction in IC at exhaustion (r=-0.56 and r=-0.62, respectively; P<0.05). Neither dyspnea nor leg discomfort correlated with the amount of muscle fatigue. In conclusion, high-intensity exercise induces quadriceps, diaphragm and less frequently abdominal contractile fatigue in this group of COPD patients. In addition, the rise in end-expiratory lung volume and diaphragm flattening associated with dynamic hyperinflation in COPD might limit the development of abdominal and diaphragm muscle fatigue. This study underlines that both respiratory and quadriceps fatigue should be considered to understand the complex interplay of factors leading to exercise intolerance in COPD patients.
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Affiliation(s)
- Damien Bachasson
- Grenoble Alpes University, HP2 Laboratory, Grenoble, France
- INSERM, U1042, Grenoble, France
- CHU, Grenoble Locomotor Unit, Reeducation & Physiology, Clinical Physiology, Sleep and Exercise, Grenoble, France
| | - Bernard Wuyam
- Grenoble Alpes University, HP2 Laboratory, Grenoble, France
- INSERM, U1042, Grenoble, France
- CHU, Grenoble Locomotor Unit, Reeducation & Physiology, Clinical Physiology, Sleep and Exercise, Grenoble, France
| | - Jean-Louis Pepin
- Grenoble Alpes University, HP2 Laboratory, Grenoble, France
- INSERM, U1042, Grenoble, France
- CHU, Grenoble Locomotor Unit, Reeducation & Physiology, Clinical Physiology, Sleep and Exercise, Grenoble, France
| | - Renaud Tamisier
- Grenoble Alpes University, HP2 Laboratory, Grenoble, France
- INSERM, U1042, Grenoble, France
- CHU, Grenoble Locomotor Unit, Reeducation & Physiology, Clinical Physiology, Sleep and Exercise, Grenoble, France
| | - Patrick Levy
- Grenoble Alpes University, HP2 Laboratory, Grenoble, France
- INSERM, U1042, Grenoble, France
- CHU, Grenoble Locomotor Unit, Reeducation & Physiology, Clinical Physiology, Sleep and Exercise, Grenoble, France
| | - Samuel Verges
- Grenoble Alpes University, HP2 Laboratory, Grenoble, France
- INSERM, U1042, Grenoble, France
- * E-mail:
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24
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Abstract
During dynamic exercise, the healthy pulmonary system faces several major challenges, including decreases in mixed venous oxygen content and increases in mixed venous carbon dioxide. As such, the ventilatory demand is increased, while the rising cardiac output means that blood will have considerably less time in the pulmonary capillaries to accomplish gas exchange. Blood gas homeostasis must be accomplished by precise regulation of alveolar ventilation via medullary neural networks and sensory reflex mechanisms. It is equally important that cardiovascular and pulmonary system responses to exercise be precisely matched to the increase in metabolic requirements, and that the substantial gas transport needs of both respiratory and locomotor muscles be considered. Our article addresses each of these topics with emphasis on the healthy, young adult exercising in normoxia. We review recent evidence concerning how exercise hyperpnea influences sympathetic vasoconstrictor outflow and the effect this might have on the ability to perform muscular work. We also review sex-based differences in lung mechanics.
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Affiliation(s)
- Andrew William Sheel
- The School of Kinesiology, The University of British Columbia, Vancouver, Canada.
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25
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Zhang D, Gong H, Lu G, Guo H, Li R, Zhong N, Polkey M, Luo Y. Respiratory motor output during an inspiratory capacity maneuver is preserved despite submaximal exercise. Respir Physiol Neurobiol 2013; 189:87-92. [DOI: 10.1016/j.resp.2013.07.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 06/26/2013] [Accepted: 07/03/2013] [Indexed: 11/25/2022]
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26
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Kealy S, Hussey J, Lane SJ. Reasons for Exercise Intolerance in Patients with Chronic Obstructive Pulmonary Disease. PHYSICAL THERAPY REVIEWS 2013. [DOI: 10.1179/108331903225001372] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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27
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Finucane KE, Singh B. Diaphragm efficiency estimated as power output relative to activation in chronic obstructive pulmonary disease. J Appl Physiol (1985) 2012; 113:1567-75. [PMID: 22995393 DOI: 10.1152/japplphysiol.01453.2011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Muscle efficiency increases with fiber length and decreases with load. Diaphragm efficiency (Eff(di)) in healthy humans, measured as power output (Wdi) relative to the root mean square of diaphragm electromyogram (RMS(di)), increases with hyperpnea due to phasic activity of abdominal muscles acting to increase diaphragm length at end expiration (L(di ee)) and decrease inspiratory load. In chronic obstructive pulmonary disease (COPD), hyperpnea may decrease Eff(di) if L(di ee) decreases and load increases due to airflow obstruction and dynamic hyperinflation. To examine this hypothesis, we measured Eff(di) in six COPD subjects (mean forced expiratory volume in 1 s: 54% predicted) when breathing air and at intervals during progressive hypercapnic hyperpnea. Wdi was measured as the product of mean inspiratory transdiaphragmatic pressure (ΔPdi(mean)), diaphragm tidal volume measured fluoroscopically, and 1/inspiratory duration. Results were compared with those of six healthy subjects reported previously. In COPD, L(di ee) was normal when breathing air. ΔPdi(mean) and Wdi increased normally, and RMS(di) increased disproportionately (P = 0.01) with hyperpnea, and, unlike health, inspiratory capacity (IC), L(di ee), and Eff(di) did not increase. IC and L(di ee) were constant with hyperpnea because mean expiratory flow increased as expiratory duration decreased (r(2) = 0.65), and because expiratory flow was terminated actively by the balance between expiratory and inspiratory muscle forces near end expiration, and these forces increased proportionately with hyperpnea (r(2) = 0.49). At maximum ventilation, diaphragm radius of curvature at end inspiration increased in COPD (P = 0.04) but not controls; diaphragm radius of curvature at end inspiration and ln(Eff(di)) were negatively correlated (P = 0.01). Thus in COPD with modest airflow obstruction, Eff(di) did not increase normally with hyperpnea due to a constant L(di ee) and inspiratory flattening of the diaphragm.
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Affiliation(s)
- Kevin E Finucane
- Department of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital, Nedlands, WA 6009, Australia.
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28
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Reilly CC, Ward K, Jolley CJ, Frank LA, Elston C, Moxham J, Rafferty GF. Effect of endurance exercise on respiratory muscle function in patients with cystic fibrosis. Respir Physiol Neurobiol 2012; 180:316-22. [DOI: 10.1016/j.resp.2011.12.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 12/15/2011] [Accepted: 12/20/2011] [Indexed: 11/17/2022]
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29
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El-Khoury R, Bradford A, O'Halloran KD. Chronic hypobaric hypoxia increases isolated rat fast-twitch and slow-twitch limb muscle force and fatigue. Physiol Res 2012; 61:195-201. [PMID: 22292723 DOI: 10.33549/physiolres.932140] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Chronic hypoxia alters respiratory muscle force and fatigue, effects that could be attributed to hypoxia and/or increased activation due to hyperventilation. We hypothesized that chronic hypoxia is associated with phenotypic change in non-respiratory muscles and therefore we tested the hypothesis that chronic hypobaric hypoxia increases limb muscle force and fatigue. Adult male Wistar rats were exposed to normoxia or hypobaric hypoxia (PB=450 mm Hg) for 6 weeks. At the end of the treatment period, soleus (SOL) and extensor digitorum longus (EDL) muscles were removed under pentobarbitone anaesthesia and strips were mounted for isometric force determination in Krebs solution in standard water-jacketed organ baths at 25 °C. Isometric twitch and tetanic force, contractile kinetics, force-frequency relationship and fatigue characteristics were determined in response to electrical field stimulation. Chronic hypoxia increased specific force in SOL and EDL compared to age-matched normoxic controls. Furthermore, chronic hypoxia decreased endurance in both limb muscles. We conclude that hypoxia elicits functional plasticity in limb muscles perhaps due to oxidative stress. Our results may have implications for respiratory disorders that are characterized by prolonged hypoxia such as chronic obstructive pulmonary disease (COPD).
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Affiliation(s)
- R El-Khoury
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, St. Stephen’s Green, Dublin, Ireland
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30
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Zainuldin R, Mackey MG, Alison JA. Optimal intensity and type of leg exercise training for people with chronic obstructive pulmonary disease. Cochrane Database Syst Rev 2011; 2011:CD008008. [PMID: 22071841 PMCID: PMC8939846 DOI: 10.1002/14651858.cd008008.pub2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Intensity of exercise is considered a key determinant of training response, however, no systematic review has investigated the effects of different levels of training intensity on exercise capacity, functional exercise capacity and health-related quality of life (HRQoL) in people with chronic obstructive pulmonary disease (COPD). As type of training (continuous or interval) may also affect training response, the effects of the type of training in COPD also require investigation. OBJECTIVES To determine the effects of training intensity (higher versus lower) or type (continuous versus interval training) on primary outcomes in exercise capacity and secondary outcomes in symptoms and HRQoL for people with COPD. SEARCH METHODS We searched for studies in any language from the Cochrane Airways Group Specialised Register, CENTRAL, MEDLINE, EMBASE, CINAHL, AMED, PsycINFO and PubMed. Searches were current as of June 2011. SELECTION CRITERIA We included randomised controlled trials comparing higher training intensity to lower training intensity or comparing continuous training to interval training in people with COPD. We excluded studies that compared exercise training with no exercise training. DATA COLLECTION AND ANALYSIS We pooled results of comparable groups of studies and calculated the treatment effect and 95% confidence intervals (CI) using a random-effects model. We made two separate comparisons of effects between: 1) higher and lower training intensity; 2) continuous and interval training. We contacted authors of missing data. MAIN RESULTS We analysed three included studies (231 participants) for comparisons between higher and lower-intensity training and eight included studies (367 participants) for comparisons between continuous and interval training. Primary outcomes were outcomes at peak exercise (peak work rate, peak oxygen consumption, peak minute ventilation and lactate threshold), at isowork or isotime, endurance time on a constant work rate test and functional exercise capacity (six-minute walk distance). When comparing higher versus lower-intensity training, the pooled primary outcomes were endurance time and six-minute walk distance. There were no significant differences in endurance time improvement (mean difference (MD) 1.07 minutes; 95% CI -1.53 to 3.67) and six-minute walk distance improvement (MD 2.8 metres; 95% CI -10.1 to 15.6) following higher or lower-intensity training. However, heterogeneity of the endurance time results between studies was significant. When comparing continuous and interval training, there were no significant differences in any of the primary outcomes, except for oxygen consumption at isotime (MD 0.08; 95% CI 0.01 to 0.16) but the treatment effect was not considered clinically important. According to the GRADE system, studies were of low to moderate quality. AUTHORS' CONCLUSIONS Comparisons between the higher and lower training intensity were limited due to the small number of included studies and participants. Consequently, there are insufficient data to draw any conclusions on exercise capacity, symptoms and HRQoL for this comparison. For comparisons between continuous and interval training, both appear to be equally effective in improving exercise capacity, symptoms and HRQoL.
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Affiliation(s)
- Rahizan Zainuldin
- Discipline of Physiotherapy, The University of Sydney, Sydney, Australia.
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31
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Abstract
Large numbers of people travel to high altitudes, entering an environment of hypobaric hypoxia. Exposure to low oxygen tension leads to a series of important physiologic responses that allow individuals to tolerate these hypoxic conditions. However, in some cases hypoxia triggers maladaptive responses that lead to various forms of acute and chronic high altitude illness, such as high-altitude pulmonary edema or chronic mountain sickness. Because the respiratory system plays a critical role in these adaptive and maladaptive responses, patients with underlying lung disease may be at increased risk for complications in this environment and warrant careful evaluation before any planned sojourn to higher altitudes. In this review, we describe respiratory disorders that occur with both acute and chronic exposures to high altitudes. These disorders may occur in any individual who ascends to high altitude, regardless of his/her baseline pulmonary status. We then consider the safety of high-altitude travel in patients with various forms of underlying lung disease. The available data regarding how these patients fare in hypoxic conditions are reviewed, and recommendations are provided for management prior to and during the planned sojourn.
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Affiliation(s)
- Joshua O Stream
- University of Utah, Department of Anesthesiology, 30 North 1900 East, Room 3C444, Salt Lake City, UT 84132, USA.
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32
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Luo Y, Li R, Jolley C, Wu H, Steier J, Moxham J, Zhong N. Neural Respiratory Drive in Patients with COPD during Exercise Tests. Respiration 2011; 81:294-301. [DOI: 10.1159/000317136] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Accepted: 04/05/2010] [Indexed: 11/19/2022] Open
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Qin YY, Steier J, Jolley C, Moxham J, Zhong NS, Luo YM. Efficiency of Neural Drive During Exercise in Patients With COPD and Healthy Subjects. Chest 2010; 138:1309-15. [DOI: 10.1378/chest.09-2824] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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Gigliotti F. Mechanisms of dyspnea in healthy subjects. Multidiscip Respir Med 2010; 5:195-201. [PMID: 22958405 PMCID: PMC3463042 DOI: 10.1186/2049-6958-5-3-195] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Accepted: 04/06/2010] [Indexed: 11/18/2022] Open
Abstract
Dyspnea is a general term used to characterize a range of different descriptors; it varies in intensity, and is influenced by a wide variety of factors such as cultural expectations and the patient's experiences. Healthy subjects can experience dyspnea in different situations, e.g. at high altitude, after breath-holding, during stressful situations that cause anxiety or panic, and more commonly during strenuous exercise. Discussing the mechanisms of dyspnea we need to briefly take into account the physiological mechanisms underlying the sensation of dyspnea: the functional status of the respiratory muscles, the role of chemoreceptors and mechanoreceptors, and how the sense of respiratory motor output reaches a level of conscious awareness. We also need to take into account theories on the pathophysiological mechanisms of the sensation of dyspnea and the possibility that each pathophysiological mechanism produces a distinct quality of breathing discomfort. The terms used by subjects to identify different characteristics of breathing discomfort - dyspnea descriptors - may contribute to understanding the mechanisms of dyspnea and providing the rationale for a specific diagnosis.
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Affiliation(s)
- Francesco Gigliotti
- Department of Pulmonary Rehabilitation, Fondazione Don C, Gnocchi, Florence, Italy.
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Amann M, Regan MS, Kobitary M, Eldridge MW, Boutellier U, Pegelow DF, Dempsey JA. Impact of pulmonary system limitations on locomotor muscle fatigue in patients with COPD. Am J Physiol Regul Integr Comp Physiol 2010; 299:R314-24. [PMID: 20445160 DOI: 10.1152/ajpregu.00183.2010] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We examined the effects of respiratory muscle work [inspiratory (W(r-insp)); expiratory (W(r-exp))] and arterial oxygenation (Sp(O(2))) on exercise-induced locomotor muscle fatigue in patients with chronic obstructive pulmonary disease (COPD). Eight patients (FEV, 48 +/- 4%) performed constant-load cycling to exhaustion (Ctrl; 9.8 +/- 1.2 min). In subsequent trials, the identical exercise was repeated with 1) proportional assist ventilation + heliox (PAV); 2) heliox (He:21% O(2)); 3) 60% O(2) inspirate (hyperoxia); or 4) hyperoxic heliox mixture (He:40% O(2)). Five age-matched healthy control subjects performed Ctrl exercise at the same relative workload but for 14.7 min ( approximately best COPD performance). Exercise-induced quadriceps fatigue was assessed via changes in quadriceps twitch force (Q(tw,pot)) from before to 10 min after exercise in response to supramaximal femoral nerve stimulation. During Ctrl, absolute workload (124 +/- 6 vs. 62 +/- 7 W), W(r-insp) (207 +/- 18 vs. 301 +/- 37 cmH(2)O x s x min(-1)), W(r-exp) (172 +/- 15 vs. 635 +/- 58 cmH(2)O x s x min(-1)), and Sp(O(2)) (96 +/- 1% vs. 87 +/- 3%) differed between control subjects and patients. Various interventions altered W(r-insp), W(r-exp), and Sp(O(2)) from Ctrl (PAV: -55 +/- 5%, -21 +/- 7%, +6 +/- 2%; He:21% O(2): -16 +/- 2%, -25 +/- 5%, +4 +/- 1%; hyperoxia: -11 +/- 2%, -17 +/- 4%, +16 +/- 4%; He:40% O(2): -22 +/- 2%, -27 +/- 6%, +15 +/- 4%). Ten minutes after Ctrl exercise, Q(tw,pot) was reduced by 25 +/- 2% (P < 0.01) in all COPD and 2 +/- 1% (P = 0.07) in healthy control subjects. In COPD, DeltaQ(tw,pot) was attenuated by one-third after each interventional trial; however, most of the exercise-induced reductions in Q(tw,pot) remained. Our findings suggest that the high susceptibility to locomotor muscle fatigue in patients with COPD is in part attributable to insufficient O(2) transport as a consequence of exaggerated arterial hypoxemia and/or excessive respiratory muscle work but also support a critical role for the well-known altered intrinsic muscle characteristics in these patients.
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Affiliation(s)
- Markus Amann
- John Rankin Laboratory of Pulmonary Medicine, University of Wisconsin-Madison Medical School, Madison, Wisconsin, USA.
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Hopkinson NS, Dayer MJ, Moxham J, Polkey MI. Abdominal muscle fatigue following exercise in chronic obstructive pulmonary disease. Respir Res 2010; 11:15. [PMID: 20132549 PMCID: PMC2824704 DOI: 10.1186/1465-9921-11-15] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Accepted: 02/04/2010] [Indexed: 11/16/2022] Open
Abstract
Background In patients with chronic obstructive pulmonary disease, a restriction on maximum ventilatory capacity contributes to exercise limitation. It has been demonstrated that the diaphragm in COPD is relatively protected from fatigue during exercise. Because of expiratory flow limitation the abdominal muscles are activated early during exercise in COPD. This adds significantly to the work of breathing and may therefore contribute to exercise limitation. In healthy subjects, prior expiratory muscle fatigue has been shown itself to contribute to the development of quadriceps fatigue. It is not known whether fatigue of the abdominal muscles occurs during exercise in COPD. Methods Twitch gastric pressure (TwT10Pga), elicited by magnetic stimulation over the 10th thoracic vertebra and twitch transdiaphragmatic pressure (TwPdi), elicited by bilateral anterolateral magnetic phrenic nerve stimulation were measured before and after symptom-limited, incremental cycle ergometry in patients with COPD. Results Twenty-three COPD patients, with a mean (SD) FEV1 40.8(23.1)% predicted, achieved a mean peak workload of 53.5(15.9) W. Following exercise, TwT10Pga fell from 51.3(27.1) cmH2O to 47.4(25.2) cmH2O (p = 0.011). TwPdi did not change significantly; pre 17.0(6.4) cmH2O post 17.5(5.9) cmH2O (p = 0.7). Fatiguers, defined as having a fall TwT10Pga ≥ 10% had significantly worse lung gas transfer, but did not differ in other exercise parameters. Conclusions In patients with COPD, abdominal muscle but not diaphragm fatigue develops following symptom limited incremental cycle ergometry. Further work is needed to establish whether abdominal muscle fatigue is relevant to exercise limitation in COPD, perhaps indirectly through an effect on quadriceps fatigability.
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Affiliation(s)
- Nicholas S Hopkinson
- National Heart and Lung Institute, Imperial College, Royal Brompton Hospital, Fulham Rd, London SW3 6NP, UK.
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Raupach T, Bahr F, Herrmann P, Lüthje L, Hasenfuss G, Andreas S. Inspiratory resistive loading does not increase sympathetic tone in COPD. Respir Med 2010; 104:107-13. [DOI: 10.1016/j.rmed.2009.06.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Revised: 06/11/2009] [Accepted: 06/15/2009] [Indexed: 10/20/2022]
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Perez Bogerd S, Selleron B, Hotton R, Ferrali O, Sergysels R. Les techniques de médecine physique peuvent-elles pallier la distension ? Rev Mal Respir 2009; 26:1107-17. [DOI: 10.1016/s0761-8425(09)73537-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Abstract
Respiratory rehabilitation is known to improve outcomes in patients with chronic obstructive pulmonary disease (COPD). The question addressed in the present review is whether these beneficial effects are related to improvements in inspiratory muscle function. Respiratory muscle fatigue often did not occur during exercise in patients with COPD, since exercise limitation usually occurred when significant force reserve in the inspiratory muscles was still present. Notwithstanding, a number of observations may provide indirect evidence that respiratory muscle fatigue may occur during exercise. Some evidence is present that, in normal humans, whole body exercise training improved inspiratory muscle endurance, but no studies are available in patients with COPD. Animal studies invariably demonstrated that exercise training increased the number of oxidative fibers and oxidative enzyme activity in inspiratory muscles. These effects, however, were considerably smaller than the effects found on peripheral muscles with similar fiber composition. Clear evidence indicated that inspiratory muscle training (IMT) improved inspiratory muscle function. Two large meta-analyses indicated that, if the training load was properly controlled, IMT alone or combined with general exercise reconditioning improved inspiratory muscle strength and endurance and dyspnea. The combination did not result in greater improvements in functional exercise capacity. Animal studies and one patient study confirmed the occurrence of structural remodeling of the inspiratory muscles in response to IMT. The final question is whether improvements in inspiratory muscle function produced by IMT lead to improved outcomes in COPD. In all five studies in which training load was adequately controlled, a significant reduction of dyspnea during activities of daily living was found. Eight randomized studies examined the effects of the combination. Greater improvements in exercise capacity were only found in three studies, and none showed a greater reduction in dyspnea.
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McKenzie DK, Butler JE, Gandevia SC. Respiratory muscle function and activation in chronic obstructive pulmonary disease. J Appl Physiol (1985) 2009; 107:621-9. [PMID: 19390004 DOI: 10.1152/japplphysiol.00163.2009] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Inspiratory muscles are uniquely adapted for endurance, but their function is compromised in chronic obstructive pulmonary disease (COPD) due to increased loads, reduced mechanical advantage, and increased ventilatory requirements. The hyperinflation of COPD reduces the flow and pressure-generating capacity of the diaphragm. This is compensated by a threefold increase in neural drive, adaptations of the chest wall and diaphragm shape to accommodate the increased volume, and adaptations of muscle fibers to preserve strength and increase endurance. Paradoxical indrawing of the lower costal margin during inspiration in severe COPD (Hoover's sign) correlates with high inspiratory drive and severe airflow obstruction rather than contraction of radially oriented diaphragm fibers. The inspiratory muscles remain highly resistant to fatigue in patients with COPD, and the ultimate development of ventilatory failure is associated with insufficient central drive. Sleep is associated with reduced respiratory drive and impairments of lung and chest wall function, which are exaggerated in COPD patients. Profound hypoxemia and hypercapnia can occur in rapid eye movement sleep and contribute to the development of cor pulmonale. Inspiratory muscles adapt to chronic loading with an increased proportion of slow, fatigue-resistant fiber types, increased oxidative capacity, and reduced fiber cross-sectional area, but the capacity of the diaphragm to increase ventilation in exercise is compromised in COPD. In COPD, neural drive to the diaphragm increases to near maximal levels in exercise, but it does not develop peripheral muscle fatigue. The improvement in exercise capacity and dyspnea following lung volume reduction surgery is associated with a substantial reduction in neural drive to the inspiratory muscles.
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Mechanisms of activity-related dyspnea in pulmonary diseases. Respir Physiol Neurobiol 2009; 167:116-32. [DOI: 10.1016/j.resp.2009.01.010] [Citation(s) in RCA: 161] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Accepted: 01/30/2009] [Indexed: 01/22/2023]
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42
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Effect of expiratory resistive loading on inspiratory and expiratory muscle fatigue. Respir Physiol Neurobiol 2009; 166:164-74. [DOI: 10.1016/j.resp.2009.03.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Revised: 03/02/2009] [Accepted: 03/05/2009] [Indexed: 11/20/2022]
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43
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Kim HC, Mofarrahi M, Hussain SNA. Skeletal muscle dysfunction in patients with chronic obstructive pulmonary disease. Int J Chron Obstruct Pulmon Dis 2009; 3:637-58. [PMID: 19281080 PMCID: PMC2650609 DOI: 10.2147/copd.s4480] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Chronic obstructive pulmonary disease (COPD) is a debilitating disease characterized by inflammation-induced airflow limitation and parenchymal destruction. In addition to pulmonary manifestations, patients with COPD develop systemic problems, including skeletal muscle and other organ-specific dysfunctions, nutritional abnormalities, weight loss, and adverse psychological responses. Patients with COPD often complain of dyspnea on exertion, reduced exercise capacity, and develop a progressive decline in lung function with increasing age. These symptoms have been attributed to increases in the work of breathing and in impairments in gas exchange that result from airflow limitation and dynamic hyperinflation. However, there is mounting evidence to suggest that skeletal muscle dysfunction, independent of lung function, contributes significantly to reduced exercise capacity and poor quality of life in these patients. Limb and ventilatory skeletal muscle dysfunction in COPD patients has been attributed to a myriad of factors, including the presence of low grade systemic inflammatory processes, nutritional depletion, corticosteroid medications, chronic inactivity, age, hypoxemia, smoking, oxidative and nitrosative stresses, protein degradation and changes in vascular density. This review briefly summarizes the contribution of these factors to overall skeletal muscle dysfunction in patients with COPD, with particular attention paid to the latest advances in the field.
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Affiliation(s)
- Ho Cheol Kim
- Department of Internal Medicine, College of Medicine, Gyeongsang National University, Gyeongsang University Hospital, Jinju, Korea
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44
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Abstract
Static lung hyperinflation is defined as the elevation of end- expiratory lung volume above its predicted value, with no increase in end-expiratory alveolar pressure, which remains equal to atmospheric pressure. Dynamic hyperinflation is the transient increase of this volume above the relaxation volume. In patients with COPD, dynamic hyperinflation is mainly determined by the mechanical properties of the respiratory system. Its measurement relies on plethysmography and, during exercise, inspiratory capacity. During exercise, dynamic hyperinflation attenuates expiratory flow limitation but increases the inspiratory loading and induces functional weakness of the diaphragm. It also has haemodynamic consequences and results in more rapid, shallow breathing and progressive reduction in dynamic lung compliance. These events explain exercise intolerance. Several approaches may help combat dynamic hyperinflation and its deleterious clinical effects: bronchodilators, hyperoxia, helium-oxygen mixtures, lung volume reduction surgery...
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Affiliation(s)
- D-E O'donnell
- Division of Respiratory and critical care medicine, Department of Medicine, Queen's University, Kingston, Ontario, Canada.
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Aliverti A. Lung and chest wall mechanics during exercise: Effects of expiratory flow limitation. Respir Physiol Neurobiol 2008; 163:90-9. [PMID: 18721912 DOI: 10.1016/j.resp.2008.07.025] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2008] [Revised: 07/23/2008] [Accepted: 07/24/2008] [Indexed: 11/17/2022]
Affiliation(s)
- Andrea Aliverti
- TBM Lab, Dipartimento di Bioingegneria, Politecnico di Milano, P. zza L. da Vinci 32, 20133 Milano, Italy.
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46
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O'Donnell DE, Webb KA. The major limitation to exercise performance in COPD is dynamic hyperinflation. J Appl Physiol (1985) 2008; 105:753-5; discussion 755-7. [DOI: 10.1152/japplphysiol.90336.2008b] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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47
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Laveneziana P, Parker CM, O'Donnell DE. Ventilatory constraints and dyspnea during exercise in chronic obstructive pulmonary disease. Appl Physiol Nutr Metab 2008; 32:1225-38. [PMID: 18059601 DOI: 10.1139/h07-119] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Dyspnea (respiratory difficulty) and activity limitation are the primary symptoms of chronic obstructive pulmonary disease (COPD) and progress relentlessly as the disease advances, contributing to reduced quality of life. In COPD, the mechanisms of dyspnea are multifactorial, but abnormal dynamic ventilatory mechanics are believed to play a central role. In flow-limited patients with COPD, dynamic lung hyperinflation (DH) occurs during exercise and has serious sensory and mechanical consequences. In several studies, indices of DH strongly correlate with ratings of dyspnea intensity during exercise, and strategies that reduce resting hyperinflation (either pharmacological or surgical) consistently result in reduced exertional dyspnea. The mechanisms by which DH gives rise to exertional dyspnea and exercise intolerance are complex, but recent mechanistic studies suggest that DH-induced inspiratory muscle loading, restriction of tidal volume expansion during exercise, and consequent neuromechanical uncoupling of the respiratory system are key components. This review examines the specific derangements of ventilatory mechanics that occur in COPD during exercise and attempts to provide a mechanistic rationale for the attendant respiratory discomfort and activity limitation.
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Affiliation(s)
- Pierantonio Laveneziana
- Division of Respiratory and Critical Care Medicine, Department of Medicine, Queen's University, 102 Stuart St., Kingston, ON K7L 2V6
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48
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Ottenheijm CAC, Heunks LMA, Dekhuijzen RPN. Diaphragm adaptations in patients with COPD. Respir Res 2008; 9:12. [PMID: 18218129 PMCID: PMC2248576 DOI: 10.1186/1465-9921-9-12] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2007] [Accepted: 01/24/2008] [Indexed: 01/03/2023] Open
Abstract
Inspiratory muscle weakness in patients with COPD is of major clinical relevance. For instance, maximum inspiratory pressure generation is an independent determinant of survival in severe COPD. Traditionally, inspiratory muscle weakness has been ascribed to hyperinflation-induced diaphragm shortening. However, more recently, invasive evaluation of diaphragm contractile function, structure, and biochemistry demonstrated that cellular and molecular alterations occur, of which several can be considered pathologic of nature. Whereas the fiber type shift towards oxidative type I fibers in COPD diaphragm is regarded beneficial, rendering the overloaded diaphragm more resistant to fatigue, the reduction of diaphragm fiber force generation in vitro likely contributes to diaphragm weakness. The reduced diaphragm force generation at single fiber level is associated with loss of myosin content in these fibers. Moreover, the diaphragm in COPD is exposed to oxidative stress and sarcomeric injury. This review postulates that the oxidative stress and sarcomeric injury activate proteolytic machinery, leading to contractile protein wasting and, consequently, loss of force generating capacity of diaphragm fibers in patients with COPD. Interestingly, several of these presumed pathologic alterations are already present early in the course of the disease (GOLD I/II), although these patients appear not limited in their daily life activities. Treatment of diaphragm dysfunction in COPD is complex since its etiology is unclear, but recent findings indicate the ubiquitin-proteasome pathway as a prime target to attenuate diaphragm wasting in COPD.
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Affiliation(s)
- Coen A C Ottenheijm
- Dept. of Molecular and Cellular Biology, University of Arizona, Tucson, USA.
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Girard O, Lattier G, Maffiuletti NA, Micallef JP, Millet GP. Neuromuscular fatigue during a prolonged intermittent exercise: Application to tennis. J Electromyogr Kinesiol 2007; 18:1038-46. [PMID: 17611122 DOI: 10.1016/j.jelekin.2007.05.005] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2007] [Revised: 04/24/2007] [Accepted: 05/11/2007] [Indexed: 10/23/2022] Open
Abstract
The time course of alteration in neuromuscular function of the knee extensor muscles was characterized during a prolonged intermittent exercise. Maximal voluntary contraction (MVC) and surface EMG activity of both vastii were measured during brief interruptions before (T(0)), during (30, 60, 90, 120, 150 and 180min: T(30), T(60), T(90), T(120), T(150), T(180)) and 30min after (T(+30)) a 3h tennis match in 12 trained players. M-wave and twitch contractile properties were analyzed following single stimuli. Short tetani at 20Hz and 80Hz were also applied to six subjects at T(0) and T(180). Significant reductions in MVC (P<0.05; -9%) and electromyographic activity normalized to the M wave for both vastii (P<0.01) occurred with fatigue at T(180). No significant changes in M-wave duration and amplitude nor in twitch contractile properties were observed. The ratio between the torques evoked by 20Hz and 80Hz stimulation declined significantly (P<0.001; -12%) after exercise. Central activation failure and alterations in excitation-contraction coupling are probable mechanisms contributing to the moderate impairment of the neuromuscular function during prolonged tennis playing.
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Affiliation(s)
- Olivier Girard
- UPRES - EA 2991, Faculty of Sport Sciences, Montpellier, France.
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50
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Ottenheijm CAC, Heunks LMA, Dekhuijzen PNR. Diaphragm muscle fiber dysfunction in chronic obstructive pulmonary disease: toward a pathophysiological concept. Am J Respir Crit Care Med 2007; 175:1233-40. [PMID: 17413128 DOI: 10.1164/rccm.200701-020pp] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Inspiratory muscle weakness in patients with chronic obstructive pulmonary disease (COPD) is of major clinical relevance; maximum inspiratory pressure generation is an independent determinant of survival in severe COPD. Traditionally, inspiratory muscle weakness has been ascribed to hyperinflation-induced diaphragm shortening. However, more recently, invasive evaluation of diaphragm contractile function, structure, and biochemistry demonstrated that cellular and molecular alterations occur, of which several can be considered of pathologic nature. Although the fiber-type shift toward oxidative type I fibers in COPD diaphragm is regarded as beneficial, rendering the overloaded diaphragm more resistant to fatigue, the reduction of diaphragm fiber force generation in vitro likely contributes to diaphragm weakness. The reduced diaphragm force generation at single-fiber level is associated with loss of myosin content. Moreover, the diaphragm in COPD is exposed to oxidative stress and sarcomeric injury. The current Pulmonary Perspective postulates that the oxidative stress and sarcomeric injury activate proteolytic machinery, leading to contractile protein wasting and, consequently, loss of force-generating capacity of diaphragm fibers in patients with COPD. Interestingly, several of these presumed pathologic alterations are already present early in the course of the disease (GOLD I/II), although these patients do not appear to be limited in their daily-life activities. Therefore, investigating in vivo diaphragm function in mild to moderate COPD should be the focus of future research. Treatment of diaphragm dysfunction in COPD is complex because its etiology is unclear, but recent findings show promise for the use of proteasome inhibitors in syndromes associated with muscle wasting, such as the diaphragm in COPD.
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Affiliation(s)
- Coen A C Ottenheijm
- Department of Pulmonary Diseases, 454 Radboud University, Nijmegen Medical Centre, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands.
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