Definition & Diagnosis (GOLD)
"COPD is a heterogeneous lung condition characterised by chronic respiratory symptoms (dyspnoea, cough, sputum, and/or exacerbations) due to abnormalities of the airways (bronchitis, bronchiolitis) and/or alveoli (emphysema) that cause persistent, often progressive, airflow obstruction."
GOLD definition of COPD.Clinical features: insidious onset, usually age > 40; progressive & persistent dyspnoea; no marked nocturnal/diurnal variation and no allergic association (contrast with asthma); cough ยฑ sputum; ยฑ wheeze, accessory muscle use, barrel chest, cyanosis. Extrapulmonary: weight loss, skeletal-muscle dysfunction, pulmonary hypertension & right-ventricular failure (cor pulmonale), and peripheral vascular disease.
The Spectrum of COPD
Emphysema (pathological definition)
Permanent enlargement of airspaces distal to the terminal bronchioles, with destruction of their walls and without obvious fibrosis โ loss of elastic recoil.
Chronic bronchitis (clinical definition)
Chronic productive cough for โฅ 3 months in each of 2 successive years, other causes excluded.
The third component is small-airway disease โ narrowing/obliteration of small bronchioles. Most patients have a mix; the common final pathway is expiratory airflow limitation.
GOLD Grades, Risk Factors & Pack-Years
| GOLD grade (post-bronchodilator FEVโ, % predicted, when FEVโ/FVC < 0.7) | Severity |
|---|---|
| GOLD 1 โ FEVโ โฅ 80% | Mild |
| GOLD 2 โ 50 โค FEVโ < 80% | Moderate |
| GOLD 3 โ 30 โค FEVโ < 50% | Severe |
| GOLD 4 โ FEVโ < 30% | Very severe |
- Risk factors: tobacco/biomass smoke, occupational dusts & fumes, air pollution, ฮฑโ-antitrypsin deficiency, recurrent childhood respiratory infection, low birth weight.
- Smoking index (SI) = cigarettes/day ร years of smoking.
- Pack-years = (cigarettes/day ร years) รท 20 (1 pack = 20 cigarettes). Example: 20/day for 10 years โ SI 200, 10 pack-years.
- The greater the pack-years, the greater the likelihood of smoking-related disease and adverse peri-operative events.