Figure 4
Model simulations and measured data for six patients selected to represent typical cases. Model fitted simulations (curves) and measured data (crosses) describing (i) inspired oxygen fraction (FiO2) versus arterial oxygen saturation (SaO2) and (ii) FiO2 versus the partial pressure of oxygen in arterial blood (PaO2)/FiO2 ratio. (a) Normal subject [14], (b) cardiac incompensation patient [14], (c) gynaecological laparotomy patient [14], (d) cardiac surgery patient [15], (e) intensive care patient [14], and (f) previously unpublished intensive care data. Curves, parameter values and fitting residuals (root mean square (RMS)) for the 'effective shunt' model (dashed lines, 'effective shunt' parameter) and for the two-parameter model (solid lines, shunt and ΔPO2 parameters). Thick lines, range of FiO2 giving a SaO2 of 92–98%.