Rotary blood pump control using integrated inlet pressure sensor

Abstract

Due to improved reliability and reduced risk of thromboembolic events, continuous flow left ventricular assist devices are being used more commonly as a long term treatment for end-stage heart failure. As more and more patients with these devices are leaving the hospital, a reliable control system is needed that can adjust pump support in response to changes in physiologic demand. An inlet pressure sensor has been developed that can be integrated with existing assist devices. A control system has been designed to adjust pump speed based on peak-to-peak changes in inlet pressure. The inlet pressure sensor and control system have been tested with the HeartMate II axial flow blood pump using a mock circulatory loop and an active left ventricle model. The closed loop control system increased total systemic flow and reduced ventricular load following a change in preload as compared to fixed speed control. The increase in systemic flow occurred under all operating conditions, and maximum unloading occurred in the case of reduced ventricular contractility.

Rotary Ventricular Assist Device Control With a Fiber Bragg Grating Pressure Sensor

“…Previously, only two fully described experimental pressure sensors have been incorporated into the VAD inlet and used for physiological control purposes [28], [29]. Both studies used a novel MEMs diaphragm-based pressure sensor that could be incorporated directly into a VAD inlet.…”

An Implantable Intravascular Pressure Sensor for a Ventricular Assist Device

“…Furthermore, pulsatile pumps can alter filling and ejection times based on preload conditions. Most commercial continuous flow pumps though are operated in a fixed speed setting [ 4 ]. If the flow is too high, pressure at the inlet can drop below atmospheric pressure, and a suction event can occur at the inflow cannula.…”

“…If the flow is too high, pressure at the inlet can drop below atmospheric pressure, and a suction event can occur at the inflow cannula. Heart rate, arterial pressure and blood volume, which change with daily activities, affect this unloading point for a fixed pump speed [ 4 ]. These events can be detected by monitoring the pressure at the inlet and the outlet of the pump [ 4 , 5 ].…”

“…Heart rate, arterial pressure and blood volume, which change with daily activities, affect this unloading point for a fixed pump speed [ 4 ]. These events can be detected by monitoring the pressure at the inlet and the outlet of the pump [ 4 , 5 ]. The development of an implantable pressure sensor dedicated to VAD control is the focus of this paper.…”

“…The hemodynamic data gathered by pressure sensors, together with measurements from other physiological and engineering sensors will enable improved pump control. Additionally, the real-time sensor data will help the physician to make appropriate decisions on the patient’s treatment and to tune the parameters of the VAD for weaning application [ 3 , 4 , 21 ].…”