Aortic pressure detection simulation for counterpulsation cardiac assistance

The robustness of aortic pressure (Pa)-based counterpulsation cardiac assist device (CAD) controllers varies with the ability of the CAD controller to properly trigger on Pa signals for sinusoid rhythms as well as for non-sinusoid rhythms and non-ideal signals resulting from surgical intervention. A robust Pa triggering algorithm was derived using a matched filter and “riding clipper” technique. The matched filter “templates” utilized were derivative finite impulse response (FIR) filters previously used for Pa threshold detection. The resulting Pa detection digital filter modeled the detection of a comparator “riding clipper” analog filter. In order to empirically determine the robustness of the Pa triggering algorithm, a simulation detection platform was devised. Simulation experiments utilized a specific Pa trace cardiothoracic surgery artifact or physiological variation model to determine the capability of the Pa trigger algorithm to withstand the effects of the Pa detection impediments while maintaining 100% accuracy of the dicrotic notch detection. Pa triggering was unhindered by clinical conditions, including changes in the Pa baseline, Pa trace attenuation, uniformly distributed noise and Gaussian distributed noise. Pa triggering was also unhindered by degrees of Pa trace biological variations, including dicrotic notch attenuation and heart rate variability due to respiration