What is Oxygen Therapy?

Oxygen therapy refers to the administration of supplemental oxygen as part of managing illness. In healthy individuals, oxygen is absorbed from the air in adequate amounts, but certain diseases and conditions can prevent some people from absorbing enough oxygen.

It may be administered as a medical intervention to manage short-term (acute) or emergency situations or as a part of long-term patient care. Oxygen therapy may therefore be a key tool in the hospital setting to manage a medical emergency or in the home setting to manage long-standing illness.

Oxygen is vital for metabolic processes in cells and therefore the function of tissues within the body. The atmospheric content of oxygen within room air is only 21%. Although this amount is adequate for healthy individuals, those with certain diseases can benefit from an increased oxygen fraction in the gas they breathe, which will increase the oxygen content of their blood.

Some acute and long-term (chronic) illnesses can reduce the amount of oxygen that is transferred from the alveoli in the lungs to the blood. Examples of these conditions include chronic obstructive pulmonary disease (COPD) and pneumonia. In people with these conditions, oxygen therapy can help them function better and become more active. A doctor performs tests such as the pulse oximetry test or arterial blood gas test to decide whether or not a person has a low oxygen level and requires oxygen therapy

For most of the diseases that affect oxygen absorption, increasing the oxygen fraction to around 30 % to 35% is enough to make a significant improvement. This can be done using a nasal cannula, which is made up of two plastic tubes that are fitted into the nostrils. When 100% oxygen is needed, a tight-fitting face mask can be used and for infants, a 100% oxygen can be delivered to an incubator.

Oxygen can also be delivered by placing a small tube in the windpipe at the front of the neck. The delivery of oxygen in this way is referred to as transtracheal oxygen therapy. A person who receives transtracheal oxygen therapy must have a humidifier attached to the oxygen system to add moisture because the oxygen does not pass through the mouth or nose. The addition of this moisture stops the airways from becoming too dry.

Oxygen can also be administered using breathing support systems such as ventilators or a continuous positive airway pressure machine.

Oxygen Therapy and Delivery - How to Prescribe Oxygen

Patient outlook

As well as improving bodily function and activity in emergency situations, oxygen therapy can help to improve shortness of breath, tiredness, and sleep disturbances among those with breathing disorders such as sleep apnea. It can also increase lifespan in those with COPD.

In cases where long-term therapy is required, people’s lives do not need to be restricted as the availability of portable oxygen units means the therapy can be administered while people are moving around and carrying out regular daily activities.

Acute diseases that affect the blood oxygen level

Oxygen therapy may be administered in hospital if someone suddenly develops an illness that prevents proper oxygen absorption. This therapy is stopped once the person has recovered from the condition. Some examples of illnesses where this short-term oxygen therapy is administered include the following:


This is a lung infection that can cause extreme inflammation of the alveoli and prevent oxygen moving from these air sacs into the bloodstream.

Bronchopulmonary dysplasia or respiratory distress syndrome in premature babies

These are both serious lung conditions that can develop in premature babies. Such babies may be administered supplemental oxygen using a ventilator, a tube placed in the nostril or a nasal continuous positive airway pressure machine.

Asthma attack

A severe asthma attack can inflame and narrow the airways, therefore requiring oxygen therapy if the attack cannot be managed using the medication a patient has been prescribed.

Chronic diseases that affect the blood oxygen level

People with certain chronic diseases may require long-term oxygen therapy at home. Examples of these conditions include the following:

Cystic fibrosis

Cystic fibrosis is a genetic condition that affects the secretory glands that produce mucus and sweat. Patients with this condition develop a build up of viscous, sticky mucus in their airways. This provides an environment that promotes bacterial growth and people with cystic fibrosis experience recurrent and severe lung infections that eventually cause serious lung damage.

Chronic obstructive pulmonary disease

Here, permanent damage to the alveoli prevents oxygen from moving out of the alveoli and into the blood. As the condition is progressive, COPD only worsens over time.

Late-stage heart failure

Here, the heart fails to pump enough blood around the body to provide it with an adequate level of oxygen.

Sleep apnea

This is a sleep disorder characterized by shallow or infrequent breathing that can lead to a low blood oxygen level while a patient is asleep.

Ongoing care

After starting oxygen therapy, patients should attend regular check-ups to ensure they are adjusting their therapy correctly. The doctor provides advice on how much oxygen is needed and whether or note the flow rate requires adjustment.
People should seek immediate advice if they experience any of the following problems while using their oxygen therapy:

  • Confusion or increased anxiety level
  • Breathing changes such as wheezing or shortness of breath
  • Signs of infection such as fever or increased mucus production
  • A blue tinge to the fingernails or lips, which may indicate a low blood oxygen level.

Further Reading

Last Updated: Jun 17, 2023

Sally Robertson

Written by

Sally Robertson

Sally first developed an interest in medical communications when she took on the role of Journal Development Editor for BioMed Central (BMC), after having graduated with a degree in biomedical science from Greenwich University.


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