Hyperbaric Oxygen Therapy (HBOT) — CPB 0172 | AETNA Coverage Update

Aetna modified CPB 0172 for hyperbaric oxygen therapy (HBOT), effective October 15, 2025. Here's what billing teams need to do.

Aetna, a CVS Health company, updated its HBOT coverage policy under CPB 0172 Aetna system, expanding the list of medically necessary indications while adding specific documentation thresholds that can end coverage mid-treatment. The primary billing codes affected are CPT 99183 (physician supervision per session) and HCPCS G0277 (full body chamber, per 30-minute interval). If your team bills HBOT for Aetna members, this coverage policy changes your documentation game — not just your code set.

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Quick-Reference Table

Field	Detail Copy
Payer	Aetna, a CVS Health company
Policy	Hyperbaric Oxygen Therapy (HBOT) — CPB 0172
Policy Code	CPB 0172
Change Type	Modified
Effective Date	October 15, 2025
Impact Level	High
Specialties Affected	Wound care, orthopedic surgery, plastic surgery, infectious disease, ophthalmology, emergency medicine, vascular surgery
Key Action	Audit documentation protocols for every active HBOT patient before October 15, 2025, and confirm session counts align with per-indication limits

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Aetna Hyperbaric Oxygen Therapy Coverage Criteria and Medical Necessity Requirements 2025

The Aetna HBOT coverage policy under CPB 0172 ties medical necessity tightly to specific conditions, session counts, and documentation checkpoints. This is not a policy where clinical judgment alone carries the claim. Each covered indication comes with its own session limit, and Aetna will apply those limits during review.

Aetna covers systemic HBOT — billed as CPT 99183 and HCPCS G0277 — for the following conditions, each with a defined treatment ceiling:

Central retinal artery occlusion (CRAO): Twice daily to clinical plateau, typically less than one week; up to 10 days total

Chronic refractory osteomyelitis, Stage 3 or 4: Must be confirmed by X-ray, MRI, or bone culture. Patient must have failed a six-week course of parenteral antibiotics (or appropriate oral alternatives) and at least one surgical debridement attempt, unless contraindicated. Up to 40 sessions

Compartment syndrome: Twice daily for two to seven days

Compromised skin grafts and flaps (where hypoxia or decreased perfusion has compromised viability acutely): Photo documentation with ruler required

That osteomyelitis requirement deserves attention. Aetna added an explicit note: chronic refractory osteomyelitis can occur without an open wound, and HBOT is still a covered option in those cases. If your team has been declining to submit HBOT claims for osteomyelitis patients without wounds, revisit those cases before October 15, 2025.

For osteomyelitis cases with wounds, Aetna requires photographic documentation with a ruler after every 15 treatments and at minimum every 30 days during HBOT. Miss that window and you're exposed on prior authorization disputes and claim denial. Continued HBOT is not considered medically necessary if measurable healing has not occurred within any 30-day treatment period.

Prior authorization requirements are not explicitly outlined within the CPB 0172 summary, but given the session-specific limits and documentation triggers built into this policy, treat every Aetna HBOT case as prior auth-sensitive. Confirm requirements with Aetna directly for each plan type — commercial and Medicare Advantage plans may differ.

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Aetna Hyperbaric Oxygen Therapy Exclusions and Non-Covered Indications

Two HCPCS codes land on the non-covered list under this coverage policy: A4575 (topical hyperbaric oxygen chamber, disposable) and E0446 (topical oxygen delivery system). Aetna does not cover topical HBOT for any indication listed in CPB 0172.

This is a meaningful distinction. Systemic HBOT — the full-body pressurized chamber billed under G0277 — is what the covered criteria apply to. Topical oxygen devices are categorically excluded. If your wound care program bills A4575 or E0446 for Aetna members, those claims will not survive review under this policy. Stop submitting them or document a payer-specific appeal rationale before doing so.

Splitting skin grafts or artificial skin substitutes for maintenance — rather than acute compromise — are also not covered under the compromised skin grafts indication. Aetna draws a hard line between acute viability threats and ongoing maintenance.

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Coverage Indications at a Glance

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Aetna Hyperbaric Oxygen Therapy Billing Guidelines and Action Items 2025

The real issue with this update is documentation. The session limits were always there in some form, but the October 15, 2025 version codifies mid-treatment documentation checkpoints that can terminate reimbursement if your team misses them. Here's what to do now.

Copy Action Items

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CPT, HCPCS, and ICD-10 Codes for Hyperbaric Oxygen Therapy Under CPB 0172

Covered CPT and HCPCS Codes (When Selection Criteria Are Met)

Code	Type	Description Copy
99183	CPT	Physician attendance and supervision of hyperbaric oxygen therapy, per session
G0277	HCPCS	Hyperbaric oxygen under pressure, full body chamber, per 30-minute interval

Not Covered HCPCS Codes

Code	Type	Description	Reason Copy
A4575	HCPCS	Topical hyperbaric oxygen chamber, disposable	Not covered for any indication listed in CPB 0172
E0446	HCPCS	Topical oxygen delivery system, not otherwise specified, includes all supplies and accessories	Not covered for any indication listed in CPB 0172

Other CPT Codes Related to CPB 0172 (Supporting Documentation / Workup)

These codes appear in the policy as related codes — used for diagnostic workup and staging that supports HBOT medical necessity. They are not HBOT billing codes, but your claims may reference these for documentation of required imaging, cultures, or vascular studies.

Mastectomy (Breast Reconstruction Context)

Spine Imaging

Pelvis and Hip Imaging

Microbiology / Bone Culture

Vascular Studies

Code	Type	Description Copy
93922	CPT	Limited bilateral noninvasive physiologic studies of upper or lower extremity arteries
93923	CPT	Complete bilateral noninvasive physiologic studies of upper or lower extremity arteries, 3 or more levels

Other HCPCS Codes Related to CPB 0172

These antibiotic and chemotherapy codes appear in the policy as related codes — primarily relevant to the osteomyelitis criteria (antibiotic failure requirement) and oncologic HBOT indications.

Key ICD-10-CM Diagnosis Codes

The full policy references 758 ICD-10-CM codes. The two explicitly provided in the policy data are:

Code	Description Copy
A02.21	Salmonella meningitis
A04.71	Enterocolitis due to Clostridium difficile
A04.72	Enterocolitis due to Clostridium difficile

The complete ICD-10-CM code list for CPB 0172 spans 758 codes across infectious, musculoskeletal, vascular, and oncologic categories. Pull the full list from the policy source to map your ICD-10 codes against covered indications before the October 15, 2025 effective date.

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