SLIDING MODE CONTROL FOR DEPTH OF ANESTHESIA

This paper proposes a sliding mode control for depth of anesthesia. A robustly tuned controller brings the patient to a desired level of hypnosis- This is based on the standard pharmacokinetic/pharmaco-dynamic patient model that is described by two compartments. First, the drug enters the body in the central compartment, where the drug metabolism and elimination occurs. This compartment is connected with the peripheral compartment, with distinct equilibrating rates. The control system contains a sliding mode controller, an observer and two additional proportional integral control channels for the patient and for the reduced patient model. The main problem in the proposed control structure is how to preserve system stability in the presence of the exogenous disturbance. Introduction of proportional integral control channels is necessary to guarantee asymptotic stability of the control system and its robustness to the disturbances. The effectiveness of the proposed control is demonstrated by simulation on an example.