Exactly linearizing adaptive control of propofol and remifentanil using a reduced Wiener model for the depth of anesthesia

A closed-loop adaptive controller for propofol and remifentanil administration using BIS measurements is proposed in this paper. The controller design relies on a reduced MISO Wiener model for the depth of anesthesia. The exact linearization of this minimal Wiener structure using the model continuous-time parameter estimates calculated online by an extended Kalman filter is a key point in the design. A linear quadratic gaussian controller is developed for the exactly linearized system. Good results were obtained when the robustness of the proposed controller was assessed with respect to inter and intrapatient variability through Monte Carlo simulations on a database of 500 patients.