Photoplethysmographic assessment of hemodynamic variations using pulsatile tissue blood volume.

Sympathetic responses to provocative tests have shown to provide an early prognosis of abnormalities in the human autonomic nervous system. Photoplethysmographic signal characteristics have been studied to identify vascular diseases. However, knowledge about the pulse-added arterial volume of the photoplethysmographic waveforms during these clinical investigations is limited. In all, 16 normotensive adults (9 men) were recruited to perform 3 provocative test (2 postural changes and 1 resistive breathing) activities with photoplethysmographic signals being monitored on the upper and lower peripheries using customized devices. In all, 4 parameters derived from the photoplethysmographic waveforms that related to the pulsatile tissue blood volume changes were then assessed. The results obtained showed that amplitude-related parameters during these activities showed significant changes (>9.63%; P < .05). However, comparison of pulse-added arterial volume showed insignificant changes (<5.56%; P > .05) for all test settings. Hence, the findings herein suggest that there is clinical potential in using this aspect of the photoplethysmographic waveform.