According to the severity of the patient’s condition, different oxygen therapy methods are used: 1. Long-term home oxygen therapy: when the patient’s finger pulse oxygen saturation of arterial blood is <88% and partial pressure of oxygen is <55 mmHg, it can improve the patient's hypoxic state and activity tolerance; 2. Venturi mask oxygenation: when the patient has more severe respiratory failure, it can improve the hypoxic state and carbon dioxide retention and prevent pulmonary encephalopathy; 3. Non-invasive ventilator: when the patient's respiratory work is extremely poor, a non-invasive ventilator can be used to help the patient overcome airway resistance and reduce respiratory work.