Respiratory · Year 1 · from Respiratory
Case 1: Severe COPD with Hyperinflation
Clinical Image
Source: Wikimedia Commons - Normal vs Emphysema - CC BY 3.0, Blausen Medical
Case Presentation
A 68-year-old man with a 50 pack-year smoking history presents to the pulmonary clinic for evaluation of progressive dyspnea over the past 2 years. He reports dyspnea on exertion that now limits him to walking one block on flat ground before needing to rest. He describes a chronic productive cough with white sputum for many years. He denies recent fever, hemoptysis, or chest pain. On examination, he appears thin with a barrel-shaped chest. Vital signs show respiratory rate 20/min, heart rate 88 bpm, blood pressure 138/82 mmHg, and oxygen saturation 91% on room air. Chest examination reveals decreased breath sounds bilaterally, prolonged expiratory phase, and distant heart sounds. He demonstrates pursed-lip breathing during conversation.
Pulmonary function testing reveals: FEV1 1.2 L (38% predicted), FVC 3.1 L (78% predicted), FEV1/FVC ratio 0.39, TLC 8.2 L (135% predicted), RV 4.8 L (220% predicted), and DLCO 45% predicted. Chest X-ray shows hyperinflated lungs with flattened diaphragms, increased retrosternal airspace on lateral view, and a small, vertically oriented heart. These findings are consistent with severe COPD with emphysema phenotype.
The patient is started on combination long-acting muscarinic antagonist/long-acting beta-agonist inhaler therapy, referred to pulmonary rehabilitation, and counseled on smoking cessation. Supplemental oxygen is prescribed for use during exertion based on desaturation with a 6-minute walk test.
Key Learning Points
- Hyperinflation in COPD results from air trapping due to loss of elastic recoil and dynamic airway collapse during expiration
- Increased total lung capacity (TLC > 120% predicted) and increased residual volume (RV > 120% predicted) are hallmarks of hyperinflation
- The RV/TLC ratio increases as proportionally more air becomes trapped
- Flattened diaphragms from hyperinflation place respiratory muscles at mechanical disadvantage, increasing work of breathing
- Pursed-lip breathing creates positive end-expiratory pressure that helps maintain airway patency during expiration