Estimation of the distribution profile of airway resistance in the lungs.
The distribution profile of resistance in a series lung model consisting of airways of 23 generations with alveoli was estimated in 10 healthy subjects and 7 subjects with chronic pulmonary emphysema. Forced oscillation was applied to the subjects at the mouth using a complex wave composed of sine waves at frequencies through the range 4 to 20 Hz in 1-Hz steps. The pleural pressure was measured with a catheter-tip micromanometer, which was installed in an esophageal balloon. The frequency dependency of the pulmonary impedance was analyzed using a penalty function method, and a stable estimate of the distribution profile of resistance in the lungs was thus obtained. The central airway resistance (defined as the resistance from generation 0 to generation 7) was estimated as 1.18 +/- 0.37 cm H2O/liter/sec in the healthy subjects and 1.03 +/- 1.13 cm H2O/liter/sec in the subjects with chronic pulmonary emphysema. The peripheral airway resistance (defined as the resistance from generation 8 to generation 23) was estimated as 0.06 +/- 0.03 cm H2O/liter/sec in the healthy subjects and 6.38 +/- 3.77 cm H2O/liter/sec in the subjects with chronic pulmonary emphysema.
Department of Medicine, School of Medicine, Keio University, Tokyo, Japan.
H
H
Kobayashi
T
T
Abe
T
T
Kawashiro
K
K
Tanabe
T
T
Yokoyama
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000403:Airway Resistance; D006801:Humans; D008168:Lung / Q000502:physiology*; D008365:Manometry / Q000295:instrumentation; D008875:Middle Aged; D008954:Models, Biological; D011656:Pulmonary Emphysema / Q000503:physiopathology*; D012815:Signal Processing, Computer-Assisted