Optimized reference signal for induction of general anesthesia with propofol

In this paper we propose the use of an optimization strategy for the computation of an optimized reference (command) input to be applied to a proportional-integral-derivative (PID) based closed-loop control system for the administration of propofol during the induction phase of general anesthesia. The bispectral index scale (BIS) is the controlled variable. The proposed methodology explicitly takes into account the dynamics of the PID controller in the calculation of the reference input to minimize the induction time of anesthesia while limiting the undershoot of the BIS level. The effectiveness of the proposed methodology is assessed in simulation by means of a Monte Carlo method and the performance is compared with that of an optimally tuned PID controller and with that of a recently devised optimized feedforward control law. The effect of the PID tuning on the obtainable performance is also investigated.