ModifiedUnitedHealthcarePolicy OUTPATIENT 051.5

Hyperbaric Oxygen Therapy and Topical Oxygen Therapy

Defines UnitedHealthcare coverage stance and medical necessity criteria for hyperbaric oxygen therapy (HBOT), mild HBOT (mHBOT), and topical oxygen therapy (TOT) for various indications; applies to providers submitting claims and requesting authorization under this policy.

Policy Summary

PayerUnitedHealthcare

PolicyHyperbaric Oxygen Therapy and Topical Oxygen Therapy

Policy CodePolicy OUTPATIENT 051.5

Change TypeMaterial revision — coverage and definitions updated (mHBOT designated not medically necessary)

Effective DateJul 1, 2025

Next Review Date

Key ActionObtain prior authorization documenting indication, timing, and planned HBOT course to support medical necessity.

SourceLink

POLICY UPDATE CHANGES

Added language to indicate Mild Hyperbaric Oxygen Therapy (mHBOT) is unproven and not medically necessary for any indication due to insufficient evidence of efficacy; this device does not meet the definition of HBOT.

Replaced language about HMOT being unproven for all other indications with wording that HBOT is unproven and not medically necessary due to insufficient evidence for indications not listed as medically necessary.

Added definition of 'Mild Hyperbaric Oxygen Therapy (mHBOT)' and updated supporting information, description of services, clinical evidence, FDA, and references sections.

16+listed medically necessary HBOT indications

>=1.4 ATAminimum pressure to meet HBOT definition

mHBOT not coveredmHBOT status

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TOT not coveredTOT status for wounds

Codes listedcodes provided

Coverage Criteria for HBOT, mHBOT, and TOT

Coverage stance and supporting evidence

Coverage stance and supporting evidence — summary of policy position mapped to guideline- and evidence-based sources for HBOT, mHBOT, and TOT.

HBOT is considered medically necessary for the indications listed elsewhere in this policy when the specific coverage criteria for each indication are met; this stance is supported by multiple professional society recommendations and systematic reviews that demonstrate benefit for select conditions (see evidence summaries).

For delayed radiation injury (soft tissue and bony necrosis), systematic reviews, meta-analyses, and guideline statements (Cochrane updates, ECRI assessment, UHMS, ASCRS, ECHM) report improved symptom control, mucosal healing, and wound outcomes with HBOT; treatment courses are commonly in the 30–60 session range at 2.0–2.5 ATA for 90–120 minutes depending on clinical response.

For diabetic lower extremity wounds (DFUs), systematic reviews and guideline panels (ECRI, Cochrane, SVS/APMA/SVM, IWGDF, UHMS) indicate HBOT can increase short-term ulcer healing rates and may reduce major amputations in selected patients (typically ischemic or Wagner grade ≥3 wounds or wounds that fail to improve after an adequate trial of standard care). The body of evidence shows benefit for specific populations but notes limitations including small trials and variable longer-term effects.

For carbon monoxide poisoning, randomized trials, meta-analyses, and UHMS guidance indicate HBOT reduces some neuropsychological sequelae and is recommended by UHMS, though trial heterogeneity and limitations mean the net benefit may vary by timing and patient factors.

For central retinal artery occlusion, pooled analyses and UHMS guidance suggest hyperbaric oxygen can improve visual acuity when administered promptly (ideally within 24 hours) with treatment regimens individualized by response.

For chronic refractory osteomyelitis, necrotizing soft tissue infections, gas gangrene, intracranial abscesses (selected cases), and large thermal burns, the evidence base (systematic reviews, observational series, and UHMS/ECHM recommendations) supports HBOT as an adjunctive therapy in specific clinical contexts where conventional therapy is insufficient or mortality/morbidity is high.

Clinical practice guidelines from specialty societies (for example UHMS, ECHM, ASCRS, IWGDF, SVS/APMA/SVM, AAO-HNS) generally endorse HBOT for a subset of the indications listed in this policy, often with stipulations about timing, severity, and failure of standard therapy.

Topical oxygen therapy (TOT): Systematic reviews and technology assessments report mixed and limited-quality evidence. Some RCTs and meta-analyses show improved short-term wound healing rates when TOT is added to standard care for selected chronic wounds, but overall evidence quality, heterogeneity of devices/methods, short follow-up, and inconsistent outcomes lead major hyperbaric societies (UHMS) and some assessments (ECRI) to conclude routine use is not established and further high-quality RCTs are needed.

Mild hyperbaric oxygen therapy (mHBOT) delivered at pressures < 1.4 ATA in low-pressure fabric chambers does not meet the definition of HBOT. UHMS and other expert bodies state these devices do not achieve the pressures/oxygen exposures required for UHMS-approved indications; evidence is insufficient to support mHBOT for any indication and it is considered unproven and not medically necessary.

Across indications, high-quality randomized controlled trial evidence is limited for many conditions; where observational data predominate, favorable outcomes are often reported but subject to bias. Therefore, policy coverage aligns with indications supported by higher-quality evidence and guideline consensus and specifies that uses not listed as medically necessary are considered unproven and not medically necessary.

Operational note: When HBOT is requested for a covered indication, documentation must demonstrate the eligible clinical diagnosis, failure or insufficiency of standard therapies when required by the indication (for example adequate trial of optimized wound care for DFUs), timing relative to symptom onset when relevant (e.g., ISSHL, central retinal artery occlusion), and treatment parameters consistent with guideline-recommended dosing (pressure, session duration, and total number of treatments).

Coding and Technical Parameters

Referenced Procedure / HCPCS / CPT Codesmixed

99183	Physician or other qualified health care professional attendance and supervision of hyperbaric oxygen therapy, per session
A4575	Topical hyperbaric oxygen chamber, disposable
E0446	Topical oxygen delivery system, not otherwise specified, includes all supplies and accessories
G0277	Hyperbaric oxygen under pressure, full body chamber; per 30 minute interval

Covered/Referenced Codesmixed

No codes listed

HBOT pressure threshold

HBOT minimum pressure to meet definition>= 1.4 ATA (pressure during treatment while breathing near 100% oxygen)

Clinical purpose thresholdFor clinical purposes, chamber pressure must equal or exceed 1.4 ATA to qualify as therapeutic HBOT

Distinguishing from mHBOTPressures <1.4 ATA do not meet the HBOT pressure threshold and are considered mHBOT or low-pressure devices

Conservative therapy duration

Typical conservative therapy duration before HBOT for DFUMinimum of 4 weeks of standard wound therapy; many guidelines specify 4–6 weeks before adjunctive HBOT

IWGDF recommendationUse HBOT as adjunct for ischemic ulcers that fail to heal after four to six weeks despite optimal care (IWGDF, 2023)

Provider Actions, Prior Authorization, and Documentation

Prior Authorization

Prior Authorization: indication, timing, and planned duration

Prior authorization is required for listed HBOT and TOT procedure codes when the clinical indication aligns with this policy. Obtain authorization before initiating therapy whenever possible; include the expected start date and planned treatment duration in the request (see recommended session ranges by indication below). Member-specific benefit plans govern prior authorization requirements — verify the member's plan prior to scheduling.

Include expected initiation date and planned number of sessions
If urgent therapy is needed, notify payer and document clinical urgency

Prior Authorization

Prior Authorization for HBOT in DFU and Radiation Injury

For diabetic foot ulcers (DFU) and delayed radiation injury, prior authorization must document that UBH criteria in this policy are met. For DFU, document Wagner grade and evidence of failure of adequate conservative management (see DFU documentation block). For delayed radiation injury, document multidisciplinary evaluation and planned course (commonly 30–60 HBOT sessions at 2.0–2.5 ATA for 90–120 minutes each).

DFU: Wagner Grade (preferably ≥3) or failed 4–6 weeks of optimal standard care

Background and Context

Hyperbaric Oxygen Therapy (HBOT) is a whole‑body therapy in which the patient breathes near‑100% oxygen while inside a pressurized chamber. To meet the therapeutic definition in this policy HBOT must be delivered at pressures of at least 1.4 ATA with near 100% oxygen. HBOT may be provided in Class A (multi‑person) or Class B (mono‑place) chambers and is used as primary or adjunctive therapy for a defined set of indications. By contrast, mHBOT (low‑pressure fabric chambers delivering 1.4 ATA) and Topical Oxygen Therapy (TOT) (direct application of oxygen to a wound at slightly above atmospheric pressure) do not meet the HBOT definition and have distinct, limited evidence bases.

Definitions

Definition — Hyperbaric Oxygen Therapy (HBOT)

DefinitionHyperbaric Oxygen Therapy (HBOT): Intermittent breathing of near 100% oxygen inside a chamber pressurized to >= 1.4 ATA; may be primary or adjunctive therapy (UHMS).

Delivery systemsAdministered in Class A (multi-person) or Class B (mono) chambers; Class A typically pressurized with air while individuals breathe near 100% oxygen via masks or hoods

Therapeutic intentUsed to improve tissue oxygenation as primary treatment or as adjunct to surgical/pharmacologic interventions

Definition — Mild Hyperbaric Oxygen Therapy (mHBOT)

DefinitionMild Hyperbaric Oxygen Therapy (mHBOT): Use of low-pressure fabric chambers delivering pressures less than 1.4 ATA (typically air-compressed); does not meet the clinical definition of therapeutic HBOT.

Regulatory note

Revision History and Policy Changes

2025-07-01policy_revisionLatest

Revised coverage rationale: added language designating Mild Hyperbaric Oxygen Therapy (mHBOT) as unproven and not medically necessary for any indication, clarified that HBOT is unproven/not medically necessary for indications not listed as medically necessary, updated definitions and supporting information, and archived previous policy version OUTPATIENT 051.4.

Policy Summary

PayerUnitedHealthcare

PolicyHyperbaric Oxygen Therapy and Topical Oxygen Therapy

Policy CodePolicy OUTPATIENT 051.5

Change TypeMaterial revision — coverage and definitions updated (mHBOT designated not medically necessary)

Effective DateJul 1, 2025

Next Review Date

Key ActionObtain prior authorization documenting indication, timing, and planned HBOT course to support medical necessity.

SourceLink

On This Page

SVS/ APMA/ SVM guidanceAdjunctive HBOT recommended when ulcers fail to show 50% area reduction after a minimum of four weeks of standard therapy

HBOT typical course

Typical treatment pressure range2.0–2.5 ATA (daily treatments for many indications such as radiation injury)

Typical number of treatmentsApproximately 30–60 hyperbaric treatment sessions for radiation injury and many DFU courses

Typical session lengthEach session commonly lasts 90–120 minutes when delivered daily at 2.0–2.5 ATA

Radiation injury: multidisciplinary consult and plan for 30–60 sessions at 2.0–2.5 ATA

Prior Authorization

ISSHL timing and concurrent therapy requirement

For idiopathic sudden sensorineural hearing loss (ISSHL), prior authorization should reflect timing relative to symptom onset and concurrent steroid therapy. Initial HBOT is indicated when given with steroids within 14 days of onset; salvage HBOT when combined with steroids may be authorized up to one month from onset. Document steroid administration and timing.

Initial therapy: HBOT + corticosteroids within 14 days of ISSHL onset
Salvage therapy: HBOT + corticosteroids up to 1 month from onset

Note

Check member plan for prior authorization

Check the member specific benefit plan before requesting or authorizing HBOT/TOT. The member contract controls coverage determinations; state or federal mandates may also affect coverage. If there is any conflict, the member's plan document governs.

Verify benefit coverage, prior authorization rules, and any plan limits before scheduling treatment

Denial Risk

Evidence insufficiency may trigger denial

When the evidence base for an indication is insufficient (for example, compromised grafts/flaps per ECRI), authorization may be denied or deferred pending additional documentation or peer review. Providers should be prepared to supply supporting literature or case-specific rationale when requesting coverage for indications noted as having low or insufficient evidence.

Compromised grafts/flaps: evidence insufficient per ECRI — may trigger denial
TOT for wounds and mHBOT: designated unproven — likely denial risk

Documentation Required

Documentation gap may trigger denial

Missing or incomplete clinical documentation frequently triggers denials. For DFU HBOT requests, absent ulcer severity, duration of conservative therapy, or perfusion status are common documentation gaps. Ensure all required clinical details are present in the prior authorization and medical record.

Common gaps: Wagner grade, duration and response to 4–6 weeks of standard care, objective perfusion data (ABI, toe pressures, TcPO2)
Billing documentation must indicate HBOT pressure ≥1.4 ATA and near-100% oxygen when claiming systemic HBOT

Denial Risk

Delay of standard treatment risk

HBOT should not delay critical or standard therapies. Do not transfer or defer essential surgical, infectious disease, or critical care interventions solely to provide HBOT. Authorization or scheduling of HBOT must not result in postponement of urgent standard treatments.

If HBOT availability would delay critical care or surgery, document rationale and coordinate multidisciplinary care
Avoid transferring patients exclusively for HBOT if it would delay necessary standard therapy

Documentation Required

Required clinical and billing documentation

Required clinical and billing documentation must be included in the prior authorization and the medical record: pressure delivered (≥1.4 ATA for systemic HBOT), oxygen concentration (near 100% inhaled oxygen), treatment duration per session, number of sessions planned, and alignment with a listed medical indication. For TOT, document adjunctive role and prior standard care attempts when applicable.

Document chamber type (Class A or B), per-session pressure and minutes, and total planned sessions
Include supporting objective tests (ABI, toe pressures, TcPO2) when perfusion is relevant

Prior Authorization

Document recommended treatment duration and timing

Document recommended treatment duration and timing for the specific indication when requesting authorization. Examples: refractory chronic osteomyelitis — prolonged courses may be needed (ECHM suggests up to ~60 sessions over ~11–12 weeks); compromised grafts/flaps — begin as soon as diagnosis made and continue daily until tissue viability determined; radiation injury — commonly 30–60 sessions at 2.0–2.5 ATA for 90–120 minutes.

Refractory osteomyelitis: consider ≥60 sessions over ~11–12 weeks (per ECHM)
Compromised grafts/flaps: initiate as soon as possible; initial 2–3 sessions/day in some protocols then daily until outcome determined
Radiation injury: 30–60 sessions at 2.0–2.5 ATA, 90–120 minutes each

Documentation Required

Required clinical documentation for DFU HBOT

For DFU prior authorization and chart documentation, include ulcer grade (Wagner), objective perfusion measures, documentation of at least 4 weeks (commonly 4–6) of adequate conservative management with response (or lack thereof), recent debridement or surgical interventions, and plan for adjunctive HBOT to be added to standard wound care.

Specify Wagner grade (UHMS recommends Grade ≥3 for systemic HBOT benefit)
Document 4–6 weeks of standard care with <50% wound area reduction or inadequate healing
Include evidence of adequate perfusion or rationale if ischemic

Prior Authorization

Intracranial abscess documentation and multidisciplinary involvement

For intracranial abscess, involve a multidisciplinary team early (neurosurgery, neurology, infectious disease) when considering adjunct HBOT. Authorization requests should document abscess characteristics (multiple, deep/dominant location), host factors, prior surgical feasibility, and failure or deterioration despite standard surgical and antibiotic therapy.

Indications favoring HBOT: multiple abscesses, deep/dominant location, compromised host, contraindication to surgery, lack of response to standard therapy
Document multidisciplinary consultations and timing of HBOT relative to other therapies

Some low-pressure devices have FDA 510(k) clearance only for acute mountain sickness; they are not equivalent to HBOT for clinical indications

UHMS positionUHMS states mHBOT results in exposure to <1.4 ATA while breathing air and does not achieve minimum pressures/oxygen levels required for UHMS-approved indications

Definition — Topical Oxygen Therapy (TOT)

DefinitionTopical Oxygen Therapy (TOT): Direct application of oxygen to a wound site either intermittently at slightly above atmospheric pressure or continuously via a cannula under a dressing.

Intended effectProposed to oxygenate hypoxic wound tissue when blood flow is inadequate to meet healing demands

Delivery approachesMethods include enclosing a limb in a sealed bag or continuous oxygen delivery under film-covered dressings via cannula

Definition — Neuropsychological sequelae (CO poisoning)

DefinitionNeuropsychological sequelae (CO poisoning): Cognitive and neurobehavioral symptoms after carbon monoxide poisoning, including headache, memory impairment, difficulty concentrating, and disturbed sleep as reported in RCT meta-analyses.

Evidence contextSystematic reviews of RCTs found mixed results but some studies report reduced incidence of these sequelae with HBOT versus normobaric oxygen

Definition — Visual acuity (VA) improvement (RAO)

DefinitionVisual acuity (VA) improvement (retinal artery occlusion): Measured improvement in vision after retinal artery occlusion; meta-analysis showed oxygen therapy (including 100% HBOT) was associated with markedly increased probability of VA improvement.

Timing/detailGreatest benefit observed when treatment exceeds nine hours total and is started early (within three months, ideally within 24 hours for best outcomes)

Definition — Wagner Grade 3 DFU

DefinitionWagner Grade 3 DFU: A diabetic foot ulcer classification with deep ulceration involving structures such as tendon, bone, or joint; used to identify candidates for adjunctive HBOT per UHMS guidance.

UHMS recommendationUHMS recommends HBOT for Wagner Grade 3 or higher DFUs that have not shown significant improvement after 30 days of treatment; HBOT not suggested for Grade 2 or lower

Definition — mild Hyperbaric Oxygen Therapy (mHBOT) (duplicate inventory entry)

Duplicate definition notemHBOT: Low-pressure hyperbaric chambers delivering <1.4 ATA while breathing air; does not meet therapeutic HBOT definition and is not equivalent to HBOT.

Clinical implicationBecause mHBOT pressures are <1.4 ATA, these devices do not achieve the oxygenation levels required for UHMS-approved indications

Definition — Mild Hyperbaric Oxygen Therapy (mHBOT) — policy identification of device category

Policy device category identificationMild Hyperbaric Oxygen Therapy (mHBOT) is identified as a category of low-pressure hyperbaric devices that do not meet the definition of conventional HBOT and are considered unproven and not medically necessary for any indication.

Regulatory and professional concernsAMA and UHMS have raised safety and efficacy concerns; FDA 510(k) clearances for some devices are limited to altitude sickness, not therapeutic HBOT indications

Policy changePolicy revision (07/01/2025) added language declaring mHBOT unproven and not medically necessary for any indication due to insufficient evidence