Figure 1: Effect site concentration versus time illustrating the PK variability following a bolus and/or infusion administrations of propofol, remifentanil, and fentanyl. The top figure shows a visualization of the anesthetic administrations; the vertical green bars indicate fentanyl bolus administrations, the horizontal red bar indicates the length of the remifentanil infusion administration, the vertical blue bar indicates the time of the propofol bolus administration, and the horizontal blue bar indicates the length of the propofol infusion administration. The bottom three figures illustrate the distribution of the effect site concentration predictions the black line shows the PK prediction, the dark blue shows the middle 68% predictions, and the light blue shows the variance of 95% of the predictions. The left arrow indicates the peak induction pharmacodynamic effect and the right arrow indicates the 50% probability of emergence. The four clinical time points of interest are indicated by the black arrows on the bottom figure at the time point of laryngoscopy (L), skin incision (S), emergence (E), and time to enter PACU (P).