Stridor

Stridor is a harsh breathing noise produced by obstruction in the larynx or trachea. Mostly during inspiration.

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What causes stridor?

• Most often, stridor is caused by croup.
• High degree of overlap of clinical manifestations.
• Supplemental oxygen therapy can be misleading because a child in severe distress may turn pink while on oxygen.

How does stridor manifest itself?

• Acute partial obstruction of the upper respiratory tract is manifested by stridor and increased work of breathing - retraction of the pliable areas of the chest and the participation of accessory muscles.
• Signs of deterioration requiring urgent intervention include hypoxia, fatigue, changes in level of consciousness, and increased work of breathing.
• Caution towards children who show no interest in their surroundings.

How is stridor recognized?

Compare SpO2 in air and 100% oxygen.

Differential diagnosis

• Croup - rough barking cough, fever, looks bad, but progresses favorably.
• Epiglottitis - intoxication, no cough, low stridor on inhalation and exhalation, salivation.
• Foreign body - sudden onset without prodromal period, cough, suffocation and aphonia.
• Anaphylaxis - swelling of the face and tongue, wheezing in the lungs, urticarial rash.
• Retropharyngeal abscess - high fever, neck tension, dysphagia, accumulation of secretory products.
• Bacterial tracheitis - intoxication, pain in the projection of the trachea.
• Pre-existing stridor - congenital anomalies, laryngomalacia, or subglottic stenosis.

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What should be done if there is stridor?

• It is better to leave the child sitting quietly in a comfortable position on the parent's lap.
• Examine carefully without touching the child.
• Assess the severity of respiratory distress and make assumptions about the most likely cause of what is happening.
• If the condition worsens, prepare for intubation.

Anesthesia in a child with airway obstruction

• Seek help from a more experienced anesthesiologist and ENT specialist.
• Inhalation induction in the operating room in a calm environment.
• 100% O2 and sevoflurane (or halothane if experienced; halothane is preferred for maintaining depth of anesthesia).
• Induction can be performed with the child sitting alone or on a parent's lap if this position provides the best airway patency.
• PPD with a face mask - if the child tolerates it.
• Achieving adequate depth of anesthesia will take some time.
• Maintain spontaneous breathing, constantly monitoring whether it is possible to ventilate with a bag. If yes, if necessary, gently assist inhalation, trying not to distend the stomach. As soon as sufficient depth of anesthesia is achieved - direct laryngoscopy without muscle relaxants. Intubate if possible - a tube significantly smaller than would be expected with croup may be required (do not cut the ETT in advance). Intubation can be difficult with epiglottitis - look for air bubbles coming out of the glottis when it opens. Then insert a guide bougie and lead the ETT through it. In most cases, an experienced anesthesiologist can intubate a child with stridor; rigid bronchoscopy in the hands of an experienced ENT surgeon can be life-saving.

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Further management

• After intubation, maintain anesthesia (intravenous propofol infusion or inhalational anesthetic).
• Dexamethasone 0.6 mg/kg intravenously may be useful if not given previously.
• Transfer to pediatric intensive care unit.
• Cefotaxime intravenously 50 mg/kg every 6 hours or ceftriaxone intravenously 50 mg/kg every 12 hours (epiglottitis).
• Extubation: Dexamethasone is often given (IV 0.25 mg/kg every 6 hours for 2 or 3 doses) at least 6 hours before extubation. A small air leak around the ETT should be present at 20 cm H2O before attempting extubation.
• Soft tissue radiography usually does not add useful information. Even if there is a leak, in some cases reintubation will still be required due to swelling.