Pulse Pressure Variation Estimation Based on Rank-Order Filters

We describe a methodology to estimate the pulse pressure variation ∆Pp index from the arterial blood pressure (ABP) signal alone. This eliminates the need for simultaneously acquiring and monitoring airway pressure. The technique uses nonlinear rank-order filters to demodulate the respiratory component modulating the ABP signal. Furthermore, we present a simple mathematical model that can be used to generate synthetic arterial pressure signals with similar time, frequency, and variability characteristics to real ABP signals. Preliminary results on synthetic ABP suggest that rank-based estimation of ∆Pp may be as accurate as the current methods, which require simultaneous ABP and airway pressure acquisition and monitoring. Keywords— Cardiac index (CI), fluid responsiveness, pulse pressure (PP), pulse pressure variation (∆Pp), positive endexpiratory pressure (PEEP), rank-order filters, respiratory changes in systolic pressure, volume expansion (VE).