Frequency and Time-Frequency Based Indices For Suction Detection in Rotary Blood Pumps

A new suction detection system for rotary blood pumps used in left ventricular assist devices is presented. The system is based on frequency indices combined with a time-frequency extraction feature algorithm. The frequency based indices can detect the changes in the harmonic and subharmonic energy content of the pump flow signal, when a suction event is occurring. The time-frequency extraction feature algorithm can track variations in the standard deviation of the instantaneous frequency of that signal. These two pieces of information are then combined in a weighted decision system to generate a suction alarm. The proposed system has been tested in simulations, in a mock-loop system, and in-vivo tests and produced very satisfactory results