Reduced chattering target-tracking sliding mode control for intraprocedural propofol control.

This manuscript presents a reduced chattering sliding mode control (SMC) strategy for automatically regulating the depth of hypnosis (DoH) during general anesthesia (GA). The controller uses DoH as the controlled variable and assumes an infusion pump as the actuator. A linear model serves as an approximation in the SMC law, while a sigmoidal function is used instead of the sign function to mitigate chattering. The scheme adopts a tracking-based approach to handle induction and maintenance phases of GA. The method is evaluated through simulations with and without pain stimuli and noise, using real-patient pharmacokinetic and pharmacodynamic parameters and incorporating the dynamic behavior of the DoH monitor. Results showed no high-frequency chattering and demonstrated robust performance, suggesting that the proposed approach is promising for real-world clinical applications.