A new method of analysing pulmonary quasi-static pressure-volume curves in normal subjects and in patients with chronic airflow obstruction.
1. Exponential analysis of lung pressure-volume curves is used to deal with the non-linearity of the pressure-volume relationship. A major problem of this procedure is to define the lower volume limit for exponential curve fitting. 2. In 12 healthy subjects and 24 patients with chronic airflow obstruction, a cubic function was fitted to the quasi-static pressure-volume curves to define an inflection point. 3. The exponential function of Colebatch et al. (Colebatch, H.J.H., Ng, C.K.Y. & Nikov, N.J. Applied Physiol. 1979; 46, 387-93) was then fitted to the data for volumes above the inflection point. 4. Exponential analysis with a cubic determination of an inflection point provides an objective way to describe the elastic properties of the human lungs in vivo.
Gugger
M
M
University Department of Respiratory Medicine, Rayne Laboratory, City Hospital, Edinburgh, U.K.
Wraith
P K
PK
Sudlow
M F
MF
D000328:Adult; D000368:Aged; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D005652:Functional Residual Capacity / Q000502:physiology; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008173:Lung Diseases, Obstructive / Q000503:physiopathology*; D008176:Lung Volume Measurements; D008297:Male; D008433:Mathematics; D008875:Middle Aged; D011312:Pressure; D014109:Total Lung Capacity / Q000502:physiology