Lung Ultrasound: An Initial Bedside 'Spirometry' Tool in Diagnosing Obstructive Syndrome

Introduction Chronic obstructive pulmonary disease (COPD), composed of emphysema and chronic bronchitis, is a leading global health burden. Differentiating these phenotypes at the bedside is essential, as emphysema management focuses on relieving hyperinflation and cautious oxygen titration, while chronic bronchitis requires secretion clearance, infection control, and tailored oxygen therapy. Conventional bedside tools lack accuracy for this purpose. Lung ultrasound (LUS), with novel pleural, sub pleural markers such as the Twinkling White Area (TWA) and rib shadow geometry, offers a potential solution. To our knowledge, this is the first study to investigate the role of LUS in phenotyping COPD. Aim: To assess the diagnostic utility of TWA morphology (length, width, density), rib shadow characteristics (W, W2), and rib-to-pleural line distance (“high of ribs”) during rest, inspiration, and expiration, in distinguishing normal lungs from emphysema and chronic bronchitis. This study is first of three approaches: the first examines the echographic characteristics of emphysema compared to normal subjects; the second compares chronic bronchitis with normal subjects; and the third focuses on the echographic features that differentiate emphysema from chronic bronchitis. The current manuscript presents the lung ultrasound findings in emphysema. Methods: A prospective observational study was conducted on 105 individuals (25 controls, 40 emphysemas, 40 bronchitis), using a 2–5 MHz handheld Clarius ultrasound probe. Four thoracic regions were scanned. Quantitative measurements were analyzed via PCA, ANOVA, ROC analysis, and logistic regression. Results and discussion PCA revealed three major components explaining 61.6% of variance; the dominant contributor was TWA length during inspiration and expiration. ANOVA showed significant regional differences, with high expiration rib (F = 60.77, p < 0.0001) and TWA length expiration (up to −40% in Region 1) as leading discriminators. The best single variable was TWA length during expiration (cut-off: −50.2), with sensitivity 78.8%, specificity 85.1%, and AUC = 0.743. A five-variable logistic regression model achieved AUC = 0.728 (train), 0.716 (10-fold CV), with length TWA and W2 rib shadow as key predictors. Conclusion: Lung ultrasound enables accurate bedside identification of emphysematous remodeling, particularly through expiratory shortening and widening of TWA, rib shadow distortion, and pleural-rib distance reduction. These sonographic patterns are storytellers that reflect regional and phenotypic heterogeneity and may serve as real-time, non-invasive surrogates for spirometry in the evaluation of obstructive syndromes.