About Hyperbaric Oxygen Therapy

Hyperbaric oxygen therapy is a medical treatment proven safe and effective for a number of diseases and conditions. It is administered using devices, known as hyperbaric chambers, which can be safely occupied at greater than normal atmospheric pressure in the presence of pure oxygen.

Patients undergoing hyperbaric treatment breathe 100% oxygen for a prescribed amount of time at a specific pressure. Patients may receive anywhere from one to dozens of treatments, depending on their medical needs.

Hyperbaric treatment centers can be found at hospitals, outpatient facilities, and independent clinics. Treatment centers vary in the type of hyperbaric chambers they use, the medical conditions they treat, and in other ways.

Hyperbaric chambers are registered medical devices and are regulated by the US Food and Drug Administration. Hyperbaric oxygen therapy is a medical treatment for which a doctor's prescription is required.


When hyperbaric oxygen helps

Although it is most commonly recognized as the cure for scuba divers suffering decompression sickness, known as “the bends”, hyperbaric oxygen therapy is also respected by medical professionals as an advanced treatment for a range of acute and persistent illnesses. It has been cleared and approved for 14 medical conditions.

Promising research results have been published for a few others. For many other medical problems, particularly neurological conditions, clinical studies have found little or no evidence to justify the use of hyperbaric oxygen therapy.

The HyperbaricLink Evidence Index provides an at-a-glance summary of the state of clinical evidence for each condition listed. Evidence Index scores reflect our interpretation of the published consensus of the most authoritative and reliable scientific sources. Read about the Evidence Index to learn more about how scores are assigned.

 Learn more about diseases and conditions treated with hyperbaric oxygen therapy, including approval status and patient resources.

Diseases and Conditions

How it works = ( Pressure ➕ Oxygen ➕ Time ) Chamber

Safe, proper hyperbaric oxygen therapy delivers a carefully managed dosage of pressure and pure oxygen over a prescribed period of time in an approved hyperbaric chamber.


The word hyperbaric means above-normal pressure. Hyperbaric oxygen therapy is delivered in a chamber pressurized at 1.4 to 3.5 times the normal sea-level atmospheric pressure of 14.696 pounds per square inch.


Patients breathe 100% oxygen during hyperbaric oxygen therapy, sometimes with short “air breaks” of normal air. Normal air contains 21% oxygen, 78% nitrogen, trace amounts of other gases, and water vapor. Air breaks ensure patients will avoid oxygen toxicity.

 Oxygen used in hyperbaric treatment is a medical-grade gas considered a prescription drug by the FDA. It is often supplied to hyperbaric chambers by a hospital's central oxygen system. Patients may not obtain medical oxygen in portable containers without a doctor's prescription and should not use it in ways other than as prescribed by their doctor.


Most hyperbaric treatments, often called “dives”, last between 50 and 90 minutes. Patients may expect to spend extra time at the treatment center consulting with the clinical staff and changing clothes before entering and after exiting the chamber.

Some conditions, such as acute carbon monoxide poisoning and decompression sickness, may be treated successfully in just 1 to 3 dives. Patients with diabetic foot ulcers and other chronic wounds may undergo 40 or more daily treatments, 5 to 6 days per week, for a number of weeks.

 Hyperbaric oxygen is serious medicine that should always be prescribed by a physician. Treatments should always be supervised by a qualified hyperbaric specialist physician (MD or DO) assisted by a certified hyperbaric technician (CHT).


There are two basic types of hyperbaric chambers:

  • Monoplace chambers are filled with 100% oxygen during treatment and hold one patient. Patients recline during treatment. Most modern monoplace chambers have clear acrylic walls so medical personnel can monitor the patient.
  • Multiplace chambers can treat more than one patient at a time and patients can be accompanied by healthcare professionals. In multiplace chambers the pressurized atmosphere is a standard mix of gases, and patients receive 100% oxygen through a mask or hood.

Each type of chamber has particular benefits for specific medical problems. Some treatment centers have both monoplace and multiplace chambers.

 Learn more about hyperbaric chamber types and their benefits.

Hyperbaric Chamber Types

Hyperbaric Oxygen Physiology: What Happens in the Body

The hyperbaric oxygen environment changes the relative pressures of oxygen, nitrogen, and other gases in the blood, organs, and tissues. Normally oxygen is carried by hemoglobin on red blood cells. Under higher pressures, oxygen dissolves in the blood plasma, as well. So breathing pure oxygen in a hyperbaric chamber increases the oxygen-carrying capacity of blood.

Oxygen is a potent antibacterial agent. It is especially toxic to certain kinds of bacteria (anaerobes) that cause life-threatening infections. Increasing the supply of oxygen to the infected tissue helps kill the bacteria.

In some conditions, such as crush injuries, skin grafts, and chronic wounds, healing is inhibited by a restriction of blood flow to the injured part of the body. Healing is promoted by maximizing the amount of oxygen in the blood that can reach the injured area.

Side Effects

No effective medical treatment comes without the risk of some adverse reactions. The rates of complication for hyperbaric oxygen therapy are very low. Potentially serious side effects include trauma to the middle ear, the eye (progressive myopia or cataracts), the lungs (pulmonary edema), and the brain (seizure), as well as claustrophobia. The Undersea and Hyperbaric Medical Society provides an informative page on side effects.

Hyperbaric Treatment Center Types

Over 1,000 facilities in the US and many more around the world offer hyperbaric oxygen therapy. The capabilities of a treatment center depend on the type of facility, the types of hyperbaric chambers it uses, and the medical specialties of its clinicians.

There are three basic types of hyperbaric treatment centers:

  • Hospitals—may provide emergency hyperbaric treatment of acute conditions
  • Outpatient facilities—often focus on wound care for ambulatory patients
  • Independent clinics—vary widely in capabilities and practice areas

Some hyperbaric treatment centers are accredited by the Undersea and Hyperbaric Medical Society, a sign that they have met certain standards of practice. Many are also accredited by the Joint Commission, the largest quality assurance organization for hospitals in the United States.

 Learn more about hyperbaric treatment center types and their capabilities.

Treatment Center Types

Cost and Reimbursement for Hyperbaric Oxygen Therapy

Fees for hyperbaric oxygen therapy can range from around $200 per treatment in independent clinics to over $1,000 in hospitals, depending on the type of treatment center, physician consultation fees, and other factors. Emergency hyperbaric treatment for acute conditions such as central retinal artery occlusion or necrotizing fasciitis may cost more than routine treatment of a chronic wound at an outpatient clinic.

Fortunately, Medicare, Medicaid, and private insurers generally reimburse for the treatment of approved indications and occasionally reimburse for the treatment of off-label or alternative indications. Reimbursement rates and criteria may vary widely by insurance carrier, type of treatment center, and by state or region.

Hyperbaric treatment for decompression sickness as a result of a scuba diving accident are generally not covered by standard health insurance plans, but the Diver's Alert Network (DAN), a leading scuba diving safety organization, provides a comprehensive diving insurance program that covers hyperbaric treatment.

“Mild Hyperbaric Oxygen Therapy”

So-called “mild HBOT” (mHBOT) is administered in inflatable bags that operate with room air (21% oxygen) at slightly increased pressure; less than 1.5 times the normal atmosphere. Medical experts do not consider this to be enough pressure to qualify as hyperbaric treatment. All such treatment is considered “off-label”.

A small minority of these devices are FDA-cleared for the treatment of Acute Mountain Sickness (AMS). The rationale for applying this approval to these devices is dubious, as treatment of AMS with a pressure device is only done at altitude and only as a means of facilitating the transportation of patients with severe AMS to a lower altitude. Mild HBOT devices require an electrical supply to operate and there are few outlets in high-altitude alpine environments.

None of these devices have been FDA-cleared to treat any other disease or condition. No widely accepted clinicial evidence exists to demonstrate these devices have any medical benefit.

 Important Safety Precaution: Using medical oxygen or oxygen concentrators with mild HBOT devices may create a fire hazard and may constitute an illegal adulteration of a medical device. The Undersea and Hyperbaric Medical Society (UHMS) warns that hyperbaric treatment should not be self-administered or administered in the home.

Heathcare consumers should exercise caution when evaluating the claims made by manufacturers or dealers of inflatable devices designed for use in the home and should never combine medical devices in ways that have not been approved by the FDA and prescribed by a doctor.

Still have questions?

Answers to many common questions about hyperbaric oxygen therapy can be found here:

Frequently Asked Questions


Treatment Center Directory

The HyperbaricLink directory provides extensive information about participating hyperbaric treatment centers, including:

  • treatment center type
  • practice areas and capabilities
  • accreditations and certifications
  • clinical staff
  • hyperbaric chamber types
  • hours of operation
  • map and directions
  • contact information

 Use the directory to learn more about hyperbaric facilities in your area.

Find Treatment Centers
US Food and Drug Administration, Center for Devices and Radiological Health. Retrieved 11 August 2011.
Undersea and Hyperbaric Medical Society, Indications for Hyperbaric Oxygen Therapy. Retrieved 02 May 2015.
Page Data
Updated: 26 Aug 2015 07:48 PM
Created: 08 Oct 2010 12:00 AM
By: About the authors »