The metabolic process of the human body is the process of biological oxidation, and the oxygen needed in the metabolic process enters human blood through the respiratory system, combines with the hemoglobin in red blood cells (Hb) to form oxygenated hemoglobin (HbO2), and then transports it to the tissues and cells of various parts of the human body.





　　Blood oxygen saturation (SpO2) is the percentage of the capacity of oxygenated hemoglobin (HbO2) in the blood in the total capacity of the binding hemoglobin (Hb), that is, the concentration of blood oxygen in the blood, which is an important physiological parameter of respiration and circulation. According to BORSAM Biomedical,Functional oxygen saturation is the ratio of HbO2 concentration to HbO2+Hb concentration, different from the percentage of oxyhemoglobin. Therefore, monitoring arterial oxygen saturation (SaO2) can be used to estimate pulmonary oxygenation and hemoglobin oxygen-carrying capacity, according to sonoma.

　　The main indexes of oximeter were pulse rate, oxygen saturation and perfusion index (PI). As we know, oxygen saturation is one of the most important basic data in clinical treatment.According to BORSAM Biomedical, Blood oxygen saturation refers to the percentage of total blood capacity of bound O2 in total binding O2 capacity.