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.
Ellis
Tim
T
Biomed. Signal Process. Lab., Electrical & Computer Engineering, Portland State Univ., OR, USA. taellis@pdx.edu
McNames
James
J
Goldstein
Brahm
B
D001698:Biomedical Engineering; D001930:Brain Injuries / Q000503:physiopathology; D006801:Humans; D019586:Intracranial Hypertension / Q000175:diagnosis / Q000503:physiopathology; D007427:Intracranial Pressure; D016018:Least-Squares Analysis; D008991:Monitoring, Physiologic / Q000706:statistics & numerical data*; D012815:Signal Processing, Computer-Assisted; D013997:Time Factors