A 65-year-old man comes to the office due to worsening exertional dyspnea over the past 3 months. This past year, he has had 4 respiratory infections that improved with medical therapy. The patient does not use alcohol or illicit drugs and has smoked 1½ packs of cigarettes daily for 30 years. Temperature is 36.7 C (98.1 F) , pulse is 76/min, and respirations are 18/min. On physical examination, breath sounds are diffusely decreased. Chest radiography reveals flattened hemidiaphragms, increased radiolucency of the lungs, and a long, narrow heart shadow. This patient's pulmonary function testing will most likely show which of the following patterns of findings?

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11ec160b_3b32_aa50_9249_718b0213718b_MD0001_00 This patient's clinical picture is consistent with chronic obstructive pulmonary disease (COPD), which is a combination of chronic bronchitis and emphysema and is most commonly due to heavy smoking. Patients typically have progressive dyspnea and recurrent upper respiratory infections (characteristic of chronic bronchitis). Air trapping and airway obstruction in COPD reduce both forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) on pulmonary function testing (PFT). Because the decrease in FEV1 is more profound, the FEV1/FVC ratio is also reduced, which is the hallmark of obstructive lung disease on PFT. Air trapping raises functional residual capacity, causing respiration to occur at a higher baseline lung volume. The residual volume (RV) is increased. Total lung capacity (TLC) is also increased. (Choices A and B) RV and TLC values are rarely discordant; therefore, these PFT findings are unlikely to represent true clinical findings. (Choice D) Normal RV with increased TLC can be seen in highly trained athletes due to increased vital capacity. (Choice E) Decreased RV and TLC, along with decreased FVC and increased or normal FEV1/FVC ratio, are seen with restrictive lung disease (eg, pulmonary fibrosis). FEV1 decreases in this setting but to a lesser extent than FVC. Educational objective: Chronic obstructive pulmonary disease is a combination of emphysema and chronic bronchitis and commonly presents with progressive dyspnea and recurrent upper respiratory infections. Bronchial obstruction and alveolar destruction cause air trapping that manifests on pulmonary function testing as decreased forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and FEV1/FVC ratio. Residual volume and total lung capacity are increased.

A 65-Year-Old Man Comes to the Office Due to Worsening