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Adequate anesthesia can be defined as a reversible pharmacological state where the patient's muscle relaxation, analgesia and hypnosis are provided. Muscle relaxation is induced to facilitate the access to internal organs and to depress movement response to surgical stimulation. Analgesia is pain relief. Hypnosis is a general term indicating unconcsciousness and absence of post operative recall of events occurred during surgery. Anesthesiologists administer drugs and adjust several medical devices to achieve such goals and to compensate for the effect of surgical manipulation while maintainig the vital functons of the patient. This is done based on some vital parameter specific target values and monitor readings. Thus, anesthesiologists adopt the role of a feedback controller and it is natural to ask whether automatic controllers are capable of taking over and/or improving parts os such a complex decision process.


Over the past years our group has developed different model-based controllers for ventilation, blood pressure, depth of anesthesia and muscular relaxation (Former Projects). However, the major issue of controlling patient's analgesia is still open. Current research focuses on providing adequate analgesia during surgery, in the postoperative setting and for conscious sedation. The design of open loop (TCI pumps) and closed loop systems for the automatic delivery of the drugs are based on pharmacokinetic and pharmacodynamic models containing "population" parameters, i.e., representative of the "average" patient. These models are identified in ad-hoc studies, but it is known that the experimental setup influences the parameter estimation and, as a consequence, the performances of the model predictions. Therefore, one of our focuses is to define guidelines for optimal experiment design. Because of the large patients inter-variability, a model containing "population" parameters could fail to predict the response of a specific patient to a defined input. Therefore individualization of the model parameters is needed.