A simulation study on optimal IMC based PI/PID controller for mean arterial blood pressure

PurposeBlood pressure of postoperative patient, especially adult cardiac patient, increases due to hypertension which can be lowered by injecting an anti-hypertension vasodilator drug sodium nitroprusside (SNP). Monitor and control of dose of drug infusion on patient is necessary to reduce the blood pressure to a prescribed level, which is an important issue in biomedical engineering drug delivery problems. So, there is a need of advanced control system which improves the health of patient in less time and also reduces clinical expenses.MethodsIn literature, patient’s response to the infusion of drug (SNP model) is modelled. This model has five parameters that vary from patient to patient depending upon his sensitivity to drug. The main objective of our proposed work is to design a robust controller based on internal model control (IMC) structure that works effectively with different types of patient. Here, IMC based one-degree-of-freedom proportional integral (ODF-PI) and two-degree-of-freedom proportional integral derivative (TDF-PID) controllers are designed by utilizing the optimal value of SNP model gain k. Unlike the conventional PI/PID controllers, IMC based PI/PID controller has only one tuning parameter λ which is tuned on the basis of the maximum sensitivity MS.ResultsThe resulting controllers achieve better robust performance criteria for nominal as well as sensitive and insensitive patients.ConclusionsThe proposed technique is stable, accurate and applicable to a wide range of physiological variations in patient parameters.