What causes barrel chest in patients with COPD?

Barrel chest in patients with chronic obstructive pulmonary disease (COPD) primarily occurs due to air trapping in the lungs. In COPD, the airways become obstructed, making it difficult for patients to exhale fully. This leads to an accumulation of air in the alveoli, which causes them to become overinflated. As a result, the thoracic cavity expands, giving the chest a rounded, barrel-like appearance.

This characteristic change in chest shape is an adaptive response to prolonged over-inflation and reflects the underlying pathology associated with compromised lung function. While other factors like decreased lung capacity and chest wall deformities can impact respiratory mechanics, it is the air trapping that specifically leads to the classic barrel chest observed in COPD patients. Increased physical activity does not contribute to the development of barrel chest; rather, it can sometimes help maintain overall lung function and prevent deconditioning.