Reconstruction Of Brachial Arterial Pulsation From Finger Arterial Pressure

As far as the continuous noninvasive measure ments of finger arterial pressure are concerned, substantial differences at times appear when finger pressure is compared to invasive brachial wave shapes. We therefore decided to study such shape changes by determining the pressure trans fer function, H(f), between the brachial artery and the finger, for frequency, f, out to 25 Hz. 25 subjects have been studied. Invasive brachial and noninvasive finger pressures were simultane ously recorded. The individual H(f) was computed by Fourier analysis and an analytical expression of H(f) was estimated by fitting an analog model. In each subject, the brachial pressure was reconstructed on the basis of the finger pressure and the inverse of H(f). At last, the delay be tween the original and the reconstructed brachial waves was adjusted and their rms difference was computed. At this extent, only the variable part of the signals were taken into consideration. The error is less than 495, when the reconstruction is