Smoke Inhalation

Sanjay V. Mehta MD, MEd, FRCPC, FAAP, FACEP

EPIDEMIOLOGY

Most life-threatening burns are from house fires, followed by ignition of non-flameretardant clothes.
Of fire-related deaths in children, 82% die at the scene of the fire, 7% die at local hospitals, and 11% die at burn centers.¹
House fires victims have a higher case fatality rate compared to burns from other causes, presumably from the added trauma of an inhalation injury.
Pulmonary failure is one of the leading causes of death in the burn patient, with a 3.6-fold increase in the death rate as the result of concomitant burn and inhalation injury.
- Children under 3 years are at a higher risk both with and without inhalation injury.

PATHOPHYSIOLOGY

The airway is most commonly affected by smoke, superheated air, and/or steam.
- Frequently occurs in the absence of significant burns.
Inhaling hot gases burns the upper airway, leading to progressive edema and airway obstruction.
- Heat, asphyxiants, particulate matter, and irritants damage the airway.
- Lower airway injury is from exposure to toxic combustion products.
Numerous chemicals are produced in house fires: Hydrochloric acid, chlorine gas, carbon monoxide (CO), acrolein, aldehydes, benzene, phosgene, and cyanide.
- Can cause chemical asphyxia, local anesthesia, and mucosal and cellular damage.
- Pulmonary irritation can lead to:
  - Bronchospasm.
  - Increased secretions.
  - Debris.
  - Atelectasis.
  - Acute respiratory distress syndrome.
Respiratory failure can result from:
- Loss of airway patency.
- Bronchospasm.
- Pulmonary edema.
- Diminished ciliary activity.
- Intrapulmonary shunting from small airway occlusion (i.e., bronchiolar obstruction).
- Diminished lung compliance.
- Pneumonia.

CLASSIFICATION

INITIAL MANAGEMENT

Maintain ABCs.
Provide 100% oxygen.
When to consider smoke inhalational injury²,³:
- Altered mental status.
- Chest pain.
- Dyspnea.
- Respiratory compromise.
- Need for cardiopulmonary resuscitation on-scene.
- Burn in a closed space.
- Potential CO poisoning.
Intubation should be considered if (Table 15-1):
- Upper airway patency is threatened.
- Gas exchange or lung compliance is altered.
- Mental status is altered.
Early intubation prevents the later, difficult intubation of a child with severe pharyngeal and subglottic swelling.
- Ensure bag-valve mask ventilation is possible before attempting laryngoscopy.
- If rapid-sequence intubation is required, consider:
  - Backup with ENT and anesthesia.
  - Having alternative, difficult airway equipment ready (e.g., difficult airway cart with fiberoptic laryngoscope, gum bougie, and surgical airway equipment).
  - Ketamine for sedation if any evidence of bronchospasm.
  - Using a narrower, reinforced tube.
  - See Chapter 3 on Airway Management for details.
- If successful intubation, do not cut the endotracheal tube.
  - Oropharyngeal edema will progressively increase and require a longer tube over the next 1 to 3 days.
If unable to oxygenate or ventilate, needle cricothyroidotomy is needed.
- See Chapter 21 on Procedures for details.
Consider at least two large-bore intravenous cannulae to provide fluid resuscitation, as in all trauma patients.

EVALUATION

History

Associated trauma.
Impaired mentation.
Confinement in a closed, burning environment with gas, fumes, or steam exposure.
Nature of materials at scene, and agents involved (grease, oil, plastic substances, fumes, chemical exposure, etc.).