LETTER
Bronchodilator Response Assessment of the Small Airways Obstructive Pattern
Plamen Bokov1, 2, Clémence Martin1, Sémia Graba1, Karine Gillet-Juvin1, Mohamed Essalhi1, Christophe Delclaux1, 2, *
Article Information
Identifiers and Pagination:
Year: 2017Volume: 11
First Page: 47
Last Page: 53
Publisher ID: TORMJ-11-47
DOI: 10.2174/1874306401711010047
Article History:
Received Date: 26/04/2017Revision Received Date: 25/05/2017
Acceptance Date: 06/07/2017
Electronic publication date: 25/07/2017
Collection year: 2017
open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: https://creativecommons.org/licenses/by/4.0/legalcode. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Abstract
Background:
A concomitant decrease in FEV1 and FVC with normal FEV1/FVC ratio and TLC defines small airways obstructive pattern (SAOP) and constitutes a classic pitfall of pulmonary-function-tests interpretation.
Objective:
To evaluate the prevalence of flow- (FEV1 increase≥12% and 200 mL), volume- (FVC or inspiratory capacity [IC] increase≥12% and 200 mL), flow and volume-, and non-response to bronchodilation in patients with SAOP. An additional objective was to assess whether impulse oscillometry (IOS) parameters allow the diagnosis of SAOP and its reversibility.
Methods:
Fifty consecutive adult patients with SAOP (FEV1 and FVC < lower limit of normal, FEV1/FVC and TLC > lower limit of normal) diagnosed on spirometry and plethysmography underwent the assessment of reversibility (400 µg salbutamol) on FEV1, FVC, IC and IOS parameters.
Results:
The diseases most frequently associated with SAOP were COPD and asthma (26 and 15 patients, respectively). Six patients were flow-responders, 20 were volume-responders, 9 were flow and volume-responders and 15 patients were non-responders. Overall, 26 patients had a significant improvement of IC, and 35 / 50 (70%, 95%CI: 57-83) exhibited a significant bronchodilator response. The difference between Rrs5Hz and Rrs20Hz was increased in 28/50 patients (56%, 95%CI: 42-70 with value higher than upper limit of normal) and its decrease after bronchodilator significantly correlated to FEV1 increase only, suggesting proximal airway assessment.
Conclusion:
A significant reversibility, mainly assessed on IC increase, is frequent in Small Airways Obstructive Pattern. Impulse oscillometry is of limited value in this context because of its low sensitivity.
