Photoplethysmography (PPG)
Photoplethysmography (PPG) is a non-invasive optical technique that measures blood volume changes in tissue by detecting how light is absorbed or reflected. It powers pulse oximeters and wearable devices to track heart rate and oxygen saturation.
What is Photoplethysmography (PPG)?
Photoplethysmography (PPG) is an optical sensing method that detects changes in blood volume just beneath the skin. A small light source shines into the tissue, and a photodetector measures how much light is absorbed or reflected back as blood pulses through the microvasculature with each heartbeat.
Because the technique is non-invasive and requires only a light and a sensor, it can be built into compact, low-cost devices. The rhythmic waveform it produces reflects the cardiac cycle, which can then be processed to estimate physiological signals.
Why does PPG matter in clinical settings?
PPG is the engine behind fingertip pulse oximeters and many consumer wearables, allowing continuous, painless monitoring of heart rate and blood oxygen saturation. In perioperative and recovery environments, this kind of continuous vital-sign tracking supports early detection of deterioration without drawing blood or interrupting the patient.
For ambulatory surgery centers, reliable pulse oximetry built on PPG is a baseline safety requirement during anesthesia, sedation, and post-anesthesia recovery, where oxygenation must be watched closely before a patient is cleared for discharge.
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