Performance evaluation of two published closed-loop control systems using bispectral index monitoring: a simulation...

Area of Science:

• Anesthesiology
• Control Systems Engineering
• Medical Simulation

Background:

• Automated closed-loop control systems offer potential improvements in patient care quality.
• Ensuring the safety of these systems under extreme conditions is paramount.
• This study introduces a simulation methodology for testing automated controllers in anesthesia.

Purpose of the Study:

• To develop and apply a simulation methodology for evaluating automated anesthesia controllers.
• To compare the performance of a model-based controller against a proportional integral derivative (PID) controller for Bispectral Index (BIS)-guided propofol administration.

Main Methods:

• A patient simulator was created to emulate BIS data output.
• Input scripts defined patient characteristics, target BIS values, and surgical events.
• Two controllers (model-based and PID) were tested on 10 virtual patients across different BIS targets (30, 50, 70).
• Performance was evaluated using metrics like prediction error, divergence, wobble, and time within target range.

Main Results:

• The PID controller showed a significantly smaller median prediction error.
• The model-based controller exhibited a smaller median absolute prediction error, particularly at BIS targets of 30 and 50.
• Both controllers were tested under simulated extreme conditions.

Conclusions:

• A patient-individualized, model-based adaptive closed-loop system with effect site control provided superior BIS control compared to a standard PID controller with plasma site control.
• The model-based controller demonstrated robust performance without behavioral issues, even under simulated extreme conditions.
• Simulation is a viable method for assessing the safety and efficacy of automated anesthesia control systems.