Abstract
Assessment of dyspnoea severity during incremental cardiopulmonary exercise testing (CPET) has long been hampered by the lack of reference ranges as a function of work rate (WR) and ventilation (V̇E). This is particularly relevant to cycling, a testing modality which overtaxes the leg muscles leading to a heightened sensation of leg discomfort.
Reference ranges based on dyspnoea percentiles (0–10 Borg scale) at standardised WRs and V̇E were established in 275 apparently healthy subjects aged 20–85 (131 men). They were compared with values recorded in a randomly selected “validation” sample (N=451, 224 men). Their usefulness in properly uncovering the severity of exertional dyspnoea were tested in 167 subjects under investigation for chronic dyspnoea (“testing sample”) who terminated CPET due to leg discomfort (86 men).
Iso-WR and, to a lesser extent, iso-V̇E reference ranges (5th–25th, 25th–50th, 50–75th and 75th–95th percentiles) increased as a function of age, being systematically higher in women (p<0.01). There was no significant differences in percentiles distribution between “reference” and “validation” samples (p>0.05). Submaximal dyspnoea-WR scores lied within the 75th–95th or >95th percentiles in 108/118 (91.5%) subjects of the “testing” sample who showed physiological abnormalities known to elicit exertional dyspnoea i.e., ventilatory inefficiency and/or critical inspiratory constraints. In contrast, dyspnoea scores typically lied in the 5th–50th range in subjects without those abnormalities (p<0.001).
This frame of reference might prove useful to uncover the severity of exertional dyspnoea in subjects who otherwise would be labeled as “non-dyspneic” while providing mechanistic insights into the genesis of this distressing symptom.
Footnotes
This manuscript has recently been accepted for publication in the European Respiratory Journal. It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJ online. Please open or download the PDF to view this article.
Conflict of interest: Dr. NEDER has nothing to disclose.
Conflict of interest: Dr. BERTON has nothing to disclose.
Conflict of interest: Dr. NERY has nothing to disclose.
Conflict of interest: Dr. O'DONNELL has nothing to disclose.
Conflict of interest: Dr. TAN reports grants from Canadian Respiratory Research Network , grants from AstraZeneca Canada Ltd, grants from Boehringer Ingelheim Canada Ltd, grants from GlaxoSmithKline Canada Ltd, grants from Novartis, grants from Canadian Institutes of Health Research , grants from Respiratory Health Network of the Fonds de la recherche en santé du Québec , grants from Merck, grants from Nycomed, grants from Pfizer Canada Ltd, from Theratechnologies, during the conduct of the study;.
Conflict of interest: Dr. Bourbeau reports grants from CIHR, grants from Canadian Respiratory Research Network (CRRN), personal fees from Canadian Thoracic Society, personal fees from CHEST, grants from Foundation of the MUHC, grants from Aerocrine, grants and personal fees from AstraZeneca, grants and personal fees from Boehringer Ingelheim, grants and personal fees from Grifols, grants and personal fees from GlaxoSmithKline, grants and personal fees from Novartis, grants and personal fees from Trudell, outside the submitted work;.
- Received January 29, 2020.
- Accepted May 12, 2020.
- Copyright ©ERS 2020