Hyperbaric Oxygen for UHMS-Approved Indications: Wound Healing, CO Poisoning, and Decompression Sickness

What is established

Hyperbaric oxygen therapy (HBOT) means breathing oxygen at a pressure greater than sea-level atmospheric pressure inside a sealed chamber. The physiology is well understood: increased pressure dissolves far more oxygen into blood plasma than normal breathing does, raising tissue oxygen delivery even where blood flow is impaired. As a procedure, HBOT is established medicine with decades of use in hospital and specialist settings.[4]

The Undersea and Hyperbaric Medical Society (UHMS) maintains the reference list of indications for which HBOT is considered standard of care and typically reimbursed. The 2024 edition lists roughly fifteen approved indications, most recently adding avascular necrosis. This list matters because it draws a hard line: HBOT being an established procedure does not mean every proposed use of it is established. Each indication on the list earned its place through its own body of evidence, graded separately.[4]

What the evidence shows for diabetic foot ulcers and chronic wounds

The Cochrane systematic review of HBOT for chronic wounds pooled twelve randomized trials and found that HBOT improved the proportion of diabetic foot ulcers healed in the short term, and the evidence suggested a possible reduction in major amputation. That is a meaningful clinical signal for a patient population where amputation is the outcome everyone is trying to avoid.[2]

A more recent meta-analysis of fourteen controlled trials covering 768 patients reinforced this, finding significantly higher rates of complete ulcer healing and a meaningfully lower rate of major amputation with adjunct HBOT compared with standard wound care alone. The same analysis found adverse events were significantly more common in the HBOT group than in controls, which is the trade-off that has to be weighed alongside the benefit rather than ignored.[3]

Both reviews are honest about their limits. The Cochrane authors found no clear benefit on longer-term healing once follow-up extended well past the treatment course, and most included trials were small with some risk of bias. The 2021 meta-analysis noted that only six of its fourteen included studies had performed a formal sample-size calculation up front, and heterogeneity between trials was substantial. This is real evidence, not proof beyond doubt, and it supports a defined, monitored use rather than a blanket claim that HBOT heals wounds.[2][3]

What the evidence shows for acute carbon monoxide poisoning

The most cited trial in this indication is a double-blind randomized controlled trial in which patients with acute CO poisoning received either three hyperbaric oxygen sessions within 24 hours or an equivalent course of normobaric oxygen. Patients treated with HBOT had fewer cognitive sequelae at six weeks and the benefit persisted at twelve months.[1]

This trial is well designed by the standards of a genuinely difficult field to study (patients present as emergencies, informed consent windows are short, and blinding a pressurized chamber is hard) but it is a single-center result, and the treatment intensity was not perfectly matched between the two study arms, which drew methodological criticism at the time and afterward. Other randomized trials of HBOT in acute CO poisoning have not produced fully consistent results, and there is genuine, ongoing disagreement in the specialty literature about how strong this evidence really is even though CO poisoning remains on the UHMS approved list.[1]

The trap: one approved list, evidence of very different strength

The UHMS list is a consensus indications manual, not a ranked evidence table. Sitting on the same list does not mean two indications have comparably strong trial support. Diabetic foot ulcers have multiple randomized trials and two independent systematic reviews behind them. Acute CO poisoning has a smaller and more contested trial base, resting heavily on one frequently criticized study. Both are legitimately "approved," but a patient or clinician reading "UHMS-approved" as a single quality signal is missing the more important question, which is what the underlying trials for that specific indication actually show.[4][1]

What remains uncertain

For chronic wounds, the honest gap is durability: short-term healing improves, but the Cochrane review found no clear advantage once follow-up extended further out, and amputation reduction, while promising, is not established with the same certainty as short-term healing. HBOT also comes with a measurably higher adverse-event rate than standard wound care, which has to be part of any patient conversation, not a footnote.[2][3]

For CO poisoning, the field has not settled the question the way the wound-healing literature has. The pivotal trial supporting HBOT is one strong study, not a consistent multi-trial signal, and it is reasonable for a treating physician to weigh that when deciding urgency and course length in an individual emergency, rather than treating the UHMS listing as settling the clinical evidence question by itself.[1][4]

What this means for you

AION offers hyperbaric oxygen only within the boundaries this evidence actually supports, and only after a physician has confirmed the diagnosis it is being offered for. A non-healing diabetic foot ulcer or a documented acute CO exposure is a defined clinical situation with its own workup, not a reason to add HBOT to a general wellness plan.[2][1]

There is no fixed HBOT protocol applied to everyone. Session number, pressure, and duration are decisions your physician makes against the specific indication, your wound status or exposure severity, and ongoing monitoring, because the adverse-event profile documented in the wound-healing trials is real and needs active management, not just disclosure.[3]

If you or a referring physician raise HBOT for a use outside this approved list, that becomes its own separate evidence question with its own review, the same way wound healing and CO poisoning are treated here as two separate bodies of evidence rather than one blanket approval.[4]