Foreign body in the airway

Pathophysiology and Effect on Respiration

The entry of a foreign body (along with inflammatory edema, trauma, or croup) is one of the main causes of laryngeal stenosis.

When the glottis narrows, the carbon dioxide content in the blood rises rapidly (hypercapnia). This triggers a compensatory restructuring of the entire respiratory act: to deliver the required volume of air into the lungs, inspiration becomes significantly more prolonged, while expiration and the pause between respiratory movements become shorter. Clinically, this condition manifests as inspiratory dyspnea (the patient has difficulty inhaling).

Clinical stages of laryngeal stenosis

The severity of the condition and emergency care tactics depend on the degree of airway lumen narrowing. Four consecutive stages are distinguished:

1. Stage I (compensation). The width of the glottis is 5–6 mm. Respiratory regulation successfully compensates for the narrowing. Breathing becomes noisy, and the respiratory rate decreases. Inspiration is noticeably prolonged, while expiration is sharp and short. Dyspnea appears only upon physical exertion. The patient is calm.
2. Stage II (subcompensation). The glottis narrows to 4–5 mm. Breathing is performed with immense effort, and the pause between inspiration and expiration disappears. Retraction of compliant chest areas (intercostal spaces, supraclavicular fossae) is objectively noticeable. The patient assumes a forced position: sitting with the head thrown back and hands resting on the edge of the bed. Agitation and acrocyanosis appear.
3. Stage III (decompensation). The lumen is narrowed to 2–3 mm. Extreme agitation develops: the patient tosses about, experiences severe fear ("eyes bulging"), and tears clothing off the neck. The skin becomes covered in cold, sticky sweat, and the face acquires a purple-cyanotic hue. Breathing becomes frequent and shallow, the chest is almost immobile, and the larynx makes sharp up-and-down movements. The voice and cough become silent, and tachycardia increases.
4. Stage IV (asphyxia). The glottis width is 1 mm or less. Consciousness is confused or completely absent. Breathing is undetectable or acquires a pathological pattern (Cheyne-Stokes respiration). The skin is pale and cyanotic, and the pupils are markedly dilated. Cardiac activity still continues, but without emergency care, a fatal outcome ensues.

Aspiration in Newborns

A special variant of airway obstruction is aspiration in infants. The foreign body in this case is milk (due to choking during feeding) or amniotic fluid mixed with meconium.

This leads to neonatal asphyxia, the severity of which is assessed using the Apgar score at the 1st and 5th minutes of life, as well as blood acid-base balance (ABB) parameters. In severe asphyxia (0–3 Apgar points), cord blood pH drops below 7.0, and the buffer base deficit reaches -15 mEq/L.

In amniotic fluid aspiration, the initial stage of resuscitation is the immediate restoration of airway patency: tracheal intubation is performed followed by suctioning of the tracheobronchial tree.

Diagnostic Algorithm and Emergency Care

In acute injuries such as foreign body aspiration, the patient is often uncooperative (lethargic, aggressive, or unconscious). A full examination in the first minutes is impossible.

Priority actions:

• Assessment of the general condition and identification of life-threatening disorders (acute respiratory failure, shock).
• Diagnosis is performed strictly in parallel with resuscitation measures.

Emergency care:

• For foreign bodies, first aid is provided using the chest thrust method.
• If spontaneous breathing is absent or inadequate (convulsive, shallow), artificial lung ventilation (ALV) with an Ambu bag via a mask or endotracheal tube is indicated.
• If heart rate drops below 80 beats per minute against the background of ALV (in children), chest compressions on a hard surface are immediately started at a rate of 2 compressions per second.

Class and exam questions

What else to study on this topic

• Differential diagnosis of causes of laryngeal stenosis (edema, trauma, false croup)
• Algorithm for establishing a provisional and clinical diagnosis in acute injuries
• Indications and technique for performing artificial lung ventilation (ALV) with an Ambu bag
• Assessment of the severity of neonatal asphyxia using the Apgar scale and blood ABB
• Technique for performing chest compressions in newborns

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.