Oximetry is an abbreviation, actually it is the oxygen saturation, oxygen saturation is mainly the total amount of oxygenated hemoglobin inside the blood, the percentage of the total combined hemoglobin is the blood concentration, simply put, it is an important physiological parameter of microcirculation, mainly monitoring the arterial oxygen saturation, which can evaluate the pulmonary oxyhemoglobin and oxygen-carrying capacity. Normal human arterial oxygen saturation is 98% and venous oxygen saturation is 75%. The oxygen required for daily metabolism is mainly through the respiratory system, which perfectly combines human blood as well as red blood cells inside hemoglobin into oxygenated hemoglobin and then reprograms it, and different cell groups measure the blood carrying capacity through saturation.