Seamless integration of target-controlled infusion and closed-loop anesthesia

The anesthetic drug propofol is commonly used to control hypnotic depth (suppression of awareness) in patients undergoing surgery or intensive care. In addition to manual titration, a model-based open-loop feed-forward strategy called target-controlled infusion (TCI) has attained some clinical popularity. Research on closed-loop control, with awareness estimates derived from an electroencephalogram (EEG), has proven feasible through several extensive clinical studies over the past decades. While TCI is vulnerable to model imperfections, closed-loop control is susceptible to corrupt measurements. By combining Kalman-filter-based state estimation with model predictive control (MPC), we introduce a novel anesthetic dosing regimen that can transition seamlessly between TCI and closed-loop control, thus constituting an adequate trade-off between model and measurement reliance. We introduce this regimen and provide a realistic simulation example that highlights its strengths compared to pure TCI or closed-loop control of propofol infusion.