Quantifying the shape of the maximal expiratory flow-volume curve in mild COPD

Paolo B Dominelli; Glen E Foster; Jordan A Guenette; Hans C Haverkamp; Neil D Eves; Giulio S Dominelli; William R Henderson; Denis E O'Donnell; A William Sheel

doi:10.1016/j.resp.2015.08.002

Quantifying the shape of the maximal expiratory flow-volume curve in mild COPD

Respir Physiol Neurobiol. 2015 Dec:219:30-5. doi: 10.1016/j.resp.2015.08.002. Epub 2015 Aug 12.

Authors

Paolo B Dominelli¹, Glen E Foster², Jordan A Guenette³, Hans C Haverkamp⁴, Neil D Eves², Giulio S Dominelli⁵, William R Henderson⁶, Denis E O'Donnell⁷, A William Sheel⁸

Affiliations

¹ School of Kinesiology, University of British Columbia, Vancouver, BC, Canada. Electronic address: [email protected].
² Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC, Canada.
³ Centre for Heart Lung Innovation and Department of Physical Therapy, University of British Columbia, St. Paul's Hospital, Vancouver, BC, Canada.
⁴ Johnson State College, Johnson, VT, United States.
⁵ Division of Respirology, University of British Columbia, Vancouver, BC, Canada.
⁶ School of Kinesiology, University of British Columbia, Vancouver, BC, Canada; Division of Critical Care Medicine, University of British Columbia, Vancouver, BC, Canada.
⁷ Respiratory Investigation Unit, Department of Medicine, Queen's University & Kingston General Hospital, Kingston, Ontario, Canada.
⁸ School of Kinesiology, University of British Columbia, Vancouver, BC, Canada.

PMID: 26275685
DOI: 10.1016/j.resp.2015.08.002

Abstract

Maximal expiratory flow-volume (MEFV) curve evaluation using absolute and percent predicted values of flow and volume are used to diagnose respiratory disease, but the shape of the curve is rarely used. Three mathematical methods were used to quantify shape of MEFV curves in subjects with mild COPD (n=19) and matched healthy controls (n=15). Those with mild COPD had a significantly greater slope-ratio (SR) (1.90 ± 0.24 vs. 1.28 ± 0.32) and Beta-angle (160 ± 6.7 vs. 186 ± 15.0) compared to healthy individuals (p<0.05). The flow-ratio method showed no difference between groups. A significant positive SR-volume relationship during expiration was observed in a greater number of mild COPD subjects (94%) compared to controls (20%) (p<0.001). With its increased spatial resolution and the potential to discern etiology behind specific curvature, we suggest using the SR method when available. The change in SR throughout expiration could help identify those who fall within the lower limit of normal lung function and those who may have pathological obstruction.

Keywords: Effort independent; Lung heterogeneity; Pulmonary function; Slope-ratio; Spirometry.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Aged
Female
Humans
Lung Volume Measurements
Male
Maximal Expiratory Flow-Volume Curves*
Middle Aged
Pulmonary Disease, Chronic Obstructive / physiopathology*
Retrospective Studies

Grants and funding

Canadian Institutes of Health Research/Canada