Neurophysiological mechanisms of exertional dyspnoea in fibrotic interstitial lung disease

Schaeffer, Michele R.; Ryerson, Christopher J.; Ramsook, Andrew H.; Molgat‐Seon, Yannick; Wilkie, Sabrina S.; Dhillon, Satvir S.; Mitchell, Reid; Sheel, A. William; Khalil, Nasreen; Camp, Pat G.; Guenette, Jordan A.

doi:10.1183/13993003.01726-2017

Cited by 31 publications

(24 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In chronic obstructive pulmonary disease (COPD), resting IND is increased 2-fold (EMGdi %max >20%) vs. age-matched health ( 39 , 90 ). Similar magnitudes of increase are seen in interstitial lung disease (ILD) ( 55 , 102 ) and cystic fibrosis ( 49 ). This is linked to pathophysiologic alterations in mechanical and chemical factors ( 103 ) and can already appear in very early disease, as detailed in the accompanying review by ( 104 ): “Dyspnea and Exercise Limitation in COPD: the value of CPET.”…”

Section: Neural Drive In the Evaluation Of The Breathless Patientmentioning

confidence: 60%

Clinical Utility of Measuring Inspiratory Neural Drive During Cardiopulmonary Exercise Testing (CPET)

2020

View full text Add to dashboard Cite

Cardiopulmonary exercise testing (CPET) has traditionally included ventilatory and metabolic measurements alongside electrocardiographic characterization; however, research increasingly acknowledges the utility of also measuring inspiratory neural drive (IND) through its surrogate measure of diaphragmatic electromyography (EMGdi). While true IND also encompasses the activation of non-diaphragmatic respiratory muscles, the current review focuses on diaphragmatic measurements, providing information about additional inspiratory muscle groups for context where appropriate. Evaluation of IND provides mechanistic insight into the origins of dyspnea and exercise limitation across pathologies; yields valuable information reflecting the integration of diverse mechanical, chemical, locomotor, and metabolic afferent signals; and can help assess the efficacy of therapeutic interventions. Further, IND measurement during the physiologic stress of exercise is uniquely poised to reveal the underpinnings of physiologic limitations masked during resting and unloaded breathing, with important information provided not only at peak exercise, but throughout exercise protocols. As our understanding of IND presentation across varying conditions continues to grow and methods for its measurement become more accessible, the translation of these principles into clinical settings is a logical next step in facilitating appropriate and nuanced management tailored to each individual's unique physiology. This review provides an overview of the current state of understanding of IND measurement during CPET: its origins, known patterns of behavior and links with dyspnea in health and major respiratory diseases, and the possibility of expanding this approach to applications beyond exercise.

show abstract

Section: Neural Drive In the Evaluation Of The Breathless Patientmentioning

confidence: 60%

Clinical Utility of Measuring Inspiratory Neural Drive During Cardiopulmonary Exercise Testing (CPET)

2020

View full text Add to dashboard Cite

show abstract

“…A growing body of research has shown that pulmonary gas-exchange abnormalities and ventilatory inefficiency (i.e., elevated V E /V CO 2 slope and nadir) are key mechanisms of dyspnea and exercise intolerance in patients with interstitial lung disease (ILD; Faisal et al, 2016;Schaeffer et al, 2018). The increased V E /V CO 2 during exercise in ILD appears to be due to the combination of increased dead space and hyperventilation (Agusti et al, 1991;Faisal et al, 2016).…”

Section: Interstitial Lung Diseasementioning

confidence: 99%

“…The increased V E /V CO 2 during exercise in ILD appears to be due to the combination of increased dead space and hyperventilation (Agusti et al, 1991;Faisal et al, 2016). During exercise in patients with ILD, dynamic restrictive mechanical constraints, secondary to increased lung elastic recoil, increase inspiratory elastic loading, and patients often adopt a more rapid and shallow breathing pattern during exercise to minimize the inspiratory elastic work of breathing (Faisal et al, 2016;Schaeffer et al, 2018). Although the reduction in tidal volume is an effective strategy to minimize the elastic work of breathing during exercise, the compensatory tachypnea increases anatomical dead space and, ultimately, V E /V CO 2 (Faisal et al, 2016;Schaeffer et al, 2018).…”

Section: Interstitial Lung Diseasementioning

confidence: 99%

Measurement and Interpretation of Exercise Ventilatory Efficiency

2020

View full text Add to dashboard Cite

Cardiopulmonary exercise testing (CPET) is a method for evaluating pulmonary and cardiocirculatory abnormalities, dyspnea, and exercise tolerance in healthy individuals and patients with chronic conditions. During exercise, ventilation (V E) increases in proportion to metabolic demand [i.e., carbon dioxide production (V CO 2)] to maintain arterial blood gas and acid-base balance. The response of V E relative to V CO 2 (V E /V CO 2) is commonly termed ventilatory efficiency and is becoming a common physiological tool, in conjunction with other key variables such as operating lung volumes, to evaluate exercise responses in patients with chronic conditions. A growing body of research has shown that the V E /V CO 2 response to exercise is elevated in conditions such as chronic heart failure (CHF), pulmonary hypertension (PH), interstitial lung disease (ILD), and chronic obstructive pulmonary disease (COPD). Importantly, this potentiated V E /V CO 2 response contributes to dyspnea and exercise intolerance. The clinical significance of ventilatory inefficiency is demonstrated by findings showing that the elevated V E /V CO 2 response to exercise is an independent predictor of mortality in patients with CHF, PH, and COPD. In this article, the underlying physiology, measurement, and interpretation of exercise ventilatory efficiency during CPET are reviewed. Additionally, exercise ventilatory efficiency in varying disease states is briefly discussed.

show abstract

“…This notion is supported by the fact that when patients with ILD are given supplemental oxygen during constant-load exercise, the neural respiratory drive to the diaphragm decreases along with their perception of dyspnea (Schaeffer et al, 2017b). Neural respiratory drive to the diaphragm can be estimated during CPET using esophageal electromyography (Faisal et al, 2016;Schaeffer et al, 2018). Given that ILD primarily affects the lungs, it is logical to assume that ventilatory factors would lead to the increased perception of exertional dyspnea.…”

Section: Sensory Responsesmentioning

confidence: 99%

“…During incremental exercise, patients with ILD report higher levels of dyspnea than healthy individuals for a given absolute exercise intensity or V̇ E ( O’Donnell et al, 1998 ; Faisal et al, 2016 ). The increased dyspnea is thought to reflect the awareness of an increased neural respiratory drive necessitated by the aforementioned pathophysiological alterations in respiratory mechanics and pulmonary gas exchange efficiency ( Schaeffer et al, 2018 ). This notion is supported by the fact that when patients with ILD are given supplemental oxygen during constant-load exercise, the neural respiratory drive to the diaphragm decreases along with their perception of dyspnea ( Schaeffer et al, 2017b ).…”

Section: Introductionmentioning

confidence: 99%

Cardiopulmonary Exercise Testing in Patients With Interstitial Lung Disease

et al. 2020

Self Cite

View full text Add to dashboard Cite

Interstitial lung disease (ILD) is a heterogeneous group of conditions characterized by fibrosis and/or inflammation of the lung parenchyma. The pathogenesis of ILD consistently results in exertional dyspnea and exercise intolerance. Cardiopulmonary exercise testing (CPET) provides important information concerning the pathophysiology of ILD that can help inform patient management. Despite the purported benefits of CPET, its clinical utility in ILD is not well defined; however, there is a growing body of evidence that provides insight into the potential value of CPET in ILD. Characteristic responses to CPET in patients with ILD include exercise-induced arterial hypoxemia, an exaggerated ventilatory response, a rapid and shallow breathing pattern, critically low inspiratory reserve volume, and elevated sensations of dyspnea and leg discomfort. CPET is used in ILD to determine cause(s) of symptoms such as exertional dyspnea, evaluate functional capacity, inform exercise prescription, and determine the effects of pharmacological and non-pharmacological interventions on exercise capacity and exertional symptoms. However, preliminary evidence suggests that CPET in ILD may also provide valuable prognostic information and can be used to ascertain the degree of exercise-induced pulmonary hypertension. Despite these recent advances, additional research is required to confirm the utility of CPET in patients with ILD. This brief review outlines the clinical utility of CPET in patients with ILD. Typical patterns of response are described and practical issues concerning CPET interpretation in ILD are addressed. Additionally, important unanswered questions relating to the clinical utility of CPET in the assessment, prognostication, and management of patients with ILD are identified.

show abstract

Neurophysiological mechanisms of exertional dyspnoea in fibrotic interstitial lung disease

Cited by 31 publications

References 23 publications

Clinical Utility of Measuring Inspiratory Neural Drive During Cardiopulmonary Exercise Testing (CPET)

Clinical Utility of Measuring Inspiratory Neural Drive During Cardiopulmonary Exercise Testing (CPET)

Measurement and Interpretation of Exercise Ventilatory Efficiency

Cardiopulmonary Exercise Testing in Patients With Interstitial Lung Disease

Contact Info

Product

Resources

About