Expiratory gas concentration curves for examination of uneven distribution of ventilation and perfusion in the lung. Second communication: experiments.

Abstract

The experiments in this paper pertain to theory developed in a preceding article of Respiration Recording of expiratory gas concentration curves yield parameter values with good reproducibility, e. g. RHe, MHe, He1.5, measures for several aspects of uneven ventilation, and Rco2 a measure for unequal distribution of ventilation-perfusion ratio in the lung. The minimum radius of curvature of He and CO2 curves, RHe and Rco2 resp., is compared with clinical diagnoses and a correlation is shown of RHe, Rco2 and emphysema. The values of RHe and Rco2 correlate significantly with other lung function parameters. The pathological slope (M) of the alveolar plateau is suggested to be caused by a gradual change in ratio between the flows from individual lung regions. This is proved with bronchospirometry. With the parameter He1•5 it might be possible to reveal disturbances in small parts of the lung.