Experimental Investigation of the Roles of Blood Volume and Density in Finger Photoplethysmography

Sleep apnea: a review of diagnostic sensors, algorithms, and therapies

“…Photoplethymography (PPG) is an uncomplicated and relatively inexpensive optical measurement technique that has been used to detect variations of blood volume in the microvascular bed of tissue. Using simultaneous reflective PPG and a force sensor, placed on the opposite sides of the same fingertip, Keikhosravi et al (2013) showed that the photoplethysmogram signal is mainly due to volume changes not the blood compression and rarefaction induced by heartbeat. Although, PPG has traditionally been used to measure oxygen saturation and heart rate determination, it has shown that its capability and usefulness is not limited to the calculation of the aforementioned physiological parameters.…”

Design of an ultrasonic physiotherapy system with pulse wave feedback control

“…volume [9]. The collected pulse statistics are transmitted to the ultrasonic frequency DDS (Direct Digital Synthesizer) as critical parameters of ultrasonic power control.…”