A client with COPD develops a barrel chest over time. What is the primary reason for this change?

A. Decreased lung compliance – While lung compliance may be affected in COPD, it is not the direct cause of barrel chest. B. Pneumonia – Pneumonia is an acute infection and does not cause the chronic structural change of barrel chest. C. Air trapping and hyperinflation of the lungs – In COPD, especially emphysema, chronic air trapping and lung hyperinflation lead to an increase in the anterior-posterior diameter of the chest, resulting in a barrel-shaped chest. D. Increased pulmonary blood pressure – While pulmonary hypertension can occur with advanced COPD, it is not responsible for the barrel chest appearance.