Oxygen & Hyperbaric - Clinical uses
Recognised medical indications for HBOT
Last updated 30 September 2026. How we write this .
A recognised indication is a specific condition experts accept HBOT for. European experts accept about 30 in three tiers, NHS England funds two, and none rests on the highest grade of evidence.
Start here A recognised indication is a specific condition experts accept HBOT for. European experts accept about 30 in three tiers, NHS England funds two, and none rests on the highest grade of evidence.
By the end, you will understand Who decides what counts? Why do the most accepted uses have no trials? Why is carbon monoxide still argued over? Key words used in this lesson Double-blind Neither the participants nor the researchers assessing them know who received which intervention. This guards against expectation shaping both how people feel and how outcomes get recorded. Hyperbaric Above normal atmospheric pressure. Hyperbaric oxygen therapy involves breathing oxygen in a pressurised chamber, which increases the amount dissolved in the blood. Full plain-English glossary
Where this information comes from Claim-cited evidence. Central research claims on this lesson are linked to specific studies or official guidance.
This lesson links the specific studies and guidance used for its central claims.
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A recognised indication is a specific medical condition for which an expert body or a health service accepts hyperbaric oxygen therapy (HBOT) as a reasonable treatment. Which conditions count depends on who you ask. Europe's specialist committee accepts around 30, in three tiers of confidence. NHS England pays for just two. And not one condition on the European list is backed by the top grade of trial evidence.
Who decides what counts?
Three kinds of organisation make these calls, and they ask different questions. Specialist societies, such as the Undersea and Hyperbaric Medical Society in the US and the European Committee for Hyperbaric Medicine (ECHM), ask whether the evidence and expert experience support using HBOT. Guideline bodies such as NICE ask whether a treatment is clinically and cost effective. Funders such as NHS England decide what they will actually pay for. A condition can be accepted by one and rejected by another.
The ECHM's most recent full review was its tenth consensus conference, held in April 2016 and published by Daniel Mathieu, Alessandro Marroni and Jacek Kot in 2017. Experts graded the research using GRADE, a standard system for rating evidence, then voted on each recommendation. Type 1 means strongly recommended, Type 2 means suggested, and Type 3 means optional. No condition reached Level A, the grade given when there are enough randomised trials.
Nine conditions made Type 1: carbon monoxide poisoning, open fractures with crush injury, jaw bone damage from radiotherapy and its prevention after dental extraction, radiation damage to the bladder or rectum, decompression illness, gas embolism, certain severe bacterial infections, and sudden deafness. Type 2 includes diabetic foot lesions, failing skin grafts and chronic bone infection. Brain injury appears only in Type 3, and only in highly selected patients.
For the first time, the conference also said where HBOT should not be used. It gave Type 1 recommendations against treating autism, multiple sclerosis, cerebral palsy, tinnitus, placental insufficiency and the acute phase of stroke.
Why do the most accepted uses have no trials?
Decompression illness and gas embolism sit at the top of every list, yet the ECHM rated the evidence for them only Level C: conditions where proper randomised trials are not possible, but international expert agreement is wide. A 2012 Cochrane review led by Bennett put it bluntly. Recompression is the standard treatment, but there is no randomised trial evidence for its use.
The reason is ethical rather than scientific. Nobody will randomly assign a paralysed diver to no treatment. The only two trials the review found, with 268 patients between them, compared additions to recompression. Adding an anti-inflammatory drug, tenoxicam, cut the number of chamber sessions needed from three to two, and a helium and oxygen mix also reduced repeat sessions. Neither improved the chance of recovery. The case for recompression rests on physics and decades of clinical experience instead.
Why is carbon monoxide still argued over?
Carbon monoxide poisoning is a Type 1 indication in Europe, yet NHS England does not routinely fund HBOT for it. The trials explain the split. A 2011 Cochrane review led by Buckley found six usable trials with 1,361 participants. Two found fewer neurological problems at one month with HBOT, and four did not. Pooled together, they showed no significant benefit.
The reviewers found flaws in every trial. Both positive trials were stopped early because they appeared to show benefit, which tends to exaggerate an effect. The negative trials were weak too: some excluded the most severely poisoned patients, and one lost many people to follow-up.
One negative trial stands out. At the Alfred Hospital in Melbourne, Scheinkestel's team compared hyperbaric with normal-pressure oxygen in a double-blind design, using sham chamber sessions so patients did not know which they had. Both groups received high-dose oxygen. The hyperbaric group needed extra treatments more often, 28% against 15%, and did worse on a learning test at the end of treatment. Delayed neurological problems appeared only in the hyperbaric group. The authors said they could not recommend HBOT for carbon monoxide poisoning.
Can a recognised use be overturned?
Yes, and radiotherapy damage shows how. Months or years after radiotherapy, some tissues heal poorly. A 2023 Cochrane review led by Lin pooled 18 studies with 1,071 participants. HBOT may help resolve this late radiation injury in the head, neck, bladder and rectum, and may sharply reduce wounds breaking open after head and neck surgery. The reviewers rated most of this evidence low certainty.
Then came HOPON, a UK trial run through the Cancer Research UK Liverpool trials unit. It randomised 144 people who needed teeth removed or implants fitted in a jaw previously treated with high-dose radiotherapy. Six months later, jaw bone damage had developed in 6.4% of the HBOT group and 5.7% of those without it. Earlier trials had reported rates of 14% to 30% without HBOT. The authors wrote that their findings challenge a long-established standard of care. The ECHM had made this a Type 1 indication in 2016, three years before HOPON was published.
Sudden deafness, another Type 1 use, is less clear-cut. A 2012 Cochrane review found seven small trials with 392 participants, generally of poor quality. In sudden hearing loss of recent onset, HBOT improved hearing, roughly one extra good result for every five people treated, but the reviewers said the clinical significance was unclear. They found no benefit for long-standing hearing loss or tinnitus.
What does this mean in the UK?
NHS England runs HBOT as a national service rather than handing it to local health boards. In 2023/24 it paid £8.2 million a year to seven independent providers running eight centres, mostly near the coast. In a September 2024 consultation it proposed cutting to six centres, while keeping every part of England within four hours by road. That fits Health and Safety Executive guidance that treatment for decompression illness should ideally start within six hours of symptoms. Every centre must be able to care for critically ill patients, including during treatment.
Diabetic foot ulcers show the split between bodies most clearly. The ECHM suggests HBOT for diabetic foot lesions. NICE's diabetic foot guideline says not to offer it to treat diabetic foot ulcers, except as part of a clinical trial.
Where does that leave the evidence? Agreement is strongest where the physics is clearest and trials are impossible, as with bubbles in the blood. Where trials can be done, the results are mixed, and some long-standing uses have not held up. Any list of indications is a snapshot that can lag years behind the latest trial.
If anyone becomes unwell after a sea dive, British Sub-Aqua Club advice is to dial 999 or call the Coastguard. If you think you have been exposed to carbon monoxide, get into fresh air and call NHS 111, or 999 if someone is struggling to breathe, confused or unconscious.
This lesson is general education about how hyperbaric indications are decided, not medical advice. Whether HBOT is right for any condition is a decision for an NHS or specialist hyperbaric doctor.
Related in this classroom The studies behind this page Tenth European Consensus Conference on Hyperbaric Medicine: recommendations for accepted and non-accepted clinical indications and practice of hyperbaric oxygen treatment - Diving and Hyperbaric Medicine, 2017Recompression and adjunctive therapy for decompression illness - Cochrane Database of Systematic Reviews, 2012Hyperbaric oxygen for carbon monoxide poisoning - Cochrane Database of Systematic Reviews, 2011Hyperbaric or normobaric oxygen for acute carbon monoxide poisoning: a randomised controlled clinical trial - Medical Journal of Australia, 1999Hyperbaric oxygen therapy for late radiation tissue injury - Cochrane Database of Systematic Reviews, 2023HOPON (Hyperbaric Oxygen for the Prevention of Osteoradionecrosis): a randomized controlled trial of hyperbaric oxygen to prevent osteoradionecrosis of the irradiated mandible after dentoalveolar surgery - International Journal of Radiation Oncology, Biology, Physics, 2019Hyperbaric oxygen for idiopathic sudden sensorineural hearing loss and tinnitus - Cochrane Database of Systematic Reviews, 2012Reviewing hyperbaric oxygen services: consultation guide - NHS England, 2024Sources for this classroom
Educational content only. Not medical advice, diagnosis or treatment. Always consult a qualified healthcare professional before changing your health regimen.