慢性肺気腫とびまん性肺線維症の呼吸機能の推移に関する研究

抄録

Fourty-nine patients with pulmonary emphysema and diffuse fibrotic change in the lungs (pulmonary fibrosis) were repeatedly studied in terms of changes in lung volumes and blood gas for more than two years. The lung volumes were measured according to the helium dilution method during the stable stage of illness. The annual change was estimated by applying the least-squares regression of obtained values against time. It was also estimated in fifty-one healthy control subjects, and was compared with that in the patients. Blood gas was measured during both the stable and exacerbated stages of illness under normal conditions. The annual change in blood gas was calculated only from the data in the stable stage.
The mean annual changes in patients with pulmonary emphysema were decreases of 0.071l/yr for IRV, 0.040 for ERV, 0.055 for IC, and 0.092 for VC; and increases of 0.243 for RV, 0.174 for FRC, 0.118 for TLC, and 2.98%/yr for RV/TLC. The changes in these parameters were greater than those observed in the healthy subjects (p<0.05). Patients with pulmonary fibrosis showed greater decreases in ERV, VC, and TLC than did the healthy subjects; their mean annual changes were decreases of 0.061, 0.058, and 0.067, respectively. Although arterial blood gas in these patients changed little during the stable stage, a decrease in PaO₂ and an increase in AaDO₂ in patients with pulmonary fibrosis were statistically significant. (p<0.05) During the exacerbated stage, decreases in PaO₂ and increases in AaDO₂ in both groups of patients were marked. A number of patients with pulmonary emphysema showed hypercapnia, especially those whose PaO₂ was below 50 torr. On the other hand, no patients with pulmonary fibrosis showed hypercapnia even during the stage of exacerbation. Changes observed during exacerbation were greater than those observed during the stable stage.