Semiautomatic algorithm to remove resonance artifacts from the direct radial artery pressure.

Resonance artifacts introduced by the catheter-manometer system are removed from the direct radial artery pressure using a three-step algorithm. First, the fast-flush method is used to identify the natural frequency and damping coefficient of the monitoring system by digitizing and analyzing the pressure transient created by the flush. Second, resistor, capacitor, and inductor values are found for an RLC second-order model of the catheter-manometer system in use. Third, the algorithm predicts the undistorted radial artery pressure, removing the resonance artifacts by inverse-filtering the digitized monitored pressure waveform using the RLC circuit derived previously. The algorithm was implemented using a personal computer, but it could also be used without the computer by incorporating an analog-to-digital convertor and a microprocessor in the hemodynamic monitor.