ADAPTIVE CONTROL OF LOW-FLOW ANAESTHESIA USING A MIXTURE OF ANAESTHETIC GASES

摘要

This paper investigates the automatic control of low-flow inhalational anaesthesia using a mixture of isoflurane and nitruous oxide gases. An adaptive constrained multivariable GPC method is used to compute the isoflurane infusion rate and the nitrous oxide concentration in the fresh gas based on measurements of the endtidal isoflurane concentration and mean arterial prex`ssure (MAP). In the second part of the paper, the same strategy is employed to control the end-tidal isoflurane concentration using the fresh-gas flow rate and the isoflurane infusion rate as manipulated variables. The feasibility of the proposed control strategies is evaluated on an extended nonlinear compartmental model of the anaesthesia system, which include the pharmacokinetic and pharmacodynamic equations associated with the second anaesthetic gas. Numerical simulations are used to demonstrate the approach.