Silence of the lungs: comparing measures of slow and noncommunicating lung units from pulmonary function tests with computed tomography
Author(s)
Type
Journal Article
Abstract
Multiple breath washout (MBW) has successfully assessed the silent lung zone particularly in cystic fibrosis lung disease, however, it is limited to the communicating lung only. There are a number of different pulmonary function methods that can assess what is commonly referred to as trapped air, with varying approaches and sensitivity. Twenty-five people with cystic fibrosis (pwCF) underwent MBW, spirometry, body plethysmography, and spirometry-controlled computed tomography (spiro-CT) on the same day. PwCF also performed extensions to MBW that evaluate air trapping, including our novel extension (MBWShX), which reveals the extent of underventilated lung units (UVLU). In addition, we used two previously established 5-breath methods that provide a volume of trapped gas (VTG). We used trapped air % from spiro-CT as the gold standard for comparison. UVLU derived from MBWShX showed the best agreement with trapped air %, both in terms of correlation (RS 0.89, P < 0.0001) and sensitivity (79%). Bland–Altman analysis demonstrated a significant underestimation of the VTG by both 5-breath methods (−249 mL [95% CI −10,796; 580 mL] and −203 mL [95% CI −997; 591 mL], respectively). Parameters from both spirometry and body plethysmography were suboptimal at assessing this pathophysiology. The parameters from MBWShX demonstrated the best relationship with spiro-CT and had the best sensitivity compared with the other pulmonary function methods assessed in this study. MBWShX shows promise to assess and monitor this critical pathophysiological feature, which has been shown to be a driver of lung disease progression in pwCF.
NEW & NOTEWORTHY We consider the term “trapped air” either in the use of imaging or pulmonary function testing, something of a misnomer that can lead to an inaccurate assessment of an important physiological feature. Instead, we propose the term underventilated lung units (UVLU). Of the many pulmonary function methods we used in this study, we found that the use of multiple breath washout with short extension (MBWShX) to be the best nonimaging method.
NEW & NOTEWORTHY We consider the term “trapped air” either in the use of imaging or pulmonary function testing, something of a misnomer that can lead to an inaccurate assessment of an important physiological feature. Instead, we propose the term underventilated lung units (UVLU). Of the many pulmonary function methods we used in this study, we found that the use of multiple breath washout with short extension (MBWShX) to be the best nonimaging method.
Date Issued
2024-10-01
Date Acceptance
2024-08-06
Citation
Journal of Applied Physiology, 2024, 137 (4), pp.883-891
ISSN
8750-7587
Publisher
American Physiological Society
Start Page
883
End Page
891
Journal / Book Title
Journal of Applied Physiology
Volume
137
Issue
4
Copyright Statement
© 2024 The Authors. Licensed under Creative Commons Attribution CC-BY 4.0. Published by the American Physiological Society.883J Appl Physiol 137: 883–891, 2024.
License URL
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/39116346
Subjects
air trapping
CF
CHILDREN
CLEARANCE INDEX
collateral ventilation
COLLATERAL VENTILATION
cystic fibrosis (CF)
CYSTIC-FIBROSIS
DISEASE
Life Sciences & Biomedicine
MULTIPLE
Physiology
pulmonary function testing (PFT)
pulmonary physiology
Science & Technology
SPIROMETRY
Sport Sciences
TRAPPED GAS
VOLUME
Publication Status
Published
Coverage Spatial
United States
Date Publish Online
2024-09-23