Tt. Bauer et al., Functional variables associated with the clinical grade of dyspnoea in coal miners with pneumoconiosis and mild bronchial obstruction, OCC ENVIR M, 58(12), 2001, pp. 794-799
Citations number
30
Categorie Soggetti
Envirnomentale Medicine & Public Health","Pharmacology & Toxicology
Objectives-Dyspnoea is a common symptom in coal miners with pneumoconiosis.
Among others, gas exchange disturbances due to airway obstruction or misma
tch between ventilation and perfusion may be underlying mechanisms. The val
idation of dyspnoea by the degree of airway obstruction is controversial, b
ecause the extent of airway obstruction often does not correlate with the c
linical grade of breathlessness.
Methods-The association was investigated between breathlessness (self repor
ted, on a six point scale) and indices of submaximal spiroergometry in 66 c
oal workers with radiographically confirmed pneumoconiosis (International L
abour Organisation (ILO) grade of profusion greater than or equal to 1/0, m
ean (SD) age 64 (5.5) years, mean (SD) forced expired volume in 1 second (F
EV) 77.5 (22.9) % predicted).
Results-The clinical degree of breathlessness was independently associated
with minute ventilation/oxygen consumption ((V)over dotE/(V)over dotO(2)) r
atio (beta 0.423, 95% confidence interval (95% CI) 0.18 to 0.67, p=0.001) a
nd smoking (beta 0.318, 95% CI 0.21 to 1.79, p=0.014) in a multiple linear
regression analysis. The (V)over dotE/(V)over dotO(2) ratio (beta 0.556, 95
% CI 0.20 to 0.90, p=0.003) was also the best predictor of breathlessness w
hen only coal miners with airway obstruction (FEV1 < 80% predicted) were an
alyzed.
Conclusion-The (V)over dot/(V)over dotO(2) ratio as a measurement of mismat
ch between ventilation and perfusion predicted the clinical grade of breath
lessness better than measurements of bronchial obstruction at rest in coal
workers with pneumoconiosis.