[Single-breath and rebreathing methods for measurement of pulmonary diffusing function: a comparative study].

Area of Science:

• Pulmonary Physiology
• Respiratory Medicine
• Diagnostic Testing

Background:

• Pulmonary diffusing capacity is a key indicator of lung function.
• Single-breath (SB) and re-breathing (RB) methods are used to measure diffusing capacity.
• Understanding discrepancies between these methods is crucial for accurate diagnosis.

Purpose of the Study:

• To compare pulmonary diffusing capacity measurements using SB and RB methods.
• To evaluate the differences in normal subjects, Interstitial Lung Disease (ILD) patients, and Chronic Obstructive Pulmonary Disease (COPD) patients.
• To assess the clinical applicability of the RB method.

Main Methods:

• A cohort of 3 groups (control, ILD, COPD) underwent SB and RB pulmonary diffusing capacity tests.
• SB-DLCO%pred from the normal group served as a standard for adjusting RB measurements.
• Statistical analyses included independent-sample t-tests, One-Way ANOVA, and ROC curve analysis.

Main Results:

• Significant differences were observed between SB and RB measurements before correction in all groups.
• After correction, significant differences persisted in ILD (DLCO%pred, DLCO/VA%pred) and COPD (DLCO/VA%pred) groups.
• RB method showed a stronger correlation with test time in COPD patients, and ROC analysis indicated diagnostic potential for RB-DLCO%pred in ILD and RB-DLCO/VA%pred in COPD.

Conclusions:

• Discrepancies exist between SB and RB methods for measuring pulmonary diffusing capacity.
• The predictive values for the RB method require further validation.
• The RB method appears more physiologically consistent and potentially better for detecting lung disease states.