History and Facts of Hyperbaric Oxygen Therapy?

Hyperbaric medicine is not a new concept. Since the late 1800s, it has been used. However, until the second half of the twentieth century, it was only used to treat divers and those who had had decompression accidents. Its beneficial process was based on Boyle’s Law, a basic concept. Hyperbaric oxygen therapy was initially invented in the U.S. at the start of the 20th era. This was the time when Orville Cunningham used oxygen with utmost purity to treat a patient who had died of influenza. He built a hyperbaric chamber, later its use for other situations failed so he dismantled it. 

Dr. J. Leonard Corning created the first hyperbaric chamber in the United States in 1891 in New York. Corning became interested in HBOT after witnessing severe decompression disease among Hudson Tunnel construction workers, who suffered from acute muscle pain and paralysis after working below sea level all day. This was a quite good practice in bridge construction, with the Brooklyn Bridge in the 1889s being the most renowned example.

Soon after, Dr. Orval Cunningham, chairman of the Department of Anesthesiology at Kansas University Medical School, investigated the use of hyperbaric oxygen therapy for pandemic influenza after noticing that death rates from the 1918 “Spanish influenza” pandemic were greater in higher altitudes than in coastal areas, which he associated to barometric pressure.

In the 1930s, a Brazilian physician by the name of Álvaro Osório de Almeida, recognized the extreme benefits of hyperbaric therapy and published many papers on this study and the effects of high pressured oxygen for the body, especially on tumors on animals. Later the US Navy researched the use of HBOT to treat decompression sickness. A long report on this HBOT research was published by Behnke and Shaw in the late 1930s. In the 1960s, this therapy was also beneficial to combat carbon monoxide poisoning. It is still used to treat scuba divers and people who have been exposed to carbon monoxide, such as firefighters and miners. This has grown to treat several illnesses and finally been FDA approved by US Government Agencies.

The Undersea and Hyperbaric Medical Society (UHMS) was established in 1967. In the fields of hyperbaric and dive medicine, the UHMS is an international nonprofit organization that serves over 2,000 physicians, scientists, associates, and nurses from over 30 countries. The UHMS publishes policy guidelines and advocates for the use of HBOT in a diverse range of conditions including new uses and applications, in addition to serving as an important source of scientific and medical information pertaining to hyperbaric medicine through its bimonthly, peer-reviewed journal, seminars, curricula, credentialing, and sessions.


What is Hyperbaric Oxygen Therapy?

Breathing oxygen with atmospheric pressure up to three times higher than normal is known as hyperbaric oxygen therapy (HBOT). HBOT can be used as a stand-alone treatment or as a supplement to surgical and/or pharmacological procedures. Hyperbaric oxygen is described by the Undersea and Hyperbaric Medical Society (UHMS) as “An operation in which someone respires almost 100% oxygen routinely while pressing pressure higher than sea level within a hyperbaric chamber (1 atmosphere absolute, or ATA). The pressure must equal or exceed 1.4 ATA for therapeutic purposes when breathing about 100 percent oxygen.” 

If you’re going through an FDA-approved HBOT treatment, then you will enter a singular space to inhale 100% pure oxygen in a pressurized environment, 1.6 to 4 times more pressure than sea level. Increased pressure will raise the oxygen levels in your body; the objective being to saturate the tissues with sufficient oxygen to patch up nerves and reinstate usual body function. 

Usually, real industry-approved high-pressure Hyperbaric Oxygen chambers use pressures of 2.0 to 3.0 ATA, while low-pressure therapy may be conducted at 1.5 to 2.0 ATA. When lower pressure chambers are used such as the inflatable HBOT’s, treatment time may be long and not very effective.

HBOT aims to break the cycle of inflammation, starvation of oxygen, and tissue death.

There are three main types of hyperbaric oxygen chambers available: 

  • Monoplace chambers 
  • Multiplace chambers 
  • Mild, or Soft chambers  

Monoplace Chambers

Monoplace Chambers are single person chambers. They can be pressurized by normal air or by medical oxygen. Monoplace chambers usually contain pressures between 1.5-3.0 ATA. If this chamber is pressurized by 100 percent oxygen, the patient breaths oxygen directly from the ambient chamber environment.  If the chamber is pressurized with medical grade air, the patient breathes 100 percent oxygen through a mask. Monoplace chambers can be made from steel, aluminum or acrylic.  At Under Pressure Hyperbarics our chambers are made of acrylic allowing patients to comfortably watch television (TV), with an audio system attached internally to monitor the patient through outside the chamber at all times which communicates with hyperbaric technicians. These chambers are found in both private and FDA-approved hospitals to treat different medical conditions.

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Multiplace Chambers

These chambers are built for multiple patients and more than one patient at a time. They can be smaller for two patients at a time, or more commonly six to twelve patients. Multi-place chambers are often able to be pressurized to greater pressure than Monoplace chambers.  These chambers are often used for divers who require greater pressures to undo the effects of decompression illness. Patients may lay down, sit down on a bench or maybe receiving therapy with the other patients which is accompanied by the hyperbaric technicians. Multiplace chambers are generally found in large hospitals, trauma centers and military bases.

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Mild Chambers(mHBOT)

These chambers are different from the other two due to their structure, capabilities, and pattern. These are also called soft chambers as a lot of mHBOT chambers are constructed from material which is typically elastic/plastic used to create a shell of chamber. These are usually approved to patients with acute mountain sickness up to 1.3 ATA (10 feet under seawater). These chambers are pressurized with air or oxygen concentrators as opposed to medical grade gases. Mild chambers have limited application because of the inability to reach therapeutic pressures.



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Portable soft sided mHBOT chamber uses oxygen concentrator.

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The-Cube or Hyper-Cube is another low pressure (mHBOT) hyperbaric chamber. Pressurized with Air.


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Newer mHBOT chamber from Europe and Asia.  Not yet approved for human use in the US.  Lacking FDA, PVHO and ASME clearance. Pressurized with an oxygen concentrator.



Scientific studies of the effectiveness of HBOT are only conducted at pressures starting at 1.5 atmospheres, so the health benefits of these soft hyperbaric chambers cannot be accurately measured.

Soft hyperbaric chambers are authorized by the FDA only for the treatment of acute mountain sickness. It’s currently not known whether these types of chambers can help with other medical conditions.


The Science Behind Hyperbaric Oxygen Therapy

You are reading everything about hyperbaric oxygen therapy, but knowing the science behind hyperbaric is where it gets interesting. Hyperbaric Oxygen Therapy involves breathing in 100% pure oxygen while sitting or laying down in a pressurized chamber. The whole process is often pain-free and non-invasive. While inside a chamber, you will be breathing 10 to 20 times more oxygen than you would regularly breathe through the concentrated 21% oxygen you get from the current air outside. Your blood carries the oxygen throughout your body and delivers it to the places that need it most. Usually, your brain takes the majority of the oxygen for itself because it’s the powerhouse of the body that survives on oxygen, but in an excess supply situation that is created like this, your whole body gets oxygen delivered. This promotes accelerated healing and fighting of bacteria to stimulate new tissue growth. 

When looking at Hyperbaric Oxygen Therapy (HBOT) you wonder what the word consists of. “Hyper” means increased, while “baric” is related to pressure. So this is relatable when you are using increased pressure with oxygen inside an HBOT chamber. To make HBOT more simple in how it works, let’s look at a bottle of soda for example. When you pick up a soda before opening it, it usually is still with no bubbles. This is because the Soda has been pressurized under the bottle. When the bottle is open, you notice more and more fizz and bubbles starting to form and this is because the volume of the bubble increases and pressure is released. Now, let’s take a human example. When a person enters a pressurized chamber, the oxygen under pressure will deliver throughout the body more smoothly and make it to places that it wouldn’t usually reach, helping the body build new tissues and increasing organ functionality.

HBOT is being utilized to treat a variety of illnesses, but the Food and Drug Administration (FDA) has authorized HBOT treatment for 14 illnesses and diseases. This set of illnesses is usually covered by Medicare, subject to certain conditions’ criteria (check with your insurance company to confirm coverage under your plan). Nevertheless, many trials have shown that HBOT is successful in treating a variety of other illnesses, and it has been permitted for practice in more than 50 countries across the world.

Oxygen, which is carried out in the blood, is bound to the hemoglobin, which at least 97 percent is saturated at normal environmental pressure. As the level of pressure is raised, oxygen is carried out into the plasma through the blood (Henry’s Law), giving authority to carry out the oxygen to reach the areas of the body which usually do not enhance healing. This condition generally for the people who have medical conditions that bound the oxygen-carrying ability of the blood.

4 physical laws should be considered when looking at the properties of Hyperbaric Oxygen Therapy ( HBOT). Since the participant is taking in 100% pure oxygen, the density and solubility of oxygen are all maximized. Oxygen delivery to the body depends on arterial oxygen content, cardiac output, and blood flow. We can calculate the arterial oxygen content using Hemoglobin concentration, arterial partial pressure of oxygen and hemoglobin saturation.

Dalton’s Law of Partial Pressures

Dalton’s Law describes the relationship of the pressure of individual gases in a mixture to the total pressure of the gas mixture. The law states that the total pressure of a mixture of gases is equal to the sum of partial pressures of the component of individual gases in the mixture.

Boyle’s Law

Boyle’s Law relates to the volume and density of gas to pressure the gas at constant temperature. The volume of gas is inversely proportional to the pressure. The density on the other hand is directly proportional to pressure.

Graham’s Law

Graham’s Law describes the connection of pressure of gas to how it moves. It shows how oxygen and carbon dioxide move independently from high pressure to low pressure. He examined the diffusion of one liquid into another, then dividing the particles into two classes.

Henry’s Law

Henry’s law is the amount of gas dissolved in a liquid is equal to the partial pressure of the gas above the liquid. In turn, the solubility of a gas in a liquid is directly proportional to pressure in contact with the liquid.


Physiological and Biochemical Aspects of Hyperbaric Medicine

The plasma oxygen content at sea is 3 ml/l. Tissue needs approximately 60 ml of oxygen per liter of blood flow to keep its cells functioning (provided that adequate perfusion is performed) however tissue requirements vary. Dissolved oxygen in plasma at three atmospheres (304 kPa) surpasses 60 ml/l, almost adequate for the residual total oxygen need of several tissues without the aid of hemoglobin-binding oxygen. This is useful when cross-matching is challenging or when religious convictions limit blood transmissions, such as carbon monoxide toxins or severe anemia. At 300 kPa, blood oxygen stress reaches almost 270 kPa and it reaches approximately 53 kPa in tissue. The gradient of tissue-cell diffusion is increased, improving the provision of cellular oxygen. Improved angiogenesis is one of the hyperoxia’s possible benefits of hyperoxia. The synthesis of the collagen matrix necessary for angiogenesis is inhibited by hypoxia. The increased tissue partial oxygen pressure, inducing angiogenesis, and wound healing in irradiated tissue is more effective than normobaric oxygen. Hyperbaric oxygen in non-irradiated tissues, however, further research is needed to confirm that the healing process can also be assisted by poor perfusion. The physical features of gases dictate the usefulness in decompression disease and embolism of arterial gas hyperbaric oxygen therapy. The law of Boyle asserts that the volume of the gas is inversely proportional to the pressure applied in an enclosed region. At 300 kPa, bubble volume is reduced by approximately 2/3. Intravascular bubbles are obstructed and migrate to minor arteries, lowering the incidence of tissue injury. When the inert gas in the bubble is substituted with oxygen, which is readily digested by the tissue, the gas bubble dissolves quicker.


How Can Hyperbaric Oxygen Therapy (HBOT) Help? 

With over 50 years of documented research and over a dozen FDA-approved uses, HBOT has been slowly growing past the scepticism and finally getting approved by the medical community as an alternative medicine that is essential to healing and reverse aging. 

Here are a few factors on how HBOT helps the body:

  • HBOT promotes the growth of new skin cells and collagen (connective tissue). It accomplishes this by promoting the development of new blood vessels. It also induces the production of specific chemicals in cells, such as vascular endothelial growth factor. These attract in and excite the endothelial cells that are required for healing.
  • HBOT boosts the body’s immune system by blocking the action of dangerous microorganisms. Certain bacteria’s toxins can be rendered inactive by HBOT. It also raises the concentration of oxygen in the tissues. This aids their resistance against infection. In addition, the therapy boosts white blood cell’s ability to detect and destroy invaders.
  • “Reperfusion damage” is avoided with HBOT. After oxygen is depleted, the blood supply returns to the tissues causing substantial tissue damage. When blood flow is disturbed, for example by crush wounds, the damaged cells produce a chain of events that lead to the production of harmful oxygen radicals. These substances can cause irreversible harm to the tissue and restrict blood arteries, halting blood flow. HBOT increases radical scavenger oxygen in the body to look for problem molecules to enable repair.
  • HBOT promotes wound healing by delivering oxygen-rich plasma to tissue that is deficient in oxygen. Wound injuries damage the blood vessels in the body, causing fluid to flow into the tissues and create swelling. The injured cells are deprived of oxygen because of the swelling, and tissue begins to die. HBOT lowers swelling while also providing oxygen to the tissues. The amount of oxygen in the blood increases as the pressure in the chamber rises. HBOT tries to disrupt the cycle of tissue death, swelling, and oxygen deprivation.


Conditions That Hyperbaric Oxygen Therapy Can Help? 

Hyperbaric oxygen treatment has been suggested and utilized in a wide range of medical diseases over the past 100 years, frequently without proper scientific proof of efficacy or safety. As a result, there has been a lot of medical skepticism about its use. Finally, within the last few decades, we have seen real experiments and studies on the real benefits of how Hyperbaric can be used and how it has become an industry standard for alternative medicine for healing. The HBOT has now been licensed by the Food and Drug Administration (FDA) as a treatment for various diseases, but some people are calling for more approvals. There are several approved indications of hyperbaric oxygen below.

Main treatment with scientific evidence

  • Air or Gas Embolism
  • Carbon Monoxide Poisoning 
  • Central Retinal Artery Occlusion
  • Chronic Refractory Osteomyelitis
  • Crush Injury & Other Acute Traumatic Ischemias
  • Decompression Sickness
  • Diabetic Lower Extremity Wounds
  • Failed Skin Grafts & Flaps
  • Gas Gangrene
  • Necrotizing Soft Tissue Infections
  • Radiation Tissue Damage
  • Severe Anemia (Acute anemia used as a bridge therapy)
  • Sudden Sensorineural Hearing Loss
  • Thermal Burns (severe)
  • Intracranial Abscess

Adjunctive treatment with scientific evidence

  • Osteoradionecrosis
  • Clostridial myonecrosis
  • Compromised skin graft and flaps healing

Non-Approved Conditions Still Testing

  • Radiation-induced injury
  • Refractory osteomyelitis
  • Prolonged wound healing failure
  • Gas infection 
  • Infatuation damage
  • Section disease 
  • Acute marginal ischemia 
  • Improved curative in designated problem injuries
  • Necrotizing soft tissue infections 
  • TBI
  • Stroke
  • Autism
  • Cancer
  • Diabetes
  • Sports Injuries

The healing powers of HBOT can be thanked by a couple of benefits. These benefits include hyperoxygenation, anti-inflammation, Immune Boost, Neovascularization, Stem Cell Growth, and reverse-aging of telomeres. 


What Happens During Hyperbaric Oxygen Therapy? 

When we are talking about true medical-grade Hyperbaric oxygen therapy chambers, you should always be advised and prescribed before entering the chamber. Hyperbaric oxygen chambers are available in several hospitals. In sessions lasting up to two hours, people rest, sit, or lie comfortably in these chambers and take deep breaths.

At the beginning of every session your vitals will be checked by trained technicians and assure the safety of the patient, remove the electronic device, watch, jewelry, and perfumes/lotions. In this session they will provide you with a water bottle, 100 percent cotton gown and blanket for a comfortable experience into the chamber. Water bottles will be helpful to clear ears by the chamber pressure. 

After entering into the chamber, the television (TV) or music will be turned on of your choice by the technician, or you can also take a rest. In this whole session or therapy technician is always present beside you for your guidance (ear popping sensation like flying an airplane). After the session, vitals will be rechecked again by the technician.

There are several parts to finishing treatment for HBOT:

  1. The first stage when entering the chamber includes the compression or many times referred to as the diving stage. This is when the chamber is pressurized to the prescribed depth, mostly from 2.0 to 3.0 atm. 
  2. The chamber now is maintained at the pressure prescribed and now you can put on your oxygen mask where you will now breathe in 100% pure oxygen under pressure.
  3. Patients are allowed two air breaks and allowed to take in water during the treatment process.
  4. After the treatment comes to its closing time, usually between 1-2 hours, the tank is depressurized and the treatment is finished. 

When pressure is increased, such as in an airplane or the mountains, your ears may feel plugged. The ears can be “popped” back to normal hearing levels by simply swallowing or chewing gum.

The extra oxygen is carried throughout the body by your blood, infusing the afflicted tissues that require it so they can begin to recover. You may feel dizzy after completing a session. Claustrophobia, tiredness, and headaches are among the mild side effects.

You will need more than a few treatments to see changes, so check ahead to see if your insurance company, Medicaid, or Medicare will pay the costs for your specific needs.


Risks of Hyperbaric Oxygen Therapy

There are numerous situations in which the risks of hyperbaric oxygen therapy are involved but highly unlikely as you will have a full-body assessment and be recommended by a doctor before going into the chamber.

To prevent oxygen poisoning, it is suggested to take short breaks during the process. This will prevent the normal air pressure in the body, this will also prevent tissues in the body while taking the oxygen in a greater amount. This is necessary to give an oxygen dose in the treatment which will be resolute precisely for each person. 

Some side effects for HBOT include:

  • Claustrophobia
  • Barotrauma
  • Fatigue
  • Ear Pain
  • Vision Change
  • Lightheadedness
  • Oxygen poisoning

Most side effects are very minor as there have been years of studies and experiments on the true benefits. If problems continue after therapy, it’s suggested to seek medical help.


The Future of Hyperbaric Oxygen Therapy

When the FDA warned against using HBOT for unapproved reasons in 2013, the Alliance for Natural Health slammed the announcement as “deceptive.”

HBOT supporters want it to become a standard treatment for a variety of illnesses. They believe that increased pressure and oxygen can help with a variety of body functions, citing several studies to back up their claims.

HBOT has been proposed as an alternative therapy for autism, attention deficit hyperactivity disorder (ADHD), cerebral palsy, post-traumatic stress disorder (PTSD), and other conditions.

Some people believe that employing HBOT to help veterans improve their quality of life is a good idea. Those who have had a traumatic brain injury (TBI) or who have PTSD may benefit from the treatment, according to proponents.

The effects of HBOT on TBI have been studied by researchers. HBOT may improve a person’s Glasgow Coma Scale score after a TBI, according to a 2016 meta-analysis, but there isn’t enough data to support its use to treat PTSD.

Additional benefits of HBOT are still being researched, but the FDA needs more evidence before declaring such usage to be safe and effective. Every year new studies are being conducted and there will be new indications and approvals by the FDA as HBOT becomes more prominent. 

It is safe to say Hyperbaric oxygen therapy (HBO) has a huge role in modern medical practice. It is safe in most cases but has some side effects, but what medicine does not. There are many indications for hyperbaric oxygen therapy and it is continuously growing in research and government approvals. Results show that this is an effective treatment to treat complex wounds and diseases. The future of HBOT is going to be in a steep incline as it has just grown past just being medical treatment and grown to be included part of the beauty and spa community where people can use the benefits of HBOT for new industries. Hyperbaric will soon be grown to a household name in the near future, but for now. While HBOT is growing as alternative medicine, it will take time for it to start becoming a primary medicine for many people. 


Edwards, Melissa L. (2010). Hyperbaric oxygen therapy. Part 1: history and principles. Journal of Veterinary Emergency and Critical Care, 20(3), 284-288. 

Jain, Kewal K. (2017). Physical, physiological, and biochemical aspects of hyperbaric oxygenation. In Textbook of hyperbaric medicine (pp. 11-22): Springer.

Mitchell, Simon J, & Bennett, Michael H. (2014). Unestablished indications for hyperbaric oxygen therapy. Diving Hyperb Med, 44(4), 228-234. 

Plafki, C, Peters, P, Almeling, M, Welslau, W, & Busch, Ruth. (2000). Complications and side effects of hyperbaric oxygen therapy. Aviation, space, and environmental medicine, 71(2), 119-124. 

Singh, Shailendra, & Gambert, Steven R. (2014). Hyperbaric oxygen therapy: a brief history and review of its benefits and indications for the older adult patient. Annals of Long-Term Care, 22(7-8), 37-42.

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