Oxygen therapy means using an oxygen tank or a machine to breathe in air that contains more oxygen than normal.

Oxygen therapy increases the amount of oxygen in the lungs and the bloodstream. A person with a health problem such as chronic obstructive pulmonary disease (COPD) may need oxygen therapy if there are signs that the cells of the body are not getting enough oxygen.

Oxygen therapy may be given by different methods, including a:

• Tube placed under a person's nose (nasal cannula).
• Plastic mask placed over a person's mouth and nose.
• Tube (endotracheal tube) placed into the mouth and down the windpipe of a person who cannot breathe independently. The tube is attached to a machine (ventilator) that breathes for the person.