The utility of spirometry and single breath gas transfer measurements to identify low total lung capacity
File(s)
Published version
Author(s)
Knox-Brown, Ben
Alexiou, Chara
Stanojevic, Sanja
Sylvester, Karl P
Type
Journal Article
Abstract
Background
Measurement of total lung capacity (TLC) requires large and expensive equipment. We aimed to investigate whether spirometric restriction and low alveolar volume measured by single breath gas transfer (VA) can be used to identify those with a low TLC.
Methods
We retrospectively analysed data from adults referred to Cambridge University Hospitals between January 2016 and December 2023. We investigated the utility of spirometric restriction (FVC <LLN with FEV1/FVC ≥LLN) and reduced VA (<LLN), to discriminate low TLC measured by plethysmography (TLCpleth <LLN). We assessed agreement between definitions using the Cohen's Kappa coefficient and the discriminative ability of spirometric restriction and reduced VA to identify TLCpleth <LLN.
Results
Data from 7923 patients were included. The majority (94%) of patients were of European ancestry, 51% were female. Mean age was 58 years. 11% of patients had a TLCpleth <LLN, of which 27% also had spirometric restriction, and 95% had a VA <LLN. Agreement between spirometric restriction and TLCpleth <LLN was fair (kappa =0.37). Spirometric restriction had low sensitivity (27%) but high specificity (99%) for discriminating TLCpleth <LLN. Agreement between VA <LLN and TLCpleth <LLN was substantial (kappa=0.63). VA <LLN had good sensitivity (95%) and specificity (89%) for discriminating TLCpleth <LLN, except for in patients with the most severe airflow obstruction.
Conclusions
A FVC in the healthy range is an effective tool for ruling out restriction. Low VA can be used to accurately identify those with a low TLC, negating the need for formal measurement of static lung volumes when identifying restrictive lung disease.
Measurement of total lung capacity (TLC) requires large and expensive equipment. We aimed to investigate whether spirometric restriction and low alveolar volume measured by single breath gas transfer (VA) can be used to identify those with a low TLC.
Methods
We retrospectively analysed data from adults referred to Cambridge University Hospitals between January 2016 and December 2023. We investigated the utility of spirometric restriction (FVC <LLN with FEV1/FVC ≥LLN) and reduced VA (<LLN), to discriminate low TLC measured by plethysmography (TLCpleth <LLN). We assessed agreement between definitions using the Cohen's Kappa coefficient and the discriminative ability of spirometric restriction and reduced VA to identify TLCpleth <LLN.
Results
Data from 7923 patients were included. The majority (94%) of patients were of European ancestry, 51% were female. Mean age was 58 years. 11% of patients had a TLCpleth <LLN, of which 27% also had spirometric restriction, and 95% had a VA <LLN. Agreement between spirometric restriction and TLCpleth <LLN was fair (kappa =0.37). Spirometric restriction had low sensitivity (27%) but high specificity (99%) for discriminating TLCpleth <LLN. Agreement between VA <LLN and TLCpleth <LLN was substantial (kappa=0.63). VA <LLN had good sensitivity (95%) and specificity (89%) for discriminating TLCpleth <LLN, except for in patients with the most severe airflow obstruction.
Conclusions
A FVC in the healthy range is an effective tool for ruling out restriction. Low VA can be used to accurately identify those with a low TLC, negating the need for formal measurement of static lung volumes when identifying restrictive lung disease.
Date Issued
2025-09-01
Date Acceptance
2025-02-12
Citation
ERJ Open Research, 2025, 11 (5)
ISSN
2312-0541
Publisher
European Respiratory Society
Start Page
00038
End Page
2025
Journal / Book Title
ERJ Open Research
Volume
11
Issue
5
Copyright Statement
Copyright ©The authors 2025. This version is distributed under the terms of the Creative Commons Attribution Non-Commercial Licence 4.0. For commercial reproduction rights and permissions contact permissions@ersnet.org
License URL
Identifier
10.1183/23120541.00038-2025)
Publication Status
Published
Date Publish Online
2025-02-27