Models for control of intravenous anesthesia

Modeling is fundamental to both feed-forward and feedback control. Within automated anesthesia the two paradigms are usually referred to as target-controlled infusion (TCI) and closed-loop drug delivery, respectively. In both cases, the objective is to control a system with anesthetic drug infusion rate as input, and (measured) clinical effect as output. The input is related to the output through the pharmacokinetics (PK) and pharmacodynamics (PD) of the patient. This chapter gives an introduction to PKPD modeling in automated anesthesia management, intended to be accessible to both anesthesiology and (control) engineering researchers. The following topics are discussed: the role of modeling; the classic PKPD structure used in clinical pharmacology; anesthesia modeling and identification for closed-loop control; inter-patient variability and model uncertainty; disturbance, noise and equipment models. The chapter emphasizes electroencephalogram-guided control of propofol.