Calculation of the Mean Pressure with Less Delay for Real-Time Clinical Monitoring

The mean of cardiovascular pressure signals is an important metric in patient monitoring applications for many types of diseases and injuries. It is typically calculated with a moving average of 3-8 s of the pulsatile signal. This method of calculating the mean introduces a delay of 1.5-4 s. We demonstrate that an FIR filter with coefficients calculated with a least squares error (LSE) estimator can reduce this delay without a clinically significant impact on the accuracy of the displayed signal. Preliminary results with intracranial pressure signals show that the delay can be completely eliminated with a maximum root-mean-square error of approximately 1 mmHg. Reduction or elimination of this delay could permit patient monitors to display the mean in real time and permit clinicians to respond to acute events more rapidly