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Abstract
In 39 nonsmoking cement workers and in 23 nonsmoking controls of similar age and size maximal expiratory flows at higher and at lower lung volumes were measured. All workers had the one second forced expiratory volume/forced vital capacity (FEV1/FVC) ratio 75% or more. While there was no difference in mean values of maximal expiratory flow for the liter of air after 200 ml had been exhaled (MEFR200–1,200) between two groups, the mean values of maximal midexpiratory flow (MMEF) and maximal expiratory flow in the third quarter of vital capacity (E50–75) were substantially lower in cement workers than in controls. The difference in E50–75 was statistically significant (P<.O5).
The use of indexes of maximal expiratory flow at lower lung volumes is, therefore, recommended for early detection of expiratory airflow obstruction in cement workers. The possible role of small airways obstruction, reduction in elastic recoil of the lung, or both, in the observed flow retardation is discussed.