Aetna modified CPB 0518 covering inhaled nitric oxide (INO) therapy, effective September 26, 2025. Here's what billing teams need to know.
Aetna, a CVS Health company, updated its inhaled nitric oxide coverage policy under CPB 0518 in the Aetna system. This update affects billing for INO therapy across neonatal hypoxic respiratory failure, congenital heart disease post-op management, and pulmonary hypertension diagnostic workups. Relevant codes include CPT 93463, 94002, 94003, and 94004. If your team bills INO therapy for any of these indications, review the updated criteria before September 26, 2025.
Quick-Reference Table
| Field | Detail |
|---|---|
| Payer | Aetna |
| Policy | Nitric Oxide, Inhalational (INO) — CPB 0518 |
| Policy Code | CPB 0518 |
| Change Type | Modified |
| Effective Date | September 26, 2025 |
| Impact Level | High |
| Specialties Affected | Neonatology, Pediatric Cardiology, Pulmonology, Critical Care, Respiratory Therapy |
| Key Action | Audit active INO authorizations against the two-part neonatal criteria and the 4-day and 14-day review triggers before September 26, 2025 |
Aetna Inhaled Nitric Oxide Coverage Criteria and Medical Necessity Requirements 2025
Aetna's coverage policy for inhaled nitric oxide is narrow by design. Three indications qualify for medical necessity coverage. Each has its own criteria and duration limits. Get these wrong and you're looking at a claim denial.
Indication 1: Neonatal Hypoxic Respiratory Failure
Aetna covers INO therapy for neonates at 34 weeks gestation or greater with hypoxic respiratory failure. Both of the following conditions must be met:
| # | Covered Indication |
|---|---|
| 1 | The neonate does not have congenital diaphragmatic hernia (CDH) |
| 2 | Conventional therapies have failed or are expected to fail |
Conventional therapies include high-concentration oxygen, hyperventilation, high-frequency ventilation, alkalosis induction, neuromuscular blockade, and sedation. If your clinical team hasn't documented failure or anticipated failure of these treatments, the claim won't hold up.
The CDH exclusion is hard. There is no path to coverage for neonates with congenital diaphragmatic hernia under this indication. Don't try to route around it.
INO therapy beyond four days triggers a medical necessity review. This isn't a soft guideline — it's a billing checkpoint. If the neonate is still on INO at day four, your team needs documentation ready and a prior authorization request in motion before day five.
Indication 2: Post-Operative Pulmonary Hypertensive Crisis in Congenital Heart Disease
Aetna covers INO for post-operative management of pulmonary hypertensive crisis in infants and children with congenital heart disease. This is the cleanest of the three indications — no duration limit is specified in the policy, and there's no conventional-therapy failure requirement. But the cardiovascular CPT codes 33016–37790 are excluded under this policy unless you're billing specifically for post-operative management of pulmonary hypertensive crisis. That's a critical distinction. Make sure your billing team ties the procedure to the right indication in the claim.
Indication 3: Diagnostic Use for Pulmonary Vaso-Reactivity Assessment
Aetna covers diagnostic INO use to assess pulmonary vaso-reactivity in patients with pulmonary hypertension. CPT 93463 — pharmacologic agent administration, including inhaled nitric oxide — is the relevant code here. This is a different clinical context than therapeutic INO, and Aetna separates them clearly.
The duration limit here is 14 days if oxygen desaturation has resolved. Beyond 14 days, a medical director review is required. If you're billing CPT 93463 past that threshold, get the review documented and tied to the claim before submitting.
Aetna Inhaled Nitric Oxide Exclusions and Non-Covered Indications
The biggest exclusion in this policy is one many teams miss: neonates with congenital diaphragmatic hernia do not qualify for INO coverage under the neonatal hypoxic respiratory failure indication. Period.
Cardiovascular System CPT codes 33016 through 37790 are listed as not covered when selection criteria are met — except for the post-operative pulmonary hypertensive crisis indication in infants and children with congenital heart disease. If you're billing those cardiovascular codes for any other INO-related indication, Aetna will not reimburse.
Home visits for respiratory therapy (CPT 99503) appear in this policy as a related code. But there's no specific coverage language tying home-based INO to a covered indication. If your team is billing 99503 in connection with INO therapy at home, verify coverage before submitting.
Coverage Indications at a Glance
| Indication | Status | Relevant Codes | Notes |
|---|---|---|---|
| Neonatal hypoxic respiratory failure (≥34 weeks gestation, no CDH, conventional therapies failed/expected to fail) | Covered | CPT 94002, 94003, 94004 | INO >4 days requires medical necessity review; CDH is a hard exclusion |
| Post-operative pulmonary hypertensive crisis in infants/children with congenital heart disease | Covered | CPT codes 33016–37790 (this indication only) | No duration limit specified; CVS codes excluded for all other indications |
| Diagnostic INO for pulmonary vaso-reactivity in pulmonary hypertension | Covered | CPT 93463 | Covered ≤14 days if O₂ desaturation resolved; medical director review required beyond 14 days |
| Neonatal hypoxic respiratory failure with congenital diaphragmatic hernia | Not Covered | — | Hard exclusion; no exceptions documented |
| CVT cardiovascular procedures (CPT 33016–37790) outside post-op pulmonary hypertensive crisis | Not Covered | CPT 33016–37790 | Covered only for post-op pulmonary hypertensive crisis in congenital heart disease |
Aetna Inhaled Nitric Oxide Billing Guidelines and Action Items 2025
| # | Action Item |
|---|---|
| 1 | Audit every active INO authorization before September 26, 2025. Confirm each case maps to one of the three covered indications. If it doesn't meet Aetna's criteria exactly, expect a denial. Review neonatal cases especially hard — the CDH exclusion and the conventional therapy failure requirement both need clean documentation in the record. |
| 2 | Set a day-four flag for neonatal INO cases. When a neonate starts INO therapy, put a reminder in your workflow at day four. That's when medical necessity review kicks in. Your team needs clinical documentation ready and a prior authorization request submitted before therapy continues past that threshold. |
| 3 | Set a 14-day flag for diagnostic INO cases billed under CPT 93463. If the patient's oxygen desaturation has resolved, coverage stops at 14 days. If desaturation hasn't resolved and therapy continues, a medical director review is required. Document the clinical rationale clearly and get that review in writing before billing beyond the 14-day mark. |
| 4 | Separate your congenital heart disease post-op claims from other CVS procedure codes. CPT codes 33016–37790 are not covered under this policy unless the indication is post-operative management of pulmonary hypertensive crisis in infants or children with congenital heart disease. If you're billing those codes for INO therapy in any other context, you'll get denied. Update your charge capture to flag this distinction. |
| 5 | Train your clinical documentation team on the "conventional therapy failure" requirement. For neonatal cases, Aetna requires that conventional therapies have failed or are expected to fail. The record needs to show which therapies were tried, what the clinical response was, and why INO was necessary. Vague documentation won't survive a medical necessity review. |
| 6 | Confirm diagnosis codes align with covered ICD-10-CM indications. This policy covers a wide range of diagnoses — from pulmonary hypertension (I27.0, I27.20–I27.29) to acute respiratory distress syndrome (J80) to sickle-cell disorders (D57 range) to cystic fibrosis (E84.0–E84.9). Make sure the ICD-10 on the claim matches the clinical indication you're billing. A mismatch between the diagnosis and the INO indication is a fast path to a claim denial. |
If your facility handles high volumes of neonatal INO or pediatric cardiac cases and you're unsure how this policy interacts with your payer mix or authorization workflows, talk to your compliance officer before the September 26, 2025 effective date.
| Previous Version | Current Version |
|---|---|
| Coverage is considered experimental and investigational for all indications | Coverage is considered medically necessary when specific criteria are met |
| Prior authorization is not required | Prior authorization is required for initial treatment |
| Documentation must include clinical history | Documentation must include clinical history |
| Re-review every 24 months | Re-review every 12 months with updated clinical documentation |
CPT, HCPCS, and ICD-10 Codes for Inhaled Nitric Oxide Under CPB 0518
CPT Codes — Other Codes Related to This Policy
| Code | Type | Description |
|---|---|---|
| 93463 | CPT | Pharmacologic agent administration (e.g., inhaled nitric oxide, intravenous infusion of nitroprusside) — used for diagnostic pulmonary vaso-reactivity assessment |
| 94002 | CPT | Ventilation assist and management, initiation of pressure or volume preset ventilators for assisted or controlled breathing — hospital inpatient/observation, initial day |
| 94003 | CPT | Ventilation assist and management, initiation of pressure or volume preset ventilators for assisted or controlled breathing — hospital inpatient/observation, subsequent days |
| 94004 | CPT | Ventilation assist and management, initiation of pressure or volume preset ventilators for assisted or controlled breathing — nursing facility, per day |
| 99503 | CPT | Home visit for respiratory therapy care (e.g., bronchodilator, oxygen therapy, respiratory assessment) |
Not Covered CPT Codes (Unless Post-Op Pulmonary Hypertensive Crisis Indication Is Met)
| Code | Type | Description | Reason |
|---|---|---|---|
| 33016–37790 | CPT | Cardiovascular System procedures | Not covered unless billing for post-operative management of pulmonary hypertensive crisis in infants/children with congenital heart disease |
Key ICD-10-CM Diagnosis Codes
| Code | Description |
|---|---|
| I27.0 | Primary pulmonary hypertension |
| I27.20 | Other secondary pulmonary hypertension |
| I27.21 | Other secondary pulmonary hypertension |
| I27.22 | Other secondary pulmonary hypertension |
| I27.23 | Other secondary pulmonary hypertension |
| I27.24 | Other secondary pulmonary hypertension |
| I27.25 | Other secondary pulmonary hypertension |
| I27.26 | Other secondary pulmonary hypertension |
| I27.27 | Other secondary pulmonary hypertension |
| I27.28 | Other secondary pulmonary hypertension |
| I27.29 | Other secondary pulmonary hypertension |
| J80 | Acute respiratory distress syndrome |
| J84.10 | Pulmonary fibrosis, unspecified |
| J84.112 | Idiopathic pulmonary fibrosis |
| J84.170–J84.178 | Other interstitial pulmonary diseases with fibrosis in diseases classified elsewhere |
| J95.1 | Acute pulmonary insufficiency following thoracic surgery |
| J95.2 | Acute pulmonary insufficiency following nonthoracic surgery |
| J95.3 | Chronic pulmonary insufficiency following surgery |
| J95.821 | Postprocedural respiratory failure |
| J21.0–J21.9 | Acute bronchiolitis |
| J12.81 | Pneumonia due to SARS-associated coronavirus |
| J12.82 | Pneumonia due to coronavirus disease 2019 |
| E84.0–E84.9 | Cystic fibrosis |
| D57.00–D57.219, D57.411–D57.819 | Sickle-cell disorders |
| I26.09 | Other pulmonary embolism with acute cor pulmonale |
| I26.99 | Other pulmonary embolism without acute cor pulmonale |
| I24.1 | Dressler's syndrome / Post-cardiac arrest syndrome |
| I50.1–I50.9 | Heart failure (after hemorrhagic shock and trauma pneumonectomy) |
| B50.0–B54 | Malaria |
| B96.5 | Pseudomonas (aeruginosa) as the cause of diseases classified elsewhere |
| A31.0–A31.9 | Infection due to other mycobacteria |
The full ICD-10-CM code list under CPB 0518 includes 174 codes. The table above reflects the codes provided in the policy data. Confirm the complete list against the source policy at Aetna's clinical policy bulletins before submitting claims.
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