Jun. 11 , 2019
Measurement of blood oxygen saturation is generally divided into two types, electrochemical and optical.
Electrochemical method is to collect arterial blood from the human body, and then use blood gas analyzer to measure the value of hemorrhage oxygen saturation. This is an invasive measurement method and cannot be continuously monitored.
Optical measurement is a non-invasive method using photoelectric sensors. It is based on the principle that the absorption of light by arterial blood changes with arterial pulsation. The most used method is pulse oximeter. Two light-emitting tubes are mounted on one side of the instrument Disposable Spo2 Sensor, respectively emitting red and infrared light, and a photodetector is mounted on the other side to convert the detected red and infrared light transmitted through the finger artery into an electrical signal. Since the absorption coefficients of these two kinds of light are constant by skin, muscle, fat, venous blood, pigment and bone, only the concentration of HbO2 and Hb in the arterial blood flow changes periodically with the arteries of the blood, causing photodetection. The signal strength of the output of the device changes periodically. By processing these periodically changing signals, the corresponding oxygen saturation can be measured and the pulse rate calculated.