Hyperbaric Oxygen denied as experimental or investigational by Aetna?

Aetna's specific coverage criteria for hyperbaric oxygen are defined in its own published medical/coverage policy and the FDA-approved prescribing label. A successful appeal documents that your medical records satisfy each criterion those sources list — confirmed diagnosis, any required prior treatments (with dates and outcomes), and clinical severity. If the exact criteria weren't included with your denial, request them in writing; your appeal then maps each requirement to the matching fact in your chart.

## Why Aetna Denied Hyperbaric Oxygen as "Experimental" — and How to Appeal

Aetna's "experimental or investigational" denial for hyperbaric oxygen therapy (HBOT) means Aetna determined, based on its internal clinical policy, that HBOT lacks sufficient evidence of safety and effectiveness for your specific diagnosis. This is one of the most contested denial categories — and one where external review often favors patients — because HBOT has FDA-cleared indications for a defined list of conditions, and Aetna's coverage policy may be narrower than what FDA clearance and professional societies support.

The critical distinction to establish in your appeal: is the use of HBOT for your diagnosis supported by the FDA's cleared indications and by the applicable specialty guideline organization (such as the Undersea and Hyperbaric Medical Society, UHMS)? If so, Aetna's experimental classification may be inconsistent with the weight of accepted medical evidence.

## Your Federal Appeal Rights

• Internal appeal: ERISA §503 and ACA §2719 require a full-and-fair internal review. File within the timeframe on your denial letter (typically 180 days).
• External review: This denial type is especially strong for external review. An IRO is required to apply an "accepted medical evidence" standard under ACA §2719, not simply defer to Aetna's policy. You generally have four months (180 days) from the final adverse determination to request IRO review.
• Expedited review: Request if the condition is urgent (e.g., active necrotizing infection, threatened limb). Aetna must respond within 72 hours on an expedited internal review.

## Documentation to Gather

1. FDA clearance documentation — identify the specific FDA-cleared indication that covers your diagnosis, from FDA's official labeling or 510(k) clearance records, and attach it to your appeal. 2. UHMS or specialty society position — obtain your prescribing physician's letter referencing the relevant guideline organization (e.g., UHMS Indications for Hyperbaric Oxygen Therapy) and how your diagnosis falls within it. 3. Prescriber medical-necessity letter — a detailed letter explaining the clinical rationale, the mechanism by which HBOT addresses your specific condition, and why the evidence supports its use. 4. Diagnosis and clinical workup — chart notes, imaging, labs, or specialist assessments that confirm the diagnosis and severity. 5. Aetna's clinical policy — request the exact version of Aetna's HBOT clinical policy used in the denial to identify where your case may have been miscategorized.

## Criteria-Mapping Structure

Build your appeal around the specific indication Aetna classified as experimental. For each criterion in Aetna's policy, provide the corresponding evidence: FDA clearance for your indication, UHMS guideline support, and physician documentation. Frame the rebuttal as: "Aetna policy states [X] is experimental — Response: FDA cleared HBOT for [indication] as documented in [attachment]; UHMS guidance supports this use as referenced in prescriber letter dated [date]."