Our linear regression revealed similar B-values for flow volume parameters with cumulative exposure in the same order of magnitude but probably due to a smaller population, the level of significance was not always reached. Kennedy et al showed that lung function (FEVi, FEVi percent) and respiratory symptoms (byssinosis and chronic bronchitis) were related to present exposure in cotton workers; we also observed a concentration-dependent decrease in lung function with increasing present exposure. Correlation of lung function parameters to both present and cumulative exposure indicate that it is difficult to separate both effects. We are therefore uncertain if the observed effects are long or short term but presume that both influenced the results this ventolin inhalers.
In previous studies of animal feed workers, flow-volume parameters have generally been measured to evaluate short- and long-term airflow obstruction. A more sensitive analysis of the response to exposure may be possible with other lung function techniques. Rylander et al applied carbon monoxide diffusing capacity measurement and found a decrease 4 h after short-term inhalation of nebulized endotoxin, suggesting an inflammatory effect of endotoxin exposure.
Sepulveda et al applied impedance measurements to detect cotton dust-induced bronchoconstric-tion. Subjects with across-shift responses in maximal expiratory flow volume curves showed limitation of flow predominantly located in the peripheral airways and subjects with no significant alterations in maximal expiratory flow volume curves showed a central airways effect. In this cross-sectional study among animal food processors, the observed changes in impedance parameters with increasing present dust levels suggest an airflow obstruction extending to the peripheral airways. Evidence for a causal role of endotoxin in the mechanism of the observed airflow obstruction was recently provided by Kips et al.