Upper Airway Obstruction: Causes, Management

Introduction

The upper airway includes the nose, nasopharynx, oropharynx, and Larynx. The larynx also includes supraglottis, glottis, and subglottis. Upper airway obstruction (UAO) is one of the most serious emergencies.  Early diagnosis, followed by restoration of airflow, is essential to prevent cardiac arrest or irreversible brain damage that occurs within minutes of complete airway obstruction.

Upper Airway Obstruction can occur at any level of the upper respiratory tract, but the laryngeal obstruction is particularly important because the larynx is the narrowest portion of the upper airway. In adults, the glottis is the narrowest part of the larynx. In pediatric patients, the subglottis is the narrowest. Obstructions at the level of the larynx are particularly high risk.

Causes of Upper Airway Obstruction in Adults

• Foreign bodies
• Trauma
• Tumours
• Infections
• Neoplasms
• Vascular malformations
• Extrinsic compressions from neighboring structures.

Management of Upper Airway Obstruction in Adults

The key to managing a patient with upper airway obstruction is identifying the cause. Once the cause is identified, appropriate medical and surgical interventions can be employed to restore the airway.

Differential Diagnosis of Upper Airway Obstruction According to Etiology

• Traumatic Causes
  • Laryngeal stenosis 
  • Trauma.
  • Burns in the airway.
  • Acute laryngeal injury from penetrating or blunt trauma.
  • Facial injuries from road traffic accidents, falls, or other accidents.
  • Haemorrhages:
    • Nasopharynx bleeding.
    • Post-adenoidectomy bleeding.
    • Oropharynx bleeding after a tonsillectomy.
    • Larynx bleeding after laryngeal surgery.
    • Hypopharyngeal lesions causing bleeding.
• Infectious Causes
  • Suppurative parotitis (partial obstruction).
  • Peritonsillar abscess or adenoiditis.
  • Ludwig's angina.
  • Epiglottitis.
  • Laryngotracheobronchitis (or croup).
  • Diphtheria.
  • These are more common in children and often cause partial obstruction.
• Iatrogenic Causes
  • Tracheal stenosis post-tracheostomy.
  • Subglottic or tracheal stenosis post-intubation.
  • Mucus ball obstruction from the trans tracheal catheter.
• Foreign Bodies and Vocal Cord Paralysis
  • Foreign bodies (especially common in children).
  • Vocal cord paralysis, especially after thyroidectomy due to recurrent pharyngeal nerve injury leading to Stridor.
  • Bilateral RLN palsy causing stridor.
  • Superior laryngeal nerve palsy leads to indirect obstruction from aspiration (more related to the lower airway).
• Tumours
  • Laryngeal papillomatosis.
  • Tracheobronchial tumours cause airway narrowing.
• Allergic Reactions
  • Angioedema due to:
  • Food allergens.
  • Aero allergens.
  • Drug exposure leads to hypersensitivity.
  • The resulting laryngospasm can cause acute upper airway obstruction.

Pathology of Upper Airway Obstruction

• Laryngeal Amyloidosis
  • A condition where narrowing of the distal trachea occurs.
  • The narrowing is attributed to an extrinsic compression from outside the tracheal lumen.
  • Possible extrinsic factors causing the compression include vascular obstructions or malignancies.
• Foreign Body
  • A significant cause of airway obstructions.
  • This should be a primary consideration when there's a suspected possibility of airway collapse.
• Epiglottitis
  • Epiglottitis is a pediatric emergency characterized by inflammation of the airway structures. Direct examination of the epiglottis or larynx is ideally avoided. If the airway is secured with intubation, an examination can be safely performed. The avoidance of direct examination is due to the risk of triggering laryngospasm, which can cause airway obstruction.
  • The diagnosis is primarily based on history, clinical examination, and X-ray. Direct or fiber optic examination is rarely done. Before any laryngeal examination, the airway is first secured through tracheostomy or intubation.
• Peritonsillar Abscess
  • The presence of a peritonsillar abscess can lead to upper airway obstruction, which typically results in partial obstruction.

Clinical signs and symptoms of Upper Airway Obstruction

• Cough
• Dyspnoea: Most Important Symptom
• Noisy breathing, which can manifest as:

• Stertor: Low-pitched noise from pharyngeal airway collapse.
• Stridor: High-pitched noise from the collapse of the laryngeal or tracheal airway.

• Voice change: The airway plays a role in voice production, and obstructions can affect voice quality.
• Throat pain and neck pain.
• Dysphagia
• Odynophagia
• Drooling of saliva.
• Use of accessory muscles of respiration, indicating increased effort to breathe.
• The feeling of choking or suffocation.

Types of Upper Airway Obstruction

1. Complete Upper Airway Obstruction

• Rapidly progressing series of events.
• Quick action is crucial in cases of complete airway obstruction.
• The universal choking sign is a key indicator, prompting immediate intervention.

2. Partial Upper Airway Obstruction

• Signs and symptoms may be mild, but as they worsen, they can cause:
  • Coughing
  • Inspiratory stridor
  • Noisy respiration
  • Dysphonia
  • Aphonia
  • Choking
  • Drooling
  • Gagging
  • Tachypnea might be present but not as intense as in complete obstruction.
  • Use of accessory muscles of respiration 
• In partial obstruction, there's some restriction to airflow, but it's not entirely blocked.
• Though concerning, it is not an immediate emergency like complete obstruction, as patients can still breathe and maintain oxygen saturation.

Features of Airway Obstruction

• Stridor
  • The cardinal sign of upper airway obstruction is stridor.
  • Occurs in both partial and complete obstruction.
  • More common in complete obstruction.
  • Indicates narrowing or collapse of the larynx or trachea.
• Gurgling Sounds
  • Result from secretions or fluid in the upper airway.
  • Indicate retention of fluids or secretions in upper airways.
• Stertor
  • Sound resulting from the collapse of the pharyngeal airway.
  • Linked with obstructions in the nasopharyngeal, oropharyngeal, nasal, and oral cavities.
  • Nasopharyngeal and oropharyngeal obstructions, like peritonsillar abscess or adenoiditis, can produce stertor.
• Hoarseness
  • An abnormal, deep, harsh voice is generally caused by irritation of, or injury to, the vocal cords.
  • The greater the degree of hoarseness, the greater the severity of the laryngeal damage.
  • Aphonia is almost always associated with very severe injury.
• Other Symptoms 
  • Drooling, bleeding intercostal recession, flaring of the nostrils, and suprasternal retraction are the other symptoms.
  • Dyspnoea, feeble cough, respiratory distress, and signs of hypoxaemia and hypercarbia, such as anxiety, confusion, lethargy, and cyanosis, may be present as the obstruction worsens.
  • Powerful inspiratory efforts against an obstruction may produce dermal ecchymoses and subcutaneous emphysema.
  • Partial airway obstruction that is worsening should be aggressively managed, and if it is rapidly progressing, immediate preparation for treatment as complete
  • obstruction should be made.
• In an unconscious or sedated patient, the first sign of airway obstruction may be the inability to ventilate with a bag valve mask after an attempt to open the airway with a jaw-thrust maneuver.

Location of Obstruction

• Symptoms from Different Airways
  • Pharyngeal Airways: Produces a stuttering sound.
  • Retention of Secretion: Causes a gurgling sound.
  • Laryngeal Level: Stridor is a common symptom.
• Key Locations for Stridor:
  • Inspiratory stridor: Obstruction at or Above the glottis.
  • Expiratory stridor: Obstruction of intra-thoracic airway.
  • Biphasic stridor: Associated lesion between the glottis and cervical trachea.
• Stridors due to nasal, nasopharyngeal, or oropharyngeal causes are less common.

Investigation Of Airway

• If the airway is stable but the underlying cause is not obvious, a Fiberoptic examination 
  • Always be prepared for complications during the fiberoptic examination.
  • Keep intubation equipment on standby.
  • Have a "crash cart" or immediate emergency response tools available.
  • Ensure facilities for a flash cut are in readiness.
• CT scan:
  • Can provide comprehensive details about the nature of the obstruction.
  • Identify foreign bodies, tumours, extrinsic compression, or vascular anomalies.
  • Determine the extent of the airway compromise.
  • Provides a wide spectrum of information about the airway and its surrounding structures.
• SPIROMETRY
  • It can be used in patients with gradual and mild symptoms of UAO
  • Determines if an obstruction is extrathoracic and intrathoracic.
  • Spirometry is not indicated for acute airway obstruction.
• BRONCHOSCOPY
  • Direct visualization of the entire structures of the nose, nasopharynx, oropharynx, larynx, vocal cord, subglottic, trachea, carina, bifurcation bronchus, and second-degree bifurcation of the bronchus.
  • Detects mechanical obstructions, mucous plugs, extrinsic compressions, strictures, and stenosis.
  • Flexible bronchoscopy can be used to establish the diagnosis as well as deliver treatment, including laser therapy, photo resection, electrocautery, balloon bronchoplasty, and tracheal stenting
• Safety Precautions:
  • Ensure a secured airway or means to establish one rapidly.
  • Be prepared for potential airway collapse during bronchoscopy.
  • Always have a crash cart and resuscitation equipment on standby.

Interventions in Upper Airway Obstruction

• Medical Interventions:
  • Heimlich maneuver
  • Airway Devices: Placement of oropharyngeal or nasopharyngeal airways to maintain airway patency.
  • Endotracheal Intubation
  • Racemic epinephrine
  • corticosteroids
  • Heliox Inhalation: Mixed gas therapy that can improve airflow in certain obstructive conditions.
• Surgical/Bronchoscopic Interventions:
  • Fiberoptic Intubation
  • Cricothyroidotomy
  • Tracheostomy
  • Balloon Dilatation
  • Airway Stenting

Heimlich Manoeuvre

• The Heimlich maneuver is recommended for relief of airway obstruction in adults and children.
• The subdiaphragmatic abdominal thrust given standing behind the patient can force air from the lungs; this may be sufficient to create an artificial cough and expel a foreign body from the airway.
• The risk associated: Pneumomediastinum, Pneumopericardium, surgical emphysema and gastric rupture

Maneuvers to Open Airway

• Head Tilt:
  • Helps in opening the oropharyngeal airway by moving the tongue away from the back of the throat.
• Jaw Thrust:
  • It aids in opening the oropharyngeal airway, which is especially useful in trauma patients to avoid cervical spine movement.
• Triple Airway Maneuver:
  • Components:

• Chin Lift: Lift the chin upward.
• Head Tilt: Tilt the head backward.
• Separation of Teeth: Open the mouth.

Also Read: Larynx Inflammatory Lesions 

Methods used in the treatment of Upper Airway Obstruction

1. Endotrach
   • Endotracheal Intubation
   • Key Points to consider:
   • Evaluate Mouth Opening(>40mm>
     • Conditions like trismus due to a peritonsillar abscess or Ludwig's angina can complicate intubation.
   • Dentition 
   • Cervical Spine Mobility(Flexion-extension)
   • Thyromental Distance(Normal is >3 finger breadths)
   • Temporomandibular joint Function:
2. Transtracheal Cannulation

• Purpose:
  • Used in emergencies when intubation isn't possible.
  • Provides an alternate method to secure the airway.
• Procedure:
  • Locate the cricothyroid membrane.
  • Make a puncture at the level of the cricothyroid membrane using a large-bore IV cannula.
• Connection to Ambu bag:
  • Direct connection of the cannula to an ambu bag is not feasible.
  • Use a 7mm endotracheal tube adapter inserted into the barrel of a syringe to make the connection.
  • This setup allows for some amount of ventilation for the patient.

3. Crico Thyroidotomy

The risk of laryngeal trauma is high in inexperienced hands. Once the airway has been secured, a formal endoscopy should be carried out, and the cricothyroidotomy should be converted to a tracheostomy if prolonged ventilation is required.

1. Tracheostomy

Tracheostomy is the definitive management for upper airway obstruction but is often hazardous in the emergency setting. An emergency tracheostomy is best performed using a vertical incision under local anesthesia to avoid bleeding as far as possible while providing good access.

Frequently Asked Questions

Q: What is the cardinal sign of upper airway obstruction?

Answer: Stridor

Q: What is the definitive management of upper airway obstruction?

Answer: Tracheostomy

Q: What is the most important symptom of Upper Airway Obstruction?

Answer: Dyspnea is the Most Important Symptom of upper airway obstruction.

Hope you found this blog helpful for your ENT residency Larynx preparation. For more informative and interesting posts like these, keep reading PrepLadder’s blogs.