An anti-suction control for an intra-aorta pump using blood assistant index: a numerical simulation

With the extensive use of the left ventricular assist device (LVAD) as a treatment of heart failure, suction detection has become a key issue that directly affects the treatment. To detect the phenomenon of suction, a blood assistant index (BAI) is defined, which reflects the unloading level of the pump. The BAI is a ratio of the external work of LVAD and the input power of cardiovascular system. Using the theory of model-free adaptive control algorithm, an anti-suction controller, which chooses the heart rate and BAI as control variables, is designed. As a key feature, the proposed control algorithm adjusts the pump speed according to not only the blood demand of circulatory system but also the function of the native heart. Subsequently, the performance and robustness of the controller are evaluated using a numerical simulation of the assisted circulation and an in vitro experiment. The simulation and experimental results demonstrate that the BAI detects the suction occur accurately, and the controller can maintain the heart rate and BAI tracking the reference values with a response time of less than 6 s.