Oxygen inhalation is the process of inhaling gases greater than or equal to the concentration of oxygen in the air through a nasal cannula or mask to improve the hypoxic condition. The most common condition is a cardiopulmonary problem, as chronic bronchitis, pneumonia, or other problems with the lungs can interfere with the inhalation of oxygen and cause a decrease in the amount of oxygen in the body, resulting in a hypoxic condition. In addition, lung problems can be combined with heart problems in severe cases, both of which can cause impaired lung ventilation and air exchange, which can lead to hypoxemia. If there is severe anemia, the oxygen-carrying capacity of hemoglobin is reduced, which is also a major factor in oxygen deprivation. There are also other toxicities that can cause a decrease in blood oxygen levels. So this time through the inhalation of oxygen can improve these symptoms, if the lack of oxygen is serious, the concentration of oxygen inhalation can be appropriately increased, the highest concentration is 100% oxygen. Generally, the inhalation of 100 percent oxygen should not be too long, and other comprehensive treatment should be carried out when necessary.