# Inhalation Injury

Manage inhalation injury as concurrent upper-airway edema, tracheobronchial and alveolar toxic injury, and carbon monoxide or cyanide poisoning. Early airway control, toxin-directed treatment, bronchoscopy-guided airway clearance, and serial respiratory reassessment address deterioration that can evolve after the initial examination.

**Clinical question:** How should physicians identify, stabilize, evaluate, and monitor acute smoke or chemical inhalation injury?

Updated: 2026-09-15T17:32:28.168336+00:00

## What matters in practice
- Treat suspected inhalation injury as three potentially simultaneous processes: supraglottic thermal injury, subglottic toxic airway/parenchymal injury, and systemic poisoning by absorbed toxins. [14]
- Intubate early when airway injury is present or evolving; progressive mucosal edema can obscure anatomy and cause fatal airway obstruction. [13]
- A closed-space fire or explosion, singed nasal vibrissae, carbonaceous sputum, and elevated carbon monoxide or cyanide levels increase suspicion, but lower-airway injury requires direct respiratory assessment. [13]
- Fiberoptic bronchoscopy can establish subglottic injury and provide therapeutic airway clearance; chest CT and bronchoscopic grading may refine prognosis. [12][21]
- Persistent hypotension and acidemia despite adequate arterial oxygenation should prompt concern for severe cyanide toxicity in smoke exposure. [20]
- Respiratory injury may progress after presentation; serial examination, oxygenation assessment, airway clearance, and escalation for respiratory failure are central to management. [5][16]

## Secure the airway before edema makes intubation difficult

Airway decisions precede definitive grading of lower-airway injury.

Immediately remove smoldering or restrictive clothing, administer oxygen, and perform an ABC assessment. A closed-space explosion or fire, singed nasal vibrissae, carbonaceous sputum, or elevated carbon monoxide or cyanide levels should trigger focused evaluation for inhalation injury. [13]

Proceed with early endotracheal intubation when airway injury is present or there is concern for progressive obstruction. Mucosal swelling and edema can progressively obliterate normal upper-airway structures; delaying airway control converts a controlled procedure into a difficult or failed airway. [13]

Separate upper-airway thermal injury from lower-airway toxic injury at the bedside. Inhaled heat predominantly injures the upper airway because heat dissipates efficiently above the vocal cords, whereas smoke particulates and respiratory irritants produce distal airway inflammation, edema, casts, obstruction, and ventilation-perfusion mismatch. A reassuring initial oropharyngeal examination does not exclude evolving tracheobronchial injury. [4][5]

If respiratory failure develops, use invasive mechanical ventilation and frequent reassessment for obstruction, declining compliance, pulmonary edema, and acute respiratory distress syndrome. In inhalation injury associated with blast exposure, positive-pressure ventilation may increase barotrauma risk; use the lowest effective pressures and evaluate abrupt deterioration for air leak or other blast-lung complications. [13]
- Remove smoldering clothing and avoid a secondary fire hazard around high-flow oxygen. [13]
- Assess for concurrent cutaneous burns, traumatic injury, aspiration, and exposure in an enclosed or oxygen-depleted environment; these modify airway and ventilatory risk. [10][13]
- Transfer or discuss early with a burn center when inhalation injury accompanies significant burns or requires serial bronchoscopy, ventilatory support, or airway intervention. [5][12]

*Immediate clinical patterns that direct the first intervention. [5][13][14][20]*

| Clinical pattern | Key discriminator | Immediate next step |
| --- | --- | --- |
| Supraglottic thermal injury | Evidence of airway injury with concern for progressive mucosal edema or obstruction. [13][14] | Early endotracheal intubation before anatomy becomes obscured. [13] |
| Subglottic smoke injury | Carbonaceous sputum, airway debris, wheeze, impaired clearance, or worsening oxygenation after smoke exposure. [5][13] | Humidification, aggressive airway toilet, bronchodilator-directed treatment of bronchospasm, and fiberoptic airway evaluation when indicated. [5][12] |
| Carbon monoxide or cyanide exposure | Closed-space fire; elevated carbon monoxide or cyanide level; or persistent hypotension and acidemia despite adequate arterial oxygenation. [13][20] | Treat systemic intoxication concurrently while continuing airway and respiratory support. [5][20] |
| Chemical irritant exposure | Prominent eye, nose, throat, or bronchial irritation after a known corrosive or oxidant gas exposure. [16][18] | Oxygen for respiratory symptoms, aerosolized bronchodilator for bronchospasm, decontamination, and serial reassessment for delayed pulmonary injury. [18] |

## Define the anatomic injury and identify systemic toxins

No single bedside finding grades all components of inhalation injury.

Frame the evaluation around three anatomically and clinically distinct injuries: supraglottic thermal injury, subglottic airway and alveolar poisoning, and systemic toxicity from absorbed low-molecular-weight toxins. Exposure duration, smoke temperature, smoke composition, and patient airway size influence severity; infants can obstruct more rapidly because of their smaller airway diameter. [14]

For suspected tracheobronchial injury, use fiberoptic bronchoscopy to inspect the airway and remove obstructing material when needed. Bronchoscopy is both diagnostic and therapeutic, and fiberoptic airway evaluation at admission can identify patients who need subsequent airway intervention or aggressive pulmonary toilet. [12][13]

Use chest CT as an adjunct when the clinical course or prognostic assessment is unclear; CT and bronchoscopic grading may provide a more nuanced assessment than nonspecific examination findings alone. Bronchoscopy with biopsy has been reported to predict ARDS in burn patients, but routine biopsy is not required for initial stabilization and should not delay airway management. [21][22]

Obtain oxygenation assessment with pulse oximetry and, when respiratory distress or an abnormal pulmonary examination is present, arterial blood gas measurement and chest radiography. This approach is specifically recommended in hydrocarbon vapor exposure and provides a practical escalation pathway for inhalational respiratory injury more broadly. [19]

Evaluate carbon monoxide and cyanide exposure in the clinical context of a closed-space fire or combustion exposure. Carbon monoxide or cyanide levels support the diagnosis when available; cyanide poisoning should be suspected when hypotension and acidemia persist despite adequate arterial oxygenation. [13][20]
- Do not use a single physical-examination sign to rule out distal smoke injury; historical examination findings and bronchoscopy have historically been the principal diagnostic tools, and neither alone captures every clinical trajectory. [21]
- Interpret a normal early chest radiograph cautiously when the exposure history and airway findings remain concerning; smoke-related inflammatory injury can evolve into pulmonary edema, cast formation, obstruction, and impaired gas exchange. [5]
- Add continuous cardiac rhythm monitoring and intravenous access in seriously ill chemical-exposure patients, especially with coma, hypotension, seizures, or arrhythmia. [17][18]

### Exposure-specific clues

Smoke from fire is heterogeneous and may contain particulate matter, respiratory irritants, systemic toxins, and heat. The clinically important consequence is coexistence of mucosal edema, impaired secretion clearance, airway obstruction, and systemic toxic exposure rather than a single uniform injury pattern. [5][14]

Known chemical exposures require agent-specific expectations. Chlorine reacts with moisture to form hypochlorous and hydrochloric acids, amplifying oxidizing and corrosive effects; ammonia can produce immediate upper-airway narrowing and swelling, and pulmonary injury may continue to evolve for 18 to 24 hours. [16][18]
- For chlorine-associated respiratory symptoms, give supplemental oxygen and treat bronchospasm with an aerosolized bronchodilator. [18]
- For ammonia exposure, admit pulmonary edema to an ICU and observe initially symptomatic inhalation-exposure patients with periodic reexamination because injury can progress over 18 to 24 hours. [16]
- For gasoline vapor exposure with respiratory distress or abnormal pulmonary examination, obtain pulse oximetry or arterial blood gas measurement and chest radiography; use aerosolized bronchodilators for bronchospasm and avoid epinephrine-related agents because of arrhythmia risk. [19]

## Treat obstruction, secretion retention, and gas-exchange failure

Supportive respiratory care remains the core treatment while injury evolves.

Use humidification and aggressive pulmonary toilet for smoke-related tracheobronchial injury, particularly when soot, tenacious secretions, or bronchial casts impair ventilation. Smoke particulate injury initiates airway inflammation that promotes pulmonary edema, cast formation, airway obstruction, loss of hypoxic pulmonary vasoconstriction, and ventilation-perfusion mismatch. [5]

Treat bronchospasm with inhaled beta2-agonist therapy. For chemical exposures, aerosolized bronchodilators are recommended when bronchospasm is present; in mixed exposures, consider myocardial vulnerability before selecting the bronchodilator, because bronchial sensitizing agents may add risk. [5][18]

Use bronchoscopy for diagnostic inspection and therapeutic clearance when airway debris, casts, or retained secretions are contributing to obstruction or inadequate airway toilet. Repeat airway inspection is part of standardized multidisciplinary management in high-acuity smoke injury when ongoing clearance is needed. [8][12]

Nebulized heparin and N-acetylcysteine are used in some inhalation-injury protocols to address fibrinous casts and secretion burden, often with beta2-agonist therapy. However, adjuncts including bronchodilators, mucolytics, inhaled anticoagulants, nonconventional ventilator modes, prone positioning, and extracorporeal membrane oxygenation lack definitive efficacy evidence; do not substitute these measures for airway protection, ventilation, humidification, and airway clearance. [5][21]
- Escalate ventilatory support for worsening oxygenation, increased work of breathing, declining pulmonary compliance, or evolving ARDS. [5][6]
- Reassess for mucus plugging or bronchial casts when ventilator pressures rise, wheezing persists, or lobar ventilation becomes asymmetric; bronchoscopic clearance is the relevant therapeutic procedure. [5][12]
- Consider extracorporeal support only as rescue-level management in severe refractory respiratory failure; its role in inhalation injury remains an adjunct without definitive efficacy evidence. [21]

### What not to overinterpret

Do not infer benefit for routine corticosteroid therapy solely from its proposed anti-inflammatory role. Corticosteroids have been suggested in inhalation injury, but current reviews identify major treatment adjuncts as lacking definitive efficacy evidence. [8][21]

Do not assume that inhaled anticoagulant therapy is systemically equivalent to therapeutic parenteral anticoagulation. A review of nebulized unfractionated heparin reports minimal systemic absorption and no observed increase in bleeding in summarized inhalation-injury data, but clinical benefit remains uncertain and local burn-center protocols should govern use. [23][21]

*Respiratory management linked to the dominant physiologic problem. [5][8][12][18][21][23]*

| Problem | Action | Decision boundary |
| --- | --- | --- |
| Threatened upper airway | Early endotracheal intubation. [13] | Do not wait for progressive edema to obscure the airway. [13] |
| Bronchospasm | Aerosolized bronchodilator and supplemental oxygen for respiratory symptoms. [18] | Choose agents cautiously in mixed chemical exposure when myocardial risk is relevant. [18] |
| Soot, casts, or retained secretions | Humidification, aggressive airway toilet, and bronchoscopy for diagnostic inspection and therapeutic clearance. [5][12] | Repeat clearance when obstruction or secretion retention persists. [8] |
| Severe gas-exchange failure | Mechanical ventilation with reassessment for ARDS and barotrauma. [5][13] | ECMO and other advanced adjuncts are rescue considerations, not established routine therapies. [21] |
| Fibrinous airway injury | Consider protocolized nebulized heparin-based therapy where used. [5][23] | Benefit is not definitive; maintain standard airway and ventilatory care. [21] |

## Treat carbon monoxide and cyanide risk in parallel with pulmonary injury

Normal arterial oxygenation does not exclude a life-threatening combustion toxin.

In a smoke-exposed patient, assess for systemic toxic injury concurrently with airway management. Carbon monoxide and cyanide toxicity should be suspected after open-fire exposure, especially in enclosed spaces; elevated carbon monoxide or cyanide levels strengthen suspicion when testing is available. [10][13]

Prioritize cyanide toxicity when shock physiology is disproportionate to the pulmonary examination: persistent hypotension and acidemia despite adequate arterial oxygenation are hallmark features of severe cyanide poisoning. Hydrogen sulfide poisoning can produce a similar clinical picture, so occupational, industrial, sewage, and confined-space history matters. [20]

Continue respiratory support while toxin-directed therapy is undertaken. Smoke-inhalation reviews identify specific treatment of carbon monoxide and cyanide intoxication as part of management, but treatment of the pulmonary component remains airway control, ventilation, humidification, and airway toilet. [5]
- Obtain exposure details from EMS, fire personnel, family, or coworkers: enclosed versus open space, combustion source, industrial chemical involvement, duration, loss of consciousness, and co-exposed victims. These details shift concern toward asphyxiant, irritant, or corrosive mechanisms. [5][13][17][20]
- Do not defer cyanide consideration because arterial oxygenation appears adequate; severe cyanide toxicity is characterized by hypotension and acidemia despite adequate arterial oxygenation. [20]
- Treat coma, hypotension, seizures, and arrhythmias with conventional critical-care stabilization while the toxicologic differential is pursued. [17][18]

## Monitor for delayed airway and pulmonary deterioration

Disposition depends on trajectory, not only the arrival examination.

Observe symptomatic inhalation-exposure patients with serial respiratory examinations because pulmonary injury can progress after the initial encounter. After ammonia inhalation, progression may continue for 18 to 24 hours; pulmonary edema requires ICU admission. [16]

For intubated smoke-injury patients, monitor ventilatory requirements, airway patency, secretion burden, oxygenation, and evidence of pulmonary edema, obstruction, or ARDS. Inhalation injury is associated with prolonged ventilatory support and increased ICU and hospital utilization when acute lung injury develops. [5][6]

Plan postacute pulmonary follow-up after severe chemical inhalation injury. Ammonia survivors may have residual bronchoconstriction, bronchiectasis, small-airway disease, chronic obstructive pulmonary disease, chronic cough, asthma, or fibrosis; repeat pulmonary function testing annually is recommended in the ATSDR ammonia guidance. [16]

Maintain a low threshold to reassess chronic respiratory symptoms after major toxic dust or smoke exposure. Occupational toxicant inhalation cohorts demonstrate clinically important coexistence of lower-airway disease with upper aerodigestive disease and GERD-related complexity, which can alter the diagnostic approach to persistent cough or dyspnea. [15]
- ICU-level monitoring is appropriate for pulmonary edema, invasive ventilation, escalating oxygen requirement, severe bronchospasm, shock, or suspected major systemic toxin exposure. [16][20]
- Repeat bronchoscopy when ongoing airway debris or obstruction requires clearance rather than using a single initial examination as definitive management. [8][12]
- At follow-up, obtain spirometry or formal pulmonary function testing for persistent cough, wheeze, exertional dyspnea, or suspected small-airway disease after severe irritant exposure. [16]

*Disposition and longitudinal monitoring based on the evolving injury pattern. [5][8][16][20]*

| Finding or trajectory | Disposition or monitoring action | Rationale |
| --- | --- | --- |
| Pulmonary edema after ammonia inhalation | Admit to ICU. [16] | Pulmonary injury may evolve for 18 to 24 hours. [16] |
| Symptomatic chemical inhalation without pulmonary edema | Observe carefully with periodic respiratory reexamination. [16] | Delayed progression can occur after the initial assessment. [16] |
| Intubated smoke injury with secretion retention or obstruction | Serial ventilatory assessment and repeat airway inspection/clearance as needed. [8][12] | Airway debris and bronchial casts can perpetuate obstruction and impaired gas exchange. [5] |
| Severe irritant-inhalation survivor with persistent respiratory symptoms | Repeat pulmonary function testing; annual testing is recommended after ammonia inhalation injury. [16] | Residual bronchoconstriction, small-airway disease, bronchiectasis, and chronic obstructive disease may occur. [16] |
| Persistent shock and acidemia despite adequate arterial oxygenation | Critical-care monitoring while evaluating and treating cyanide or hydrogen sulfide toxicity. [20] | This pattern is characteristic of severe cyanide toxicity and can occur with hydrogen sulfide poisoning. [20] |

## References
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## Editorial note

Prepared from cited clinical literature using Astra's research workflow. Verify recommendations against current guidance and patient-specific factors.