Physiological Control Law for Rotary Blood Pumps with Full-State Feedback Method

Abstract

One concern about pulsatile rotary blood pumps is their physiological controller reactions when “venous return” changes. When a patient rises from a supine to a standing position, the blood volume in the leg veins is raised, owing to vasodilation, thus venous returns to the right atrium, and consequently, the left atrium is reduced. In this work, a physiological control law using a full-state feedback control method was developed in order to drive mechanical circulatory support. This strategy was used as a validated state-space pump model, to implement the controller and regulate the desired reference flow. The control law was assessed using a software model of the hemodynamical cardiovascular system interacting with the left ventricular assist device in different physiological conditions ranging from rest to exercise scenarios. Under these scenarios, heart failure disease was simulated by changing the hemodynamic parameters of the total blood volume, heart rate, cardiac contractility, and systemic peripheral resistance. The results were numerically observed during the postural changes. The rate of change in the physiological variables showed that the proposed control law can regulate the desired reference pump flow with minimal error within the acceptable clinical range in order to prevent suction and over perfusion.

In Silico Evaluation of a Physiological Controller for a Rotary Blood Pump Based on a Sensorless Estimator

“…However, 75% of HF is caused by a predominant left ventricular failure. Therefore, IRBPs are increasingly used for patients with chronic heart disease; they require a complex control technique [3]. The traditional control methods used by these devices have different limitations when adjusting the pump speed under various physiological conditions of the heart [4].…”

“…In addition, a fullstate FBC method has also been developed and evaluated. For instance, Bakouri et al [3] used the FSC technique to regulate the pulsatility of the pump flow. This method was implemented to emulate the Frank-Starling mechanism to prevent suction or overperfusion.…”

A Flow Sensor-Based Suction-Index Control Strategy for Rotary Left Ventricular Assist Devices

“…Suction detection algorithms based on a variety of pump signals for rotary LVADs have been proposed [ 13 , 14 , 15 , 16 ], however, these algorithms only detect suction events after they have occurred, which results in myocardial damage. Many physiological control strategies have also been developed that aim to reduce LV suction events [ 17 , 18 , 19 , 20 , 21 , 22 ], but some of these require the measurement of ventricular pressure and/or volume, which require sensors that are in contact with blood, and thus susceptible to thrombosis or failure, while others may not be able to generate sufficient perfusion during varying physiological conditions. Our group and others have developed sensorless algorithms [ 23 , 24 , 25 , 26 ] with model-based parameter estimation strategies.…”