Studies on the Measurement of the Intrapulmonary Gas Distribution by the Helium Closed Circuit Method Using Changeable Volume Modification

　Various indices to detect the impairment of intrapulmonary gas distribution, qualitatively and quantitatively, were proposed on the basis of the analysis of the intrapulmonary helium curve which was obtained during the measurement of the functional residual capacity by a changeable volume modification of the helium closed circuit method.

　The values of mixing efficiency and slow space by these new modifications corresponded quite well with the values obtained by the constant volume modification.