A patient with an oxygen concentration of only 70% can die within 24 hours without treatment such as oxygenation. Blood oxygen concentration and oxygen saturation are the ratio of the amount of oxygen actually bound by hemoglobin to the amount of oxygen that can theoretically be bound by hemoglobin. The normal blood oxygen concentration is 95%-99%. A reduced blood oxygen concentration will cause cellular hypoxia in the body, and when it is lower than 70%, the cells are severely hypoxic and cannot carry out aerobic metabolism to obtain energy, and the tissues and organs cannot work normally, which seriously endangers the patient’s life and can lead to death within 24 hours. If the patient’s blood oxygen concentration is low and timely oxygen therapy is carried out, or the primary disease is lifted, the patient’s body can gradually compensate and recover despite the lack of oxygen. In addition, since brain cells and cardiac muscle cells are particularly sensitive to hypoxia, those with low blood oxygen concentration should be treated promptly to avoid irreversible brain damage or cardiac muscle damage.