THE BENEFITS OF USING GUYTON'S MODEL IN HYPOTENSIVE CONTROL SYSTEM

In order to improve the applications of intraoperation and internal medicine, this paper presents a method of hypotensive control. The mean arterial pressure (MAP) is decreased and maintained at a low level during anaesthesia by controlling sodium nitroprusside (SNP) infusing rate. In this system, a new dynamical model of MAP response to SNP is modified based on Guyton's model of cardiovascular dynamics. The resulting model is not only useful to design a PID controller, but also for studying the behaviors of patients under anaesthesia condition, such as the perfusion of organs and the reaction of the body at hypotensive state. A fuzzy gain scheduler (FGS) is online updated for tuning the PID gains during control activities to handle the behaviors of the body. Simulation results prove the benefits of using Guyton's model, and indicate the safety and stability of the control system.