When should inhalation injury be suspected in a burn patient?

When to Suspect Inhalation Injury in Burn Patients

Suspect inhalation injury immediately in any patient exposed to fire in an enclosed space, and do not rely on normal oxygen saturation, chest X-ray, or arterial blood gases to exclude the diagnosis. 1, 2

High-Risk Exposure History

Inhalation injury should be suspected based on the following exposure and environmental factors:

• Fire in an enclosed space is the single most important historical feature that should trigger suspicion 3, 1, 2
• Exposure to vapors or inhaled smoke in any confined area 1, 2
• Duration of smoke exposure correlates with severity of airway injury 4

Physical Examination Findings

Look for these specific clinical signs that indicate possible inhalation injury:

• Carbonaceous (blackish) sputum is the most indicative finding of actual smoke inhalation into the lower airways 2
• Soot on the face, around the nose, or in the mouth 1, 2
• Singed nasal hairs or facial hair 1, 2
• Facial burns, particularly involving the whole face 1
• Deep circular neck burns 1
• Dysphonia (hoarse voice) 3, 1

Respiratory Symptoms

Any of these respiratory manifestations should heighten suspicion:

• Dyspnea or difficulty breathing 3, 1
• Wheezing 3, 1, 2
• Stridor 1
• Respiratory distress of any degree 3, 1

Critical Diagnostic Pitfall

Normal initial diagnostic tests do NOT exclude inhalation injury and should not provide false reassurance. 1, 2 Specifically:

• Normal oxygen saturation (>90%) does not exclude inhalation injury 1, 2
• Normal chest X-ray does not exclude inhalation injury 3, 2
• Normal arterial blood gases do not exclude inhalation injury 3, 1
• Normal FEV1/FVC ratio cannot exclude inhalation injury 2
• Normal bronchoscopy findings do not completely exclude injury 2

Pediatric Considerations

Inhalation injury is less common in children (incidence 4.5% before age 12) because most pediatric burns result from scalding rather than fire 3. However:

• When present, smoke inhalation increases pediatric mortality three-fold 3, 1
• Children with TBSA <10% and smoke inhalation are 10 times more likely to die than similar children without inhalation 3
• Do NOT intubate children burned by hot fluid (scalding) solely based on facial/neck burns in the absence of respiratory distress 3

Immediate Management Implications

Once inhalation injury is suspected:

• Activate emergency medical services immediately, as airway obstruction from edema can develop rapidly and unpredictably 1
• Administer 100% high-flow oxygen immediately without waiting for pulse oximetry or blood gas results 1
• Provide continuous high-dependency monitoring with frequent airway reassessments 1
• Maintain head-up positioning and keep the patient nil-by-mouth 1
• Arrange early specialist consultation from a burn center team 1
• Perform regular reassessment for progressive airway edema, as injury can evolve over time 2

When to Intubate Immediately

Proceed with immediate intubation without delay if any of these features are present:

• Severe respiratory distress 1
• Severe hypoxia or hypercapnia 1, 5
• Coma or altered mental status 1, 5
• Symptoms of airway obstruction 1
• Deep circular neck burn with severe burns involving the whole face 1
• Very extensive burns (TBSA ≥40%) with facial involvement 1

Role of Bronchoscopy

• Flexible bronchoscopy is the gold standard for confirming smoke inhalation injury 3, 1, 2
• Severity of bronchoscopic lesions correlates with morbidity, ICU length of stay, duration of mechanical ventilation, and hypoxemia severity 3, 1, 2
• Bronchoscopy should only be performed in patients who are already intubated due to risk of clinical deterioration during the procedure 3, 1
• Bronchoscopy should not delay transfer to a burn center 3, 1