Blood oxygen saturation rate is the rate of oxygen in the arterial vessels. SpO2 helps to meet the oxygen
demands to the body and organs. Low SpO2 levels can indicate increased risk to the organs; because of
dissatisfy the oxygen demands. Aged people and patients with cardiac diseases have lover SpO2 saturation
levels. Clinically accepted, that 95% of oxygen saturation is the normal hemoglobin level . Therefore,
lower than a normal level indicates that supplementary oxygen is required.
This method employs PPG technology and is fully non-invasive and usually uses two light sources (660 nm
and 940 nm) and light detector (see appendix E for more details). Continuous measuring of the blood oxygen
saturation is called pulse oxymetry, which was developed by Aoyagi at 1979.