In what situations is administering oxygen helpful?

Administering oxygen (via a “nasal cannula”) can relieve breathing difficulties. The administration of oxygen—which can also be provided at home using an oxygen tank—increases blood oxygen saturation, reduces any sensation of shortness of breath and respiratory distress, and alleviates the strain on respiratory function. As a result, this can lead (as with the administration of morphine and benzodiazepines) to a “double effect” that shortens the remaining life expectancy.