Overview
Definition:
Postextubation stridor is a common complication following endotracheal intubation, characterized by a high-pitched, noisy respiration that occurs when airflow is partially obstructed in the upper airway, typically above the vocal cords
It signifies edema or injury to the subglottic or glottic regions
Racemic epinephrine and corticosteroids are key pharmacological agents used in its management.
Epidemiology:
The incidence of postextubation stridor varies widely, ranging from 2% to 25% in pediatric populations, depending on factors such as duration of intubation, endotracheal tube size, patient age, and underlying airway pathology
Factors increasing risk include prolonged intubation (>48-72 hours), repeated intubation attempts, and a large endotracheal tube relative to the patient's trachea.
Clinical Significance:
Postextubation stridor can lead to significant patient distress, increased work of breathing, hypoxemia, and in severe cases, reintubation
Effective management is crucial to prevent airway compromise, reduce hospital length of stay, and avoid the morbidity associated with reintubation
Understanding the role of racemic epinephrine and steroids is vital for pediatric residents preparing for DNB and NEET SS examinations.
Clinical Presentation
Symptoms:
Audible inspiratory stridor
Increased work of breathing
Tachypnea
Retractions (suprasternal, intercostal)
Barking cough
Hoarseness
Restlessness and irritability
Reduced air entry on auscultation.
Signs:
High-pitched, inspiratory noise heard best over the neck
Presence of retractions
Nasal flaring
Use of accessory muscles of respiration
Cyanosis in severe cases
May have decreased or absent vocal cord movement on laryngoscopy.
Diagnostic Criteria:
Diagnosis is primarily clinical, based on the presence of audible stridor after endotracheal tube removal
Objective assessment of severity can be done using scoring systems like the Modified Stridor Score or objective measures of respiratory distress
Flexible laryngoscopy or bronchoscopy may be used to visualize the airway and identify the site and extent of edema or injury.
Diagnostic Approach
History Taking:
Detailed history of intubation duration
Endotracheal tube size and type
Number of intubation attempts
History of previous airway procedures
Underlying conditions predisposing to airway edema (e.g., viral infections, allergies)
Presence of symptoms prior to intubation (e.g., croup, stridor).
Physical Examination:
Assess respiratory rate, depth, and pattern
Observe for signs of increased work of breathing (retractions, nasal flaring)
Auscultate lungs for air entry and adventitious sounds
Palpate for crepitus
Examine the neck for tenderness or swelling
Assess for signs of systemic illness or allergy.
Investigations:
While often a clinical diagnosis, flexible laryngoscopy or bronchoscopy can confirm the diagnosis, assess severity, and identify the specific site of airway compromise (glottic, subglottic, tracheal edema)
Chest X-ray is generally not helpful for stridor itself but may identify associated pneumonia or other pulmonary pathology
Blood gas analysis can assess for hypoxemia or hypercapnia
White blood cell count may be elevated in cases of infection.
Differential Diagnosis:
Croup (laryngotracheobronchitis)
Laryngomalacia/Tracheomalacia
Foreign body aspiration
Bacterial tracheitis
Vocal cord paralysis
Allergic reaction (anaphylaxis)
Bronchiolitis
Post-operative surgical airway complications.
Management
Initial Management:
Assess airway patency and degree of respiratory distress
Administer humidified oxygen
Monitor vital signs, including oxygen saturation and respiratory rate closely
Elevate the head of the bed to improve ventilation.
Medical Management:
Racemic epinephrine: typically administered via nebulizer (0.05 mL/kg of 1:1000 solution, maximum 0.5 mL diluted in 3 mL saline)
It causes vasoconstriction of mucosal vessels, reducing edema
Effects are temporary (duration ~2 hours), requiring repeated doses
Corticosteroids: Dexamethasone (0.5-1 mg/kg IV/IM) or Methylprednisolone (1-2 mg/kg IV) are often given to reduce inflammation and edema
Onset of action is delayed (4-6 hours)
Monitor for side effects of steroids
Antibiotics are indicated if bacterial tracheitis or pneumonia is suspected.
Surgical Management:
Reintubation is indicated for severe stridor with signs of airway compromise, hypoxemia, significant hypercapnia, or failure to respond to medical therapy
Tracheostomy may be considered for prolonged or recurrent stridor unresponsive to medical management, or in cases of severe, long-standing subglottic stenosis.
Supportive Care:
Continuous pulse oximetry monitoring
Maintain adequate hydration
Pain and sedation management if indicated, but cautiously to avoid masking respiratory distress
Close observation for signs of worsening respiratory status
Regular pulmonary toilet to clear secretions.
Complications
Early Complications:
Respiratory failure requiring reintubation
Hypoxemia
Hypercapnia
Airway trauma from repeated intubation attempts
Pneumonia
Otitis media due to prolonged intubation.
Late Complications:
Subglottic stenosis
Tracheal granulomas
Voice changes
Chronic airway issues
Recurrent stridor
Psychological impact on the child and family.
Prevention Strategies:
Use of appropriate size endotracheal tube (avoiding excessive pressure on mucosa)
Minimize duration of intubation
Use of uncuffed tubes in neonates and young infants when feasible
Gentle intubation technique
Judicious use of sedation to allow for spontaneous breathing trials when appropriate
Consider airway assessment (laryngoscopy) prior to extubation in high-risk patients.
Prognosis
Factors Affecting Prognosis:
Severity of stridor at presentation
Underlying cause of airway injury
Response to medical therapy
Development of complications like subglottic stenosis
Duration of intubation
Age of the patient.
Outcomes:
Most cases of mild to moderate postextubation stridor resolve with medical management within 24-72 hours
Severe stridor or complications may necessitate reintubation or surgical intervention, impacting the long-term outcome
Early and appropriate management improves prognosis.
Follow Up:
Patients with significant stridor, recurrent episodes, or evidence of subglottic stenosis require close follow-up with pediatric pulmonology or otolaryngology
This may involve repeat laryngoscopy/bronchoscopy, voice assessments, and monitoring for respiratory symptoms
Education of parents on warning signs is crucial.
Key Points
Exam Focus:
Racemic epinephrine is a vasoconstrictor that reduces mucosal edema
its effect is temporary
Corticosteroids reduce inflammation
their effect is delayed
Reintubation is indicated for severe respiratory distress or failure of medical management
Prevention strategies are crucial for minimizing incidence.
Clinical Pearls:
Always assess the airway after extubation, especially in at-risk patients
A trial of humidified air and observation for 1-2 hours post-extubation can help identify early stridor
Doses of racemic epinephrine are per kg and capped
Steroids take time to work, so combine with epinephrine initially for moderate stridor.
Common Mistakes:
Underestimating the severity of stridor
Delaying reintubation in a deteriorating patient
Relying solely on steroids without immediate-acting agents like epinephrine for significant stridor
Failing to counsel parents about potential recurrence or warning signs
Not considering differential diagnoses of upper airway obstruction.