Article Text

Download PDFPDF
Functional variables associated with the clinical grade of dyspnoea in coal miners with pneumoconiosis and mild bronchial obstruction


OBJECTIVES Dyspnoea is a common symptom in coal miners with pneumoconiosis. Among others, gas exchange disturbances due to airway obstruction or mismatch between ventilation and perfusion may be underlying mechanisms. The validation of dyspnoea by the degree of airway obstruction is controversial, because the extent of airway obstruction often does not correlate with the clinical grade of breathlessness.

METHODS The association was investigated between breathlessness (self reported, on a six point scale) and indices of submaximal spiroergometry in 66 coal workers with radiographically confirmed pneumoconiosis (International Labour Organisation (ILO) grade of profusion ⩾1/0, mean (SD) age 64 (5.5) years, mean (SD) forced expired volume in 1 second (FEV1) 77.5 (22.9) % predicted).

RESULTS The clinical degree of breathlessness was independently associated with minute ventilation/oxygen consumption (V˙E/V˙O2) ratio (β 0.423, 95% confidence interval (95% CI) 0.18 to 0.67, p=0.001) and smoking (β 0.318, 95% CI 0.21 to 1.79, p=0.014) in a multiple linear regression analysis. The V˙E/V˙O2 ratio (β 0.556, 95% CI 0.20 to 0.90, p=0.003) was also the best predictor of breathlessness when only coal miners with airway obstruction (FEV1 < 80% predicted) were analyzed.

CONCLUSION TheV˙E/V˙O2 ratio as a measurement of mismatch between ventilation and perfusion predicted the clinical grade of breathlessness better than measurements of bronchial obstruction at rest in coal workers with pneumoconiosis.

  • coal workers' pneumoconiosis
  • bronchial obstruction
  • ventilation

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.