OVERVIEW

What is inhalation injury?

Inhalation injury, commonly known as respiratory tract burns, refers to damage to the respiratory tract or even lung tissue caused by heat and/or smoke (primarily high-temperature steam, flames, hot liquids, etc.). It has a high incidence and mortality rate and is currently one of the leading causes of death from burns.

How do inhalation injuries differ between children and adults? What aspects require attention?

The differences in the progression, diagnosis, and treatment of inhalation injuries between children and adults primarily stem from the unique anatomical and physiological characteristics of a child's respiratory system.

Therefore, if a child is suspected of having moderate or severe inhalation injury, endotracheal intubation or tracheotomy (tracheotomy is preferred whenever possible) should be performed as early as possible. Special attention must be paid to airway care, including enhanced humidification and lavage. Mechanical ventilation parameters should be adjusted according to the characteristics of a child's airway. Additionally, differences in fluid volume and infusion rate, as well as medication dosages compared to adults, must be carefully considered.

Families who understand these points can better cooperate with medical staff for efficient treatment. Necessary treatments should be administered promptly without excessive hesitation.

SYMPTOMS

Under what circumstances does inhalation injury commonly occur?

Consider the possibility of inhalation injury if the following conditions are present after a burn:

• Burns occurring in an enclosed environment;

• History of loud cries or running in the fire scene;

• Burns on the face, neck, and anterior chest, especially deep burns around the mouth and nose;

• Singed nasal hair, swollen lips, redness and blisters in the oral cavity and pharynx, or pale mucous membranes;

• Irritating cough with carbon particles in the sputum;

• Hoarseness, difficulty or pain when swallowing;

• Shortness of breath and/or wheezing (a whistling sound in the throat).

None of the above conditions alone can definitively confirm or rule out a diagnosis of inhalation injury. Further objective auxiliary examinations are required for a final diagnosis.

What are the main manifestations of inhalation injury?

The main manifestations of inhalation injury include:

• Frequent presence of burns on the face, neck, and anterior chest, singed nasal hair, swollen lips, etc.;

• Hoarseness and stridor;

• Irritating cough with a "gong-like" sound, accompanied by pain. Carbon particles or blood in the sputum;

• Shortness of breath and flaring nostrils;

• Possible toxic symptoms, such as impaired consciousness, convulsions, or even coma.

What is the most severe consequence of inhalation injury?

Moderate to severe inhalation injury often rapidly leads to respiratory distress, refractory hypoxemia, airway obstruction due to shedding of damaged mucosa, and massive bleeding, all of which can result in coma, respiratory failure, or even sudden death.

According to incomplete statistics, the mortality rate of inhalation injury ranges from 16.3% to 31.42% or even higher.

Is inhalation injury combined with pre-existing lung disease more severe?

Yes.

In the early stages of inhalation injury, the severity depends on the intensity of the causative factors (e.g., high-temperature steam, flames, hot liquids) and is less related to pre-existing lung conditions.

However, during treatment and recovery, pre-existing lung diseases reduce local resistance and limit the lung's compensatory and regenerative capacity, making recovery from inhalation injury more difficult and prolonged, with a higher likelihood of complications.

CAUSES

Can inhaling smoke at a fire scene cause poisoning?

Possibly.

Large amounts of smoke at a fire scene can lead to systemic poisoning. The manifestations of poisoning vary depending on the burning materials, especially with the development of modern building materials, making the toxic components more complex. Common chemical poisonings include:

• Carbon monoxide poisoning: Caused by incomplete combustion of materials at the fire scene, leading to systemic hypoxia.

• Cyanide poisoning: Certain inorganic cyanides, such as acetonitrile, acrylonitrile, and isocyanates, rapidly release cyanide ions in the body, inhibiting mitochondrial function and oxygen utilization. This causes severe hypoxia.

• Arsenic poisoning: In confined spaces or fire scenes caused by fireworks, arsenic levels rise sharply, leading to systemic poisoning and local irritation symptoms.

Is inhalation injury inevitable at a fire scene? How can it be minimized?

Blindly shouting for help or running without protective measures significantly increases the risk of inhalation injury. Incomplete statistics show that the incidence of inhalation injury at fire scenes ranges from 16% to 25% or even higher.

To minimize inhalation injury, stay calm, avoid running or shouting blindly, quickly open doors and windows for oxygen, and cover your nose and mouth with a thick wet towel (or other cotton fabric if unavailable). Since smoke rises, stay low to the ground when moving through thick smoke.

Can inhalation injury occur in electrical or chemical burn patients?

Strictly speaking, electrical and chemical burns do not directly cause inhalation injury. However, inhaling vaporized chemicals or accidentally ingesting them, as well as smoke from high-voltage-induced tissue carbonization, can still lead to varying degrees of inhalation injury.

DIAGNOSIS

What tests are needed for inhalation injury?

Common diagnostic tests for inhalation injury include:

• Chest X-ray or CT scan: A non-invasive test to preliminarily assess the presence and severity of inhalation injury.

• Fiberoptic bronchoscopy: A minimally invasive procedure that directly visualizes airway damage to confirm inhalation injury.

• Pulmonary function tests (airway patency, oxygenation, etc.): Primarily help indirectly evaluate the severity of inhalation injury.

• Other laboratory tests (blood gas analysis, carboxyhemoglobin, blood cyanide concentration, plasma lactate, etc.): Aid in diagnosis and severity assessment.

Due to the acute onset and critical condition of inhalation injury (especially moderate to severe cases), both outpatient and bedside tests carry significant risks. Combined with poor patient tolerance and the fact that most tests are not the "gold standard" for diagnosis, inhalation injury is primarily diagnosed clinically based on symptoms and medical history. Auxiliary tests serve only as indirect evidence.

What is the most reliable test for diagnosing inhalation injury?

Fiberoptic bronchoscopy is the most direct and accurate method for diagnosing inhalation injury. It allows direct visualization of major airway damage, enables pathological tissue sampling, and can also be used for treatment, making it the primary diagnostic and therapeutic approach.

How is the severity of inhalation injury classified?

Inhalation injury is categorized into three severity levels:

• Mild inhalation injury: Lesions are limited to the mouth, nasal cavity, and pharynx. The condition is relatively mild with a good prognosis.

• Moderate inhalation injury: Lesions primarily affect the pharynx, larynx, and bronchi. The condition is more severe, with a generally good prognosis, but complications (e.g., infection, bleeding) may affect outcomes.

• Severe inhalation injury: Lesions extend to the bronchi, bronchioles, or even alveoli. The condition is critical with a poor prognosis.

Clinically, moderate and severe inhalation injuries are further divided into four stages (which may overlap or transition, making clear distinctions difficult) to assist in evaluating disease progression:

• Acute respiratory insufficiency stage;

• Pulmonary edema stage;

• Pulmonary infection stage;

• Recovery stage.

Mild inhalation injury typically lacks distinct clinical stages.

TREATMENT

Does inhalation injury require hospitalization?

It depends.

Patients with mild inhalation injury diagnosed clinically may not need hospitalization but should remain under observation; moderate and severe inhalation injuries require hospitalization.

Which department should treat inhalation injury?

Inhalation injury falls under the scope of burn surgery and should be treated in the burn department. During treatment, the respiratory department may participate in consultations to provide relevant diagnostic and treatment recommendations.

Does inhalation injury require surgery?

Generally, airway and lung injuries caused by inhalation injury do not require surgical treatment.

Early emergency measures include tracheotomy (a vital method to maintain airway patency and save lives) and thoracotomy for hemostasis.

Later complications such as subglottic stenosis, endobronchial polyps, bronchiectasis, vocal cord fixation or fusion, and dysphonia may require interventional or surgical treatment.

How is inhalation injury treated?

In brief, treatment for inhalation injury includes: oxygen therapy, relieving airway obstruction and maintaining airway patency, treatment for poisoning, mechanical ventilation (respirator), airway humidification and lavage, fluid therapy, infection prevention, exogenous pulmonary surfactant therapy (using medication to restore alveolar function), extracorporeal membrane oxygenation (a specialized and complex treatment to improve hypoxia), and systemic supportive therapy.

Are anti-inflammatory drugs needed for inhalation injury?

Infections in inhalation injury mainly arise from four sources: weakened respiratory defense post-injury, respiratory lesions (bleeding, secretions, etc.) post-injury, iatrogenic factors, and hematogenous infections from wounds.

Therefore, early oral or intravenous anti-inflammatory and anti-infection treatment is recommended for inhalation injury.

Can inhalation injury be completely cured?

Not necessarily.

There have been reports of complete recovery from inhalation injuries of any severity. Mild inhalation injuries have fewer complications and sequelae during treatment, with better prognoses, while moderate and severe inhalation injuries have more and more severe complications and sequelae, with poorer prognoses.

When does a patient with inhalation injury require a tracheotomy?

• Mechanical obstruction of the upper airway, especially in cases of deep burns to the face, neck, or chest, where edema fluid accumulates in the soft tissues of the neck and laryngopharynx, worsening upper airway obstruction.

• Respiratory irritation, excessive and thick secretions, weak cough, and blockage of the trachea by large amounts of sputum and necrotic tissue.

• Burns around the face, mouth, or nose, hoarseness, and rapidly worsening edema with potential laryngeal obstruction.

• Severe burns requiring prone positioning, which may exacerbate laryngeal edema and airway obstruction.

• Severe lung injury requiring mechanical ventilation.

• Concurrent severe chest or brain trauma.

• Difficulty in endotracheal intubation.

• Expected prolonged endotracheal intubation or inability to extubate within a short time.

These indications are not rigid rules but should be managed based on the patient's actual clinical condition.

How to effectively remove sputum crusts, blood crusts, and secretions from the airway in inhalation injury?

• In nursing, frequent position changes, turning, and back patting should be performed, encouraging deep breathing and coughing. Each suction should follow sterile procedures, with gentle actions and controlled duration.

• In treatment, focus on airway humidification and lavage. For patients without an artificial airway (e.g., endotracheal intubation or tracheotomy), humidification is mainly achieved through nebulization. For those with an artificial airway, humidification is enhanced through nebulization and continuous airway drip. Patients on ventilators should use machines with humidification devices. If conventional suction methods fail to remove thick secretions and necrotic tissue, lavage and suction can be performed under bronchoscopic guidance.

These measures may seem to prevent complete rest or cause discomfort, but they are essential. Family members should assist medical staff in persuasion and encouragement.

When does a patient with inhalation injury require ventilator treatment?

When heat or inhaled substances cause severe lung damage, or when hypoxia cannot be improved by oxygen therapy alone, a ventilator (mechanical ventilation) is needed.

Indications for ventilator use in inhalation injury:

• PaO₂ remains below 70 mmHg despite high-concentration oxygen.

• Respiratory rate consistently exceeds 40 breaths/min; PaCO₂ is below 25 mmHg or above 45 mmHg.

• PaO₂/FiO₂ is below 300 mmHg or progressively declining.

These indications are not rigid rules but should be managed based on the patient's actual clinical condition.

Can inhalation injury cause adverse effects after recovery?

It depends.

• Mild inhalation injury can heal completely without sequelae.

• Moderate and severe inhalation injuries, especially severe ones, may leave sequelae such as subglottic stenosis, bronchial asthma, or pulmonary fibrosis.

Some sequelae may improve with treatment, while others may not.

What are the new developments in inhalation injury treatment?

Overall, treatment for inhalation injury still follows conventional methods, including oxygen therapy and mechanical ventilation. Some theoretical and pharmaceutical updates may exist but offer limited clinical benefits.

In mechanical ventilation, high-frequency oscillatory ventilation and extracorporeal membrane oxygenation are newer methods with good clinical outcomes, expected to play significant roles in future inhalation injury treatment.

In lung tissue repair for inhalation injury, stem cell transplantation has shown promising results in animal experiments and is likely to become an important treatment method.

Additionally, some anti-inflammatory treatments (antagonists) have shown effects but require further clinical validation.

Patients and families should seek treatment at正规 hospitals and avoid unverified remedies.

How to treat poisoning caused by inhalation injury?

• Carbon monoxide poisoning: Quickly remove the patient from the fire scene and provide oxygen or mechanical ventilation. Severe cases may require hyperbaric oxygen therapy.

• Cyanide poisoning: Administer specific antidotes early, such as amyl nitrite inhalation or injection.

• Arsenic poisoning:

  • Induce vomiting, gastric lavage, and cleansing to eliminate toxins.
  • Administer specific antidotes like sulfhydryl drugs.
  • Hemodialysis or hemoperfusion can help remove arsenic and mitigate renal failure effects.
  • Other symptomatic and supportive treatments.

DIET & LIFESTYLE

What should patients with inhalation injury pay attention to in their diet?

Generally, there are no special dietary requirements for inhalation injury. It is recommended to choose easily digestible high-protein foods. In addition to three main meals a day, dietary arrangements can be adjusted based on overall nutritional status. Foods rich in vitamin A, vitamin E, and vitamin C are advised, while animal fats, sweets, and spicy or irritating foods should be consumed sparingly.

What should patients with inhalation injury pay attention to during recovery?

During the recovery period from inhalation injury, both local lung function and overall immunity remain relatively weak.

• Ensure adequate rest and maintain a regular daily routine;
• Strengthen nutritional support, focus on supplementing foods rich in vitamin C and vitamin E, eat smaller meals more frequently, and monitor blood sugar and lipid levels;
• Strictly avoid smoking and excessive alcohol consumption;
• Maintain personal hygiene, and seek medical attention promptly if cold symptoms appear;
• Engage in moderate exercise, particularly lung function exercises, but avoid overexertion and progress gradually.

PREVENTION

How to Avoid Inhalation Injuries at a Fire Scene

• Stay calm and identify the escape route. Thick smoke severely impairs visibility, often making it difficult to determine the direction to flee. Remain composed, avoid rushing blindly, first identify the fire source and the direction of toxic smoke flow, then avoid high-smoke areas and move upwind of the fire.

• Isolate smoke. Immediately close doors and windows connected to smoke-filled areas, and seal gaps with wet cloth to block toxic fumes.

• Secure fresh air. Open passages to smoke-free outdoor areas to maintain sufficient oxygen indoors.

• Protect airways. Cover your nose and mouth with a thick, wet towel. If unavailable, use other cotton fabrics, which can filter 60%-100% of smoke and 10%-40% of carbon monoxide.

• Escaping through smoke. If smoke is light, walk bent over; if dense, crawl close to the ground (within 30 cm). Smoke rises, so stay low when passing through thick smoke.