Post-bronchodilator FEV1/FVC below 0.7, staged by FEV1
Expansion
Diagnosis: post-bronchodilator FEV1/FVC below 0.7 in a patient with compatible symptoms and risk factors, usually smoking.
Severity by FEV1 as a percentage of predicted
- Stage 1, mild - 80 per cent or more, with symptoms
- Stage 2, moderate - 50 to 79 per cent
- Stage 3, severe - 30 to 49 per cent
- Stage 4, very severe - under 30 per cent
MRC dyspnoea scale, which correlates with disability better than FEV1 does:
- Breathless only on strenuous exercise
- Short of breath hurrying or on a slight hill
- Walks slower than contemporaries, or stops at own pace
- Stops after about 100 metres or a few minutes
- Too breathless to leave the house, or breathless dressing
Investigate for alpha-1 antitrypsin deficiency in the young, in non-smokers, where there is a family history, or where disease is disproportionately severe or basal rather than apical.
Interventions that alter mortality are few and worth knowing: smoking cessation, long term oxygen therapy for chronic hypoxia, lung volume reduction in selected patients, and vaccination. Inhalers and pulmonary rehabilitation improve symptoms, exacerbations and quality of life rather than survival.