Fig. 8.

Effect of various combinations of ventilation parameters on Sn_III with breath number for nitrogen. $\alpha ={(V_U)}_{\text{FRC}}/V_{\text{FRC}},$ where ${(V_U)}_{\text{FRC}}$ is the volume of the upper lung region at FRC; $\beta ={(V_U)}_{\mathrm{T}}/V_{\mathrm{T}},$ where ${(V_U)}_{\mathrm{T}}$ is the tidal volume entering the upper lung region; and FS_U/L = flow sequence factor between the upper and lower regions (see Eq. (4). [□] = experimental data of Crawford et al. [8]