STUDY OF ALVEOLAR FUNCTION IN PATIENTS OF FAR-ADVANCED PULMONARY TUBERCULOSIS (Particularly, Determination of Uneffective Ventilation Rate and Uneffective PuImonary Blood Flow Rate)

Abstract

Alveolar function, particularly the ventilation-perfusion relationship with the determination of the ineffective ventilation rate and the ineffective pulmonary blood flow rate, was studied in 11 normal human beings and in 60 patients of F-A pulmonary tuberculosis, classified as Fibro0cavitary group, Diffuse Miliary and Nodular group and Diffuse Exudative group. The uneffecive wnfilation rate and uneffecive pulmonary blood flow rate were determined by the ratio of respiratory dead space to tidal volume and the ratio of venous admixture to cardiac output, respectively. The following results were obtained. 1.2. The tidal volume and respiratory dead space were significantly elevated not only in resting state but also in exercise in these patients with F-A pulm. tuberculosis. The large increase in the ratio of dead space to tidal volume observed in those patients with F-A pulm. tuberculosis and the reason was primarily an increase in respiratory dead space even in resting state. 3. 4.Slight reduction of the ratio of dead space to didal volume in exercise compared with resting state was observed in all groups, even in normal group. This was primarily due to large in crease of tidal volume compared with the increase of dead space in exercise. 5. The elevation of ineffective ventilation rate ineffective pulmonary blood flow rate mean 1.16 times of the load in ventilatory work and 1.26 times of load in pulmonary circulatory work are compelled in these patients with F-A pul. tuberculosis compared with normal group in resting state. 6. The alveolar arterial O2 tension difference and the ineffective pulmonary blood flow rate in resting and exercise were significantly elevated to mean value of 37.7 mmHg and 24% respectively in these patients with F-A pulm. tuberculosis, suggesting the increase of venous admixture. 7. No significant difference of ineffective pulmonary blood flow rate and A-a gradient were observed between each group of F-A pulm. tuberculosis except of slight increase in military and medular group. 8. Evidence of impaired oxygenation was present in all group of F-A pulm. tuberculosis even in resting state. 9. The elevation of ineffective pulmonary blood flow rate was associated with the elevation of uneffective ventilation rate in all groups of F-A pulm. tuberculosis. The load was more significant in circulatory work than ventilatory work. This means the impairment of distribution of alveolar ventilation was more significant than impairment of pulmonary vascular bed.