BRACHIAL ARTERY PRESSURE RECONSTRUCTIONS

There is a delay of several dozen milliseconds between finger blood pressure pulsations and intra-brachial pulsations since the former travel further. In addition, their levels are generally lower and the waveforms appear more distorted, mainly due to reflections and pressure gradients.

To correct the distortion in finger pressure relative to brachial artery pressure, a frequency dependent filter can be used to restore the waveform at the brachial level. This brachial artery pressure reconstruction technique allows clinicians and researchers to obtain the brachial arterial pressure if they wish to perform a more precise measurement at the heart level. Waveform filtering is done in realtime.

The transfer function from brachial to finger resonates at about 8Hz (thin top trace). This causes oscillatory distortions of the finger wave. Distortions can be removed by a digital filter that has an anti-resonance at 8Hz (bottom trace). The two transfer functions compensate each other almost perfectly to produce a desirably flat overall transfer function (thick trace).

Brachial reconstruct model