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Neder JA. Cardiopulmonary exercise testing applied to respiratory medicine: Myths and facts. Respir Med 2023; 214:107249. [PMID: 37100256 DOI: 10.1016/j.rmed.2023.107249] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 03/28/2023] [Accepted: 04/18/2023] [Indexed: 04/28/2023]
Abstract
Cardiopulmonary exercise testing (CPET) remains poorly understood and, consequently, largely underused in respiratory medicine. In addition to a widespread lack of knowledge of integrative physiology, several tenets of CPET interpretation have relevant controversies and limitations which should be appropriately recognized. With the intent to provide a roadmap for the pulmonologist to realistically calibrate their expectations towards CPET, a collection of deeply entrenched beliefs is critically discussed. They include a) the actual role of CPET in uncovering the cause(s) of dyspnoea of unknown origin, b) peak O2 uptake as the key metric of cardiorespiratory capacity, c) the value of low lactate ("anaerobic") threshold to differentiate cardiocirculatory from respiratory causes of exercise limitation, d) the challenges of interpreting heart rate-based indexes of cardiovascular performance, e) the meaning of peak breathing reserve in dyspnoeic patients, f) the merits and drawbacks of measuring operating lung volumes during exercise, g) how best interpret the metrics of gas exchange inefficiency such as the ventilation-CO2 output relationship, h) when (and why) measurements of arterial blood gases are required, and i) the advantages of recording submaximal dyspnoea "quantity" and "quality". Based on a conceptual framework that links exertional dyspnoea to "excessive" and/or "restrained" breathing, I outline the approaches to CPET performance and interpretation that proved clinically more helpful in each of these scenarios. CPET to answer clinically relevant questions in pulmonology is a largely uncharted research field: I, therefore, finalize by highlighting some lines of inquiry to improve its diagnostic and prognostic yield.
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Affiliation(s)
- J Alberto Neder
- Laboratory of Clinical Exercise Physiology and Respiratory Investigation Unit, Department of Medicine, Division of Respirology, Kingston Health Sciences Center, Queen's University, Kingston, ON, Canada.
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Danzo F, Radovanovic D, Gatti M, Saad M, Perotto L, Franceschi E, Santus P. A reappraisal of inspiratory capacity in chronic obstructive pulmonary disease: clinical correlates and role of long-acting muscarinic antagonists and long-acting β2 agonists. Expert Rev Respir Med 2022; 16:623-635. [PMID: 35722753 DOI: 10.1080/17476348.2022.2090343] [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: 11/04/2022]
Abstract
INTRODUCTION In patients with chronic obstructive pulmonary disease (COPD), static and dynamic hyperinflation, together with expiratory flow limitation and gas exchange abnormalities, is one of the major causes of dyspnea, decreased exercise performance and ventilatory failure. An increase in functional residual capacity (FRC) is accompanied by a decrease in inspiratory capacity (IC), which is a volume readily available, repeatable, and simple to measure with any spirometer. Changes in IC and FRC after bronchodilation, contrary to changes in FEV1, have been closely associated with improvements in dyspnea and exercise performance. We systematically searched PubMed and Embase databases for clinical trials that assessed the effects of dual bronchodilation on inspiratory capacity in patients with COPD. AREAS COVERED Despite their pivotal role in COPD, IC and static volumes have rarely been considered as primary outcomes in randomized clinical trials assessing the efficacy of bronchodilators. Available studies on dual bronchodilation have shown a significant and persistent positive impact on IC focusing mainly on patients with moderate-to-severe COPD, whereas dynamic hyperinflation is also present at milder disease stages. EXPERT OPINION This narrative review discusses the pathophysiological and clinical importance of measuring IC in patients with COPD and how IC can be modified by maximizing bronchodilation combining long-acting muscarinic antagonists and long-acting β2 agonists.
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Affiliation(s)
- Fiammetta Danzo
- Division of Respiratory Diseases, Ospedale Luigi Sacco, Polo Universitario, ASST Fatebenefratelli-Sacco, Milano, Italy.,Department of Biomedical and Clinical Sciences (DIBIC), Università Degli Studi Di Milano, Milano, Italy
| | - Dejan Radovanovic
- Division of Respiratory Diseases, Ospedale Luigi Sacco, Polo Universitario, ASST Fatebenefratelli-Sacco, Milano, Italy
| | - Marina Gatti
- Division of Respiratory Diseases, Ospedale Luigi Sacco, Polo Universitario, ASST Fatebenefratelli-Sacco, Milano, Italy.,Department of Biomedical and Clinical Sciences (DIBIC), Università Degli Studi Di Milano, Milano, Italy
| | - Marina Saad
- Division of Respiratory Diseases, Ospedale Luigi Sacco, Polo Universitario, ASST Fatebenefratelli-Sacco, Milano, Italy.,Department of Biomedical and Clinical Sciences (DIBIC), Università Degli Studi Di Milano, Milano, Italy
| | - Luca Perotto
- Division of Respiratory Diseases, Ospedale Luigi Sacco, Polo Universitario, ASST Fatebenefratelli-Sacco, Milano, Italy.,Department of Biomedical and Clinical Sciences (DIBIC), Università Degli Studi Di Milano, Milano, Italy
| | - Elisa Franceschi
- Division of Respiratory Diseases, Ospedale Luigi Sacco, Polo Universitario, ASST Fatebenefratelli-Sacco, Milano, Italy.,Department of Biomedical and Clinical Sciences (DIBIC), Università Degli Studi Di Milano, Milano, Italy
| | - Pierachille Santus
- Division of Respiratory Diseases, Ospedale Luigi Sacco, Polo Universitario, ASST Fatebenefratelli-Sacco, Milano, Italy.,Department of Biomedical and Clinical Sciences (DIBIC), Università Degli Studi Di Milano, Milano, Italy
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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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Domnik NJ, James MD, Scheeren RE, Ayoo GA, Taylor SM, Di Luch AT, Milne KM, Vincent SG, Phillips DB, Elbehairy AF, Crinion SJ, Driver HS, Neder JA, O'Donnell DE. Deterioration of Nighttime Respiratory Mechanics in COPD: Impact of Bronchodilator Therapy. Chest 2020; 159:116-127. [PMID: 32603714 DOI: 10.1016/j.chest.2020.06.033] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 06/04/2020] [Accepted: 06/12/2020] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND COPD is associated with nighttime respiratory symptoms, poor sleep quality, and increased risk of nocturnal death. Overnight deterioration of inspiratory capacity (IC) and FEV1 have been documented previously. However, the precise nature of this deterioration and mechanisms by which evening bronchodilation may mitigate this occurrence have not been studied. RESEARCH QUESTION What is the effect of evening dosing of dual, long-acting bronchodilation on detailed nocturnal respiratory mechanics and inspiratory neural drive (IND)? STUDY DESIGN AND METHODS A double-blind, randomized, placebo-controlled crossover study assessed the effects of evening long-acting bronchodilation (aclidinium bromide/formoterol fumarate dihydrate: 400/12 μg) or placebo on morning trough IC (12 h after the dose; primary outcome) and serial overnight measurements of spirometry, dynamic respiratory mechanics, and IND (secondary outcomes). Twenty participants with COPD (moderate/severe airway obstruction and lung hyperinflation) underwent serial measurements of IC, spirometry, breathing pattern, esophageal and transdiaphragmatic pressures, and diaphragm electromyography (diaphragmatic electromyography as a percentage of maximum; IND) at 6 time points from 0 to 12 h after the dose and compared with sleeping IND. RESULTS Compared with placebo, evening bronchodilation was not associated with increased morning trough IC 12 h after the dose (P = .48); however, nadir IC (lowest IC, independent of time), peak IC, area under the curve for 12 h after the dose, and IC for 10 h after the dose were improved (P < .05). During placebo, total airways resistance, lung hyperinflation, IND, and tidal esophageal and transdiaphragmatic pressure swings all increased significantly overnight compared with baseline evening values; however, each of these parameters improved with bronchodilator treatment (P < .05) with no change in ventilation or breathing pattern. INTERPRETATION Respiratory mechanics significantly deteriorated at night during placebo. Although the morning trough IC was unchanged, evening bronchodilator treatment was associated consistently with sustained overnight improvements in dynamic respiratory mechanics and inspiratory neural drive compared with placebo CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT02429765.
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Affiliation(s)
| | - Matthew D James
- Department of Medicine, Queen's University, Kingston, Canada
| | | | - Grace A Ayoo
- Department of Medicine, Queen's University, Kingston, Canada
| | - Sarah M Taylor
- Department of Medicine, Queen's University, Kingston, Canada
| | | | - Kathryn M Milne
- Department of Medicine, Queen's University, Kingston, Canada
| | | | | | - Amany F Elbehairy
- Department of Medicine, Queen's University, Kingston, Canada; Department of Chest Diseases, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | - Sophie J Crinion
- Department of Medicine, Queen's University, Kingston, Canada; Division of Respiratory Medicine, Queen's University, Kingston, Canada; Sleep Disorders Laboratory, Kingston Health Sciences Centre, Kingston, Canada
| | - Helen S Driver
- Department of Medicine, Queen's University, Kingston, Canada; Division of Respiratory Medicine, Queen's University, Kingston, Canada; Sleep Disorders Laboratory, Kingston Health Sciences Centre, Kingston, Canada
| | - J Alberto Neder
- Department of Medicine, Queen's University, Kingston, Canada; Division of Respiratory Medicine, Queen's University, Kingston, Canada
| | - Denis E O'Donnell
- Department of Medicine, Queen's University, Kingston, Canada; Division of Respiratory Medicine, Queen's University, Kingston, Canada.
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