Design of Type-1 and Interval Type-2 Fuzzy PID Control for Anesthesia Using Genetic Algorithms

Hugo Araujo,Bo Xiao,Chuang Liu,Yanbin Zhao,H K Lam

doi:10.4236/jilsa.2014.62007

Hugo Araujo, Bo Xiao + Show 3 more

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https://doi.org/10.4236/jilsa.2014.62007

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Abstract

This paper presents the automatic drug administration for the regulation of bispectral (BIS) index in the anesthesia process during the clinical surgery by controlling the concentration target of two drugs, namely, propofol and remifentanil. To realize the automatic drug administration, real clinical data are collected for 42 patients for the construction of patients’ models consisting of pharmacokinetic and pharmacodynamic models describing the dynamics reacting to the input drugs. A nominal anesthesia model is obtained by taking the average of 42 patients’ models for the design of control scheme. Three PID controllers are employed, namely linear PID controller, type-1 (T1) fuzzy PID controller and interval type-2 (IT2) fuzzy PID controller, to regulate the BIS index using the nominal patient’s model. The PID gains and membership functions are obtained using genetic algorithm (GA) by minimizing a cost function measuring the control performance. The best trained PID controllers are tested under different scenarios and compared in terms of control performance. Simulation results show that the IT2 fuzzy PID controller offers the best control strategy regulating the BIS index while the T1 fuzzy PID controller comes the second.

Highlights

Anesthesia is a reversible state of people who are temporarily lack of consciousness in the purpose of undergoing a surgery without pain
Drug administration for anesthesia has been realized by various PID control strategies
Simulation has been conducted to regulate the output BIS value governed by this model using six control strategies including linear PID controllers, T1 fuzzy PID controllers and interval type-2 (IT2) fuzzy PID controllers

Summary

Introduction

Anesthesia is a reversible state of people who are temporarily lack of consciousness in the purpose of undergoing a surgery without pain. General process of anesthesia consists of induction, maintenance, emergence, and re-. The depth of anesthesia (DOA) represents the level of consciousness [2], which is to be controlled through the process of anesthesia for varieties of control targets such as steady error, settling time, and overshoot. In open-loop control, based on the knowledge and experience, anesthetists manually adjust the drug dosage to maintain the DOA assisted by some clinical indices of patients. In closed-loop control, the drug dosage is automatically adjusted according to some indices of DOA, which makes control input continuous and responsive [3]. The stability of closed-loop control needs to be ensured due to the automated process without supervision [5]

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