Faculty Collaboration Database

An Alternative Spirometric Measurement. Area under the Expiratory Flow-Volume Curve. Ann Am Thorac Soc 2020 May;17(5):582-588

Date

01/04/2020

Pubmed ID

31899663

Pubmed Central ID

PMC7193817

DOI

10.1513/AnnalsATS.201908-613OC

Scopus ID

2-s2.0-85083374494 (requires institutional sign-in at Scopus site)   16 Citations

Abstract

Rationale: Interpretation of spirometry is influenced by inherent limitations and by the normal or predicted reference values used. For example, traditional spirometric parameters such as "distal" airflows do not provide sufficient differentiating capacity, especially for mixed patterns or small airway disease.Objectives: We assessed the utility of an alternative spirometric parameter (area under the expiratory flow-volume curve [AEX]) in differentiating between normal, obstruction, restriction, and mixed patterns, as well as in severity stratification of traditional functional impairments.Methods: We analyzed 15,308 spirometry tests in subjects who had same-day lung volume assessments in a pulmonary function laboratory. Using Global Lung Initiative predicted values and standard criteria for pulmonary function impairment, we assessed the diagnostic performance of AEX in best-split partition and artificial neural network models.Results: The average square root AEX values were 3.32, 1.81, 2.30, and 1.64 L⋅s^-0.5 in normal, obstruction, restriction, and mixed patterns, respectively. As such, in combination with traditional spirometric measurements, the square root of AEX differentiated well between normal, obstruction, restriction, and mixed defects. Using forced expiratory volume in 1 second (FEV₁), forced vital capacity (FVC), and FEV₁/FVC z-scores plus the square root of AEX in a machine learning algorithm, diagnostic categorization of ventilatory impairments was accomplished with very low rates of misclassification (<9%). Especially for mixed ventilatory patterns, the neural network model performed best in improving the rates of diagnostic misclassification.Conclusions: Using a novel approach to lung function assessment in combination with traditional spirometric measurements, AEX differentiates well between normal, obstruction, restriction and mixed impairments, potentially obviating the need for more complex lung volume-based determinations.

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

Adult
Aged
Airway Obstruction
Area Under Curve
Female
Forced Expiratory Volume
Humans
Lung
Lung Diseases
Machine Learning
Male
Middle Aged
Predictive Value of Tests
Reference Values
Spirometry