A 58-year-old man with a 40 pack-year smoking history presents with progressive dyspnea on exertion and chronic cough productive of sputum. On examination, he has barrel chest and pursed-lip breathing. Spirometry shows: FEV₁ = 42% predicted, FVC = 78% predicted, FEV₁/FVC ratio = 0.54. What is the spirometric pattern and severity classification?

Explanation

## Spirometric Pattern Identification **Key Point:** The FEV₁/FVC ratio is the primary determinant of obstruction versus restriction. - FEV₁/FVC < 0.70 = **Obstructive pattern** (airflow limitation) - FEV₁/FVC ≥ 0.70 with reduced FVC = **Restrictive pattern** - FEV₁/FVC ≥ 0.70 with normal FVC = **Normal pattern** In this case: FEV₁/FVC = 0.54 (< 0.70) → **Obstructive pattern** ## GOLD Severity Classification for COPD | GOLD Stage | FEV₁ % Predicted | Clinical Significance | |---|---|---| | 1 (Mild) | ≥ 80% | Mild airflow limitation | | 2 (Moderate) | 50–79% | Moderate airflow limitation | | 3 (Severe) | 30–49% | Severe airflow limitation | | 4 (Very Severe) | < 30% | Very severe airflow limitation | **Clinical Pearl:** This patient's FEV₁ = 42% predicted falls into the 30–49% range, meeting **GOLD Stage 3 (Severe)** criteria. The clinical presentation (barrel chest, pursed-lip breathing, smoking history) is classic for COPD. **High-Yield:** Barrel chest and pursed-lip breathing are compensatory mechanisms in advanced COPD; they indicate chronic hyperinflation and air-trapping, not early disease. **Mnemonic: FEV₁/FVC < 0.70 = OBSTRUCTION** — remember this ratio is the gatekeeper for the obstructive vs. restrictive distinction.