Photoplethysmography of the distal pulp in the assessment of the vasospastic hand.

A procedure for assessing the peripheral vasculature and a new technique for determining the characteristics of the a.c. (arterial) photoplethysmographic (PPG) waveform are described. Comparing 12 normal female volunteers and 12 female patients with Raynaud's phenomenon, PPG amplitude is as good as the results of a standard thermographic test in distinguishing between the groups. The limb arterial flow measured by strain gauge plethysmography (SPG) and the timing of features in the PPG waveform showed differences between the groups, which did not reach statistical significance. The rise time of the PPG waveform, however, was found to be correlated with age independently of vasospasticity.