Abstract
ABSTRACT
Background and Objective
Endobronchial valve (EBV) placement reduces hyperinflation in patients with severe COPD. Eligibility criteria of EBV include total lung capacity (TLC
pleth
) ≥ 100% and residual volume (RV
pleth
) ≥ 175% by body plethysmography. In this study, we evaluated the performance of alternative modalities for predicting EBV criteria in clinical settings where body plethysmography is unavailable.
Methods
This is a single centre observational study. We recruited 41 patients with COPD at St. Marianna University Hospital. The participants underwent spirometry for VC, FVC, and FEV
1
, body plethysmography for TLC
pleth
and RV
pleth
, and the helium dilution technique for TLC
He
and RV
He
as well as CT scanning at full inspiration and expiration to calculate air volume (AV) and total lung volume (TLV), which includes both air and tissue volumes. We also estimated TLV
pleth
and RV
pleth
by using previously proposed formulas from the University of Groningen (TLC
Groningen
and RV
Groningen
) and from the University of Pittsburgh (RV
Pittsburgh
).
Results
The alternative measurements, that is, TLC
He
, AV
inspiratory CT
, TLV
inspiratory CT
, TLC
Groningen
, RV
He
, AV
inspiratory CT
– VC, AV
expiratory CT
, TLV
inspiratory CT
– VC, TLV
expiratory CT
, RV
Groningen
, and RV
Pittsburgh
, correlated well with TLC
pleth
and RV
pleth
. Receiver operating characteristic analysis to predict TLC
pleth
≥ 100%, RV
pleth
≥ 175%, or RV
pleth
≥ 150% by these alternatives yielded high area under the curve (AUC) values around 0.924–0.937. We also determined the threshold values for sensitivity = 100% (Rule‐out threshold) and specificity = 100% (Rule‐in threshold) to predict TLC
pleth
≥ 100%, RV
pleth
≥ 175%, or RV
pleth
≥ 150%.
Conclusion
Our findings indicate that, when body plethysmography is not feasible, these measurements may help identify patients likely or unlikely to meet plethysmography‐defined EBV eligibility criteria.