Principle Of Operation - Current G2 Instructions For Use Manual

Instructions for Use

12.1 Principle of Operation

Current Health calculates functional oxygen saturation (SpO2) using pulse oximetry from
the upper arm. Technical specifications are available in 18.4.2.
Pulse oximetry is a continuous and non-invasive method of measuring the level of arterial
oxygen saturation in blood. O is carried in the blood in two forms, either dissolved in
2
plasma or combined with hemoglobin. The majority of O is carried on hemoglobin.
2
Oxyhemoglobin (oxygenated blood) and deoxyhemoglobin (non-oxygenated blood) differ in
their absorption of red and infra-red light, as shown in the graph below.
Extinction Spectra for HbO2 and Hb
Current Health uses an optical sensor that shines both red and infra-red light at the skin of
the upper arm to distinguish between oxygenated blood and deoxygenated blood. Signal
data is obtained by the reflections of red and infra-red light back onto the sensor by the
blood and other tissues. The maximum radiant power of the strongest light is rated at
<15mW. The sensor converts the reflected light into an electronic signal, known as a
photoplethysmograph.
The Current Health software platform receives the photoplethysmograph from the
wearable and uses proprietary algorithms to calculate the patient's functional oxygen
saturation (% SpO2) and pulse rate.
Note that Current Health is calibrated to measure and display functional oxygen saturation
(SpO2), which is the amount of oxyhemoglobin expressed as a percentage of the
hemoglobin that is available to transport oxygen.
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