Oxygen saturation (SaO2) The percentage of the capacity of oxygen and oxygen-bound hemoglobin (HbO2) in blood to the total capacity of oxygen-bound hemoglobin (Hb), that is, the concentration of blood oxygen. The metabolic process of human body is a biological oxidation process. The oxygen needed in the metabolic process enters human blood through the respiratory system, and combines with hemoglobin (Hb) in red blood cells to form oxygen and hemoglobin (HbO2 _ 2), which are then transported to various tissues and cells of human body.
Simply put, oxygen saturation measures the ability of blood to carry and transport oxygen. A sudden drop in oxygen saturation often means insufficient breathing and it is difficult to maintain enough oxygen in the body. Normal oxygen saturation should be between 95- 100%, and reading below 90% is considered abnormal. This condition is also called hypoxia. Less than 80% is severe hypoxia.
However, this index is a medical index with low specificity. Most people normally measure 96%- 100%. When the real problem is less than 90%, it is generally a serious problem with cardiopulmonary function. If it is lower than 80%, the average person has lost consciousness and can't measure his blood oxygen clearly.
To make an inappropriate analogy, for most people who don't do extreme sports, the self-test indicator is equivalent to some unreliable battery car power display-a 50-kilometer electric donkey may be fully charged (oxygen saturation is above 95%) for 40 kilometers, and it won't be long before the power on the power display drops (oxygen saturation is below 90%) (patients with serious heart and lung diseases,