Table 2. Model Parameter Estimates for Ventilation (V̇i), Tidal Volume (VT), Respiratory Frequency (RR), Heart Rate (HR), the Hypoxic Sensitivities (ΔE/ΔSpo2), and Bispectral Index (BIS)
Baseline = control parameter value (i.e. , before drug administration); C25and C50= concentrations of alfentanil (in ng/ml) or sevoflurane (in end-tidal concentration [ET%]) giving 25% and 50% reductions in E; %CV = percentage coefficient of variation, which is a measure of the interindividual variability;
*= parameter not included in the statistical model; Imaxand Qmax= interaction parameters: Imaxvalues not significantly different from 1 are not included in the table (in these cases, the alfentanil–sevoflurane interaction is additive) and Imaxvalues greater than 1 indicate synergy; SD of the residuals = measure of goodness of fit.