Balanced Anesthesia

Anesthesia provides a suitable level of depth of hypnosis (DoH), analgesia, and neuromuscular blockade (NMB) to patients. In particular, in total intravenous anesthesia (TIVA), each of these effects is regulated by a specific drug. 


A processed electroencephalogram (pEEG) signal (for example, Bispectral Index (BIS)) can be employed to measure the DoH. It consists of a dimensionless number between 0, corresponding to EEG silence, to 100, corresponding to a fully awake patient. 

During surgical procedures, a target range between 40 and 60 is suggested to prevent awareness and to reduce the dose of anaesthetic agent. An optimal depth of sedation is a main determinant of the quality of postoperative recovery. Indeed, insufficient sedation exposes patients to awareness, with potential long-term psychological consequences, while excessively deep anesthesia induces hypotension, which is independently associated with increased postoperative morbidity and mortality. In intensive care units (ICUs), excessive sedation in critically-ill patients, suffering from acute respiratory distress syndrome (ARDS), is associated with poor outcomes and delirium. 

Objective

First, this project addresses the automatic control of general anesthesia during surgery, with the objective of developing an efficient and robust solution, to increase safety and reduce post-operative complications. The project aims to design a controller that determines the rate of the hypnotic and analgesic agents to achieve a rapid anesthesia onset and maintain the BIS signal in a safe range. The control scheme will be based on robust model predictive control. 



1) Improve safety

2) Avoid drug over/underdose

3) Reduce wake-up time

4) Reduce work-load for the anesthesiologist

The control design leverages the pharmacokinetics/pharmacodynamics model of the drugs, taking into account that, for each patient, the model parameters are uncertain. The control will minimize the time required for inducing unconsciousness, avoiding excessive undershoot of the BIS signal. The controller is designed to maintain the BIS signal in a prescribed range, despite the presence of noxious stimuli and the uncertainty in model parameters. Then, the devised methodologies will be tailored to critically-ill patients in ICUs, for which control requirements are tighter. 

This project is based on a strong cooperation between control engineers and anesthesiologists. Clinical trials on patients will be performed at the Brescia Hospital, thanks to a partnership agreement that has been signed between the University of Brescia and the hospital. 

This project has been developed under the PRIN 2022 project “ACTIVA - Automatic Control of Total IntraVenous Anesthesia”                 CUP D53D23001180006 funded by European Union – Next Generation EU.