Hyperbaric Oxygen Therapy

What is hyperbaric oxygen therapy?

Hyperbaric oxygen therapy (often shortened to HBOT) is a medical treatment in which you breathe pure oxygen while sitting or lying inside a sealed room or tube called a hyperbaric chamber. Inside the chamber, the air pressure is raised to a level higher than normal atmospheric pressure, usually between about two and three times the pressure at sea level. Under these conditions, your lungs can take in far more oxygen than they could by breathing oxygen at normal pressure, and this oxygen dissolves into your blood plasma (the liquid part of the blood) and reaches tissues that are starved of oxygen.

The extra oxygen supports several natural processes in the body. It can help fight certain infections, reduce swelling, support the growth of new blood vessels, and promote the healing of wounds that have stalled. It also helps the body clear gas bubbles and certain toxic gases from the bloodstream more quickly.

Hyperbaric oxygen therapy is a well-established treatment for a specific list of conditions. Widely accepted uses include:

• Decompression sickness (sometimes called “the bends”), a condition that can affect divers when gas bubbles form in the blood and tissues.
• Arterial gas embolism, in which gas bubbles enter the arteries.
• Carbon monoxide poisoning.
• Diabetic foot ulcers and other chronic wounds that are not healing with standard care.
• Radiation injury to soft tissue or bone that develops months or years after cancer treatment, such as damage to the jaw or bladder.
• Serious soft tissue infections, including gas gangrene and necrotizing infections (infections that destroy tissue).
• Crush injuries and some cases of severe compromised blood flow after trauma.
• Chronic bone infection (osteomyelitis) that has not responded to other treatment.
• Skin grafts or flaps that are at risk of failing.
• Severe anemia when blood transfusion is not possible.
• Sudden sensorineural hearing loss, in selected cases.
• Severe thermal burns, in selected cases.

HBOT is also marketed for many other conditions, including autism, cerebral palsy, stroke recovery, long COVID and “anti-aging.” For most of these, the scientific evidence is limited or inconclusive, and major medical bodies do not recommend hyperbaric oxygen therapy for them. This page focuses on the established medical uses.

Who is a candidate

A doctor with training in hyperbaric medicine, wound care, or a related specialty decides whether hyperbaric oxygen therapy is appropriate. In many hospitals, including some Acibadem facilities, referrals come through wound care, plastic surgery, infectious disease, or physical medicine departments. The decision is based on your diagnosis, how you have responded to other treatments, and whether you have any conditions that make the therapy unsafe.

You may be considered a candidate if you have one of the recognized indications listed above and your treating team believes that additional oxygen delivery could change the course of your condition. For chronic wounds, doctors often first check whether blood flow to the area is sufficient and whether infection, pressure, or poorly controlled blood sugar is the main barrier to healing.

Hyperbaric oxygen therapy is not suitable for everyone. The main absolute contraindication (a situation where the treatment should not be given) is an untreated pneumothorax, which is a collapsed lung with air trapped in the chest. Because pressure changes affect trapped air, this could become life-threatening in the chamber.

Relative contraindications, where the doctor weighs risks and benefits carefully, may include:

• Severe chronic lung disease such as emphysema with air trapping.
• Recent chest or ear surgery.
• Active upper respiratory or sinus infection that prevents pressure equalization in the ears.
• A history of seizures, since high-pressure oxygen can lower the seizure threshold.
• Uncontrolled high fever.
• Certain chemotherapy drugs that may interact with high oxygen levels; your oncologist will be consulted.
• Pregnancy, unless the treatment is urgently needed, for example after carbon monoxide poisoning.
• Severe claustrophobia (fear of enclosed spaces), which may be managed with support or medication in some cases.
• Implanted devices such as pacemakers, which must be confirmed safe for the pressures used.

How the procedure works

Understanding what happens before, during, and after each session in the hyperbaric chamber can make the experience less stressful.

Before the session

Your doctor will review your medical history, medications, and any implants. You may have a chest X-ray to rule out trapped air in the lungs, and an ear examination to check that your eardrums are healthy. Blood sugar is often checked in people with diabetes, because HBOT can lower blood glucose during treatment. You will be asked to change into cotton clothing provided by the unit and to remove anything that could create a spark or catch fire, including watches, jewelry, hearing aids, lighters, petroleum-based lotions, hair products, and some deodorants. Oxygen at high concentration greatly increases fire risk, so these rules are strict.

During the session

There are two main types of hyperbaric chamber. A monoplace chamber is a clear tube for one person; you lie on a padded table that slides inside, and the whole chamber is filled with oxygen. A multiplace chamber is a larger room where several people sit or lie down and breathe oxygen through a hood or mask while a trained attendant stays inside with them.

Once the chamber is sealed, the pressure is slowly increased over several minutes. This phase is called compression. You will feel fullness in your ears, similar to an airplane descent, and staff will guide you to “clear” your ears by swallowing, yawning, or gently pinching your nose and blowing. Once the target pressure is reached, you simply rest and breathe. Many units allow you to watch television, listen to music, or sleep. Sessions typically last about 90 minutes to two hours in total. In some protocols you take short “air breaks” where you breathe regular air for a few minutes to reduce the risk of oxygen toxicity.

At the end, the pressure is slowly lowered back to normal. This is called decompression and usually takes several minutes. You may feel your ears “pop” again.

After the session

Staff will check how you feel, and people with diabetes may have their blood sugar rechecked. Most people can leave the unit shortly afterward and return to normal activities the same day. Light-headedness or tiredness for a short period is common.

For chronic conditions such as non-healing wounds or radiation injury, hyperbaric oxygen therapy is given as a course, often one session per day, five days a week, for a total of roughly 20 to 40 sessions, depending on the condition and your response. For emergencies such as carbon monoxide poisoning or decompression sickness, treatment starts immediately and may involve fewer, longer, or more intensive sessions.

Preparation for hyperbaric oxygen therapy

Preparation is mostly about safety inside the chamber and about giving the therapy the best chance to work.

• Tell your team about all medications, including over-the-counter drugs and supplements. Some medicines, such as certain antibiotics or chemotherapy agents, need special attention.
• Do not smoke, and avoid nicotine products, before sessions if at all possible. Nicotine narrows blood vessels and works against the goal of delivering oxygen to tissues.
• Eat a light meal one to two hours before your session. Avoid carbonated drinks and gas-producing foods, which can cause abdominal discomfort as pressure changes.
• If you have diabetes, follow your unit’s instructions on eating and checking blood sugar before each session, since treatment can lower glucose levels.
• Report any cold, sinus congestion, ear pain, or fever before a session. Congestion can make it hard to equalize ear pressure, and the session may need to be postponed.
• Leave prohibited items at home, or in the locker provided. This includes electronic devices, lighters, and petroleum-based skin products.
• Wear only the cotton garments provided. Synthetic fabrics can generate static.
• Arrange transportation for the first sessions if you are unsure how you will feel afterward, although most people are able to drive.

Recovery and aftercare

Because hyperbaric oxygen therapy is non-invasive, there is no surgical wound to recover from, and most people resume ordinary daily activities immediately after each session. Recovery in the broader sense depends on the condition being treated.

After individual sessions, many patients notice mild fatigue, a feeling of fullness in the ears, or temporary changes in vision. These effects typically fade within hours to a few days. Fatigue often lessens as the body adjusts over the first week of a treatment course.

For chronic wounds, healing is gradual. Wound care specialists usually continue dressing changes, offloading (relieving pressure from the wound), infection control, and blood sugar management alongside HBOT, because oxygen alone is rarely enough. Progress is measured over weeks, and your team will often photograph and measure the wound at regular intervals.

For radiation injury, improvement in symptoms such as pain, bleeding, or non-healing tissue may take several weeks and may continue for a period after the course ends. For carbon monoxide poisoning or decompression sickness, some symptoms may resolve quickly while others, particularly neurological ones, may take longer or require rehabilitation. In these cases your doctor may refer you to Physical Medicine & Rehabilitation for ongoing support with strength, balance, or cognitive function.

Aftercare throughout the course typically includes:

• Attending every scheduled session, since consistency matters for cumulative effect.
• Continuing all prescribed wound care and medications.
• Keeping blood sugar well controlled if you have diabetes.
• Not smoking.
• Reporting any new ear pain, vision changes, or breathing difficulty promptly.

Risks and side effects

Hyperbaric oxygen therapy is generally considered safe when given by trained staff in a properly maintained facility, but like all treatments it carries risks. Most hyperbaric oxygen therapy side effects are mild and temporary.

Common or expected side effects:

• Ear discomfort or barotrauma. Pressure changes can stretch or, less commonly, injure the eardrum or middle ear. Difficulty equalizing pressure is the most frequent problem, and occasionally fluid or blood collects behind the eardrum. Serious eardrum rupture is uncommon and usually heals.
• Sinus pressure or pain, particularly if you have congestion.
• Temporary nearsightedness (myopia). Many patients on longer courses notice their distance vision blurs. This typically reverses within weeks to a few months after treatment ends, so new eyeglasses are usually not recommended during the course.
• Fatigue and, less often, headache after sessions.
• Low blood sugar in people with diabetes.
• Claustrophobia or anxiety in the enclosed space.

Less common but more serious risks:

• Oxygen toxicity seizures. Breathing high-pressure oxygen can, in rare cases, trigger a seizure. Air breaks and careful pressure limits reduce this risk. A seizure in the chamber is frightening but usually stops when oxygen is removed and does not typically cause lasting harm.
• Lung injury (pulmonary barotrauma). Rarely, pressure changes can damage lung tissue, especially if there is undiagnosed trapped air. This is why screening beforehand is important.
• Worsening of existing cataracts with very long courses; this is uncommon with standard treatment lengths.
• Fire. Chamber fires are extremely rare in accredited facilities, but they are catastrophic, which is why safety rules about clothing and personal items are so strict.

You should also be aware that receiving HBOT for a condition where evidence is weak may delay proven treatments and involves cost without a clear expected benefit.

Results and outlook

The expected results of hyperbaric oxygen therapy depend heavily on the condition being treated, how early treatment begins, and what other care is given at the same time.

For decompression sickness and arterial gas embolism, HBOT is the standard treatment, and prompt therapy generally offers the best chance of resolving symptoms. For severe carbon monoxide poisoning, it is widely used to speed the removal of carbon monoxide from the body and is thought to reduce the risk of later neurological problems, although the size of that benefit is still debated in the medical literature.

For diabetic foot ulcers, evidence suggests that adding hyperbaric oxygen therapy to good wound care can improve healing and may reduce the need for major amputation in selected patients, particularly those with adequate blood flow. Results vary between studies, and HBOT does not help every wound. For late radiation injury to soft tissue and bone, many patients experience meaningful symptom improvement, and HBOT is often used before dental extractions in previously irradiated jaws to lower the risk of bone death.

For the many non-approved uses promoted commercially, the honest summary is that high-quality evidence is lacking or has not shown clear benefit. Your doctor should be able to explain which category your condition falls into and what a realistic goal of treatment would be. In all cases, the outlook is best when HBOT is part of a comprehensive plan rather than a stand-alone treatment.

Cost considerations

Hyperbaric oxygen therapy cost varies widely, and no single figure applies. Several factors influence the total:

• Number of sessions. Chronic conditions usually require a course of many sessions, so the total cost is the per-session cost multiplied by the length of the course.
• Setting. Emergency treatment for divers or carbon monoxide poisoning often occurs during a hospital admission, adding inpatient charges. Outpatient courses for wounds typically involve only the sessions and clinic visits.
• Type of chamber and staffing. Multiplace chambers require an attendant inside and more staff per session.
• Associated care. Wound dressings, debridement (removal of dead tissue), laboratory tests, imaging, and specialist follow-up appointments are usually billed separately.
• Insurance coverage. Many insurers cover HBOT only for recognized indications and often require documentation that standard care has failed. Treatment for non-approved conditions is usually paid out of pocket.

Asking your treatment center for a written estimate that lists the expected number of sessions and any additional services can help you understand the likely total before starting.

Frequently asked questions

What does a hyperbaric chamber feel like inside?

Most people describe it as similar to being in an airplane during takeoff and landing. You feel pressure in your ears during compression and decompression, and the chamber may feel slightly warm at first and cooler later. In a monoplace chamber you lie down in a clear tube and can see and speak with staff through an intercom; in a multiplace chamber you sit in a room with others and breathe through a hood or mask.

How many HBOT sessions will I need?

This depends on your diagnosis. Emergencies such as decompression sickness may need one to a few sessions. Chronic conditions such as diabetic foot ulcers or radiation injury are typically treated with a course of roughly 20 to 40 daily sessions, and your doctor will reassess progress along the way and may adjust the plan.

What are the main hyperbaric oxygen therapy benefits?

For recognized indications, the benefits include faster clearance of gas bubbles and carbon monoxide, improved oxygen delivery to poorly perfused tissue, support for wound healing and new blood vessel growth, and enhanced action against certain infections. Benefits for conditions outside the accepted list are not well supported by evidence.

Is hyperbaric oxygen therapy painful?

The treatment itself is not painful. The most common discomfort is ear pressure, which can usually be relieved by swallowing or gently equalizing. If you develop actual ear pain, tell the attendant immediately so the pressure change can be slowed or paused.

Can I drive home after a hyperbaric oxygen therapy session?

Most people can. Some feel tired or light-headed briefly, and vision changes can develop over a long course, so it is sensible to arrange a ride for your first session and to reconsider if you notice blurred distance vision.

Does insurance cover hyperbaric oxygen therapy cost?

Coverage varies by insurer and country. In many systems, HBOT is covered for established indications when specific criteria are met, such as a diabetic foot ulcer that has not improved after a defined period of standard care. Treatments for conditions not on the approved list are usually not covered.

Are hyperbaric oxygen therapy side effects permanent?

Most side effects, including ear fullness, fatigue, and temporary nearsightedness, resolve after treatment ends. Rare serious events such as eardrum rupture, lung injury, or seizures are possible but uncommon, and careful screening beforehand reduces these risks.

When to see a doctor

You should be assessed by a specialist if you have a condition for which hyperbaric oxygen therapy is a recognized option and standard treatment is not working. Examples include a foot or leg wound that has not improved after several weeks of proper care, especially if you have diabetes; ongoing pain, bleeding, or tissue breakdown in an area treated with radiation months or years ago; or a chronic bone infection that keeps returning despite antibiotics.

Some situations are emergencies that require immediate medical attention, and HBOT may be part of urgent care:

• Symptoms after diving such as joint pain, numbness, weakness, confusion, or breathing difficulty, which may indicate decompression sickness or gas embolism.
• Suspected carbon monoxide exposure with headache, dizziness, nausea, confusion, or loss of consciousness.
• A rapidly spreading, painful skin infection, sometimes with blistering, discoloration, or a crackling feeling under the skin.
• Sudden hearing loss in one ear.

If you are already receiving hyperbaric oxygen therapy, contact your treatment team or seek urgent care if you experience:

• Severe or persistent ear pain, bleeding from the ear, or sudden hearing change.
• Chest pain, shortness of breath, or coughing up blood after a session.
• A seizure or an episode of confusion.
• Sudden, marked vision loss rather than gradual blurring.
• Signs of low blood sugar such as sweating, shakiness, or confusion that do not improve after eating.
• New fever, increased redness, swelling, or foul drainage from a wound being treated.

Your treating doctor can tell you which symptoms are expected during a course of HBOT and which should be considered warning signs.