Contraindications to mask oxygen inhalation: 1. oxygen inhalation is beneficial to people with respiratory dysfunction and can correct hypoxia. 2. excessive oxygen inhalation can increase the oxygen concentration in the inhaled air, which may lead to oxygen toxicity. 3. enlarged alveoli are not conducive to oxygen inhalation. 4. facial congestion is not suitable for oxygen inhalation. 5. oxygen inhalation should not be used just after strenuous exercise. Mask oxygen inhalation is a method of transferring oxygen required for breathing from storage tanks to human lungs, mainly medical oxygen masks, airline oxygen masks and oxygen masks used by airline passengers, which play an important role in disease treatment, and the method and flow of oxygen inhalation is related to the patient’s condition. High-flow oxygen inhalation refers to the inhalation oxygen concentration of more than 40%, which is common in acute lung injury and severe pneumonia, applicable to type I respiratory failure, and requires systematic monitoring in the case of treatment. If there is a decrease in systolic blood pressure and a decrease in pulse pressure, this indicates that oxygen therapy is not working and arterial blood gas analysis is a more accurate method of examination.