Normal finger blood oxygen values range from 94% to 100%. By monitoring finger oxygen saturation, it is possible to understand the level of oxygen carried by the red blood cells of human blood in combination with oxygen in the peripheral limb circulation. If this indicator is below 94% or even below 90%, it indicates that the hemoglobin in the blood is not fully bound to oxygen molecules, suggesting that the patient has an inadequate oxygen supply. Such patients are likely to have related hypoxic diseases, such as chronic obstructive pulmonary disease, pulmonary stasis, interstitial pneumonia, asthma, anemia, carboxyhemoglobinemia, alcoholism, cyanide poisoning, cardiac insufficiency, respiratory failure, and so on. The monitoring of finger oximetry may be affected by a variety of factors, such as whether it is clenched or not, whether it is aligned in the correct position, the thickness and color of the fingernails, and whether or not nail polish is applied. If one finger is worn for too long, the finger may be changed for monitoring. It is recommended that you do not eat greasy, spicy and irritating food and avoid alcohol the day before the test. When there is a decrease in finger oxygen, it is necessary to combine the patient’s clinical manifestations and blood gas analysis and other examination results to clarify the cause and diagnosis, and then follow the doctor’s instructions for symptomatic treatment.