Fig. 2. Results from the best-fitting model (including estimates of interindividual variability on ke0and effect site concentration associated with 50% maximal drug effect [Ce50]). Individual measured Bispectral Index (BIS) values and the calculated Ce versus time for the four groups, in A – D . E – H show the BIS versus Ce, based on the ke0estimate by NONMEM. To visualize the source data and results for the fixed number model, we showed the measured BIS data ≥ 90 as black circles . The second part (the sigmoid Emaxmodel using BIS < 90) data are shown as straight lines .