[Measurement of the emptying time constant of the lungs and the mathematical model of timed forced volume capacity (FVC-t) curve].
In this paper, the principle and the method of the measurement of the emptying time constant of the lungs with FVC-t curve were studied, the formula TC = 2MTTp was derived, and the lung emptying speed at the lower portion of the lung volume on the FVC-t curve from first TC to fifth TC also were determined. The results showed that the percentage of the lung volume degradation between the measurement values and the theoretical values calculated by formula V = V0e-(t/TC) is close in both of normal persons and patients with obstructive emphysema, and the TC/t1/2 is also close to the theoretical values. Thus we suggest that FVC-t curve at the lower portion of the lung volume can be expressed by the formula V = V0e-(t/TC).
Luo
Y J
YJ
First Affiliated Hospital, West China University of Medical Sciences, Chengdu.
D000328:Adult; D000368:Aged; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000503:physiopathology; D008297:Male; D008433:Mathematics; D008875:Middle Aged; D008954:Models, Biological; D011656:Pulmonary Emphysema / Q000503:physiopathology; D013147:Spirometry; D014109:Total Lung Capacity