Assessment of venous insufficiency using photoplethysmography: a comparison to strain gauge plethysmography.

@article{Hirai1985AssessmentOV,
  title={Assessment of venous insufficiency using photoplethysmography: a comparison to strain gauge plethysmography.},
  author={Masafumi Hirai and Masahiro Yoshinaga and Riichiro Nakayama},
  journal={Angiology},
  year={1985},
  volume={36 11},
  pages={
          795-801
        }
}
Simultaneous photoplethysmographic (PPG) and strain gauge plethysmographic (SPG) recordings were obtained in normal subjects and patients with venous insufficiency. In PPG tracings, a so called "negative segment," which represented a further fall below the baseline after exercising, was often observed. This negative segment is produced by blood flow from the superficial to the deep veins during relaxation, which indicates that PPG can be used to assess the circulatory hemodynamics in the skin… CONTINUE READING