Aim: This study aimed to sonographically examine the fraction of thickening in the respiratory muscles during the acute exacerbation of chronic obstructive pulmonary disease (COPD) and to determine its relationship with the clinical severity of the exacerbation.

Methods: This prospective study looked at 159 people over the age of 50 who were diagnosed with COPD using the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria and were admitted to the hospital because they were having an acute COPD flare-up. Ultrasonography was used to measure how thick the parasternal intercostals, pectoralis major, and diaphragm muscles were in each patient.

Results: Of the patients, 63 had mild, 63 had moderate, and 33 had severe exacerbations. Parasternal intercostal and pectoralis major muscle thickening fractions were significantly higher in moderate and severe exacerbations compared to mild exacerbations, while the diaphragm muscle thickening fraction was significantly lower (p<0.001). In the severe and moderate exacerbation groups, the thickening percentages of parasternal intercostal and pectoralis major muscle were significantly higher in severe exacerbation than in moderate exacerbation (p<0.001). There was no significant difference in the diaphragm muscle thickening fraction between the two groups.

Conclusion: Ultrasonography of the respiratory muscles may provide useful information in identifying COPD patients at risk of severe exacerbation, as well as a reliable and repeatable biomarker in patient follow-up.

Keywords: COPD exacerbation, parasternal muscle, respiratory muscle ultrasonography, thickening fraction