抄録
Respiratory function tests and arterial blood gas analyses were performed on 53 firebrick-makers exposed to diatomaceous earth dust and on 40 healthy farmers who served as the control group (group C).
The experimental subjects were ranging from 40 to 55 years of age. The brick-makers were subdivided into two groups based on chest X ray findings; group A of 22 brick-makers with pneumoconiosis and group B, 31 healthy brick-makers.
There were no significant differences among the three groups in the mean ages, heights, weights, indices of obesity or years as a smoker. There were no significant difference between groups A and B in the mean years of exposure to dust.
The following results were obtained:
1. The mean values of forced vital capacity/predictive vital capacity (% VC) and flow at 25% of forced vital capacity/height (V25/ht) of group A were significantly lower than those of group C, and those of foeced vital capacity (FVC), % VC, forced expiratory volume in 1 second (FEV1) and V25/ht of group B were significantly lower than those of group C.
2. There were no significant differences in the mean values of pH, PaO2 and AaDO2 between groups A and B, but there was in the case of PaCO2.
3. The relationships between AaDO2 and the obesity index, years as a smoker, V25/ht for group A and B were examined by, multiple regression analysis. Negative partial correlation coefficients were obtained for AaDO2 and V25/ht. Correlations between AaDO2 and the obesity index, years as a smoker were positive and significant.
Based on the results, it is reasonable to say that respiratory function tests are more sensitive than arterial blood gas analyses. It may also be concluded that the variables whitch caused an increase in AaDO2 were the obesity index, years as a smoker and V25/ht in brick-makers exposed to dust.
