Fig. 7. The effect site propofol concentration associated with recovery of responsiveness was independent of the rate constant, whether determined with the original (  A ) or individualized values of the rate constant (  B ), likely reflecting the slow rate of change of both plasma and effect site concentrations and hence near equilibration between them at the time of recovery of responsiveness. As with times to syringe drop and loss of responsiveness, the Bispectral Index (BIS) at recovery of responsiveness seemed to be independent of the rate of increase of effect site propofol concentration (  C ).