Abstract
Small airway and interstitial pulmonary involvements are prominent in chronic hypersensitivity pneumonitis (cHP). However, their roles on exercise limitation and the relationship with functional lung tests have not been studied in detail.
Our aim was to evaluate exercise performance and its determinants in cHP. We evaluated maximal cardiopulmonary exercise testing performance in 28 cHP patients (forced vital capacity 57±17% pred) and 18 healthy controls during cycling.
Patients had reduced exercise performance with lower peak oxygen production (16.6 (12.3–19.98) mL·kg−1·min−1 versus 25.1 (16.9–32.0), p=0.003), diminished breathing reserve (% maximal voluntary ventilation) (12 (6.4–34.8)% versus 41 (32.7–50.8)%, p<0.001) and hyperventilation (minute ventilation/carbon dioxide production slope 37±5 versus 31±4, p<0.001). All patients presented oxygen desaturation and augmented Borg dyspnoea scores (8 (5–10) versus 4 (1–7), p=0.004). The prevalence of dynamic hyperinflation was found in only 18% of patients. When comparing cHP patients with normal and low peak oxygen production (<84% pred, lower limit of normal), the latter exhibited a higher minute ventilation/carbon dioxide production slope (39±5.0 versus 34±3.6, p=0.004), lower tidal volume (0.84 (0.78–0.90) L versus 1.15 (0.97–1.67) L, p=0.002), and poorer physical functioning score on the Short form-36 health survey. Receiver operating characteristic curve analysis showed that reduced lung volumes (forced vital capacity %, total lung capacity % and diffusing capacity of the lung for carbon dioxide %) were high predictors of poor exercise capacity.
Reduced exercise capacity was prevalent in patients because of ventilatory limitation and not due to dynamic hyperinflation. Reduced lung volumes were reliable predictors of lower performance during exercise.
Abstract
Besides significant small airway involvement, reduced exercise capacity is due to ventilatory limitation and not due to dynamic hyperinflation in chronic hypersensitivity pneumonitis http://ow.ly/Ou9230kSBQz
Footnotes
This article has supplementary material available from openres.ersjournals.com
This study is registered at www.ClinicalTrials.gov with identifier number NCT 02523833.
Author contributions: O.M. Dias was responsible for the study conception, data collection, data analysis and interpretation, and drafting the article. J.G. Ferreira and L.Z. Cardenas were responsible for data collection. B.G. Baldi, C.R.R. Carvalho, F. Pennati, C. Saltio and A. Aliverti were responsible for critical revision of the article. A.L. Pereira de Albuquerque was responsible for the study design and final approval of the version to be published. All authors have read and approved the final manuscript.
Conflict of interest: Carlos Roberto Ribeiro Carvalho reports personal fees from Boehringer Ingelheim, outside the submitted work.
Support statement: Funding was received from the European Respiratory Society (Fellowship STRTF 2015). Funding information for this article has been deposited with the Crossref Funder Registry.
- Received March 12, 2018.
- Accepted July 5, 2018.
- Copyright ©ERS 2018
This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial Licence 4.0.