Oxygen is essential for life. Oxygen therapy heals wounds, fights infections, and has been approved for a number of medical uses. Continue reading to learn more about what conditions oxygen therapy could be effective for.
What is Oxygen Therapy?
Oxygen therapy is the use of supplemental oxygen to treat a variety of medical conditions. There are two main types of oxygen therapies available:
- Normobaric oxygen therapy
- Hyperbaric oxygen therapy
Normobaric oxygen therapy is supplemental oxygen administered at the same pressure of our atmosphere (1 atm). Depending on the medical condition, 40 to 100% of saturated oxygen is delivered to the body.
As excessive oxygen can be harmful, normobaric oxygen therapy should be carefully supervised. In the absence of correct medical supervision, normobaric oxygen therapy may also cause or contribute to heart disease, inflammation, diabetes, and aging [1].
Hyperbaric oxygen therapy is 100% saturated supplemental oxygen delivered at higher atmospheric pressures. Patients are placed in a high pressure, full body chamber (hyperbaric chamber). This increases oxygen delivery to all of the tissues of the body [2].
Treatment schedules of hyperbaric oxygen therapy vary between 60 to 120 minutes, 1 or more times daily [2].
Hyperbaric oxygen therapy is approved for the treatment of a number of conditions such as air or gas embolisms, burns, diabetic wounds, and traumatic ischemia.
Hardware & Equipment
During normobaric oxygen therapy, oxygen can be delivered as oxygen gas, liquid oxygen, or via oxygen concentrators.
Oxygen gas is compressed in a gas cylinder. Liquid oxygen is stored in portable tanks and is boiled to release oxygen gas. Oxygen gas cylinders are also fitted with regulators that sense a patient’s breathing rate and sends pulses of oxygen.
Oxygen concentrators are devices that take oxygen from the air and concentrate it for use.
Mechanism of Oxygen Therapy
Blood is made up of 4 components: plasma, red blood cells, white blood cells, and platelets. Oxygen is transported through red blood cells that contain the protein hemoglobin. Hemoglobin is an iron-containing protein that oxygen can bind to [3].
The only differences between normobaric and hyperbaric oxygen therapy are the pressure that they’re applied at and the method of delivery. Both forms of therapy increase the amount of oxygen that is delivered in the blood [4].
Normobaric oxygen therapy increases the binding of oxygen with blood hemoglobin [5].
Titrated normobaric oxygen therapy improves blood oxygen levels [6].
Increasing the delivery of oxygen to the body supports the healing process of damaged tissues.
Benefits of Oxygen Therapy
The FDA has approved oxygen therapy as a treatment for a number of conditions, including:
- Wounds (such as diabetic ulcers) that are resistant to healing
- Tissue damage & death associated with radiation
- Flesh-eating bacteria
- Carbon monoxide poisoning
- Decompression sickness
- Acute arterial ischemia
- Skin graft rejection
- Severe infections
- Air or gas embolism
- Severe anemia
Besides these conditions, oxygen therapy is under investigation for its potential to improve a number of other health conditions, which we will discuss in this section. Oxygen therapy is a medical procedure that comes with some risks, and it should only be administered by a trained medical professional.
Possibly Effective For
1) Acute Lung Failure
Acute lung failure is a condition that is caused by choppy or labored inhaling, causing low blood oxygen levels [7].
A meta-analysis including 703 patients concluded that emergency normobaric oxygen therapy increased the number of patients recovering from life-threatening acute lung failure [8].
A multicenter analysis of patients with lung failure indicated that normobaric oxygen therapy cleared the upper airways, improved lung function, and reduced pressure on the lungs [9].
2) COPD
Chronic obstructive pulmonary disease, or COPD, is a group of progressive lung diseases. The most common are emphysema and chronic bronchitis [10].
Smoking, breathing pollutants, and lack of a specific protein, alpha-1-antitrypsin, causes COPD [11].
Several long-term clinical studies of hundreds of patients with COPD using supplemental normobaric oxygen therapy showed [5]:
- Benefit from exercise and activity
- Reduction of anxiety
- Improved quality of life
- Prolonged lifespan
- Improved sleep quality
An observational study with 195 COPD patients for 6 months indicated that normobaric oxygen therapy improved the quality of life of patients with emphysema [12].
In 86 elderly patients with COPD, normobaric oxygen therapy reduced pressure on the heart blood vessels and improved sleep [13].
3) Cystic Fibrosis
Cystic fibrosis is a genetic condition caused by the lack of the CFTR gene. People with cystic fibrosis suffer from breathing problems [14].
A review of 11 clinical trials (RCT) with 172 participants found that supplemental normobaric oxygen therapy improved sleep patterns and quality of life [15].
In another meta-analysis of 149 people with cystic fibrosis (RCT), normobaric oxygen therapy improved exercise duration, sleep, and blood oxygen levels [16].
Insufficient Evidence For
The following purported benefits are only supported by limited, low-quality clinical studies. There is insufficient evidence to support the use of oxygen therapy for any of the below-listed uses.
4) Asthma
Asthma obstructs airways in the lungs and can cause low blood oxygen (hypoxemia) leading to severe health complications. In 106 patients with severe asthma, normobaric oxygen therapy for 2 years increased the survival of patients and reduced symptoms [17].
5) Stroke
Ischemic stroke is caused by a clot in the blood vessels that decreases blood flow to the brain and leads to cell death.
There is limited evidence in humans indicating that normobaric oxygen therapy could potentially be beneficial for stroke patients. Oxygen therapy was most beneficial when applied within the first few hours of having a stroke [18].
The importance of prompt treatment is highlighted in a clinical trial wherein delayed normobaric oxygen therapy of 40 patients did not improve the outcomes of these patients [19].
Multiple studies with rats and mice showed that additional normobaric oxygen therapy reduced blood pressure, brain swelling, brain damage, and death [20, 21, 22, 23, 24].
Contraindications of Oxygen Therapy
Before using supplemental oxygen therapy, patients must be inspected for pneumothorax. Pneumothorax is caused by the buildup of air in the space between the chest wall and the lungs. If the pneumothorax is unrecognized or untreated, using oxygen therapy could result in the lungs collapsing and ultimately death [25, 2].
Oxygen constricts blood vessels, and hyperbaric oxygen therapy might increase pressure on the heart. Patients with a history of congestive heart failure are also at risk of adverse effects [25, 2].
Other risk factors are [25, 2]:
- Hyperthyroidism
- Severe claustrophobia
- Febrile illness
- Chronic obstructive pulmonary disease (COPD)
- Seizure disorder
Highly concentrated oxygen can easily catch on fire. Therefore, fires surrounding hyperbaric oxygen chambers, oxygen gas cylinders, tanks, and concentrators are a high risk of danger [25].
To avoid adverse effects or complications, oxygen therapy should only be administered by a trained medical professional.
Side Effects of Oxygen Therapy
Normobaric is safer than hyperbaric oxygen therapy, although hyperbaric oxygen therapy may be more effective for some uses [26, 27].
Despite the potential risks and side effects, proper use of normobaric and hyperbaric oxygen therapies are considered relatively safe and low-risk interventions, assuming correct application [28].
Due to the high pressure, hyperbaric oxygen therapy has more risks than normobaric therapy [25, 29, 30, 2, 31].
