Exertional dyspnoea in COPD: the clinical utility of cardiopulmonary exercise testing

Abstract

Activity-related dyspnoea is often the most distressing symptom experienced by patients with chronic obstructive pulmonary disease (COPD) and can persist despite comprehensive medical management. It is now clear that dyspnoea during physical activity occurs across the spectrum of disease severity, even in those with mild airway obstruction. Our understanding of the nature and source of dyspnoea is incomplete, but current aetiological concepts emphasise the importance of increased central neural drive to breathe in the setting of a reduced ability of the respiratory system to appropriately respond. Since dyspnoea is provoked or aggravated by physical activity, its concurrent measurement during standardised laboratory exercise testing is clearly important. Combining measurement of perceptual and physiological responses during exercise can provide valuable insights into symptom severity and its pathophysiological underpinnings. This review summarises the abnormal physiological responses to exercise in COPD, as these form the basis for modern constructs of the neurobiology of exertional dyspnoea. The main objectives are: 1) to examine the role of cardiopulmonary exercise testing (CPET) in uncovering the physiological mechanisms of exertional dyspnoea in patients with mild-to-moderate COPD; 2) to examine the escalating negative sensory consequences of progressive respiratory impairment with disease advancement; and 3) to build a physiological rationale for individualised treatment optimisation based on CPET. @ERSpublications Measurement of symptom intensity, ventilatory control and mechanics during exercise exposes mechanisms of dyspnoea

Exertional dyspnoea in cardiorespiratory disorders: the clinical use of cardiopulmonary exercise testing

“…A clinical series of articles starting in this issue of the European Respiratory Review [10,11] will therefore focus on the clinical use of CPET to explore and unmask the mechanisms underlying dyspnoea during exercise in an abroad spectrum of cardiorespiratory disorders, covering topics including exertional dyspnoea in COPD, chronic heart failure, asthma, obesity, pulmonary arterial hypertension and interstitial lung diseases.…”

The impact of home‐based pulmonary rehabilitation on people with mild chronic obstructive pulmonary disease: A randomised controlled trial

“…It is possible that this test is not sensitive to change in people with mild disease and relatively well‐preserved exercise capacity . An alternative exercise capacity measurement such as the incremental shuttle walk test (ISWT) may be more physiologically demanding than a 6MWT in people with mild COPD and could be more sensitive to detect changes in exercise capacity . Future studies in this patient group should also take into account dyspnoea measures during activities of higher intensity or during exercise testing in addition to day‐to‐day dyspnoea assessed using the mMRC .…”

Recent Advances in Assessment of Dyspnea

“…Excessive inspiratory muscle effort occurs as a result of increased elastic loading induced by abnormal dynamic mechanics during restrictive IC situation. 10 Actually, on the S-shaped pressure-volume curves of the respiratory system, a high lung volume can force to breathe with a high respiratory pressure. Based on the changes in respiratory mechanics, the augmented efferent ventilatory drive to the respiratory muscles may reflect in the central neural pathway for the production of the sensation of work/effort.…”

“…10 In addition to this sensing system, the nasal Transient Receptor Potential Melastatin-8 (TRPM8) channel are thought to play key role in monitoring the airflow. 11 On the other hand, increased central and peripheral chemo-stimulation may arise from alveolar ventilation/perfusion abnormalities, arterial oxygen desaturation, early embolic acidosis and ergo-and metabo-receptors in skeletal muscle.…”

“…11 On the other hand, increased central and peripheral chemo-stimulation may arise from alveolar ventilation/perfusion abnormalities, arterial oxygen desaturation, early embolic acidosis and ergo-and metabo-receptors in skeletal muscle. 10 The insufficient respiratory afferent inputs in response to efferent ventilatory motor output (neuro-mechanical uncoupling)might evoke not only work/effort but also air hunger. Furthermore, the bronchospasm during exercise may induce the chest tightness.…”