Oxygen therapy for sickle cell disease

Last updated Aug. 20, 2024, by Marisa Wexler, MS
Fact-checked by Joana Carvalho, PhD

What is oxygen therapy?

Oxygen therapy, which involves having a person breathe in extra oxygen, is a medical intervention that may be used to help manage acute complications of sickle cell disease (SCD) associated with vaso-occlusion, or blood vessel blockage. It also has been proposed as a preventive or supportive measure for SCD patients in other situations, but that remains controversial.

Oxygen is a gas in the air that’s vital for generating the energy that powers the body’s essential functions. It is absorbed in the lungs when a person breathes in, and then carried out to the rest of the body by red blood cells, with the help of a protein called hemoglobin.

A genetic disorder, SCD is due to the production of an abnormal form of hemoglobin, which tends to clump inside red blood cells under low oxygen conditions, deforming them into the sickle-like shape that gives the disease its name. The deformed red blood cells are more prone to die prematurely and to get trapped inside blood vessels, blocking blood flow and depriving tissues of oxygen.

This can lead to a series of complications, including vaso-occlusive crises (VOCs), or painful episodes caused by sickle cells clogging blood vessels, and acute chest syndrome (ACS), when blood vessel blockage occurs in the lungs.

By raising blood oxygen levels, oxygen therapy ensures that tissues receive a consistent supply of oxygen, which can mitigate the effects of complications related to low oxygen levels and prevent additional medical problems.

When is oxygen therapy used in SCD?

In people with SCD, oxygen therapy primarily is used as part of the management of VOCs, although there’s still a lack of evidence supporting its effectiveness in all patients.

Sometimes called a pain crisis, a VOC occurs when deformed red blood cells get stuck inside blood vessels, blocking blood flow and preventing oxygen and nutrients from getting into tissues. When blood vessels in the lungs become obstructed, a patient may experience acute chest syndrome, a potentially life-threatening SCD complication.

During a VOC or ACS, blood oxygen levels tend to dip below normal levels. This can be determined with a pulse oximeter that measures a person’s oxygen saturation levels, or the percentage of hemoglobin in red blood cells that’s bound to oxygen. For most people, an oxygen saturation below 95% is considered worrisome.

Oxygen therapy may be used during a VOC or ACS to increase oxygen saturation, ensuring that tissues have access to enough oxygen to remain healthy.

Oxygen therapy also is recommended for patients experiencing acute chest syndrome while showing normal oxygen saturation levels. That’s because having blood oxygen saturation levels within normal range may mask oxygen deprivation in specific body regions.

The use of supplemental oxygen in sickle cell patients who are not experiencing a VOC or ACS is controversial. As the abnormal form of hemoglobin that characterizes SCD tends to behave more problematically at low oxygen levels, some experts have suggested using supplemental oxygen as a precautionary measure to help in VOC prevention with high-risk situations. These include air travel, due to oxygen levels generally being low at high altitudes.

However, no evidence supports its use in SCD patients whose oxygen saturation levels are within a normal range. Healthcare professionals also do not routinely recommend oxygen therapy as a preventive measure to SCD patients traveling by airplane.

How does the procedure work?

During oxygen therapy, typically, oxygen is inhaled either through a mask placed over the nose and mouth, or via a cannula (a slip tube with prongs that sit inside the nostrils).

When oxygen therapy is used to manage a sickle cell pain crisis, the goal is generally to continue providing supplemental oxygen until the patient’s oxygen saturation levels are within a normal range. But specific protocols — including what is considered a “normal” oxygen saturation level — can vary from center to center, and patients are advised to ask their healthcare team about what they should expect.

There are a variety of setups for delivering oxygen therapy, depending on the patient’s individual needs. Oxygen therapy can be given when a person is awake or during sleep; it may also be given at home or in a medical facility. Likewise, portable setups allow oxygen therapy to be given while a person is out and about.

Broadly, oxygen therapy systems can be divided into three main types:

compressed gas, where pure oxygen gas is stored under pressure in a large metal cylinder and released via a regulator
liquid oxygen, which uses a thermos-like container to store oxygen as an extremely cold liquid that can be released into a gas for inhalation
oxygen concentrators, which are machines that work to remove other gases, particularly nitrogen, from the surrounding air, creating oxygen-rich air for the patient to inhale.

Potential benefits of oxygen therapy

Low blood oxygen levels, or hypoxemia, can lead to serious health problems, including organ failure and avascular necrosis, or bone tissue death. Therefore, providing supplemental oxygen during VOCs and other instances where blood oxygen levels are lower than normal is standard care, helping to limit tissue damage and further complications.

In theory, oxygen therapy may also help to prevent red blood cell sickling and improve blood flow, although these potential benefits remain controversial and unproven.

Potential risks and considerations

As with any other medical procedure, oxygen therapy can cause side effects. In the general population, common side effects of oxygen therapy include:

headache
nosebleeds
tiredness or fatigue.

There are also some special considerations and certain risks to keep in mind when using supplemental oxygen in someone with SCD. For example, some data suggest the use of oxygen therapy in people with SCD can suppress red blood cell production, which may contribute to anemia.

Additionally, some SCD patients report experiencing rebound pain when oxygen therapy is stopped. This may be caused by an increase in the production of new, immature red blood cells after therapy cessation that are more prone to stick to blood vessel walls.

It also is important to follow appropriate safety steps with oxygen therapy to prevent fire. While oxygen technically is not a flammable gas, it can accelerate fires rapidly, which can be very dangerous. To minimize the risk of fire, oxygen tanks should be securely stored in areas with good ventilation, and patients should avoid smoking or being near heated devices or flames when using oxygen. Easy and quick access to fire extinguishing equipment also is recommended.

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