The duration of oxygen intake for the elderly needs to be combined with specific conditions, such as chronic respiratory failure combined with chronic obstructive pulmonary disease, daily oxygen intake time needs to be >15 hours; acute respiratory failure may need continuous oxygen intake; for some diseases may only need oxygen intake when symptoms of chest tightness occur. 1. Chronic respiratory failure combined with chronic obstructive pulmonary disease: chronic respiratory failure combined with chronic obstructive pulmonary disease, such as long-term home oxygen therapy standards, need to adhere to the daily oxygen intake, and the time of daily oxygen intake needs to be > 15 hours or more, usually through the nasal cannula inhalation of oxygen, the commonly used flow rate of 1.0 ~ 2.0L / min. 2. Acute respiratory failure: If the condition of patients with acute respiratory failure is not yet under control, continuous uninterrupted inhalation of oxygen therapy is generally required, and if oxygen inhalation fails to maintain the condition, even the use of respiratory therapy may be required. 3. Some diseases only need temporary oxygen inhalation: for example, for patients with chronic obstructive pulmonary disease and interstitial lung disease, if they do not have significant respiratory failure, and only have symptoms of chest tightness after activities, they can also inhale oxygen for a short period of time when their chest tightness is aggravated, and then stop oxygen inhalation after the symptoms are relieved. In summary, the oxygen program and duration should be directed by the doctor according to the specific situation.