EPSAC-controlled anesthesia with online gain adaptation

This paper presents the application of predictive control to drug dosing during anesthesia in patients undergoing surgery. A single-input (propofol) single-output (bispectral index (BIS)) model of the patient has been assumed for prediction. The performance of our previous strategy in drug dosing control has been improved to tackle inter-patient variability. A set of 12 patient models was studied and, in order to ensure the applicability of the proposed controller, gain adaptation in the controller is proposed. Preliminary studies have shown that due to static nonlinearity in the sigmoid curve of the patient model, feedback control is not feasible in the first part of the induction phase. Therefore, the control strategy applied in this study consists of controlling the effect site concentration (C-e) during the first phase and controlling BIS once the relation BIS/C-e has been identified. The policy of switching and adapting the control strategies shows a good performance during the induction phase in simulation studies. Clinical tests have been scheduled at the Ghent University Hospital for the coming months. Copyright (C) 2008 John Wiley & Sons, Ltd.