Non-invasive measurement of direct and reflected pulse waves in human lower limb

The non-invasive simultaneous measurement of plethysmographic signals at 3 points equally spaced enabled the calculation of the direct and reflected waves in human lower limb. The plethysmographic waves were recorded using a multichannel impedance measuring device. The reflection coefficient was calculated for frequencies up to 5 Hz in lying patients under normal conditions and in the presence of an arterial occlusion created externally using a pressure cuff. In both cases the reflection coefficient was high (0.8 and 0.84 respectively). It was therefore concluded that the presence of reflected waves cannot be neglected in the study of the pulse wave propagation at least in human lower limbs