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TL;DR: The Undersea and Hyperbaric Medical Society (UHMS) Hyperbaric Medicine Indications Manual, 15th Edition, lists 15 indications with sufficient evidence to support hyperbaric oxygen therapy as a primary or adjunctive treatment. Canadian referring physicians should match the clinical scenario to a recognised indication, document the rationale, choose the correct urgency tier, and send the referral to the nearest accredited hyperbaric unit. This guide walks through the indications list, the referral steps, and the documentation a Canadian hyperbaric facility expects to receive.
Hyperbaric oxygen therapy is a medical treatment that delivers 100 percent oxygen at pressures above one atmosphere inside a sealed chamber, raising dissolved plasma oxygen to therapeutic levels. The UHMS recognised indications list is the reference standard that Canadian hospital-based hyperbaric units, third-party insurers, and accreditation bodies use when deciding whether a case is appropriate for this treatment. The 15th Edition of the Hyperbaric Medicine Indications Manual, published in 2023 and reprinted in Undersea & Hyperbaric Medicine across 2024, is the current authoritative source (Weaver, 2024, PMID 39348519). For referring physicians, using this list correctly is the difference between a smooth referral and a case that gets declined at triage.
The UHMS recognised indications are the clinical conditions that the society has reviewed and endorsed based on published evidence and clinical experience. They are not the same as Health Canada’s chamber licensing scope, and they are not the same as provincial insurance coverage lists, but they are the clinical backbone that Canadian hyperbaric medicine programs use when accepting referrals. This guide explains the 2026 list and walks through a step-by-step referral workflow for Canadian physicians.
What are the UHMS recognised indications for hyperbaric oxygen therapy in 2026?
The UHMS indications list, as published in the 15th Edition manual and in successive reprint articles in Undersea & Hyperbaric Medicine, covers the following conditions. Canadian referring physicians can consider these as the accepted clinical scope of hyperbaric oxygen therapy for 2026.
| Indication | Urgency | Typical session count |
|---|---|---|
| Air or gas embolism | Emergent | 1 to 5 |
| Carbon monoxide poisoning (including with cyanide co-exposure) | Emergent | 1 to 3 |
| Decompression sickness | Emergent | 1 to 5 |
| Clostridial myositis and myonecrosis (gas gangrene) | Emergent | 5 to 10 |
| Necrotizing soft tissue infections | Emergent | 5 to 15 |
| Crush injury and acute traumatic ischaemia | Emergent | 6 to 12 |
| Central retinal artery occlusion | Emergent | Variable protocol |
| Intracranial abscess | Emergent to urgent | 10 to 20 |
| Severe anaemia (when transfusion is not an option) | Urgent | Variable |
| Acute thermal burn injury | Urgent | 20 to 30 |
| Compromised grafts and flaps | Urgent | 20 to 30 |
| Sudden sensorineural hearing loss (idiopathic) | Urgent (within 14 days) | 10 to 20 |
| Diabetic foot ulcers and selected problem wounds | Elective | 30 to 40 |
| Delayed radiation injury (soft tissue and bone) | Elective | 30 to 40 |
| Osteomyelitis (refractory) | Elective | 20 to 40 |
| Avascular necrosis (aseptic osteonecrosis) | Elective | Variable protocol |
Avascular necrosis and refractory osteomyelitis also appear in the full manual with conditional and adjunctive status. Canadian hyperbaric units may accept these cases after multidisciplinary review. Practical session counts are a guide; the treating hyperbaric physician adjusts protocols based on response and published evidence.
How is the UHMS indications manual structured and updated?
The UHMS Hyperbaric Oxygen Therapy Committee reviews each indication on a cyclical basis. Each chapter in the manual summarises the evidence base, the suggested protocol, the contraindications, and the expected outcomes. The 15th Edition was the first comprehensive update in several years and introduced a dosing chapter that standardises how Canadian and American units describe pressure and session length. Selected chapters have been reprinted in peer-reviewed form so that referring physicians can access them through PubMed without purchasing the manual.
Notable recent reprints include Weaver’s 2024 chapter on carbon monoxide poisoning (PMID 39348519) and Tomoye and colleagues’ 2024 chapter on intracranial abscess (PMID 39821772). Both sit firmly in the emergent tier and both require rapid communication between the referring team and the nearest hyperbaric unit. Canadian physicians who want the full evidence base should pull these reprints before sending a referral.
Which UHMS indications are most relevant for Canadian referring physicians?
Canadian referral volume is weighted toward a subset of the full list. The most common referrals to Canadian hospital-based hyperbaric programs are:
- Diabetic foot ulcers meeting Wagner grade 3 or higher, with adequate perfusion and a failed 30-day course of standard care. The 2023 International Working Group on the Diabetic Foot (IWGDF) update supports the use of hyperbaric oxygen as a conditional recommendation when best standard of care has not achieved healing (Chen et al., 2023, DOI 10.1002/dmrr.3644).
- Delayed radiation injury after pelvic, head and neck, or breast radiotherapy, especially cystitis, proctitis, osteoradionecrosis of the jaw, and soft tissue necrosis.
- Carbon monoxide poisoning after accidental exposure, with loss of consciousness, neurological findings, or ischaemic cardiac changes as standard triggers for referral.
- Idiopathic sudden sensorineural hearing loss within 14 days of onset, where early referral improves the probability of meaningful audiometric recovery.
- Necrotizing soft tissue infections as a post-operative adjunct following surgical debridement.
Decompression sickness and arterial gas embolism are less common in the inland Canadian population but remain emergent indications for coastal and dive-adjacent regions. Canada Hyperbarics maintains a list of hospitals and regulated facilities that accept emergent cases, and physicians should keep that list accessible.
What is the step-by-step referral process for a UHMS-recognised indication?
The referral workflow for a Canadian physician is consistent across indications, with small variations based on urgency tier. Follow these steps.
Step 1: Confirm the indication matches the UHMS list
Match the clinical presentation to one of the 15 primary indications. If the condition is not on the list, the referral will almost always be declined at triage unless a local multidisciplinary process has approved an off-list indication. Document the specific sub-indication in the referral note, for example “radiation cystitis, grade 3, post-prostate XRT” rather than “radiation injury.”
Step 2: Screen for absolute contraindications
Untreated pneumothorax is the one absolute contraindication recognised across all UHMS chapters. Relative contraindications include severe chronic obstructive pulmonary disease with bullae, active chemotherapy with bleomycin, uncontrolled seizure disorder, and claustrophobia that has not responded to preparation. Document your screening in the referral. A hyperbaric unit will screen again, but an early note saves time.
Step 3: Establish urgency tier
Assign one of three urgency tiers using the table above. Emergent cases need phone contact with the on-call hyperbaric physician, not a faxed referral. Urgent cases need same-week contact. Elective cases can go through the standard referral pathway.
Step 4: Assemble the clinical package
Standard documentation includes recent imaging, recent laboratory values, the treatment course that has already been attempted, current medication list, and any recent specialist reports. For diabetic foot referrals, include a transcutaneous oxygen measurement if available, HbA1c, and documentation of revascularisation status. For radiation injury referrals, include the radiotherapy plan or dose summary when obtainable.
Step 5: Contact the nearest accredited hyperbaric facility
Use the current provincial hospital directory or the Canada Hyperbarics facilities page to identify the nearest unit. Emergent referrals go by phone to the on-call number. Elective referrals go through the unit’s standard intake process. Most Canadian hospital-based hyperbaric programs accept referrals from any licensed Canadian physician, but some require the referring physician to be in the same province or health region.
Step 6: Brief the patient
Patients need to understand what a consultation involves, how many sessions a course typically includes, what the treatment feels like, and what out-of-pocket costs may apply depending on the indication and the province. Canada Hyperbarics maintains a patient-facing explainer at the conditions page that covers the common indications in plain language.
When should you refer urgently versus electively?
Triage errors are the most common reason a referral is delayed. The following rules of thumb help.
- Emergent: Any suspected air or gas embolism, any decompression sickness, any necrotizing soft tissue infection, any acute central retinal artery occlusion, and any carbon monoxide poisoning with neurological findings or a carboxyhaemoglobin level above 25 percent. Phone the on-call hyperbaric physician directly.
- Urgent: Idiopathic sudden sensorineural hearing loss within 14 days, compromised grafts or flaps within 48 hours of surgical concern, and acute thermal burn injury within 24 hours of admission. Same-week contact.
- Elective: Diabetic foot ulcers, delayed radiation injury, refractory osteomyelitis. Standard intake, usually a 1 to 4 week wait depending on the province and facility.
The central retinal artery occlusion evidence base highlights why emergent referral matters. An Australian and New Zealand survey published in Diving and Hyperbaric Medicine in 2024 found wide variability in how CRAO was treated across units, and argued for protocols that shorten the window from symptom onset to the first hyperbaric session (Emmerton et al., 2024, DOI 10.28920/dhm54.2.97-104). The Canadian lesson: phone, do not fax, for any emergent referral.
How do Canadian provincial pathways differ for UHMS-recognised indications?
The UHMS list is national in scope but Canadian access depends on which provincial health plan applies. Key differences:
- Ontario (OHIP): Hyperbaric oxygen therapy for UHMS indications is typically covered when delivered at a hospital-based program. Elective referrals go through the hospital intake process.
- British Columbia (MSP): Coverage follows the hospital-based model, with Vancouver General Hospital and smaller regional units providing the primary service points.
- Alberta (AHCIP): Coverage is provided at the Misericordia Community Hospital hyperbaric unit in Edmonton and Foothills Medical Centre in Calgary.
- Quebec (RAMQ): Coverage includes the CIUSSS and CHU hyperbaric programs for UHMS indications.
- Atlantic provinces: Nova Scotia (MSI) covers services at QEII Halifax; New Brunswick (Medicare NB), Prince Edward Island (PEI Health), and Newfoundland and Labrador (MCP) often rely on interprovincial referrals.
- Territories: No local hyperbaric units. Referrals go south, usually to Edmonton or Vancouver.
Provincial coverage matches the UHMS list for emergent indications, but elective indications such as delayed radiation injury and diabetic foot ulcers may have longer waiting periods. When the waiting period is clinically unacceptable, patients may choose to travel to a private facility at their own expense. Canadian physicians should discuss both options with the patient.
What documentation should accompany your HBOT referral?
Use the following documentation checklist for every referral, adapted from standard intake templates used by Canadian hospital-based hyperbaric programs.
- Referring physician name, licence number, province, and contact method
- Patient demographics, provincial health plan number, and emergency contact
- Specific UHMS indication matched to the case
- Urgency tier and clinical rationale
- Pertinent history, exam findings, and timeline
- Imaging reports and relevant laboratory values from the last 30 days
- Medication list and allergies
- Contraindication screen results
- Prior treatments attempted, with dates and outcomes
- Most recent specialist notes where available
- Expected session count based on the UHMS chapter, with flexibility for the hyperbaric physician to adjust
Canadian hyperbaric programs publish their intake forms on their hospital websites. Using the program’s form speeds triage. When time does not allow, a dictated letter covering the items above is acceptable, especially for emergent cases.
Frequently asked questions about referring for UHMS-recognised HBOT
Do I need to be a specialist to refer a patient for HBOT in Canada?
No. Any licensed Canadian physician can refer. Family physicians, emergency physicians, internists, and surgical specialists all refer regularly. Some programs ask for a specialist opinion before accepting elective referrals, particularly for delayed radiation injury.
Can I refer a patient for an indication that is not on the UHMS list?
Off-list referrals are sometimes accepted at private facilities or through research protocols, but provincial coverage rarely applies. The safest path is to match the case to a recognised indication first. If the evidence is emerging, discuss the patient with the hyperbaric physician by phone before formalising the referral.
What if my province does not have a hospital-based hyperbaric unit?
Interprovincial referral is the standard pathway. Atlantic Canada and the territories routinely send patients to hospital units in Nova Scotia, Quebec, Ontario, Alberta, or British Columbia. The referring province’s health plan usually covers the treatment cost under reciprocal billing, though travel and accommodation are typically not covered.
How quickly can a UHMS-recognised emergent referral start treatment?
Emergent referrals for air or gas embolism and decompression sickness can begin within hours of arrival at a hyperbaric facility. Carbon monoxide poisoning referrals typically begin within the first 6 hours of presentation. The limiting step is almost always transport time to the nearest operational chamber.
Is informed consent required before referral?
Formal informed consent for the hyperbaric procedure is obtained by the hyperbaric physician on first visit. Referring physicians should explain the general rationale and the expected visit flow, then document that the patient understands the referral destination and its purpose.
Are the UHMS indications the same as the Health Canada approval scope?
Not exactly. Health Canada licenses specific chamber models as medical devices and sets the regulatory envelope within which clinics operate. The UHMS indications list is a clinical reference for when hyperbaric oxygen is appropriate. Most Canadian hospital-based programs treat the UHMS list as the working clinical scope while remaining compliant with Health Canada device regulations.
Where can I find the full UHMS Hyperbaric Medicine Indications Manual?
The 15th Edition is available from Best Publishing Company. Individual chapters have been reprinted in Undersea & Hyperbaric Medicine over 2024 and 2025. The UHMS website at uhms.org lists the current indications and links to the clinical practice guidelines.
Next steps for Canadian referring physicians
Bookmark the UHMS indications list. Keep the contact numbers for your nearest two accredited hyperbaric programs in your referral system. Review the 15th Edition chapters most relevant to your practice area. And when a case arrives, match, screen, triage, document, and phone or fax.
Canada Hyperbarics maintains a national directory of hospitals and regulated facilities that accept UHMS-indicated referrals. The research library holds the full PubMed citations for each indication, and the FAQ covers common patient questions. Referring physicians can also consult the conditions page for plain-language explanations to share with patients before a consultation.
Medical disclaimer: This content is for informational purposes only and does not constitute medical advice. Clinical decisions about hyperbaric oxygen therapy should be made by qualified physicians in consultation with certified hyperbaric medicine specialists. Always refer to the current UHMS Hyperbaric Medicine Indications Manual and applicable provincial practice standards when making referral decisions.
References
- Weaver LK. Carbon Monoxide Poisoning (Reprinted from the 2023 Hyperbaric Indications Manual 15th Edition). Undersea Hyperb Med. 2024;51(3):253-276. PMID 39348519.
- Tomoye EO, Park CL, Folke L, Moon RE. Intracranial Abscess (Reprinted from the 2023 Hyperbaric Indications Manual 15th Edition). Undersea Hyperb Med. 2024;51(4):449-455. PMID 39821772.
- Emmerton W, Banham ND, Gawthrope IC. Survey comparing the treatment of central retinal artery occlusion with hyperbaric oxygen in Australia and New Zealand with the recommended guidelines as outlined by the Undersea and Hyperbaric Medical Society. Diving Hyperb Med. 2024;54(2):97-104. DOI 10.28920/dhm54.2.97-104.
- Chen P, Vilorio NC, Dhatariya K, et al. Guidelines on interventions to enhance healing of foot ulcers in people with diabetes (IWGDF 2023 update). Diabetes Metab Res Rev. 2024;40(3):e3644. DOI 10.1002/dmrr.3644.