Faculty Collaboration Database

Area Under the Expiratory Flow-Volume Curve (AEX): Assessing Bronchodilator Responsiveness. Lung 2020 Jun;198(3):471-480

Date

03/27/2020

Pubmed ID

32211978

Pubmed Central ID

PMC7242267

DOI

10.1007/s00408-020-00345-2

Scopus ID

2-s2.0-85083394435 (requires institutional sign-in at Scopus site)   3 Citations

Abstract

BACKGROUND: Area under expiratory flow-volume curve (AEX) is a useful spirometric tool in stratifying respiratory impairment. The AEX approximations based on isovolumic flows can be used with reasonable accuracy when AEX is unavailable. We assessed here pre- to post-bronchodilator (BD) variability of AEX₄ as a functional assessment tool for lung disorders.

METHODS: The BD response was assessed in 4330 subjects by changes in FEV₁, FVC, and AEX₄, which were derived from FVC, peak expiratory flow, and forced expiratory flow at 25%, 50%, and 75% FVC. Newly proposed BD response categories (negative, minimal, mild, moderate and marked) have been investigated in addition to standard criteria.

RESULTS: Using standard BD criteria, 24% of subjects had a positive response. Using the new BD response categories, only 23% of subjects had a negative response; 45% minimal, 18% mild, 9% moderate, and 5% had a marked BD response. Mean percent change of the square root AEX₄ was 0.3% and 14.3% in the standard BD-negative and BD-positive response groups, respectively. In the new BD response categories of negative, minimal, mild, moderate, and marked, mean percent change of square root AEX₄ was - 8.2%, 2.9%, 9.2%, 15.0%, and 24.8%, respectively.

CONCLUSIONS: Mean pre- to post-BD variability of AEX₄ was < 6% and stratified well between newly proposed categories of BD response (negative, minimal, mild, moderate and marked). We suggest that AEX₄ (AEX) could become a useful measurement for stratifying dysfunction in obstructive lung disease and invite further investigation into indications for using bronchodilator agents or disease-modifying, anti-inflammatory therapies.

Author List

Ioachimescu OC, Stoller JK

Author

Octavian C. Ioachimescu MD, PhD Vice Chair, Director, Professor in the Medicine department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Aged
Bronchodilator Agents
Exhalation
Female
Forced Expiratory Volume
Humans
Male
Middle Aged
Pulmonary Disease, Chronic Obstructive
Retrospective Studies
Spirometry
Vital Capacity