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KMID : 0381319820210020032
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Korean Journal of Occupational Health
1982 Volume.21 No. 2 p.32 ~ p.46
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Evaluation of the Pulmonary Function Impairment on Pneumoconiosis by Maximal Expiratory Flows
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Abstract
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Maximal exiratory flow-volume curves were measured on 970 pneumoconiosis patients (907 patients with small rounded opacity and 63 patients with large opacity) and 183 suspected pneumoconiosis patients from Korean anthracitic mines, in order to evaluate the ventilatory impairments of pulmonary function according to the progression of pneumoconiosis by radiographic findings. From these curves, peak flow rate(PFR) and maximal expiratory flows at 25, 50 and 75 percent of the expired forced vital capacity (Vmax 25, Vmax 50, Vmax 75) were obtained.
Pneumoconiosis was classified according to ILO U/C international classification of radiographs of pneumoconiosis with slight modification including suspected pneumoconiosis. Pneumoconiosis with small rounded opacity was further divided into 3 categories and 3 types by the profusion and the type of small rounded opacity and pneumoconiosis with large opacity was also subdivided into 3 types by the size of opacity.
The results were as follows:
1. The predicted mean values of peak flow rate and maximal expiratory flows at 25, 50 and 75 percent of the expired forced vital capacity were significantly decreased in pneumoconiosis patients with large opacity than in pneumoconiosis patients with small rounded opacity and suspected, however, no significant differences in these values were observed between pneumoconiosis patients with small rounded opacity and suspected pneumoconiosis patients. The percentages of substandard patients in PFR, Vmax 50 and Vmax 75 were 74.6％, 76.2％ and 81.0％ in pneumoconiosis patients with large opacity, 30.7％, 41.2％ and 50.3％ in pneumoconiosis patients with small rounded opacity and 27.3％, 39.3％ and 48.1％ in suspected pneumoconiosis patients.
2. The mean values of predicted maximal expiratory flows at varous lung volumes were markedly decreased in pneumoconiosis patients group over 50 years of age.
3. Vmax 50 and Vmax 75 were useful indices for evaluating the ventilatory impairments of pulmonary function in pneumoconiosis and Vmax 75 among maximal expiratory flows at various lung volumes was the most sensitive index in the evaluation of pulmonary function disability with the profusion and the type of small rounded opacity.
4. In patients with small rounded opacity, maximal expiratory flows at various lung volumes showed significant decreasing tendency with the type of small rounded opacity. The percentages of substandard patients in Vmax 50 and Vmax 75 were 34.2％ and 40.0％ in p type, 40.0％ and 50.3％ in q type, and 53.2％ and 59.0％ in r type, respectively.
5. Maximal expiratory flows at various lung volumes showed slight decreasing tendency with the profusion(category) of small rounded opacity but the significant difference was observed only between category 1 and 3, and the percentages of substandard patients in Vmax 75 were 49.7％, 49.8％ and 54.5％ in category 1, 2 and 3, respectively.
6. In pneumoconiosis patints with large opacity, maximal expiratory flows at various lung volumes showed slight decreasing tendency with the size of large opacity, however, the percentages of substandard patients in PER, Vmax 50 and Vmax 75 showed no significant differences among type A, B and C.
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