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Leahy MG, Kipp S, Sheel AW. The Effect of Waistbands on Intra-Abdominal Pressure and Respiratory Mechanics During Bodyweight Exercise. J Strength Cond Res 2024:00124278-990000000-00528. [PMID: 39178170 DOI: 10.1519/jsc.0000000000004921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/25/2024]
Abstract
ABSTRACT Leahy, MG, Kipp, S, and Sheel, AW. The effect of waistbands on intra-abdominal pressure and respiratory mechanics during bodyweight exercise. J Strength Cond Res XX(X): 000-000, 2024-Athletic apparel is often designed with high-waisted, elastic bands around the abdomen to provide comfort and support during functional exercises. The abdominal musculature aids in both active respiration and trunk stability during the exercise, but whether high-waistband athletic garments affect pulmonary function and respiratory mechanics is unknown. Ten healthy women participated in a single-visit study. Subjects were fitted with esophageal and gastric balloon-tipped catheters and completed three bouts of isometric and dynamic bodyweight squats, lunges, and planks, during which ventilation and pulmonary pressures were continuously recorded. Resting pulmonary function was unchanged by high-waistband garments. During isometric squatting exercise, peak abdominal pressure was significantly greater while wearing high-waistband garments (17 ± 6 cmH2O), relative to low-waistband garments (15 ± 6 cmH2O, p = 0.032). The work of breathing was reduced when completing dynamic squat exercise in a high-waistband garment (16.2 ± 3.9 J·min-1), relative to a low-waistband garment (18.6 ± 5.7 J·min-1, p = 0.026). High waistbands had no effect on abdominal pressures or pulmonary mechanics during lunge or plank exercises. We believe our findings indicate that high-waistband garments have the capacity to alter abdominal and ventilatory mechanics during bodyweight squatting exercises but are unlikely to have an effect during other exercise movements.
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Affiliation(s)
- Michael G Leahy
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
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2
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Holland AE, Spathis A, Marsaa K, Bausewein C, Ahmadi Z, Burge AT, Pascoe A, Gadowski AM, Collis P, Jelen T, Reilly CC, Reinke LF, Romero L, Russell AM, Saggu R, Solheim J, Vagheggini G, Vandendungen C, Wijsenbeek M, Tonia T, Smallwood N, Ekström M. European Respiratory Society clinical practice guideline on symptom management for adults with serious respiratory illness. Eur Respir J 2024; 63:2400335. [PMID: 38719772 DOI: 10.1183/13993003.00335-2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 03/19/2024] [Indexed: 06/30/2024]
Abstract
Respiratory symptoms are ubiquitous and impair health-related quality of life in people with respiratory disease. This European Respiratory Society (ERS) task force aimed to provide recommendations for symptomatic treatment in people with serious respiratory illness. The ERS task force comprised 16 members, including representatives of people with serious respiratory illness and informal caregivers. Seven questions were formulated, six in the PICO (Population, Intervention, Comparison, Outcome) format, which were addressed with full systematic reviews and evidence assessed using GRADE (Grading of Recommendations Assessment, Development and Evaluation). One question was addressed narratively. An "evidence-to-decision" framework was used to formulate recommendations. To treat symptoms in people with serious respiratory illness, the task force suggests the use of graded exercise therapy (conditional recommendation, low certainty of evidence); and suggests the use of a multicomponent services, handheld fan and breathing techniques (conditional recommendations, very low certainty of evidence). The task force suggests not to use opioids (conditional recommendation, very low certainty of evidence); and suggests either administering or not administering supplemental oxygen therapy (conditional recommendation, low certainty of evidence). The task force suggests that needs assessment tools may be used as part of a comprehensive needs assessment, but do not replace patient-centred care and shared decision making (conditional recommendation, low certainty of evidence). The low certainty of evidence, modest impact of interventions on patient-centred outcomes, and absence of effective strategies to ameliorate cough highlight the need for new approaches to reduce symptoms and enhance wellbeing for individuals who live with serious respiratory illness.
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Affiliation(s)
- Anne E Holland
- Departments of Physiotherapy and Respiratory Medicine, Alfred Health, Melbourne, Australia
- School of Translational Medicine, Monash University, Melbourne, Australia
- Institute for Breathing and Sleep, Melbourne, Australia
| | - Anna Spathis
- Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
| | - Kristoffer Marsaa
- Department of Multidisease, North Zealand Hospital, Copenhagen University, Hilleroed, Denmark
| | - Claudia Bausewein
- Department of Palliative Medicine, LMU University Hospital, LMU Munich, Munich, Germany
| | - Zainab Ahmadi
- Respiratory Medicine, Allergology and Palliative Medicine, Department of Clinical Sciences Lund, Lund University, Lund, Sweden
| | - Angela T Burge
- School of Translational Medicine, Monash University, Melbourne, Australia
- Department of Physiotherapy, Alfred Health, Melbourne, Australia
| | - Amy Pascoe
- School of Translational Medicine, Monash University, Melbourne, Australia
| | - Adelle M Gadowski
- School of Translational Medicine, Monash University, Melbourne, Australia
| | - Phil Collis
- CPROR Birmingham University, Birmingham, UK
- Patient Advisory Group, European Lung Foundation, Sheffield, UK
| | - Tessa Jelen
- Patient Advisory Group, European Lung Foundation, Sheffield, UK
| | - Charles C Reilly
- Department of Physiotherapy, King's College Hospital, London, UK
- Cicely Saunders Institute of Palliative Care, Policy and Rehabilitation, King's College London, London, UK
| | - Lynn F Reinke
- College of Nursing, University of Utah, Salt Lake City, UT, USA
| | - Lorena Romero
- The Ian Potter Library, Alfred Health, Melbourne, Australia
| | - Anne-Marie Russell
- Institute of Clinical Sciences, University of Birmingham, Birmingham, UK
- Birmingham Regional NHS Interstitial Lung Disease and Occupational Lung Disease Service, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Ravijyot Saggu
- Pharmacy Medicines Management Team, Central London Community Healthcare Trust, London, UK
| | - John Solheim
- EU-PFF - European Pulmonary Fibrosis Federation, Overijse, Belgium
- LHL-IPF, Jessheim, Norway
| | - Guido Vagheggini
- Department of Internal Medicine and Medical Specialties, Respiratory Failure Pathway, Azienda USL Toscana Nordovest, Pisa, Italy
- Fondazione Volterra Ricerche ONLUS, Volterra, Italy
| | - Chantal Vandendungen
- EU-PFF - European Pulmonary Fibrosis Federation, Overijse, Belgium
- ABFFP - Association Belge Francophone Contre la Fibrose Pulmonaire, Rebecq, Belgium
| | - Marlies Wijsenbeek
- Department of Respiratory Medicine, Erasmus University Medical Center, Center of Excellence for Interstitial Lung Disease, Rotterdam, The Netherlands
| | - Thomy Tonia
- Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
| | - Natasha Smallwood
- School of Translational Medicine, Monash University, Melbourne, Australia
- Department of Respiratory Medicine, Alfred Health, Melbourne, Australia
- Joint last authors
| | - Magnus Ekström
- Respiratory Medicine, Allergology and Palliative Medicine, Department of Clinical Sciences Lund, Lund University, Lund, Sweden
- Joint last authors
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Gerson EAM, Dominelli PB, Leahy MG, Kipp S, Guenette JA, Archiza B, Sheel AW. The effect of proportional assist ventilation on the electrical activity of the human diaphragm during exercise. Exp Physiol 2023; 108:296-306. [PMID: 36420595 PMCID: PMC10103863 DOI: 10.1113/ep090808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 11/10/2022] [Indexed: 11/25/2022]
Abstract
NEW FINDINGS What is the central question of this study? What is the effect of lowering the normally occurring work of breathing on the electrical activity and pressure generated by the diaphragm during submaximal exercise in healthy humans? What is the main finding and its importance? Ventilatory assist during exercise elicits a proportional lowering of both the work performed by the diaphragm and diaphragm electrical activity. These findings have implications for exercise training studies using proportional assist ventilation to reduce diaphragm work in patients with cardiopulmonary disease. ABSTRACT We hypothesized that when a proportional assist ventilator (PAV) is applied in order to reduce the pressure generated by the diaphragm, there would be a corresponding reduction in electrical activity of the diaphragm. Healthy participants (five male and four female) completed an incremental cycle exercise test to exhaustion in order to calculate workloads for subsequent trials. On the experimental day, participants performed submaximal cycling, and three levels of assisted ventilation were applied (low, medium and high). Ventilatory parameters, pulmonary pressures and EMG of the diaphragm (EMGdi ) were obtained. To compare the PAV conditions with spontaneous breathing intervals, ANOVA procedures were used, and significant effects were evaluated with a Tukey-Kramer test. Significance was set at P < 0.05. The work of breathing was not different between the lowest level of unloading and spontaneous breathing (P = 0.151) but was significantly lower during medium (25%, P = 0.02) and high (36%, P < 0.001) levels of PAV. The pressure-time product of the diaphragm (PTPdi ) was lower across PAV unloading conditions (P < 0.05). The EMGdi was significantly lower in medium and high PAV conditions (P = 0.035 and P < 0.001, respectively). The mean reductions of EMGdi with PAV unloading were 14, 22 and 39%, respectively. The change in EMGdi for a given lowering of PTPdi with the PAV was significantly correlated (r = 0.61, P = 0.01). Ventilatory assist during exercise elicits a reduction in the electrical activity of the diaphragm, and there is a proportional lowering of the work of breathing. Our findings have implications for exercise training studies using assisted ventilation to reduce diaphragm work in patients with cardiopulmonary disease.
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Affiliation(s)
- Emily A. M. Gerson
- School of KinesiologyThe University of British ColumbiaVancouverBritish ColumbiaCanada
| | | | - Michael G. Leahy
- School of KinesiologyThe University of British ColumbiaVancouverBritish ColumbiaCanada
| | - Shalaya Kipp
- School of KinesiologyThe University of British ColumbiaVancouverBritish ColumbiaCanada
| | - Jordan A. Guenette
- School of KinesiologyThe University of British ColumbiaVancouverBritish ColumbiaCanada
- Centre for Heart Lung InnovationProvidence ResearchThe University of British Columbia, St. Paul's HospitalVancouverBritish ColumbiaCanada
- Department of Physical TherapyFaculty of MedicineThe University of British ColumbiaVancouverBritish ColumbiaCanada
| | - Bruno Archiza
- School of KinesiologyThe University of British ColumbiaVancouverBritish ColumbiaCanada
- Department of PhysiotherapyCardiopulmonary Physiotherapy LaboratoryNucleus of Research in Physical Exercise, Federal University of Sao CarlosSao CarlosBrazil
| | - Andrew William Sheel
- School of KinesiologyThe University of British ColumbiaVancouverBritish ColumbiaCanada
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Nicolò A, Sacchetti M. Differential control of respiratory frequency and tidal volume during exercise. Eur J Appl Physiol 2023; 123:215-242. [PMID: 36326866 DOI: 10.1007/s00421-022-05077-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 10/18/2022] [Indexed: 11/06/2022]
Abstract
The lack of a testable model explaining how ventilation is regulated in different exercise conditions has been repeatedly acknowledged in the field of exercise physiology. Yet, this issue contrasts with the abundance of insightful findings produced over the last century and calls for the adoption of new integrative perspectives. In this review, we provide a methodological approach supporting the importance of producing a set of evidence by evaluating different studies together-especially those conducted in 'real' exercise conditions-instead of single studies separately. We show how the collective assessment of findings from three domains and three levels of observation support the development of a simple model of ventilatory control which proves to be effective in different exercise protocols, populations and experimental interventions. The main feature of the model is the differential control of respiratory frequency (fR) and tidal volume (VT); fR is primarily modulated by central command (especially during high-intensity exercise) and muscle afferent feedback (especially during moderate exercise) whereas VT by metabolic inputs. Furthermore, VT appears to be fine-tuned based on fR levels to match alveolar ventilation with metabolic requirements in different intensity domains, and even at a breath-by-breath level. This model reconciles the classical neuro-humoral theory with apparently contrasting findings by leveraging on the emerging control properties of the behavioural (i.e. fR) and metabolic (i.e. VT) components of minute ventilation. The integrative approach presented is expected to help in the design and interpretation of future studies on the control of fR and VT during exercise.
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Affiliation(s)
- Andrea Nicolò
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Piazza Lauro De Bosis 6, 00135, Rome, Italy.
| | - Massimo Sacchetti
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Piazza Lauro De Bosis 6, 00135, Rome, Italy
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Gindre D, Surpas P, Garcia-Tejero M, Decullier E, Bin S. Apport de l’hélium dans la réhabilitation respiratoire de patients BPCO sévères. Rev Mal Respir 2022; 39:676-684. [DOI: 10.1016/j.rmr.2022.08.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 07/18/2022] [Indexed: 11/26/2022]
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Gelinas J, Harper M, Sasso J, Wright S, Melzer B, Agar G, Guenette J, duManoir G, Roman M, Rolf JD, Eves N. Phenotyping Cardiopulmonary Exercise Limitations in Chronic Obstructive Pulmonary Disease. Front Physiol 2022; 13:816586. [PMID: 35242051 PMCID: PMC8886157 DOI: 10.3389/fphys.2022.816586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 01/26/2022] [Indexed: 11/24/2022] Open
Abstract
Background Exercise limitation in chronic obstructive pulmonary disease (COPD) is commonly attributed to abnormal ventilatory mechanics and/or skeletal muscle function, while cardiovascular contributions remain relatively understudied. To date, the integrative exercise responses associated with different cardiopulmonary exercise limitation phenotypes in COPD have not been explored but may provide novel therapeutic utility. This study determined the ventilatory, cardiovascular, and metabolic responses to incremental exercise in patients with COPD with different exercise limitation phenotypes. Methods Patients with COPD (n = 95, FEV1:23–113%pred) performed a pulmonary function test and incremental cardiopulmonary exercise test. Exercise limitation phenotypes were classified as: ventilatory [peak ventilation (VEpeak)/maximal ventilatory capacity (MVC) ≥ 85% or MVC-VEpeak ≤ 11 L/min, and peak heart rate (HRpeak) < 90%pred], cardiovascular (VEpeak/MVC < 85% or MVC-VEpeak > 11 L/min, and HRpeak ≥ 90%pred), or combined (VEpeak/MVC ≥ 85% or MVC-VEpeak ≤ 11 L/min, and HRpeak ≥ 90%pred). Results FEV1 varied within phenotype: ventilatory (23–75%pred), combined (28–90%pred), and cardiovascular (68–113%pred). The cardiovascular phenotype had less static hyperinflation, a lower end-expiratory lung volume and larger tidal volume at peak exercise compared to both other phenotypes (p < 0.01 for all). The cardiovascular phenotype reached a higher VEpeak (60.8 ± 11.5 L/min vs. 45.3 ± 15.5 L/min, p = 0.002), cardiopulmonary fitness (VO2peak: 20.6 ± 4.0 ml/kg/min vs. 15.2 ± 3.3 ml/kg/min, p < 0.001), and maximum workload (103 ± 34 W vs. 72 ± 27 W, p < 0.01) vs. the ventilatory phenotype, but was similar to the combined phenotype. Conclusion Distinct exercise limitation phenotypes were identified in COPD that were not solely dependent upon airflow limitation severity. Approximately 50% of patients reached maximal heart rate, indicating that peak cardiac output and convective O2 delivery contributed to exercise limitation. Categorizing patients with COPD phenotypically may aid in optimizing exercise prescription for rehabilitative purposes.
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Affiliation(s)
- Jinelle Gelinas
- Centre for Heart, Lung and Vascular Health, University of British Columbia, Kelowna, BC, Canada
| | - Megan Harper
- Centre for Heart, Lung and Vascular Health, University of British Columbia, Kelowna, BC, Canada
| | - John Sasso
- Centre for Heart, Lung and Vascular Health, University of British Columbia, Kelowna, BC, Canada
| | - Stephen Wright
- Centre for Heart, Lung and Vascular Health, University of British Columbia, Kelowna, BC, Canada
| | - Bernie Melzer
- Interior Health Authority, Kelowna General Hospital, Kelowna, BC, Canada
| | - Gloria Agar
- Interior Health Authority, Kelowna General Hospital, Kelowna, BC, Canada
| | - Jordan Guenette
- Department of Physical Therapy and Centre for Heart Lung Innovation, University of British Columbia and St. Paul's Hospital, Vancouver, BC, Canada
| | - Gregory duManoir
- Centre for Heart, Lung and Vascular Health, University of British Columbia, Kelowna, BC, Canada
| | - Michael Roman
- Faculty of Medicine, University of Calgary, Calgary, AB, Canada
| | - J Douglass Rolf
- Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Neil Eves
- Centre for Heart, Lung and Vascular Health, University of British Columbia, Kelowna, BC, Canada
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7
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Duke JW, Lewandowski AJ, Abman SH, Lovering AT. Physiological aspects of cardiopulmonary dysanapsis on exercise in adults born preterm. J Physiol 2022; 600:463-482. [PMID: 34961925 PMCID: PMC9036864 DOI: 10.1113/jp281848] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 12/03/2021] [Indexed: 02/03/2023] Open
Abstract
Progressive improvements in perinatal care and respiratory management of preterm infants have resulted in increased survival of newborns of extremely low gestational age over the past few decades. However, the incidence of bronchopulmonary dysplasia, the chronic lung disease after preterm birth, has not changed. Studies of the long-term follow-up of adults born preterm have shown persistent abnormalities of respiratory, cardiovascular and cardiopulmonary function, possibly leading to a lower exercise capacity. The underlying causes of these abnormalities are incompletely known, but we hypothesize that dysanapsis, i.e. discordant growth and development, in the respiratory and cardiovascular systems is a central structural feature that leads to a lower exercise capacity in young adults born preterm than those born at term. We discuss how the hypothesized system dysanapsis underscores the observed respiratory, cardiovascular and cardiopulmonary limitations. Specifically, adults born preterm have: (1) normal lung volumes but smaller airways, which causes expiratory airflow limitation and abnormal respiratory mechanics but without impacts on pulmonary gas exchange efficiency; (2) normal total cardiac size but smaller cardiac chambers; and (3) in some cases, evidence of pulmonary hypertension, particularly during exercise, suggesting a reduced pulmonary vascular capacity despite reduced cardiac output. We speculate that these underlying developmental abnormalities may accelerate the normal age-associated decline in exercise capacity, via an accelerated decline in respiratory, cardiovascular and cardiopulmonary function. Finally, we suggest areas of future research, especially the need for longitudinal and interventional studies from infancy into adulthood to better understand how preterm birth alters exercise capacity across the lifespan.
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Affiliation(s)
- Joseph W. Duke
- Northern Arizona University, Department of Biological Sciences, Flagstaff, AZ, USA
| | - Adam J. Lewandowski
- University of Oxford, Oxford Cardiovascular Clinical Research Facility, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, Oxford, UK
| | - Steven H. Abman
- University of Colorado Anschutz School of Medicine, Department of Pediatrics, Aurora, CO, USA
- Pediatric Heart Lung Center, Children’s Hospital Colorado, Aurora, CO, USA
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8
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Neder JA, Berton DC, Phillips DB, O'Donnell DE. Exertional ventilation/carbon dioxide output relationship in COPD: from physiological mechanisms to clinical applications. Eur Respir Rev 2021; 30:30/161/200190. [PMID: 34526312 PMCID: PMC9489189 DOI: 10.1183/16000617.0190-2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 09/30/2020] [Indexed: 01/09/2023] Open
Abstract
There is well established evidence that the minute ventilation (V′E)/carbon dioxide output (V′CO2) relationship is relevant to a number of patient-related outcomes in COPD. In most circumstances, an increased V′E/V′CO2 reflects an enlarged physiological dead space (“wasted” ventilation), although alveolar hyperventilation (largely due to increased chemosensitivity) may play an adjunct role, particularly in patients with coexistent cardiovascular disease. The V′E/V′CO2 nadir, in particular, has been found to be an important predictor of dyspnoea and poor exercise tolerance, even in patients with largely preserved forced expiratory volume in 1 s. As the disease progresses, a high nadir might help to unravel the cause of disproportionate breathlessness. When analysed in association with measurements of dynamic inspiratory constraints, a high V′E/V′CO2 is valuable to ascertain a role for the “lungs” in limiting dyspnoeic patients. Regardless of disease severity, cardiocirculatory (heart failure and pulmonary hypertension) and respiratory (lung fibrosis) comorbidities can further increase V′E/V′CO2. A high V′E/V′CO2 is a predictor of poor outcome in lung resection surgery, adding value to resting lung hyperinflation in predicting all-cause and respiratory mortality across the spectrum of disease severity. Considering its potential usefulness, the V′E/V′CO2 should be valued in the clinical management of patients with COPD. The minute ventilation/carbon dioxide production relationship is relevant to a number of patient-related outcomes in COPD. Minute ventilation/carbon dioxide production, therefore, should be valued in the clinical management of these patients.https://bit.ly/3df2upH
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Affiliation(s)
- J Alberto Neder
- Respiratory Investigation Unit and Laboratory of Clinical Exercise Physiology, Queen's University and Kingston General Hospital, Kingston, ON, Canada
| | - Danilo C Berton
- Respiratory Investigation Unit and Laboratory of Clinical Exercise Physiology, Queen's University and Kingston General Hospital, Kingston, ON, Canada.,Division of Respiratory Medicine, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Devin B Phillips
- Respiratory Investigation Unit and Laboratory of Clinical Exercise Physiology, Queen's University and Kingston General Hospital, Kingston, ON, Canada
| | - Denis E O'Donnell
- Respiratory Investigation Unit and Laboratory of Clinical Exercise Physiology, Queen's University and Kingston General Hospital, Kingston, ON, Canada
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9
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Cross TJ, Gideon EA, Morris SJ, Coriell CL, Hubbard CD, Duke JW. A comparison of methods used to quantify the work of breathing during exercise. J Appl Physiol (1985) 2021; 131:1123-1133. [PMID: 34410846 DOI: 10.1152/japplphysiol.00411.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The mechanical work of breathing (Wb) is an insightful tool used to assess respiratory mechanics during exercise. There are several different methods used to calculate the Wb, however, each approach having its own distinct advantages/disadvantages. To date, a comprehensive assessment of the differences in the components of Wb between these methods is lacking. We therefore sought to compare the values of Wb during graded exercise as determined via the four most popular methods: 1) pressure-volume integration; 2) the Hedstrand diagram; 3) the Otis diagram; and the 4) modified Campbell diagram. Forty-two participants (30 ± 15 yr; 16 women) performed graded cycling to volitional exhaustion. Esophageal pressure-volume loops were obtained throughout exercise. These data were used to calculate the total Wb and, where possible, its subcomponents of inspiratory and expiratory, resistive and elastic Wb, using each of the four methods. Our results demonstrate that the components of Wb were indeed different between methods across the minute ventilations engendered by graded exercise. Importantly, however, no systematic pattern in these differences could be observed. Our findings indicate that the values of Wb obtained during exercise are uniquely determined by the specific method chosen to compute its value-no two methods yield identical results. Because there is currently no "gold-standard" for measuring the Wb, it is emphasized that future investigators be cognizant of the limitations incurred by their chosen method, such that observations made by others may be interpreted with greater context, and transparency.NEW & NOTEWORTHY The measurement of the work of breathing (Wb) during exercise provides us with deep insights into respiratory (patho)physiology, and sheds light on the putative factors which lead to respiratory muscle fatigue. There are 4 popular methods available to determine the Wb. Our study demonstrates that no two of these methods produce identical values of Wb during exercise. This paper also discusses the practical and theoretical limitations of each method.
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Affiliation(s)
- Troy J Cross
- Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia.,Department of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
| | - Elizabeth A Gideon
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona
| | - Sarah J Morris
- Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
| | - Catherine L Coriell
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona
| | - Colin D Hubbard
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona
| | - Joseph W Duke
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona
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Wright SP, Cheyne WS, Gelinas JC, Harper MI, Sasso JP, Eves ND. Systolic reserve maintains left ventricular-vascular coupling when challenged by adverse breathing mechanics and hypertension in healthy adults. J Appl Physiol (1985) 2021; 130:1171-1182. [PMID: 33571052 DOI: 10.1152/japplphysiol.00833.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Augmented negative intrathoracic pressures (nITP) and dynamic hyperinflation (DH) are adverse breathing mechanics (ABM) associated with chronic obstructive pulmonary disease (COPD) that attenuate left ventricular (LV) preload and augment afterload. In COPD, hypertension (elevated systemic arterial load) commonly adds additional afterload to the LV. Combined ABM and hypertension may profoundly challenge ventricular-vascular coupling and attenuate stroke volume (SV), particularly if LV systolic reserve is limited. However, even in the healthy heart, the combined impact of ABM and systemic arterial loading on LV function and ventricular-vascular coupling has not been fully elucidated. Healthy volunteers (10 M/9 F, 24 ± 3 yr old) were challenged with mild (-10 cmH2O nITP and 25% DH) and severe (-20 cmH2O nITP and 100% DH) ABM, without and with postexercise ischemia (PEI) at each severity. LV SV, chamber geometry, end-systolic elastance (Ees), arterial elastance (Ea), and ventricular-vascular coupling (Ees:Ea) were quantified using echocardiography. Compared with resting control (58 ± 13 mL), SV decreased during mild ABM (51 ± 13 mL), mild ABM + PEI (51 ± 11 mL), severe ABM (50 ± 12 mL), and severe ABM + PEI (47 ± 11 mL) (P < 0.001); similar trends were observed for LV end-diastolic volume. The end-diastolic radius of septal curvature increased, indicating direct ventricular interaction, during severe ABM and severe ABM + PEI (P < 0.001). Compared with control (1.99 ± 0.41 mmHg/mL), Ea increased progressively with mild ABM (2.21 ± 0.47 mmHg/mL) and severe ABM (2.50 ± 0.56 mmHg/mL); at each severity, Ea was greater with superimposed PEI (P < 0.001). However, well-matched Ees increases occurred, and Ees:Ea was unchanged throughout. ABM pose a challenge to ventricular-vascular coupling that is accentuated by superimposed PEI; however, in healthy younger adults, the LV has substantial systolic reserve to maintain coupling.NEW & NOTEWORTHY In healthy younger adults, combined dynamic hyperinflation (DH) and negative intrathoracic pressures (nITP) attenuate left ventricular filling, but through different mechanisms at different severities. DH and nITP contribute to increased left ventricular afterload through mechanical effects in addition to presumed reflexive regulation, which can be further increased by elevated arterial loading. However, within this demographic, the left ventricle has substantial reserve to increase systolic performance, which matches contractility to afterload to preserve stroke volume.
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Affiliation(s)
- S P Wright
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - W S Cheyne
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - J C Gelinas
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - M I Harper
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - J P Sasso
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - N D Eves
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
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11
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Gideon EA, Cross TJ, Coriell CL, Duke JW. The effect of estimating chest wall compliance on the work of breathing during exercise as determined via the modified Campbell diagram. Am J Physiol Regul Integr Comp Physiol 2021; 320:R268-R275. [PMID: 33356877 DOI: 10.1152/ajpregu.00263.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The modified Campbell diagram provides one of the most comprehensive assessments of the work of breathing (Wb) during exercise, wherein the resistive and elastic work of inspiration and expiration are quantified. Importantly, a necessary step in constructing the modified Campbell diagram is to obtain a value for chest wall compliance (CCW). To date, it remains unknown whether estimating or directly measuring CCW impacts the Wb, as determined by the modified Campbell diagram. Therefore, the purpose of this study was to evaluate whether the components of the Wb differ when the modified Campbell diagram is constructed using an estimated versus measured value of CCW. Forty-two participants (n = 26 men, 16 women) performed graded exercise to volitional exhaustion on a cycle ergometer. CCW was measured directly at rest via quasistatic relaxation. Estimated values of CCW were taken from prior literature. The measured value of CCW was greater than that obtained via estimation (214 ± 52 mL/cmH2O vs. 189 ± 18 mL/cmH2O; P < 0.05). At modest-to-high minute ventilations (i.e., 50-200 L/min), the inspiratory elastic Wb was greater and expiratory resistive Wb was lower, when modified Campbell diagrams were constructed using estimated compared with measured values of CCW (P = 0.001). These differences were however small and never exceeded ±5%. Thus, although our findings demonstrate that estimating CCW has a measurable impact on the determination of the Wb, its effect appears relatively small within a cohort of healthy adults during graded exercise.
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Affiliation(s)
- Elizbeth A Gideon
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona
| | - Troy J Cross
- Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia.,Department of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
| | - Catherine L Coriell
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona
| | - Joseph W Duke
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona
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12
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Milne KM, Domnik NJ, Phillips DB, James MD, Vincent SG, Neder JA, O'Donnell DE. Evaluation of Dynamic Respiratory Mechanical Abnormalities During Conventional CPET. Front Med (Lausanne) 2020; 7:548. [PMID: 33072774 PMCID: PMC7533639 DOI: 10.3389/fmed.2020.00548] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 07/31/2020] [Indexed: 12/21/2022] Open
Abstract
Assessment of the ventilatory response to exercise is important in evaluating mechanisms of dyspnea and exercise intolerance in chronic cardiopulmonary diseases. The characteristic mechanical derangements that occur during exercise in chronic respiratory conditions have previously been determined in seminal studies using esophageal catheter pressure-derived measurements. In this brief review, we examine the emerging role and clinical utility of conventional assessment of dynamic respiratory mechanics during exercise testing. Thus, we provide a physiologic rationale for measuring operating lung volumes, breathing pattern, and flow-volume loops during exercise. We consider standardization of inspiratory capacity-derived measurements and their practical implementation in clinical laboratories. We examine the evidence that this iterative approach allows greater refinement in evaluation of ventilatory limitation during exercise than traditional assessments of breathing reserve. We appraise the available data on the reproducibility and responsiveness of this methodology. In particular, we review inspiratory capacity measurement and derived operating lung volumes during exercise. We demonstrate, using recent published data, how systematic evaluation of dynamic mechanical constraints, together with breathing pattern analysis, can provide valuable insights into the nature and extent of physiological impairment contributing to exercise intolerance in individuals with common chronic obstructive and restrictive respiratory disorders.
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Affiliation(s)
- Kathryn M Milne
- Respiratory Investigation Unit, Division of Respirology, Department of Medicine, Kingston Health Sciences Centre & Queen's University, Kingston, ON, Canada.,Clinician Investigator Program, Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Nicolle J Domnik
- Respiratory Investigation Unit, Division of Respirology, Department of Medicine, Kingston Health Sciences Centre & Queen's University, Kingston, ON, Canada
| | - Devin B Phillips
- Respiratory Investigation Unit, Division of Respirology, Department of Medicine, Kingston Health Sciences Centre & Queen's University, Kingston, ON, Canada
| | - Matthew D James
- Respiratory Investigation Unit, Division of Respirology, Department of Medicine, Kingston Health Sciences Centre & Queen's University, Kingston, ON, Canada
| | - Sandra G Vincent
- Respiratory Investigation Unit, Division of Respirology, Department of Medicine, Kingston Health Sciences Centre & Queen's University, Kingston, ON, Canada
| | - J Alberto Neder
- Laboratory of Clinical Exercise Physiology, Division of Respirology, Department of Medicine, Kingston Health Sciences Centre & Queen's University, Kingston, ON, Canada
| | - Denis E O'Donnell
- Respiratory Investigation Unit, Division of Respirology, Department of Medicine, Kingston Health Sciences Centre & Queen's University, Kingston, ON, Canada
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13
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Duke JW, Lovering AT. Respiratory and cardiopulmonary limitations to aerobic exercise capacity in adults born preterm. J Appl Physiol (1985) 2020; 129:718-724. [PMID: 32790592 DOI: 10.1152/japplphysiol.00419.2020] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Adults born preterm, regardless of whether they develop bronchopulmonary dysplasia, have underdeveloped respiratory and cardiopulmonary systems. The resulting impaired respiratory and cardiopulmonary systems are inadequate for the challenges imposed by aerobic exercise, which is exacerbated by the presence of bronchopulmonary dysplasia. Thus the respiratory and cardiopulmonary systems of these preterm individuals may be the most influential contributors to the significantly lower aerobic exercise capacity compared with their term born counterparts. The precise underlying cause(s) of the lower aerobic exercise capacity in adults born preterm is not entirely known but could be a number of interrelated parameters including mechanical ventilatory constraints, impaired pulmonary gas exchange efficiency, and excessive cardiopulmonary pressures. Likewise, additional aspects, such as impaired cardiovascular function and altered muscle bioenergetics, may play additional roles in limiting aerobic exercise capacity. Whether or not all or some of these aspects are present in adults born preterm and precisely how they may contribute to the lower aerobic exercise capacity are only beginning to be systematically explored. The purpose of this mini-review is to outline what is currently known about the respiratory and cardiopulmonary limitations during exercise in this population and to identify key areas where additional knowledge will help to advance this area. Additionally, where possible, we highlight the similarities and differences between obstructive lung disease resulting from preterm birth and chronic obstructive pulmonary disease (COPD) as the physiology and pathophysiology of these two forms of obstructive lung disease may not be identical.
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Affiliation(s)
- Joseph W Duke
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona
| | - Andrew T Lovering
- Department of Human Physiology, University of Oregon, Eugene, Oregon
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14
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Mann LM, Granger EA, Chan JS, Yu A, Molgat-Seon Y, Dominelli PB. Minimizing airflow turbulence in women lowers the work of breathing to levels similar to men. J Appl Physiol (1985) 2020; 129:410-418. [PMID: 32702273 DOI: 10.1152/japplphysiol.00347.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Smaller airways increase resistance and the propensity toward turbulent airflow, both of which are thought to be mechanisms behind greater resistive and total work of breathing (Wb) in females. Previous research examining the effect of airway size on the Wb between the sexes is limited by the inability to experimentally manipulate airway size. Heliox (21% oxygen, balance helium) is less dense than room air, which reduces turbulent airflow and airway resistance. The purpose of our study was to utilize heliox inspiration in women to provide a stimulus physiologically similar to increasing airway size. We hypothesized that when breathing heliox women would have a Wb similar to men breathing room air. Eighteen healthy young subjects (n = 9 women, 9 men) completed two maximal exercise tests on a cycle ergometer over 2 days. Subjects breathed room air for one test and heliox for the other. Wb was assessed with an esophageal balloon catheter. During the room air trial, when ventilations were >65 L/min, women had a significantly greater Wb compared with men (P < 0.05). The greater Wb in women was due to greater resistance to turbulent flow. For both sexes, breathing heliox resulted in increased expiratory flow (+132 ± 18% of room air), an elimination of expiratory flow limitation, and a reduction in Wb (69 ± 12% of room air) (all P < 0.05). When the women were breathing heliox, Wb was not different from that in the men breathing room air. Our findings support the idea that the smaller conducting airways in females are responsible for a greater total and resistive Wb.NEW & NOTEWORTHY When healthy young women breathe heliox gas during exercise, their work of breathing is not different from men breathing room air. Heliox inspiration reduces airway resistance and promotes laminar flow, which is a physiologically similar effect of increasing airway size. Our findings provide experimental evidence that smaller airways in women are responsible for the greater work of breathing during exercise.
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Affiliation(s)
- Leah M Mann
- Department of Kinesiology, Faculty of Applied Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Emily A Granger
- Department of Kinesiology, Faculty of Applied Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Jason S Chan
- Department of Kinesiology, Faculty of Applied Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Annie Yu
- Department of Kinesiology, Faculty of Applied Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Yannick Molgat-Seon
- Department of Kinesiology and Applied Health, Gupta Faculty of Kinesiology and Applied Health, University of Winnipeg, Winnipeg, Manitoba, Canada.,Centre for Heart and Lung Innovation, St. Paul's Hospital, Vancouver, British Columbia, Canada
| | - Paolo B Dominelli
- Department of Kinesiology, Faculty of Applied Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
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15
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Phillips DB, Collins SÉ, Bryan TL, Wong EYL, McMurtry MS, Bhutani M, Stickland MK. The effect of carotid chemoreceptor inhibition on exercise tolerance in chronic obstructive pulmonary disease: A randomized-controlled crossover trial. Respir Med 2019; 160:105815. [PMID: 31739245 DOI: 10.1016/j.rmed.2019.105815] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 10/24/2019] [Accepted: 11/05/2019] [Indexed: 11/19/2022]
Abstract
BACKGROUND Patients with chronic obstructive pulmonary disease (COPD) have an exaggerated ventilatory response to exercise, contributing to exertional dyspnea and exercise intolerance. We recently demonstrated enhanced activity and sensitivity of the carotid chemoreceptor (CC) in COPD which may alter ventilatory and cardiovascular regulation and negatively affect exercise tolerance. We sought to determine whether CC inhibition improves ventilatory and cardiovascular regulation, dyspnea and exercise tolerance in COPD. METHODS Twelve mild-moderate COPD patients (FEV1 83 ± 15 %predicted) and twelve age- and sex-matched healthy controls completed two time-to-symptom limitation (TLIM) constant load exercise tests at 75% peak power output with either intravenous saline or low-dose dopamine (2 μg·kg-1·min-1, order randomized) to inhibit the CC. Ventilatory responses were evaluated using expired gas data and dyspnea was evaluated using a modified Borg scale. Inspiratory capacity maneuvers were performed to determine operating lung volumes. Cardiac output was estimated using impedance cardiography and vascular conductance was calculated as cardiac output/mean arterial pressure (MAP). RESULTS At a standardized exercise time of 4-min and at TLIM; ventilation, operating volumes and dyspnea were unaffected by dopamine in COPD patients and controls. In COPD, dopamine decreased MAP and increased vascular conductance at all time points. In controls, dopamine increased vascular conductance at TLIM, while MAP was unaffected. CONCLUSION There was no change in time to exhaustion in either group with dopamine. These data suggest that the CC plays a role in cardiovascular regulation during exercise in COPD; however, ventilation, dyspnea and exercise tolerance were unaffected by CC inhibition in COPD patients.
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Affiliation(s)
- Devin B Phillips
- Division of Pulmonary Medicine, Faculty of Medicine and Dentistry, University of Alberta, Canada; Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Canada
| | - Sophie É Collins
- Division of Pulmonary Medicine, Faculty of Medicine and Dentistry, University of Alberta, Canada; Faculty of Rehabilitation Medicine, University of Alberta, Canada
| | - Tracey L Bryan
- Division of Pulmonary Medicine, Faculty of Medicine and Dentistry, University of Alberta, Canada
| | - Eric Y L Wong
- Division of Pulmonary Medicine, Faculty of Medicine and Dentistry, University of Alberta, Canada
| | - M Sean McMurtry
- Division of Cardiology, Faculty of Medicine and Dentistry, University of Alberta, Canada
| | - Mohit Bhutani
- Division of Pulmonary Medicine, Faculty of Medicine and Dentistry, University of Alberta, Canada
| | - Michael K Stickland
- Division of Pulmonary Medicine, Faculty of Medicine and Dentistry, University of Alberta, Canada; G.F. MacDonald Centre for Lung Health, Covenant Health, Edmonton, Alberta, Canada.
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16
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Louvaris Z, Vogiatzis I. Contrasting the physiological effects of heliox and oxygen during exercise in a patient with advanced COPD. Breathe (Sheff) 2019; 15:250-257. [PMID: 31508165 PMCID: PMC6717618 DOI: 10.1183/20734735.0197-2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
In COPD patients the ergogenic effect of heliox or oxygen breathing might be related both to improvements in ventilatory parameters (that lessen dyspnoea) and to enhanced oxygen delivery to respiratory and locomotor muscles http://bit.ly/2JlJBTc.
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Affiliation(s)
- Zafeiris Louvaris
- Faculty of Movement and Rehabilitation Sciences, Division of Respiratory Rehabilitation, Dept Rehabilitation Sciences KU Leuven, University Hospitals Leuven, Leuven, Belgium
| | - Ioannis Vogiatzis
- Dept of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University Newcastle, Newcastle, UK
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17
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Molgat-Seon Y, Dominelli PB, Peters CM, Guenette JA, Sheel AW, Gladstone IM, Lovering AT, Duke JW. Analysis of maximal expiratory flow-volume curves in adult survivors of preterm birth. Am J Physiol Regul Integr Comp Physiol 2019; 317:R588-R596. [PMID: 31433666 DOI: 10.1152/ajpregu.00114.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Adult survivors of very preterm (≤32 wk gestational age) birth without (PRE) and with bronchopulmonary dysplasia (BPD) have variable degrees of airflow obstruction at rest. Assessment of the shape of the maximal expiratory flow-volume (MEFV) curve in PRE and BPD may provide information concerning their unique pattern of airflow obstruction. The purposes of the present study were to 1) quantitatively assess the shape of the MEFV curve in PRE, BPD, and healthy adults born at full-term (CON), 2) identify where along the MEFV curve differences in shape existed between groups, and 3) determine the association between an index of MEFV curve shape and characteristics of preterm birth (i.e., gestational age, mass at birth, duration of oxygen therapy) in PRE and BPD. To do so, we calculated the average slope ratio (SR) throughout the effort-independent portion of the MEFV curve and at increments of 5% of forced vital capacity (FVC) between 20 and 80% of FVC in PRE (n = 19), BPD (n = 25), and CON (n = 20). We found that average SR was significantly higher in PRE (1.34 ± 0.35) and BPD (1.33 ± 0.45) compared with CON (1.03 ± 0.22; both P < 0.05) but similar between PRE and BPD (P = 0.99). Differences in SR between groups occurred early in expiration (i.e., 20-30% of FVC). There was no association between SR and characteristics of preterm birth in PRE and BPD groups (all P > 0.05). The mechanism(s) of increased SR during early expiration in PRE/BPD relative to CON is unknown but may be due to differences in the structural and mechanical properties of the airways.
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Affiliation(s)
- Yannick Molgat-Seon
- Department of Kinesiology and Applied Health, University of Winnipeg, Winnipeg, Manitoba, Canada.,Department of Physical Therapy, University of British Columbia, Vancouver, British Columbia, Canada.,Centre for Heart and Lung Innovation, St. Paul's Hospital, Vancouver, British Columbia, Canada
| | - Paolo B Dominelli
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Carli M Peters
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jordan A Guenette
- Department of Physical Therapy, University of British Columbia, Vancouver, British Columbia, Canada.,Centre for Heart and Lung Innovation, St. Paul's Hospital, Vancouver, British Columbia, Canada.,School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - A William Sheel
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Igor M Gladstone
- Oregon Health and Sciences University, Department of Paediatrics, Portland, Oregon
| | - Andrew T Lovering
- Department of Human Physiology, University of Oregon, Eugene, Oregon
| | - Joseph W Duke
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona
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18
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Laveneziana P, Di Paolo M. Exploring cardiopulmonary interactions during constant-workload submaximal cycle exercise in COPD patients. J Appl Physiol (1985) 2019; 127:688-690. [PMID: 31369332 DOI: 10.1152/japplphysiol.00526.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Pierantonio Laveneziana
- Sorbonne Université, INSERM, UMRS1158 Neurophysiologie respiratoire Expérimentale et clinique, Paris, France.,AP-HP Sorbonne Université, Groupe Hospitalier Pitié-Salpêtrière Charles Foix, Service des Explorations Fonctionnelles de la Respiration, de l'Exercice et de la Dyspnée du Département Médico-Universitaire « APPROCHES », Paris, France
| | - Marcello Di Paolo
- Department of Public Health and Infectious Diseases, "Sapienza" University of Rome, Rome, Italy
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19
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Laveneziana P, Albuquerque A, Aliverti A, Babb T, Barreiro E, Dres M, Dubé BP, Fauroux B, Gea J, Guenette JA, Hudson AL, Kabitz HJ, Laghi F, Langer D, Luo YM, Neder JA, O'Donnell D, Polkey MI, Rabinovich R, Rossi A, Series F, Similowski T, Spengler C, Vogiatzis I, Verges S. ERS statement on respiratory muscle testing at rest and during exercise. Eur Respir J 2019; 53:13993003.01214-2018. [DOI: 10.1183/13993003.01214-2018] [Citation(s) in RCA: 227] [Impact Index Per Article: 45.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 02/18/2019] [Indexed: 12/12/2022]
Abstract
Assessing respiratory mechanics and muscle function is critical for both clinical practice and research purposes. Several methodological developments over the past two decades have enhanced our understanding of respiratory muscle function and responses to interventions across the spectrum of health and disease. They are especially useful in diagnosing, phenotyping and assessing treatment efficacy in patients with respiratory symptoms and neuromuscular diseases. Considerable research has been undertaken over the past 17 years, since the publication of the previous American Thoracic Society (ATS)/European Respiratory Society (ERS) statement on respiratory muscle testing in 2002. Key advances have been made in the field of mechanics of breathing, respiratory muscle neurophysiology (electromyography, electroencephalography and transcranial magnetic stimulation) and on respiratory muscle imaging (ultrasound, optoelectronic plethysmography and structured light plethysmography). Accordingly, this ERS task force reviewed the field of respiratory muscle testing in health and disease, with particular reference to data obtained since the previous ATS/ERS statement. It summarises the most recent scientific and methodological developments regarding respiratory mechanics and respiratory muscle assessment by addressing the validity, precision, reproducibility, prognostic value and responsiveness to interventions of various methods. A particular emphasis is placed on assessment during exercise, which is a useful condition to stress the respiratory system.
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20
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Abstract
Dynamic hyperinflation (DH) is common in chronic obstructive pulmonary disease and is associated with dyspnea and exercise intolerance. DH also has adverse cardiac effects, although the magnitude of DH and the mechanisms responsible for the hemodynamic impairment remain unclear. We hypothesized that incrementally increasing DH would systematically reduce left ventricular (LV) end-diastolic volume (LVEDV) and LV stroke volume (LVSV) because of direct ventricular interaction. Twenty-three healthy subjects (22 ± 2 yr) were exposed to varying degrees of expiratory loading to induce DH such that inspiratory capacity was decreased by 25%, 50%, 75%, and 100% (100% DH = inspiratory capacity of resting tidal volume plus inspiratory reserve volume ≈ 0.5 l). LV volumes, LV geometry, inferior vena cava collapsibility, and LV end-systolic wall stress were assessed by triplane echocardiography. 25% DH reduced LVEDV (-6 ± 5%) and LVSV (-9 ± 8%). 50% DH elicited a similar response in LVEDV (-6 ± 7%) and LVSV (-11 ± 10%) and was associated with significant septal flattening [31 ± 32% increase in the radius of septal curvature at end diastole (RSC-ED)]. 75% DH caused a larger reduction in LVEDV and LVSV (-9 ± 7% and -16 ± 10%, respectively) and RSC-ED (49 ± 70%). 100% DH caused the largest reduction in LVEDV and LVSV (-13 ± 9% and -18 ± 9%) and an increase in RSC-ED (56 ± 63%). Inferior vena cava collapsibility and LV afterload (LV end-systolic wall stress) were unchanged at all levels of DH. Modest DH (-0.6 ± 0.2 l inspiratory reserve volume) reduced LVSV because of reduced LVEDV, likely because of increased pulmonary vascular resistance. At higher levels of DH, direct ventricular interaction may be the primary cause of attenuated LVSV, as indicated by septal flattening because of a greater relative increase in right ventricular pressure and/or mediastinal constraint. NEW & NOTEWORTHY By systematically reducing inspiratory capacity during spontaneous breathing, we demonstrate that dynamic hyperinflation (DH) progressively reduces left ventricular (LV) end diastolic volume and LV stroke volume. Evidence of significant septal flattening suggests that direct ventricular interaction may be primarily responsible for the reduced LV stroke volume during DH. Hemodynamic impairment appears to occur at relatively lower levels of DH and may have important clinical implications for patients with chronic obstructive pulmonary disease.
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Affiliation(s)
- William S Cheyne
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia , Kelowna, British Columbia , Canada
| | - Jinelle C Gelinas
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia , Kelowna, British Columbia , Canada
| | - Neil D Eves
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia , Kelowna, British Columbia , Canada
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21
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Cheyne WS, Gelinas JC, Eves ND. The haemodynamic response to incremental increases in negative intrathoracic pressure in healthy humans. Exp Physiol 2018; 103:581-589. [DOI: 10.1113/ep086654] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 01/22/2018] [Indexed: 12/19/2022]
Affiliation(s)
- William S. Cheyne
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences; University of British Columbia; Kelowna BC Canada
| | - Jinelle C. Gelinas
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences; University of British Columbia; Kelowna BC Canada
| | - Neil D. Eves
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences; University of British Columbia; Kelowna BC Canada
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22
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Brugniaux JV, Coombs GB, Barak OF, Dujic Z, Sekhon MS, Ainslie PN. Highs and lows of hyperoxia: physiological, performance, and clinical aspects. Am J Physiol Regul Integr Comp Physiol 2018; 315:R1-R27. [PMID: 29488785 DOI: 10.1152/ajpregu.00165.2017] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Molecular oxygen (O2) is a vital element in human survival and plays a major role in a diverse range of biological and physiological processes. Although normobaric hyperoxia can increase arterial oxygen content ([Formula: see text]), it also causes vasoconstriction and hence reduces O2 delivery in various vascular beds, including the heart, skeletal muscle, and brain. Thus, a seemingly paradoxical situation exists in which the administration of oxygen may place tissues at increased risk of hypoxic stress. Nevertheless, with various degrees of effectiveness, and not without consequences, supplemental oxygen is used clinically in an attempt to correct tissue hypoxia (e.g., brain ischemia, traumatic brain injury, carbon monoxide poisoning, etc.) and chronic hypoxemia (e.g., severe COPD, etc.) and to help with wound healing, necrosis, or reperfusion injuries (e.g., compromised grafts). Hyperoxia has also been used liberally by athletes in a belief that it offers performance-enhancing benefits; such benefits also extend to hypoxemic patients both at rest and during rehabilitation. This review aims to provide a comprehensive overview of the effects of hyperoxia in humans from the "bench to bedside." The first section will focus on the basic physiological principles of partial pressure of arterial O2, [Formula: see text], and barometric pressure and how these changes lead to variation in regional O2 delivery. This review provides an overview of the evidence for and against the use of hyperoxia as an aid to enhance physical performance. The final section addresses pathophysiological concepts, clinical studies, and implications for therapy. The potential of O2 toxicity and future research directions are also considered.
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Affiliation(s)
| | - Geoff B Coombs
- Centre for Heart, Lung, and Vascular Health, University of British Columbia , Kelowna, British Columbia , Canada
| | - Otto F Barak
- Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia.,Faculty of Sport and Physical Education, University of Novi Sad, Novi Sad, Serbia
| | - Zeljko Dujic
- Department of Integrative Physiology, School of Medicine, University of Split , Split , Croatia
| | - Mypinder S Sekhon
- Centre for Heart, Lung, and Vascular Health, University of British Columbia , Kelowna, British Columbia , Canada.,Division of Critical Care Medicine, Department of Medicine, Vancouver General Hospital, University of British Columbia , Vancouver, British Columbia , Canada
| | - Philip N Ainslie
- Centre for Heart, Lung, and Vascular Health, University of British Columbia , Kelowna, British Columbia , Canada
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23
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High Oxygen Delivery to Preserve Exercise Capacity in Patients with Idiopathic Pulmonary Fibrosis Treated with Nintedanib. Methodology of the HOPE-IPF Study. Ann Am Thorac Soc 2018; 13:1640-7. [PMID: 27348402 DOI: 10.1513/annalsats.201604-267oc] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
RATIONALE Pulmonary rehabilitation improves dyspnea and exercise capacity in idiopathic pulmonary fibrosis (IPF); however, it is unknown whether breathing high amounts of oxygen during exercise training leads to further benefits. OBJECTIVES Herein, we describe the design of the High Oxygen Delivery to Preserve Exercise Capacity in IPF Patients Treated with Nintedanib study (the HOPE-IPF study). The primary objective of this study is to determine the physiological and perceptual impact of breathing high levels of oxygen during exercise training in patients with IPF who are receiving antifibrotic therapy. METHODS HOPE-IPF is a two-arm double-blind multicenter randomized placebo-controlled trial of 88 patients with IPF treated with nintedanib. Patients will undergo 8 weeks of three times weekly aerobic cycle exercise training, breathing a hyperoxic gas mixture with a constant fraction of 60% inhaled oxygen, or breathing up to 40% oxygen as required to maintain an oxygen saturation level of at least 88%. MEASUREMENTS AND MAIN RESULTS End points will be assessed at baseline, postintervention (Week 8), and follow-up (Week 26). The primary analysis will compare the between-group baseline with post-training change in endurance time during constant work rate cycle exercise tests. Additional analyses will evaluate the impact of training with high oxygen delivery on 6-minute walk distance, dyspnea, physical activity, and quality of life. CONCLUSIONS The HOPE-IPF study will lead to a comprehensive understanding of IPF exercise physiology, with the potential to change clinical practice by indicating the need for increased delivery of supplemental oxygen during pulmonary rehabilitation in patients with IPF. Clinical trial registered with www.clinicaltrials.gov (NCT02551068).
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24
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Charususin N, Dacha S, Gosselink R, Decramer M, Von Leupoldt A, Reijnders T, Louvaris Z, Langer D. Respiratory muscle function and exercise limitation in patients with chronic obstructive pulmonary disease: a review. Expert Rev Respir Med 2017; 12:67-79. [DOI: 10.1080/17476348.2018.1398084] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Noppawan Charususin
- Respiratory Rehabilitation and Respiratory Division, University Hospital Leuven, Leuven, Belgium
- Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium
- Department of Physical Therapy, Thammasat University, Pathumthani, Thailand
| | - Sauwaluk Dacha
- Respiratory Rehabilitation and Respiratory Division, University Hospital Leuven, Leuven, Belgium
- Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium
- Department of Physical Therapy, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai, Thailand
| | - Rik Gosselink
- Respiratory Rehabilitation and Respiratory Division, University Hospital Leuven, Leuven, Belgium
- Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium
| | - Marc Decramer
- Respiratory Rehabilitation and Respiratory Division, University Hospital Leuven, Leuven, Belgium
| | - Andreas Von Leupoldt
- Department of Health Psychology, Faculty of Psychology and Educational Sciences, KU Leuven, Leuven, Belgium
| | - Thomas Reijnders
- Department of Health Psychology, Faculty of Psychology and Educational Sciences, KU Leuven, Leuven, Belgium
| | - Zafeiris Louvaris
- Respiratory Rehabilitation and Respiratory Division, University Hospital Leuven, Leuven, Belgium
- Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium
- Department of Critical Care Medicine and Pulmonary Services, Evangelismos Hospital, “M. Simou, and G.P. Livanos Laboratories”, National and Kapodistrian University of Athens, Athens, Greece
| | - Daniel Langer
- Respiratory Rehabilitation and Respiratory Division, University Hospital Leuven, Leuven, Belgium
- Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium
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Cheyne WS, Williams AM, Harper MI, Eves ND. Acute volume loading exacerbates direct ventricular interaction in a model of COPD. J Appl Physiol (1985) 2017; 123:1110-1117. [PMID: 28729396 DOI: 10.1152/japplphysiol.01109.2016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 06/28/2017] [Accepted: 07/18/2017] [Indexed: 11/22/2022] Open
Abstract
Volume loading increases left ventricular (LV) stroke volume (LVSV) through series interaction, but may paradoxically reduce LVSV in the presence of large increases in right ventricular (RV) afterload because of direct ventricular interaction (DVI). RV afterload is often increased in chronic obstructive pulmonary disease (COPD) as a result of pathological changes to respiratory mechanics, namely increased negative intrathoracic pressure (nITP), dynamic lung hyperinflation (DH), and increased pulmonary vascular resistance (PVR). These hallmarks of COPD negatively impact LV hemodynamics in normovolemia. However, it is unknown how these heart-lung interactions are impacted by acute volume loading. Twenty healthy subjects (23 ± 2 yr) completed the study protocol, involving acute volume loading via 20° head-down tilt (HDT) in isolation and with 1) inspiratory resistance of -20 cmH2O (HDT+nITP) and 2) nITP, expiratory resistance to induce DH and hypoxic-mediated increases in PVR (HDT+COPD model). LV volumes and geometry were assessed using triplane echocardiography. HDT significantly increased LVSV by 10 ± 10% through an 8 ± 6% increase in LV end-diastolic volume (LVEDV). HDT+nITP paradoxically decreased LVSV by 11 ± 12% and LVEDV by 6 ± 9% from supine baseline, or -14 ± 10% LVSV and -15 ± 13% LVEDV from HDT (P < 0.001). HDT+COPD model decreased LVSV (21 ± 10% and 28 ± 11%) and LVEDV (16 ± 10% and 22 ± 10%) from both supine and HDT, respectively (P < 0.001). Under all conditions, significant septal flattening (increased radius of septal curvature) occurred, indicating DVI. Thus, when RV afterload is increased and/or an external constraint to ventricular filling exists, acute volume loading appears to paradoxically reduce LVSV. These findings have important implications for understanding how volume status impacts cardiopulmonary interactions in COPD.NEW & NOTEWORTHY Volume loading may exacerbate adverse cardiopulmonary interaction in COPD; however, the mechanisms remain unclear. We found that when negative intrathoracic pressure is increased, acute volume loading paradoxically reduces stroke volume. This reduction in stroke volume is considerably greater in a model of COPD, owing to the effects of lung hyperinflation.
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Affiliation(s)
- William S Cheyne
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Alexandra M Williams
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Megan I Harper
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Neil D Eves
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
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Neder JA, Berton DC, Arbex FF, Alencar MC, Rocha A, Sperandio PA, Palange P, O'Donnell DE. Physiological and clinical relevance of exercise ventilatory efficiency in COPD. Eur Respir J 2017; 49:49/3/1602036. [PMID: 28275174 DOI: 10.1183/13993003.02036-2016] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 12/12/2016] [Indexed: 01/09/2023]
Abstract
Exercise ventilation (V'E) relative to carbon dioxide output (V'CO2 ) is particularly relevant to patients limited by the respiratory system, e.g. those with chronic obstructive pulmonary disease (COPD). High V'E-V'CO2 (poor ventilatory efficiency) has been found to be a key physiological abnormality in symptomatic patients with largely preserved forced expiratory volume in 1 s (FEV1). Establishing an association between high V'E-V'CO2 and exertional dyspnoea in mild COPD provides evidence that exercise intolerance is not a mere consequence of detraining. As the disease evolves, poor ventilatory efficiency might help explaining "out-of-proportion" breathlessness (to FEV1 impairment). Regardless, disease severity, cardiocirculatory co-morbidities such as heart failure and pulmonary hypertension have been found to increase V'E-V'CO2 In fact, a high V'E-V'CO2 has been found to be a powerful predictor of poor outcome in lung resection surgery. Moreover, a high V'E-V'CO2 has added value to resting lung hyperinflation in predicting all-cause and respiratory mortality across the spectrum of COPD severity. Documenting improved ventilatory efficiency after lung transplantation and lung volume reduction surgery provides objective evidence of treatment efficacy. Considering the usefulness of exercise ventilatory efficiency in different clinical scenarios, the V'E-V'CO2 relationship should be valued in the interpretation of cardiopulmonary exercise tests in patients with mild-to-end-stage COPD.
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Affiliation(s)
- J Alberto Neder
- Respiratory Investigation Unit and Laboratory of Clinical Exercise Physiology, Queen's University and Kingston General Hospital, Kingston, ON, Canada
| | - Danilo C Berton
- Respiratory Investigation Unit and Laboratory of Clinical Exercise Physiology, Queen's University and Kingston General Hospital, Kingston, ON, Canada.,Division of Respiratory Medicine, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Flavio F Arbex
- Pulmonary Function and Clinical Exercise Physiology, Respiratory Division, Federal University of Sao Paulo, Sao Paulo, Brazil
| | - Maria Clara Alencar
- Division of Cardiology, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Alcides Rocha
- Pulmonary Function and Clinical Exercise Physiology, Respiratory Division, Federal University of Sao Paulo, Sao Paulo, Brazil
| | - Priscila A Sperandio
- Pulmonary Function and Clinical Exercise Physiology, Respiratory Division, Federal University of Sao Paulo, Sao Paulo, Brazil
| | - Paolo Palange
- Dept of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Denis E O'Donnell
- Respiratory Investigation Unit and Laboratory of Clinical Exercise Physiology, Queen's University and Kingston General Hospital, Kingston, ON, Canada
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Ekström M, Ahmadi Z, Bornefalk‐Hermansson A, Abernethy A, Currow D. Oxygen for breathlessness in patients with chronic obstructive pulmonary disease who do not qualify for home oxygen therapy. Cochrane Database Syst Rev 2016; 11:CD006429. [PMID: 27886372 PMCID: PMC6464154 DOI: 10.1002/14651858.cd006429.pub3] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Breathlessness is a cardinal symptom of chronic obstructive pulmonary disease (COPD). Long-term oxygen therapy (LTOT) is given to improve survival time in people with COPD and severe chronic hypoxaemia at rest. The efficacy of oxygen therapy for breathlessness and health-related quality of life (HRQOL) in people with COPD and mild or no hypoxaemia who do not meet the criteria for LTOT has not been established. OBJECTIVES To determine the efficacy of oxygen versus air in mildly hypoxaemic or non-hypoxaemic patients with COPD in terms of (1) breathlessness; (2) HRQOL; (3) patient preference whether to continue therapy; and (4) oxygen-related adverse events. SEARCH METHODS We searched the Cochrane Airways Group Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and Embase, to 12 July 2016, for randomised controlled trials (RCTs). We handsearched the reference lists of included articles. SELECTION CRITERIA We included RCTs of the effects of non-invasive oxygen versus air on breathlessness, HRQOL or patient preference to continue therapy among people with COPD and mild or no hypoxaemia (partial pressure of oxygen (PaO2) > 7.3 kPa) who were not already receiving LTOT. Two review authors independently assessed articles for inclusion in the review. DATA COLLECTION AND ANALYSIS Two review authors independently collected and analysed data. We assessed risk of bias by using the Cochrane 'Risk of bias tool'. We pooled effects recorded on different scales as standardised mean differences (SMDs) with 95% confidence intervals (CIs) using random-effects models. Lower SMDs indicated decreased breathlessness and reduced HRQOL. We performed subanalyses and sensitivity analyses and assessed the quality of evidence according to the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach. MAIN RESULTS Compared with the previous review, which was published in 2011, we included 14 additional studies (493 participants), excluded one study and included data for meta-analysis of HRQOL. In total, we included in this review 44 studies including 1195 participants, and we included 33 of these (901 participants)in the meta-analysis.We found that breathlessness during exercise or daily activities was reduced by oxygen compared with air (32 studies; 865 participants; SMD -0.34, 95% CI -0.48 to -0.21; I2 = 37%; low-quality evidence). This translates to a decrease in breathlessness of about 0.7 points on a 0 to 10 numerical rating scale. In contrast, we found no effect of short-burst oxygen given before exercise (four studies; 90 participants; SMD 0.01, 95% CI -0.26 to 0.28; I2 = 0%; low-quality evidence). Oxygen reduced breathlessness measured during exercise tests (25 studies; 442 participants; SMD -0.34, 95% CI -0.46 to -0.22; I2 = 29%; moderate-quality evidence), whereas evidence of an effect on breathlessness measured in daily life was limited (two studies; 274 participants; SMD -0.13, 95% CI, -0.37 to 0.11; I2 = 0%; low-quality evidence).Oxygen did not clearly affect HRQOL (five studies; 267 participants; SMD 0.10, 95% CI -0.06 to 0.26; I2 = 0%; low-quality evidence). Patient preference and adverse events could not be analysed owing to insufficient data. AUTHORS' CONCLUSIONS We are moderately confident that oxygen can relieve breathlessness when given during exercise to mildly hypoxaemic and non-hypoxaemic people with chronic obstructive pulmonary disease who would not otherwise qualify for home oxygen therapy. Most evidence pertains to acute effects during exercise tests, and no evidence indicates that oxygen decreases breathlessness in the daily life setting. Findings show that oxygen does not affect health-related quality of life.
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Affiliation(s)
- Magnus Ekström
- Lund UniversityDepartment of Clinical Sciences, Division of Respiratory Medicine & AllergologyLundSweden
| | - Zainab Ahmadi
- Lund UniversityDepartment of Clinical Sciences, Division of Respiratory Medicine & AllergologyLundSweden
| | | | - Amy Abernethy
- Duke University Medical CenterCLHCDurhamNorth CarolinaUSA
| | - David Currow
- Flinders UniversityDepartment of Palliative and Supportive Services700 Goodwood RoadDaw ParkSAAustralia5041
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Cheyne WS, Williams AM, Harper MI, Eves ND. Heart-lung interaction in a model of COPD: importance of lung volume and direct ventricular interaction. Am J Physiol Heart Circ Physiol 2016; 311:H1367-H1374. [PMID: 27765746 DOI: 10.1152/ajpheart.00458.2016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 10/03/2016] [Indexed: 01/29/2023]
Abstract
Chronic obstructive pulmonary disease (COPD) is associated with dynamic lung hyperinflation (DH), increased pulmonary vascular resistance (PVR), and large increases in negative intrathoracic pressure (nITP). The individual and interactive effect of these stressors on left ventricular (LV) filling, emptying, and geometry and the role of direct ventricular interaction (DVI) in mediating these interactions have not been fully elucidated. Twenty healthy subjects were exposed to the following stressors alone and in combination: 1) inspiratory resistive loading of -20 cmH2O (nITP), 2) expiratory resistive loading to cause dynamic hyperinflation (DH), and 3) normobaric-hypoxia to increase PVR (hPVR). LV volumes and geometry were assessed using triplane echocardiography. LV stroke volume (LVSV) was reduced during nITP by 7 ± 7% (mean ± SD; P < 0.001) through a 4 ± 5% reduction in LV end-diastolic volume (LVEDV) (P = 0.002), while DH reduced LVSV by 12 ± 13% (P = 0.001) due to a 9 ± 10% reduction in LVEDV (P < 0.001). The combination of nITP and DH (nITP+DH) caused larger reductions in LVSV (16 ± 16%, P < 0.001) and LVEDV (12 ± 10%, P < 0.001) than nITP alone (P < 0.05). The addition of hPVR to nITP+DH did not further reduce LV volumes. Significant septal flattening (indicating DVI) occurred in all conditions, with a significantly greater leftward septal shift occurring with nITP+DH than either condition alone (P < 0.05). In summary, the interaction of nITP and DH reduces LV filling through DVI. However, DH may be more detrimental to LV hemodynamics than nITP, likely due to mediastinal constraint of the heart amplifying DVI.
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Affiliation(s)
- William S Cheyne
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Alexandra M Williams
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Megan I Harper
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Neil D Eves
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
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Dominelli PB, Henderson WR, Sheel AW. A proportional assist ventilator to unload respiratory muscles experimentally during exercise in humans. Exp Physiol 2016; 101:754-67. [PMID: 27028110 DOI: 10.1113/ep085735] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 03/22/2016] [Indexed: 11/08/2022]
Abstract
What is the central question of this study? Can a modern proportional assist ventilator (PAV) function sufficiently well to unload the respiratory muscles during exercise? What is the main finding and its importance? A PAV can be constructed with contemporary hardware and software and be used at all exercise intensities to unload the respiratory muscles by up to 70%. Previously, PAVs have allowed researchers to address many fundamental physiological problems in clinical and healthy populations, but those versions are no longer functional or available. We describe the creation of a PAV that permits researchers to use it as an experimental tool. Manipulation of the normally occurring work of breathing (WOB) during exercise can provide insights into whole-body regulatory mechanisms in clinical patients and healthy subjects. One method to reduce the WOB uses a proportional assist ventilator (PAV). Suitable commercially available units are not capable of being used during heavy exercise. This investigation was undertaken in order to create a PAV and assess the degree to which the WOB could be reduced during exercise. A PAV works by creating a positive mouth pressure (Pm ) during inspiration, which consequently reduces the WOB. Spontaneous breathing patterns can be maintained, and the amplitude of Pm is calculated using the equation of motion and predetermined proportionality constants. We generated positive Pm using a breathing apparatus consisting of rigid tubing, solenoid valves to control the airflow direction and a proportional valve connected to compressed gas. Healthy male and female subjects were able to use the PAV successfully while performing cycling exercise over a range of intensities (50-100% of maximal workload) for different durations (from 30 s to 20 min) and different protocols (constant versus progressive workload). Inspiratory WOB was reduced up to 90%, while total WOB was reduced by 70%. The greatest reduction in WOB (50-75%) occurred during submaximal exercise, but at maximal ventilations (>180 l min(-1) ) a 50% reduction was still possible. The calculated change in WOB and subsequent reduction in respiratory muscle oxygen consumption resulted in equivalent reductions in whole-body oxygen consumption. With adequate familiarization and practice, our PAV can consistently reduce the WOB across a range of exercise intensities.
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Affiliation(s)
- Paolo B Dominelli
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
| | - William R Henderson
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada.,Division of Critical Care Medicine, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - A William Sheel
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
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30
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Puente-Maestu L, Palange P, Casaburi R, Laveneziana P, Maltais F, Neder JA, O'Donnell DE, Onorati P, Porszasz J, Rabinovich R, Rossiter HB, Singh S, Troosters T, Ward S. Use of exercise testing in the evaluation of interventional efficacy: an official ERS statement. Eur Respir J 2016; 47:429-60. [DOI: 10.1183/13993003.00745-2015] [Citation(s) in RCA: 255] [Impact Index Per Article: 31.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 09/14/2015] [Indexed: 12/20/2022]
Abstract
This document reviews 1) the measurement properties of commonly used exercise tests in patients with chronic respiratory diseases and 2) published studies on their utilty and/or evaluation obtained from MEDLINE and Cochrane Library searches between 1990 and March 2015.Exercise tests are reliable and consistently responsive to rehabilitative and pharmacological interventions. Thresholds for clinically important changes in performance are available for several tests. In pulmonary arterial hypertension, the 6-min walk test (6MWT), peak oxygen uptake and ventilation/carbon dioxide output indices appear to be the variables most responsive to vasodilators. While bronchodilators do not always show clinically relevant effects in chronic obstructive pulmonary disease, high-intensity constant work-rate (endurance) tests (CWRET) are considerably more responsive than incremental exercise tests and 6MWTs. High-intensity CWRETs need to be standardised to reduce interindividual variability. Additional physiological information and responsiveness can be obtained from isotime measurements, particularly of inspiratory capacity and dyspnoea. Less evidence is available for the endurance shuttle walk test. Although the incremental shuttle walk test and 6MWT are reliable and less expensive than cardiopulmonary exercise testing, two repetitions are needed at baseline. All exercise tests are safe when recommended precautions are followed, with evidence suggesting that no test is safer than others.
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31
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Dubé BP, Laveneziana P. Exploring cardio-pulmonary interactions by examining the ventilatory, pulmonary gas exchange, and heart rate kinetics response to high-intensity cycle exercise in COPD patients. Respir Physiol Neurobiol 2015; 219:103-5. [DOI: 10.1016/j.resp.2015.09.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 09/21/2015] [Accepted: 09/22/2015] [Indexed: 11/24/2022]
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Häussermann S, Schulze A, Katz IM, Martin AR, Herpich C, Hunger T, Texereau J. Effects of a helium/oxygen mixture on individuals' lung function and metabolic cost during submaximal exercise for participants with obstructive lung diseases. Int J Chron Obstruct Pulmon Dis 2015; 10:1987-97. [PMID: 26451096 PMCID: PMC4590345 DOI: 10.2147/copd.s88965] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Helium/oxygen therapies have been studied as a means to reduce the symptoms of obstructive lung diseases with inconclusive results in clinical trials. To better understand this variability in results, an exploratory physiological study was performed comparing the effects of helium/oxygen mixture (78%/22%) to that of medical air. METHODS The gas mixtures were administered to healthy, asthmatic, and chronic obstructive pulmonary disease (COPD) participants, both moderate and severe (6 participants in each disease group, a total of 30); at rest and during submaximal cycling exercise with equivalent work rates. Measurements of ventilatory parameters, forced spirometry, and ergospirometry were obtained. RESULTS There was no statistical difference in ventilatory and cardiac responses to breathing helium/oxygen during submaximal exercise. For asthmatics, but not for the COPD participants, there was a statistically significant benefit in reduced metabolic cost, determined through measurement of oxygen uptake, for the same exercise work rate. However, the individual data show that there were a mixture of responders and nonresponders to helium/oxygen in all of the groups. CONCLUSION The inconsistent response to helium/oxygen between individuals is perhaps the key drawback to the more effective and widespread use of helium/oxygen to increase exercise capacity and for other therapeutic applications.
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Affiliation(s)
| | | | - Ira M Katz
- Medical R&D, Air Liquide Santé International, Centre de Recherche Paris-Saclay, Les Loges-en-Josas, France ; Department of Mechanical Engineering, Lafayette College, Easton, PA, USA
| | - Andrew R Martin
- Department of Mechanical Engineering, University of Alberta, Edmonton, AB, Canada
| | | | | | - Joëlle Texereau
- Medical R&D, Air Liquide Santé International, Centre de Recherche Paris-Saclay, Les Loges-en-Josas, France
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Wilkie SS, Dominelli PB, Sporer BC, Koehle MS, Sheel AW. Heliox breathing equally influences respiratory mechanics and cycling performance in trained males and females. J Appl Physiol (1985) 2015; 118:255-64. [PMID: 25429095 PMCID: PMC4312847 DOI: 10.1152/japplphysiol.00400.2014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 11/25/2014] [Indexed: 11/22/2022] Open
Abstract
In this study we tested the hypothesis that inspiring a low-density gas mixture (helium-oxygen; HeO2) would minimize mechanical ventilatory constraints and preferentially increase exercise performance in females relative to males. Trained male (n = 11, 31 yr) and female (n = 10, 26 yr) cyclists performed an incremental cycle test to exhaustion to determine maximal aerobic capacity (V̇o2max; male = 61, female = 56 ml·kg(-1)·min(-1)). A randomized, single-blinded crossover design was used for two experimental days where subjects completed a 5-km cycling time trial breathing humidified compressed room air or HeO2 (21% O2:balance He). Subjects were instrumented with an esophageal balloon for the assessment of respiratory mechanics. During the time trial, we assessed the ability of HeO2 to alleviate mechanical ventilatory constraints in three ways: 1) expiratory flow limitation, 2) utilization of ventilatory capacity, and 3) the work of breathing. We found that HeO2 significantly reduced the work of breathing, increased the size of the maximal flow-volume envelope, and reduced the fractional utilization of the maximal ventilatory capacity equally between men and women. The primary finding of this study was that inspiring HeO2 was associated with a statistically significant performance improvement of 0.7% (3.2 s) for males and 1.5% (8.1 s) for females (P < 0.05); however, there were no sex differences with respect to improvement in time trial performance (P > 0.05). Our results suggest that the extent of sex-based differences in airway anatomy, work of breathing, and expiratory flow limitation is not great enough to differentially affect whole body exercise performance.
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Affiliation(s)
- Sabrina S Wilkie
- School of Kinesiology, University of British Columbia, Vancouver, Canada
| | - Paolo B Dominelli
- School of Kinesiology, University of British Columbia, Vancouver, Canada
| | - Benjamin C Sporer
- Division of Sports Medicine, Faculty of Medicine, University of British Columbia, Vancouver, Canada; and Canada Sport Institute Pacific, Vancouver, Canada
| | - Michael S Koehle
- School of Kinesiology, University of British Columbia, Vancouver, Canada; Division of Sports Medicine, Faculty of Medicine, University of British Columbia, Vancouver, Canada; and
| | - A William Sheel
- School of Kinesiology, University of British Columbia, Vancouver, Canada;
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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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Abstract
PURPOSE Partitioning exercise by 1-legged cycling is more effective than conventional training in patients with chronic obstructive pulmonary disease. Similarly, inhaling helium-hyperoxia can extend conventional exercise tolerance. This study aimed to determine whether breathing helium-hyperoxia could increase the tolerance of a high-intensity exercise session achieved by 1-legged cycling. METHODS Participants completed 2 high-intensity, constant power, 1-legged cycle tests to intolerance (tlimit). In a randomized order, they inspired 40% oxygen with the balance helium via mask and 1-way valve, 1-legged helium-hyperoxia (1L-HH), or room air with supplemental oxygen via a nasal cannula, 1-legged nitrogen-hyperoxia (1L-NH). We assessed quadriceps fatigue from the change in maximal voluntary contraction (FMVC) and transcutaneously stimulated twitch force (Ftwitch). RESULTS Fifteen participants (forced expiratory volume in 1 second [SD] = 36 [18]% predicted; forced expiratory volume in 1 second/forced vital capacity = 34 [14]%; peak oxygen uptake = 12.8 [2.9] mL · kg · min) completed the study. Self-reported "leg fatigue" was a reason for stopping 25 of 30 tests. There was no significant difference in tlimit (0.2 [-1.4 to 1.8] min) between 1L-HH (12.2 [5.2] min) and 1L-NH (12.0 [4.1] min), or in FMVC measured shortly after HH and NH tests (P= .09). The Ftwitch was less after exercise (P< .05) in both conditions, without a difference between conditions (P= .46). CONCLUSIONS Inspiring a helium-hyperoxia mixture does not increase the endurance of what would be a typical training session, breathing supplemental oxygen, of high-intensity 1-legged constant power exercise. Leg muscle fatigue was similar after 1-legged exercise with and without breathing the helium mixture.
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Abstract
This paper reviews the medical use of helium oxygen mixture in obstructive airway disease in patients with croup, narrow endotracheal tubes (ETTs), respiratory distress syndrome, asthma, bronchiolitis, as well as patients with acute exacerbation of chronic obstructive pulmonary disease (COPD) and acute lung injury. In addition, some other indications of heliox use and some innovative methods of ventilation applied in pediatrics and adults are presented through review of the literature of current decade. Yet, to recommend heliox use seems to require more research based on clinical practice and observation through vaster and more robust investigations.
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Affiliation(s)
- Seyed Mohammadreza Hashemian
- Chronic Respiratory Disease Research Center, National Research Institute of Tuberculosis and Lung Disease, Masih Daneshvari Hospital, Tehran, Iran
| | - Farahnaz Fallahian
- Shohada Hospital Critical Care Unit, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Hill K, Holland AE. Strategies to enhance the benefits of exercise training in the respiratory patient. Clin Chest Med 2014; 35:323-36. [PMID: 24874128 DOI: 10.1016/j.ccm.2014.02.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Despite the well-established benefits of exercise training in people with chronic respiratory disease, there are a group of people in whom it confers minimal gains. Furthermore, there is increasing recognition of the prevalence of comorbid conditions among people with chronic obstructive pulmonary disease and other respiratory diseases, such as musculoskeletal disorders, which make participation in traditional exercise training programs challenging. This article focuses on several adjuncts or strategies that may be implemented by clinicians during exercise training, with the goal of optimizing the proportion of pulmonary rehabilitation participants who achieve significant and meaningful gains on program completion.
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Affiliation(s)
- Kylie Hill
- School of Physiotherapy and Exercise Science, Faculty of Health Science, Curtin University, GPO Box U1987, Perth, Western Australia 6845, Australia; Lung Institute of Western Australia, Centre for Asthma, Allergy and Respiratory Research, University of Western Australia, Hospital Avenue, Nedlands, Western Australia 6009, Australia; Physiotherapy Department, Royal Perth Hospital, Wellington Street, Perth, Western Australia 6000, Australia.
| | - Anne E Holland
- Department of Physiotherapy, La Trobe University, Level 4, The Alfred Centre, 99 Commercial Road, Melbourne, Victoria 3004, Australia; Department of Physiotherapy, Alfred Health, Commercial Road, Melbourne, Victoria 3004, Australia; Institute for Breathing and Sleep, Studley Road, Heidelberg, Victoria 3084, Australia
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El-Khatib MF, Jamaleddine G, Kanj N, Zeineddine S, Chami H, Bou-Akl I, Husari A, Alawieh M, Bou-Khalil P. Effect of heliox- and air-driven nebulized bronchodilator therapy on lung function in patients with asthma. Lung 2014; 192:377-83. [PMID: 24643901 DOI: 10.1007/s00408-014-9570-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 03/02/2014] [Indexed: 10/25/2022]
Abstract
BACKGROUND This study compares the effect of heliox-driven to that of air-driven bronchodilator therapy on the pulmonary function test (PFT) in patients with different levels of asthma severity. METHODS One-hundred thirty-two participants were included in the study. Participants underwent spirometry twice with bronchodilator testing on two consecutive days. Air-driven nebulization was used one day and heliox-driven nebulization the other day in random order crossover design. After a baseline PFT, each participant received 2.5 mg of albuterol sulfate nebulized with the randomized driving gas. Post bronchodilator PFT was repeated after 30 min. The next day, the exact same protocol was repeated, except that the other driving gas was used to nebulize the drug. Participants were subgrouped and analyzed according to their baseline FEV(1) on day 1: Group I, FEV(1) ≥80 %; Group II, 80 % > FEV(1) > 50 %; Group III, FEV(1) ≤50 %. The proportion of participants with greater than 12 % and 200-mL increases from their baseline FEV(1) and the changes from baseline in PFT variables were compared between heliox-driven versus air-driven bronchodilation therapy. RESULTS The proportion of participants with >12 % and 200-mL increases from their baseline FEV(1) with air- or heliox-driven bronchodilation was not different with respect to the proportion of participants with baseline FEV(1) ≥80 % (20 vs. 18 %, respectively) and 80 % > FEV(1) > 50 % (36 vs. 43 %, respectively), but it was significantly greater with heliox-driven bronchodilation in participants with FEV(1) ≤50 % (43 vs. 73 %, respectively; p = 0.01). Changes from baseline FVC, FEV(1), FEV(1)/FVC, FEF(25-75) %, FEF(max), FEF(25) %, FEF(50) %, and FEF(75) % were significantly larger with heliox-driven versus air-driven bronchodilation in participants with baseline FEV(1) ≤50 %. CONCLUSION Improvements in PFT variables are more frequent and profound with heliox-driven compared to air-driven bronchodilator therapy only in asthmatic patients with baseline FEV(1) ≤50 %.
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Affiliation(s)
- Mohamad F El-Khatib
- Department of Anesthesiology, American University of Beirut, Beirut, Lebanon
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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: 63] [Impact Index Per Article: 6.3] [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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Collins EG, Jelinek C, O'Connell S, Butler J, McBurney C, Gozali C, Reda D, Laghi F. Contrasting breathing retraining and helium-oxygen during pulmonary rehabilitation in COPD: a randomized clinical trial. Respir Med 2013; 108:297-306. [PMID: 24238770 DOI: 10.1016/j.rmed.2013.10.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 10/21/2013] [Accepted: 10/27/2013] [Indexed: 10/26/2022]
Abstract
BACKGROUND Breathing-retraining and helium-oxygen (heliox) have been used to improve exercise tolerance in COPD. We hypothesized that, in patients with COPD, exercise duration after exercise-training plus breathing-retraining and oxygen would be longer than after exercise-training plus heliox or after exercise-training plus oxygen alone. We also explored the short-term maintenance of gains in exercise duration after using each technique. METHODS Of 192 COPD patients recruited, 103 were randomly assigned to exercise-training plus heliox (n = 33), exercise-training plus breathing-retraining and oxygen (n = 35) and exercise-training and oxygen (n = 35). FiO2 was 0.30 during testing and training in all groups. Patients exercised on a treadmill thrice-weekly for eight weeks. Before, at completion of training, and six-weeks later, patients underwent constant-load treadmill testing. RESULTS At completion of training, improvements in exercise duration in the heliox and breathing-retraining groups were not significantly different. Compared to the exercise-training plus oxygen group, exercise duration improved more in the breathing-retraining group (P = 0.008) but not in the heliox group (P = 0.142). Hyperinflation was reduced with breathing-retraining plus oxygen compared to the other two groups. Six-weeks later, improvements in exercise duration were still greater with breathing-retraining than with exercise-training (P = 0.015). In contrast, improvements in exercise duration with heliox did not differ from those in the other two groups. CONCLUSIONS In moderate-to-severe COPD, exercise-training combined with either heliox or with breathing-retraining yielded not significantly different improvements in exercise duration - with only the latter being superior to exercise-training. Six-weeks after training, these improvements were still greater after exercise-training plus breathing-retraining than after exercise-training. TRIAL REGISTRY ClinicalTrials.gov; No.: NCT00123422.
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Affiliation(s)
- Eileen G Collins
- Center for Management of Complex Chronic Care, Physical Performance Laboratory, Research & Development Service, Edward Hines Jr. Veterans Affairs Hospital, Hines, IL, USA; Department of Biobehavioral Health Science, College of Nursing, University of Illinois at Chicago, Chicago, IL, USA.
| | - Christine Jelinek
- Center for Management of Complex Chronic Care, Physical Performance Laboratory, Research & Development Service, Edward Hines Jr. Veterans Affairs Hospital, Hines, IL, USA
| | - Susan O'Connell
- Center for Management of Complex Chronic Care, Physical Performance Laboratory, Research & Development Service, Edward Hines Jr. Veterans Affairs Hospital, Hines, IL, USA
| | - Jolene Butler
- Center for Management of Complex Chronic Care, Physical Performance Laboratory, Research & Development Service, Edward Hines Jr. Veterans Affairs Hospital, Hines, IL, USA
| | - Conor McBurney
- Center for Management of Complex Chronic Care, Physical Performance Laboratory, Research & Development Service, Edward Hines Jr. Veterans Affairs Hospital, Hines, IL, USA
| | - Christopher Gozali
- Center for Management of Complex Chronic Care, Physical Performance Laboratory, Research & Development Service, Edward Hines Jr. Veterans Affairs Hospital, Hines, IL, USA
| | - Domenic Reda
- VA Cooperative Studies Program Coordinating Center, Edward Hines Jr. Veterans Affairs Hospital, Hines, IL, USA; School of Public Health, University of Illinois at Chicago, Chicago, IL, USA
| | - Franco Laghi
- Center for Management of Complex Chronic Care, Physical Performance Laboratory, Research & Development Service, Edward Hines Jr. Veterans Affairs Hospital, Hines, IL, USA; Loyola University, Stritch School of Medicine, Maywood, IL, USA
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Dolmage TE, Evans RA, Goldstein RS. Defining hyperinflation as 'dynamic': moving toward the slope. Respir Med 2013; 107:953-8. [PMID: 23478191 DOI: 10.1016/j.rmed.2013.02.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 01/29/2013] [Accepted: 02/11/2013] [Indexed: 11/26/2022]
Abstract
Measuring the severity of dynamic hyperinflation is a useful clinical approach to assess the effect of therapeutic interventions and explain their impact on exercise tolerance. Dynamic hyperinflation is typically quantified by the change in end expiratory lung volume from rest to the end of exercise. The result may be inconsistent with disease severity and does not clearly explain how exercise tolerance improves with therapy. Using a re-examination of selected studies, we suggest an operational definition of dynamic hyperinflation using the slope derived from serial measures of inspiratory capacity expressed as a linear function of ventilation that clearly differentiates whether therapies affect static or dynamic hyperinflation or affect lung volume only as a consequence of reducing ventilation. With this approach, the magnitude of the result is consistent with disease severity and is a more reliable outcome as it uses serial measures rather than a single time point estimate. The therapies re-evaluated are breathing helium or hyperoxic gas mixtures, bronchodilation and exercise training. A clear definition of dynamic hyperinflation will assist clinicians in assessing the impact of therapeutic interventions.
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Affiliation(s)
- Thomas E Dolmage
- Department of Respiratory Medicine, West Park Healthcare Centre, Toronto M6M 2J5, Canada
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Inspiratory Capacity during Exercise: Measurement, Analysis, and Interpretation. Pulm Med 2013; 2013:956081. [PMID: 23476765 PMCID: PMC3582111 DOI: 10.1155/2013/956081] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 12/21/2012] [Indexed: 12/24/2022] Open
Abstract
Cardiopulmonary exercise testing (CPET) is an established method for evaluating dyspnea and ventilatory abnormalities. Ventilatory reserve is typically assessed as the ratio of peak exercise ventilation to maximal voluntary ventilation. Unfortunately, this crude assessment provides limited data on the factors that limit the normal ventilatory response to exercise. Additional measurements can provide a more comprehensive evaluation of respiratory mechanical constraints during CPET (e.g., expiratory flow limitation and operating lung volumes). These measurements are directly dependent on an accurate assessment of inspiratory capacity (IC) throughout rest and exercise. Despite the valuable insight that the IC provides, there are no established recommendations on how to perform the maneuver during exercise and how to analyze and interpret the data. Accordingly, the purpose of this manuscript is to comprehensively examine a number of methodological issues related to the measurement, analysis, and interpretation of the IC. We will also briefly discuss IC responses to exercise in health and disease and will consider how various therapeutic interventions influence the IC, particularly in patients with chronic obstructive pulmonary disease. Our main conclusion is that IC measurements are both reproducible and responsive to therapy and provide important information on the mechanisms of dyspnea and exercise limitation during CPET.
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Goldstein RS, Hill K, Brooks D, Dolmage TE. Pulmonary rehabilitation: a review of the recent literature. Chest 2013; 142:738-749. [PMID: 22948578 DOI: 10.1378/chest.12-0188] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Pulmonary rehabilitation (PR) is an evidence-based, multidisciplinary, comprehensive intervention that can be integrated into the management of individuals with chronic lung disease. It aims to reduce symptoms, optimize function, increase participation in daily life, and reduce health-care resource utilization. In this review, we summarize the new developments in PR over the past 5 years. Issues related to patient assessment include a comparison of cycle- and walking-based measures of exercise capacity, the emergence of multidimensional indices, the refinement of the minimal clinically important difference, and the importance of assessing physical activity. Issues related to exercise training focus on strategies to optimize the training load. We also comment on the acquisition of self-management skills, balance training, optimizing access, and maintaining gains following completion of PR.
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Affiliation(s)
- Roger S Goldstein
- Department of Respiratory Medicine, West Park Healthcare Centre, Toronto, ON, Canada; Department of Physical Therapy, University of Toronto, Toronto, ON, Canada; Department of Medicine, University of Toronto, Toronto, ON, Canada.
| | - Kylie Hill
- School of Physiotherapy and Curtin Health Innovation Research Institute, Curtin University, Bentley, WA, Australia; Lung Institute of Western Australia and Centre for Asthma, Allergy and Respiratory Research, University of Western Australia, Crawley, WA, Australia
| | - Dina Brooks
- Department of Respiratory Medicine, West Park Healthcare Centre, Toronto, ON, Canada; Department of Physical Therapy, University of Toronto, Toronto, ON, Canada
| | - Thomas E Dolmage
- Department of Respiratory Medicine, West Park Healthcare Centre, Toronto, ON, Canada; Respiratory Diagnostic and Evaluation Services, West Park Healthcare Centre, Toronto, ON, Canada
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Petrovic M, Reiter M, Zipko H, Pohl W, Wanke T. Effects of inspiratory muscle training on dynamic hyperinflation in patients with COPD. Int J Chron Obstruct Pulmon Dis 2012; 7:797-805. [PMID: 23233798 PMCID: PMC3516469 DOI: 10.2147/copd.s23784] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Dynamic hyperinflation has important clinical consequences in patients with chronic obstructive pulmonary disease (COPD). Given that most of these patients have respiratory and peripheral muscle weakness, dyspnea and functional exercise capacity may improve as a result of inspiratory muscle training (IMT). The aim of the study was to analyze the effects of IMT on exercise capacity, dyspnea, and inspiratory fraction (IF) during exercise in patients with COPD. Daily inspiratory muscle strength and endurance training was performed for 8 weeks in 10 patients with COPD GOLD II and III. Ten patients with COPD II and III served as a control group. Maximal inspiratory pressure (Pimax) and endurance time during resistive breathing maneuvers (tlim) served as parameter for inspiratory muscle capacity. Before and after training, the patients performed an incremental symptom limited exercise test to maximum and a constant load test on a cycle ergometer at 75% of the peak work rate obtained in the pretraining incremental test. ET was defined as the duration of loaded pedaling. Following IMT, there was a statistically significant increase in inspiratory muscle performance of the Pimax from 7.75 ± 0.47 to 9.15 ± 0.73 kPa (P < 0.01) and of tlim from 348 ± 54 to 467 ± 58 seconds (P < 0.01). A significant increase in IF, indicating decreased dynamic hyperinflation, was observed during both exercise tests. Further, the ratio of breathing frequency to minute ventilation (bf/V′E) decreased significantly, indicating an improved breathing pattern. A significant decrease in perception of dyspnea was also measured. Peak work rate during the incremental cycle ergometer test remained constant, while ET during the constant load test increased significantly from 597.1 ± 80.8 seconds at baseline to 733.6 ± 74.3 seconds (P < 0.01). No significant changes during either exercise tests were measured in the control group. The present study found that in patients with COPD, IMT results in improvement in performance, exercise capacity, sensation of dyspnea, and improvement in the IF prognostic factor.
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Affiliation(s)
- Milos Petrovic
- Pulmonary Department and Karl Landsteiner Institute for Clinical and Experimental Pulmology, Hietzing Hospital, Vienna, Austria.
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Effects of Heliox in Stable COPD Patients at Rest and during Exercise. Pulm Med 2012; 2012:593985. [PMID: 23094152 PMCID: PMC3475004 DOI: 10.1155/2012/593985] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 09/14/2012] [Indexed: 11/17/2022] Open
Abstract
Heliox has been administered to stable chronic obstructive pulmonary disease (COPD) patients at rest and during exercise on the assumption that this low density mixture would have reduced work of breathing, dynamic hyperinflation, and, consequently, dyspnea sensation. Contrary to these expectations, beneficial effects of heliox in these patients at rest have been reported only sporadically, and the majority of the studies performed until now suggests that heliox is not a therapeutic option in spontaneously breathing resting COPD patients. On the other hand, when it is administered to COPD patients exercising at a constant work rate, heliox systematically decreases dyspnea sensation, and, often but not always, increases exercise tolerance. For these reasons, heliox has been evaluated as a non pharmacological tool to power rehabilitation programs. The conflicting results provided by the published trials probably point at a substantial heterogeneity of the COPD patients population in terms of respiratory mechanics and gas exchange. Therefore, further studies, aimed to the identification of mechanisms conditioning the response of exercising COPD patients to heliox, are warranted, before heliox administration, which is costly and cumbersome, can be routinely used in rehabilitation programs.
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Louvaris Z, Zakynthinos S, Aliverti A, Habazettl H, Vasilopoulou M, Andrianopoulos V, Wagner H, Wagner P, Vogiatzis I. Heliox increases quadriceps muscle oxygen delivery during exercise in COPD patients with and without dynamic hyperinflation. J Appl Physiol (1985) 2012; 113:1012-23. [PMID: 22879534 DOI: 10.1152/japplphysiol.00481.2012] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Some reports suggest that heliox breathing during exercise may improve peripheral muscle oxygen availability in patients with chronic obstructive pulmonary disease (COPD). Besides COPD patients who dynamically hyperinflate during exercise (hyperinflators), there are patients who do not hyperinflate (non-hyperinflators). As heliox breathing may differently affect cardiac output in hyperinflators (by increasing preload and decreasing afterload of both ventricles) and non-hyperinflators (by increasing venous return) during exercise, it was reasoned that heliox administration would improve peripheral muscle oxygen delivery possibly by different mechanisms in those two COPD categories. Chest wall volume and respiratory muscle activity were determined during constant-load exercise at 75% peak capacity to exhaustion, while breathing room air or normoxic heliox in 17 COPD patients: 9 hyperinflators (forced expiratory volume in 1 s = 39 ± 5% predicted), and 8 non-hyperinflators (forced expiratory volume in 1 s = 48 ± 5% predicted). Quadriceps muscle blood flow was measured by near-infrared spectroscopy using indocyanine green dye. Hyperinflators and non-hyperinflators demonstrated comparable improvements in endurance time during heliox (231 ± 23 and 257 ± 28 s, respectively). At exhaustion in room air, expiratory muscle activity (expressed by peak-expiratory gastric pressure) was lower in hyperinflators than in non-hyperinflators. In hyperinflators, heliox reduced end-expiratory chest wall volume and diaphragmatic activity, and increased arterial oxygen content (by 17.8 ± 2.5 ml/l), whereas, in non-hyperinflators, heliox reduced peak-expiratory gastric pressure and increased systemic vascular conductance (by 11.0 ± 2.8 ml·min(-1)·mmHg(-1)). Quadriceps muscle blood flow and oxygen delivery significantly improved during heliox compared with room air by a comparable magnitude (in hyperinflators by 6.1 ± 1.3 ml·min(-1)·100 g(-1) and 1.3 ± 0.3 ml O(2)·min(-1)·100 g(-1), and in non-hyperinflators by 7.2 ± 1.6 ml·min(-1)·100 g(-1) and 1.6 ± 0.3 ml O(2)·min(-1)·100 g(-1), respectively). Despite similar increase in locomotor muscle oxygen delivery with heliox in both groups, the mechanisms of such improvements were different: 1) in hyperinflators, heliox increased arterial oxygen content and quadriceps blood flow at similar cardiac output, whereas 2) in non-hyperinflators, heliox improved central hemodynamics and increased systemic vascular conductance and quadriceps blood flow at similar arterial oxygen content.
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Affiliation(s)
- Zafeiris Louvaris
- Department of Critical Care Medicine and Pulmonary Services, Evangelismos Hospital, M. Simou and G.P. Livanos Laboratories, National and Kapodistrian University of Athens, Athens, Greece
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Parshall MB, Schwartzstein RM, Adams L, Banzett RB, Manning HL, Bourbeau J, Calverley PM, Gift AG, Harver A, Lareau SC, Mahler DA, Meek PM, O'Donnell DE. An official American Thoracic Society statement: update on the mechanisms, assessment, and management of dyspnea. Am J Respir Crit Care Med 2012; 185:435-52. [PMID: 22336677 PMCID: PMC5448624 DOI: 10.1164/rccm.201111-2042st] [Citation(s) in RCA: 1109] [Impact Index Per Article: 92.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Dyspnea is a common, distressing symptom of cardiopulmonary and neuromuscular diseases. Since the ATS published a consensus statement on dyspnea in 1999, there has been enormous growth in knowledge about the neurophysiology of dyspnea and increasing interest in dyspnea as a patient-reported outcome. PURPOSE The purpose of this document is to update the 1999 ATS Consensus Statement on dyspnea. METHODS An interdisciplinary committee of experts representing ATS assemblies on Nursing, Clinical Problems, Sleep and Respiratory Neurobiology, Pulmonary Rehabilitation, and Behavioral Science determined the overall scope of this update through group consensus. Focused literature reviews in key topic areas were conducted by committee members with relevant expertise. The final content of this statement was agreed upon by all members. RESULTS Progress has been made in clarifying mechanisms underlying several qualitatively and mechanistically distinct breathing sensations. Brain imaging studies have consistently shown dyspnea stimuli to be correlated with activation of cortico-limbic areas involved with interoception and nociception. Endogenous and exogenous opioids may modulate perception of dyspnea. Instruments for measuring dyspnea are often poorly characterized; a framework is proposed for more consistent identification of measurement domains. CONCLUSIONS Progress in treatment of dyspnea has not matched progress in elucidating underlying mechanisms. There is a critical need for interdisciplinary translational research to connect dyspnea mechanisms with clinical treatment and to validate dyspnea measures as patient-reported outcomes for clinical trials.
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Moga AM, de Marchie M, Saey D, Spahija J. Mechanisms of non-pharmacologic adjunct therapies used during exercise in COPD. Respir Med 2012; 106:614-26. [PMID: 22341681 DOI: 10.1016/j.rmed.2012.01.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 01/04/2012] [Accepted: 01/12/2012] [Indexed: 11/16/2022]
Abstract
Individuals with chronic obstructive pulmonary disease (COPD) are often limited in their ability to perform exercise due to a heightened sense of dyspnea and/or the occurrence of leg fatigue associated with a reduced ventilatory capacity and peripheral skeletal muscle dysfunction, respectively. Pulmonary rehabilitation programs have been shown to improve exercise tolerance and health related quality of life. Additional therapeutic approaches such as non-invasive ventilatory support (NIVS), heliox (He-O(2)) and supplemental oxygen have been used as non-pharmacologic adjuncts to exercise to enhance the ability of patients with COPD to exercise at a higher exercise-intensity and thus improve the physiological benefits of exercise. The purpose of the current review is to examine the pathophysiology of exercise limitation in COPD and to explore the physiological mechanisms underlying the effect of the adjunct therapies on exercise in patients with COPD. This review indicates that strategies that aim to unload the respiratory muscles and enhance oxygen saturation during exercise alleviate exercise limiting factors and improve exercise performance in patients with COPD. However, available data shows significant variability in the effectiveness across patients. Further research is needed to identify the most appropriate candidates for these forms of therapies.
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Affiliation(s)
- A M Moga
- School of Physical and Occupational Therapy, McGill University, 3654 Promenade Sir William Osler, Montreal, Quebec H3G 1Y5, Canada
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Parshall MB, Schwartzstein RM, Adams L, Banzett RB, Manning HL, Bourbeau J, Calverley PM, Gift AG, Harver A, Lareau SC, Mahler DA, Meek PM, O'Donnell DE. An official American Thoracic Society statement: update on the mechanisms, assessment, and management of dyspnea. Am J Respir Crit Care Med 2012. [PMID: 22336677 DOI: 10.1164/rccm.201111–2042st] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Dyspnea is a common, distressing symptom of cardiopulmonary and neuromuscular diseases. Since the ATS published a consensus statement on dyspnea in 1999, there has been enormous growth in knowledge about the neurophysiology of dyspnea and increasing interest in dyspnea as a patient-reported outcome. PURPOSE The purpose of this document is to update the 1999 ATS Consensus Statement on dyspnea. METHODS An interdisciplinary committee of experts representing ATS assemblies on Nursing, Clinical Problems, Sleep and Respiratory Neurobiology, Pulmonary Rehabilitation, and Behavioral Science determined the overall scope of this update through group consensus. Focused literature reviews in key topic areas were conducted by committee members with relevant expertise. The final content of this statement was agreed upon by all members. RESULTS Progress has been made in clarifying mechanisms underlying several qualitatively and mechanistically distinct breathing sensations. Brain imaging studies have consistently shown dyspnea stimuli to be correlated with activation of cortico-limbic areas involved with interoception and nociception. Endogenous and exogenous opioids may modulate perception of dyspnea. Instruments for measuring dyspnea are often poorly characterized; a framework is proposed for more consistent identification of measurement domains. CONCLUSIONS Progress in treatment of dyspnea has not matched progress in elucidating underlying mechanisms. There is a critical need for interdisciplinary translational research to connect dyspnea mechanisms with clinical treatment and to validate dyspnea measures as patient-reported outcomes for clinical trials.
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Uronis H, McCrory DC, Samsa G, Currow D, Abernethy A. Symptomatic oxygen for non-hypoxaemic chronic obstructive pulmonary disease. Cochrane Database Syst Rev 2011:CD006429. [PMID: 21678356 DOI: 10.1002/14651858.cd006429.pub2] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Dyspnoea is a common symptom in chronic obstructive pulmonary disease (COPD). People who are hypoxaemic may be given long-term oxygen relief therapy (LTOT) to improve their life expectancy and quality of life. However, the symptomatic benefit of home oxygen therapy in mildly or non-hypoxaemic people with COPD with dyspnoea who do not meet international funding criteria for LTOT (PaO(2)< 55 mmHg or other special cases) is unknown. OBJECTIVES To determine the efficacy of oxygen versus medical air for relief of subjective dyspnoea in mildly or non-hypoxaemic people with COPD who would not otherwise qualify for home oxygen therapy. The main outcome was patient-reported dyspnoea and secondary outcome was exercise tolerance. SEARCH STRATEGY We searched the Cochrane Airways Group Register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE, to November 2009, to identify randomised controlled trials. We handsearched reference lists of included articles. SELECTION CRITERIA We only included randomised controlled trials of oxygen versus medical air in mildly or non-hypoxaemic people with COPD. Two review authors independently assessed articles for inclusion. DATA COLLECTION AND ANALYSIS One review author completed data extraction and methodological quality assessment. A second review author then over-read evidence tables to assess for accuracy. MAIN RESULTS Twenty-eight trials on 702 patients met the criteria for inclusion; 18 trials (431 participants) were included in the meta-analysis. Oxygen reduced dyspnoea with a standardised mean difference (SMD) of -0.37 (95% confidence interval (CI) -0.50 to -0.24, P < 0.00001). We observed significant heterogeneity. AUTHORS' CONCLUSIONS Oxygen can relieve dyspnoea in mildly and non-hypoxaemic people with COPD who would not otherwise qualify for home oxygen therapy. Given the significant heterogeneity among the included studies, clinicians should continue to evaluate patients on an individual basis until supporting data from ongoing, large randomised controlled trials are available.
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Affiliation(s)
- Hope Uronis
- Division of Medical Oncology, Department of Medicine, Duke University Medical Center, Box 3841, Durham, NC, USA, 27710
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