Oxygen Therapy

When we breathe, our lungs take in oxygen (O2), a gas necessary for our body to work. Certain conditions, such as COPD (chronic obstructive pulmonary disease), result in low levels of oxygen in the blood, causing shortness of breath, tiredness, and damage to the heart and brain.

Oxygen therapy delivers extra oxygen through a tube, mask, or nasal prongs. To get this therapy, you first need to be tested for oxygen levels (arterial blood gas test). Depending on your condition, you will be given the treatment that is right for you.

How to be tested for oxygen therapy

You must first be evaluated for oxygen levels in your blood. The following tests can determine O2 levels:

  • Arterial blood gas test. The levels of oxygen and carbon dioxide are analyzed from a blood sample. For detailed information on this test, click on arterial blood gas test link above.
  • Oximeter. This is a machine that measures O2 saturation. A clip is placed on your finger, toe or earlobe. There’s no need to use needles and the test can be done while you sleep or walk. Some disadvantages include poor information compared to the arterial blood gas test and potential false readings, especially if you have poor circulation, anemia, or if you are using dark nail polish.

How is oxygen therapy done?

Extra O2 can be delivered through a tube that is placed under the nose (nasal prong), a mask placed over the mouth and nose, or a breathing tube that is placed into the mouth and down the trachea when a person can’t breathe on his or her own.

The amount of oxygen, flow rate, and number of hours per day all depend on a patient’s condition. The therapy may be given for a short or long period of time, at the hospital or at home.

There are different devices to deliver supplemental O2 at home, or by lightweight portable units. These include:

  • Oxygen cylinders. Oxygen is compressed under high pressure in portable or stationary tanks.
  • Liquid oxygen. Liquid oxygen is made by cooling oxygen gas into a liquid. In the liquid state, O2 takes less space and can be stored in lightweight tanks.
  • Oxygen concentrators. These can be portable or stationary. A stationary oxygen concentrator is an electrical device that takes O2 from the air by removing other gases.

Is oxygen therapy good for all COPD conditions?

Long-term oxygen therapy is administered for at least 16 hours a day when O2 levels in the blood are very low. However, it’s not suitable for all COPD conditions, including being short of breath.

The Phase 3 LOTT clinical trial (NCT00692198), completed in 2015, evaluated the effectiveness of long-term oxygen therapy. A total of 738 participants with moderate or stable (low blood oxygen levels during exercise) COPD were randomized to receive either long-term supplemental oxygen or no supplemental oxygen therapy. Participants were followed for one to six years.

The trial’s primary outcomes were a longer lifetime or longer time until hospitalization. The results, published in the New England Journal of Medicine in 2016, showed that long-term oxygen therapy didn’t benefit patients with moderate or stable COPD with respect to the primary outcome measures.

Risks and considerations

Oxygen therapy is generally safe. However, it carries some risks since oxygen can combust (materials burn more in an oxygen-rich atmosphere), so you should never smoke or use flammable materials nearby.

Besides COPD, this therapy may be considered for other conditions that cause short of breath or blood circulation (severe asthma, cystic fibrosis, pulmonary hypertension, or heart failure).

Hyperbaric oxygen therapy is another type of oxygen therapy that uses O2 at high pressure to treat decompression sickness, wounds and serious infections.


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