COPD and Pathophysiology of Respiratory Acidosis

A 62-year-old female patient is diagnosed with chronic obstructive pulmonary disease (COPD) and presents to the emergency department with increased shortness of breath and a productive cough. The nurse notes that the patient has a barrel-shaped chest and spent several hours gardening in the sun, resulting in mild dehydration. Lab results show respiratory acidosis with a compensatory metabolic alkalosis.

Which of the following pathophysiological changes is most likely contributing to the patient's current condition?