The science behind hyperbaric oxygen therapy

You have probably read about or heard of hyperbaric oxygen therapy. But have you ever wondered just how it worked?

Hyperbaric oxygen therapy involves breathing 100% pure oxygen whilst sitting in our pressurised chamber. The chamber simulates the pressure at approximately 2 atmospheres (2 ATA) under water. There is, of course, no water involved in this process and the whole process is non-invasive and pain-free.

Due to the increase in pressure, the patient will breathe 10 to 20 times more oxygen into their body. Your blood then carries this oxygen throughout your body and delivers it to areas where it is needed, such as wounds or infected areas.

These areas need more oxygen to survive and heal. The increased level of oxygen in the blood arriving at these areas and result in temporally restoring normal levels of blood gasses and tissue function which help to promote healing and fighting off bacteria by stimulating new capillary growth.

When blood flows normally

The air we normally breathe is made up of 21% oxygen and 79% nitrogen. When breathing the lungs transfer the oxygen to the red blood cells – via hemoglobin. The then oxygen-rich red blood cells are carried throughout the body by plasma, which travels through the blood vessels. The oxygen diffuses into the surrounding tissue and it is delivered where it is needed the most.

When blood flow is restricted

When there is a restriction (occlusion) in the blood flow due to injury or illness, the red blood cells block the blood vessel and are not able to transfer oxygen to the cells on the other side of the blockage. This can cause swelling and the area is starved of oxygen causing hypoxia – a lack of oxygen. When this happens the tissue begins to break down.

Hyperbaric oxygenation effects

Breathing 100% oxygen under pressure causes the oxygen to diffuse into the blood plasma. This oxygen-rich plasma is able to travel past the restriction, diffusing up to four times further into the tissue. The increased pressure helps to reduce swelling and discomfort while providing the body with 10 to 20 times the normal supply of oxygen to help repair tissue damaged by the original occlusion or subsequent hypoxic condition.

Regeneration of blood vessels

Hyperbaric oxygen therapy forces more oxygen into the tissue, which helps stimulate the formation of new blood vessels. These new blood vessels develop, and the oxygenated blood cells start to flow to the affected areas. This then creates the optimal environment for the body’s natural healing processes to repair the damage.

The most common treatments that Wesley Hyperbaric treat are radiation damage to the bone and soft tissue and the treatment of non-healing wounds such as diabetic ulcers or venous leg ulcers. The above process is proven to treat these conditions effectively as well as a range of other conditions.

If you are suffering from any of the conditions that are proven to be treatable with hyperbaric oxygen therapy then do get in touch with us. All you need is a referral from your GP or specialist and you can then come in for an assessment to start treatment straight away.

A brief history of hyperbaric oxygen therapy

A brief history of hyperbaric oxygen therapy

You may not have heard much about hyperbaric oxygen therapy.  You may even think it’s a newly discovered medicine that is untested and unproven. You would certainly be wrong in thinking this as the science and practice behind what we do at Wesley Hyperbaric has been around for centuries.

Looking back as far as the 1600s we can see that the use of chambers to treat conditions by changing air pressure has been practiced. Back then it was a very new science, but a science none the less. As we have had advances in understanding and technology, we have seen how the use of hyperbaric oxygen therapy has become a go-to treatment for certain conditions.

Let’s take a brief journey through the past to understand where hyperbaric oxygen therapy began and how we arrived at where we are today.


The very first steps in hyperbaric oxygen therapy were taken by a British clergyman and physician called Nathaniel Henshaw. He believed that putting a patient under pressurised conditions would leave to therapeutic benefits to certain conditions of the lungs and even to aid better digestion. He created a chamber, which is called his ‘Domicilium’ and the air pressure was driven with organ bellows. At this point in time, this was very simple – there was only a change in pressure within the chamber and no form of pure oxygen was used, in fact at this time air has not been broken down into its constituent gases. With time and further discovery, this initial invention would improve.

1830’s and 40’s

Despite the work of Robert Boyle who gave us Boyle’s Law in the 1600s. There was still much to be understood about decompression and the effects on the human. Robert Boyle had conducted experiments on small animals to understand the behavior of gasses and how the animals reacted to the changes in pressure. But it wasn’t until the 1840’s that we would be affected by decompression illness when workers such as miners, divers and tunnel construction workers were being affected by air pressure in their working conditions.

Diver’s in Portsmouth, England were affected when working to clear the wreck of HMS Royal George which has sunk in 1787 and now was proving to be a hazard to the ever growing English naval fleet. Royal engineer William Pasley decided to test his new equipment – a hard hat diving bell on this project. Men would work underwater in this diving bells and be subject to pressure changes.

Similarly, during the 1830’s bridge construction workers, miners and tunnellers would use a sealed box filled with compressed air, called a caisson, to work underwater or at great depths. This allowed them to work safely with a supply of air. The workers became known as Caisson workers, or just ‘caissons’.

As the amount of work increased and more and more workers were using these Caissons, there was an increase in reports of illnesses such as dizziness, cramping, sharp pains in the joints and abdomen and even death. The understanding for this was not understood and it became known as mysterious malady. One strange mystery to them was that the symptoms seemed to disappear when the worker returned to the pressurised chamber. Of course, we now see these as classic symptoms of decompression illness or as it’s known to divers today ‘the bends’. The term ‘the bends’ was coined later on in the 1700s when similar workers working on the Brooklyn Bridge in New York were suffering from these symptoms, many workers have lost the ability to stand up straight and were left with a permanent bend to their stature.

It was 1878 when Paul Bert proposed that the caisson workers were affected by the pressure changing too quickly which then led to the illness.

Not too long after this understand recompression chambers were built at these construction project sites to help recompress workers suffering from this illness. Effectively creating what we have today in terms of a chamber created to aid suffering patients.


By 1877 the use of hyperbaric chambers was being used in medicine. A French surgeon called Fontaine developed a portable operating theatre which was within a pressured chamber. He believed that the increase in oxygen in the patient’s blood would help with anesthesia. This allowed for a higher level of oxygen to ensure lower rates of death under anesthesia.


By the start of the twentieth century, the Royal Navy has started to take interest in hyperbaric medicine to create a solution for its divers suffering from the bends.

In 1907 Dr. John Scott Haldane was working on experiments using goats and differing depths and helped develop the first dive table for use by divers. These tables are still used today by Wesley Hyperbaric to help safely treat patients.


During the early 1900s Dr. Orval Cunningham has been working with a patient suffering from cardiovascular disease and made a link between patients who lived at higher altitudes suffering more than patients living at sea level. He believed that putting patients under even greater air pressure differences would have great benefits. He created a chamber a 27-metre chamber and started to successfully treat many conditions.

But in 1921 he took a massive step and constructed the world’s largest chamber – a chamber fit for a king! It was built in Kansas City and was 20 metres in diameter and within it there were five floors, a smoking lounge, dining room, private quarters and the décor of a fine hotel.

With claims as big as the chamber itself he was soon under the spotlight of the authorities. With his unproven claims the authorities shut down the ‘hyperbaric hospital’ and it was demolished and sold off for scrap metal for use in the war effort.


The US military began conducting research about survivable pressures.  Using hyperbaric oxygen to treat navy clearance divers with decompression sickness. The US Navy’s research has itself help develop its own dive tables. As the Royal Navy tables, these are used today for treating certain conditions in hyperbaric chambers.


By the 1960s hyperbaric chambers were being used in mainstream medicine. At Boston Children’s Hospital a chamber acquired from Harvard University was being used by Dr William F Bernhard to treat children suffering from cardiac conditions – this included the prematurely arrived son of John F Kennedy. The hospital undertook surgery on 120 infants using the chamber prior to the invention of the bypass machine.

As the research continued and further advancements were made a governing body was formed to help keep this going ­– in 1967 The Undersea and Hyperbaric Medical Society (UHMS) was founded. To this day they continue to add governance to hyperbaric medicine allowing the safe use of the medicine across the world.

UHMS helped develop a list of clinical indicators that have evidence that hyperbaric oxygen therapy can be used. As this is a wholly researched and proven list Medicare in Australia adopted this list to help patients get access to help from registered and accredited practitioners such as Wesley Hyperbaric.


As the years have gone by, the medical research has not stopped and there is an ever increasing list of conditions that hyperbaric oxygen therapy has been proven to benefit. The 1980’s saw research proving that the therapy has a massive impact on problem wounds and radiation tissue damage. These are some of the conditions that we see the most at Wesley Hyperbaric and we see a lot of success in the treatments.

So that brings us up to date on the medicine. As you have read, from the early days we have seen a lot of problems solved from industry being able to build, advances through military research and of course in the medical industry an ability to treat conditions that would have been life-threatening allowing organisations such as the Wesley Hyperbaric to give people a chance of getting over conditions and regaining their life.

But it doesn’t stop there. The most basic and early understood science such as gas laws still today form the basis for hyperbaric oxygen therapy, but as research continues and technology changes the future the medicine will continue to change and grow. Wesley Hyperbaric is playing a major part in this, conducting its own studies into conditions such as Xerostomia and pelvic irradiation damage, and prove how hyperbaric oxygen therapy can help.

It’s business as usual at Wesley Hyperbaric

At Wesley Hyperbaric no two days are the same. We are constantly welcoming new patients to the unit for treatment in the hyperbaric chamber as well as saying goodbye to patients who have successfully treated their course. But from all the conditions that we treat, what are the most common we see?

We only treat 14 conditions that have research-based evidence that proves that the treatment is beneficial. These conditions are approved by The Undersea and Hyperbaric Medical Society (UHMS) meaning that there is accreditation and proof behind our confidence that we have a solution for our patients.

Our top three conditions

Of the 14 conditions there are some we don’t see very often at all. We do, however, constantly treat certain conditions, and with every dive we undertake we see a constant flow of what we can call our top three treatments:

You can rest assured that we will not promise success for curing conditions that have not been proven to be treatable – you may have been told by other hyperbaric operators that they can offer you that miracle cure, this is unrealistic and you should avoid any businesses that offer you this.

If you or anyone you know is suffering from any of the conditions we treat then we would love to hear from you. All you need to start the process is a referral from your doctor, we can then look at getting your treatment underway. If you have any questions please call one of our friendly team members on 07 3371 6033.

When it comes to hyperbaric oxygen therapy there really is only one choice.

Having a serious medical condition is something that requires your full attention. You should ensure whatever you do, it will deliver the results you are looking for. Medical procedures should be safe, proven to work and be supervised by qualified health care professionals.

Hyperbaric oxygen therapy is one area of medicine that has many options given to you, and sometimes the providers are not always equal. There are many small operators offering mild hyperbaric treatment using portable, inflatable chambers – sometimes they might even offer you the convenience of coming to your home. These are really not true hyperbaric chambers and the benefits of using them are very questionable.

Mild hyperbaric chambers are not able to replicate the same depth as a medical grade chamber. The lack of pressure and the level and quality of the oxygen given will limit the ability to encourage healing and growth of bone and soft tissue. There is also a major concern around safety – most of the mild hyperbaric chambers are operated by non-hyperbaric qualified operators – and the important safety checks and procedures may not be in place due to the small size and inexperience of the operators. But most of all there really is no evidence that these chambers do anything for your condition and you could be wasting your money by choosing them.

For over 20 years Wesley Hyperbaric has been successfully treating patients for a range of conditions. We offer a full medical grade service and product that is accredited and approved by most major health funds – and for certain conditions, Medicare. The fact that conditions are covered by health care funds is an indication that there is sufficient scientific evidence that the treatment works. Our service offers a non-invasive and safe process. All completed under the supervision of our expert and fully qualified technicians, nurses and doctors. And we are located within the Wesley Hospital medical precinct.

The Wesley Hyperbaric offers a completely different, and superior service than those of the small mild hyperbaric chambers. The following table gives a side by side comparison to really highlight to you that when making your decision to choose hyperbaric therapy for your condition there really is only one choice you should make:

Wesley Hyperbaric Mild hyperbaric chamber
Usually Pressurised to 14 metres Only capable of depths of 2.5 metres
100 per cent oxygen Air (21 per cent oxygen 79 per cent nitrogen)
Encourages growth of bone and tissue Does not grow bone and tissue
Accredited through research No research or accreditation
Covered by major health funds and Medicare No cover for treatment
Medical grade treatment Treatment is not proven to work
Highly regulated industry No qualification or license needed
Safety technicians and monitoring of conditions to ensure safety at all times No provision of safety checks or monitoring of situations within the chamber
Arterial oxygen at 2.4 ATA 100% oxygen is 1,824 mmHg (normal air pressure is 157mmHg). This refers to how much oxygen is getting into the body, what is making the changes. Arterial oxygen at 1.3 ATA 24% oxygen is 230 mmHg (normal air pressure is 157mmHg).
Safe in the knowledge that the staff are fully qualified hyperbaric medical professionals Often a single operator, small business owner handling all the procedures and processes.

Why not take the time to read about the full range of conditions we treat at Wesley Hyperbaric. We have some case studies on our website too so you can hear about some successes we have had with our patients.

If you think you might need some more information, then please contact us and we can help you with your decision and get you on the right tracks to making a recovery.



HBOT and Idiopathic Sudden Sensorineural Hearing Loss

Idiopathic Sudden Sensorineural Hearing Loss (ISSHL) is defined as hearing loss of at least 30dB occurring within 3 days over at least three contiguous frequencies.1

The most common clinical presentation involves sudden unilateral hearing loss, tinnitus, aural fullness and vertigo. The incidence is estimated at 8-15 per 10,0000 worldwide.2

There are currently over 100 publications available evaluating the use of hyperbaric oxygen therapy (HBOT) for treatment of ISSHL, including eight randomised control trials and a Cochrane meta-analysis.

On average, HBOT has been shown to impart a 19.3dB gain for moderate hearing loss and 37.7dB gain for severe cases. 3 This improvement brings hearing deficits from the moderate/severe range into the slight/no impairment range, a significant gain that can markedly improve a patient’s quality of life.

There is currently no consensus over the aetiology of ISSHL, with suggested mechanisms including vascular occlusion, ischemia, viral infection, labyrinthine membrane breaks, immune associated disease, abnormal cochlear stress response, trauma, abnormal tissue growth, toxins, ototoxic drugs and cochlear membrane damage. 4

The rationale for the mechanism of action for HBOT in ISSHL is likely due to the high metabolism and vascular paucity of the cochlea. Tissue oxygenation of the cochlear structures occurs via diffusion from cochlear capillary networks into the perilymph and cortilymph.

Perilymph oxygen tension has been shown to decrease significantly with ISSHL. 5 Animal studies have shown that compared to room air, normobaric oxygen increases perilymph PO2 3.4 fold, while HBO2 increases perilymph PO2 9.4 fold. 6 However, only HBO2 has been shown to achieve extremely high arterial perilymphatic oxygen concentration gradients in both animals and humans. Other additional postulated benefits include anti-inflammatory effects, blunting of ischemia reperfusion injury and oedema reduction.

When ISSHL is diagnosed, immediate referral to an ENT surgeon should occur. Oral steroids at 1mg/kg/day is a common initial dose tapering over the course of 2-3 weeks.

HBOT has been shown to be most effective if delivered within 2 weeks of hearing loss, with benefit possible up to 3 months post insult.7,8 Patients with a delay of greater than 14 days, advanced age and vertigo are however associated with poorer outcomes. 8

The Cochrane analysis of HBOT for ISSHL has shown a NNT of 5.3.3

A typical treatment regimen is of 10-15 treatments breathing 100% oxygen at 2.4ATA, during which routine pure tune audiometry is undertaken on a weekly basis to track changes in hearing acuity as a response to the treatment.

There is no medicare item number for treatment of ISSHL at this point in time, but the treatment is covered by Alliance health funds so there is no out of pocket expense for their clients.

Our unit will happily asses any referred patient with ISSHL. We can then discuss options and undertake treatment if required.



1 Haberkamp TJ, Tanyeri HM. Management of idiopathic sudden sensorineural hearing Loss. Am J Otol. 1999 Sep;20:587-592
2 Lionello M, Staffieri C, Breda S, Turato C, Giacomelli L, Magnavita P, de Filippis C, Staffieri A, Marioni G Uni- and multivariate models for investigating potential prognostic factors in idiopathic sudden sensorineural hearing loss. Eur Arch Otorhinolaryngol. 2014 Mar 25.
3 Bennett MH, Kertesz T, Matthias P, Yeung P. Hyperbaric oxygen for idiopathic sensorineural hearing lossand tinnitus. Cochrane Database Sys Rev. 2010 Jan 20;(1): CD004739
4 Alimoglu Y, Inci E, Edizer DT, Ozdeilek A, Aslan M. Efficacy comparison of oral steroid, intratympanic steroid, hyperbaric oxygen and oral steroid and hyperbaric oxygen treatments in idiopathic sudden sensorineural hearing loss cases. Eur Arch otorhinology. 2011 Dec;268(12):1735-1741
5 Nagahara K, fisch U, Yagi n. Perilymph oxygenation in sudden and progressive sensorineural hearing loss. Acta Otolarygol. 1983 Jul-Aug; 96(1-2):57-68
6 Lamm C, Walliser U, Schumann K, Lamm K. Oxygen partial pressure measurements in the perilymph and the scala tympani in normo- and hyperbaric conditions. An animal experiment study. HNO. 1988 Sep;36(9):363-366
7 Marchesi G, Valetti TM, Amer M, Ross M, Tibertu R, Ferani R, Ferani R, Mauro G Di. The HBO effect in sudden hearing loss treatment. UHMS Annular Scientific Meeting Abstracts, 2000.
8 Murphy-Lavoie H, Piper S, Moon RE, LeGros T. Hyperbaric oxygen therapy for idiopathic sudden Sensorineural hearing Loss. Undersea Hyperb Med. 2012;39(3):777-792