Airway Obstruction

Airway obstruction is a partial or complete blockage of the airways that impedes airflow. An airway obstruction can be classified as upper, central, or lower depending on location. Lower airway obstruction (LAO) is usually a manifestation of chronic disease, such as asthma or chronic obstructive pulmonary disease (COPD). Upper airway obstruction (UAO) and central airway obstruction (CAO) refers to a mechanical blockage of the large airways and are potentially life-threatening events, which need to be recognized and managed promptly.

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Airway obstruction is a blockage of the airways, which impedes air flow and effective respiration.

Anatomic classification

  • Upper airway obstruction (UAO):
    • Nasopharynx, larynx, and trachea
  • Central airway obstruction (CAO):
    • Trachea and mainstem bronchi
  • Lower airway obstruction (LAO): 
    • Distal to mainstem bronchi
    • Involves small airways
    • Usually a manifestation of chronic disease


  • Exact incidence is unknown.
  • Occurs in 20%–30% of patients with lung cancer


Upper airway obstruction and CAO (large airway obstruction):

  • Masses:
    • Lung cancer most common
    • Benign masses (papillomas)
  • Aspiration of foreign body
  • Mucous plug
  • Tracheomalacia
  • Angioedema (tongue swelling)
  • Anaphylaxis
  • Obstructive sleep apnea (OSA)
  • Laryngoceles
  • Tracheal strictures/stenosis
  • Airway hematomas (trauma)
  • Extrinsic compressions (e.g., vascular rings, thyroid tumors)
  • Infections
Foreign Body Stuck between Vocal Cords

Foreign body stuck between vocal cords (bronchoscopic view)

Image: “Foreign body stuck between vocal cords” by Kamran Mottaghi et al. License: CC BY 3.0

Lower airway obstruction (small airway obstruction):

  • Asthma
  • Chronic obstructive pulmonary disease (COPD)
  • Post-infective bronchial hyperreactivity
  • Bronchiectasis and cystic fibrosis
  • Infections:
    • Allergic bronchopulmonary aspergillosis
    • Endobronchial tuberculosis



  • Extrinsic or intrinsic compression due to tumors
  • Endobronchial granulation tissue or calcifications
  • Thinning or collapse of the airway wall due to tracheomalacia
  • Airway edema due to infection, inflammation, or bleeding

Chronic and subacute

  • Minor obstruction is often asymptomatic initially.
  • Can be caused by a mass, a stricture, or external compression
  • Can be exacerbated by exertion, increased ventilatory demands (e.g., pneumonia), or progressive obstruction; and then become acute


  • Precipitating events:
    • Foreign body aspiration
    • Mucous plug
    • Laryngotracheal trauma
    • Smoke inhalation
    • Pediatric infections:
      • Epiglottitis
      • Croup
      • Tonsillar or retropharyngeal abscess
      • Diphtheria
  • Acute exacerbation of mild chronic obstruction in the setting of swelling, bleeding, or increased secretions

Clinical Presentation

Chronic and subacute

  • Symptoms are non-specific:
    • Dyspnea
    • Wheezing
    • Cough
    • Hemoptysis
    • Hoarseness
    • Chest pain
  • Frequently misdiagnosed as asthma/COPD
  • Diagnostic clues:
    • Positional symptoms rather than diurnal (day vs. evening)
    • Inspiratory wheeze (stridor)
    • History of intubation or tracheal disease (tracheal stenosis)


  • Acute onset tachypnea
  • Tachycardia
  • Inspiratory stridor
  • Wheezing
  • Increased respiratory effort: suprasternal retractions, nasal flaring, grunting
  • Gagging, gasping
  • Cyanosis
  • Obtunded mental status



History can be obtained from a responsive patient not in extremis.

  • Does the patient have a history of:
    • Respiratory disease
    • Lung or head/neck cancer
    • Foreign body aspiration
    • Previous intubation/tracheostomy
    • Neck surgery

Physical exam

  • General: 
    • Cyanosis
    • Pulse oximetry < 90%
    • Facial/neck swelling
    • Signs of respiratory distress (tachypnea, nasal flaring, gasping, use of accessory muscles)
  • Direct inspection of the airways:
    • Visual inspection (angioedema, foreign body)
    • Laryngoscopy
    • Bronchoscopy


  • Should only be performed after airway stabilization
  • Chest X-ray:
    • Mass
    • Tracheal deviation
    • Mediastinal shift
    • Endobronchial luminal defect
  • Neck X-ray:
    • Thumbprint sign for epiglottitis
  • Chest computed tomography (CT):
    • More detailed imaging than X-ray
  • Magnetic resonance imaging (MRI):
    • For vascular pathology
    • Soft tissue tumors (e.g., sarcomas)

Pulmonary function test (PFT)

For chronic/subacute symptoms in the setting of suspected obstruction:

  • Minimal variability in peak flow/spirometry
  • Characteristic “squared-off” flow-volume loop 
  • Fall in peak expiratory flow rate (PEFR) relatively greater than fall in forced expiratory volume in 1 second (FEV1)


Life-threatening obstruction

  • If a foreign body is suspected, abdominal thrusts (Heimlich maneuver) or back slaps (for infants) should be performed for responsive patients.
  • Cardiopulmonary resuscitation is initiated for unresponsive patients.
  • The goal of initial management:
    • Provide adequate oxygenation
    • Secure airway
  • The initial step is bag-mask ventilation.
  • Maneuvers to help open the airway:
    • Head tilt-chin lift (if no cervical spine trauma is suspected)
    • Jaw-thrust (allows airway opening without disturbing the cervical spine)
  • Endotracheal intubation is the definitive airway management.
  • If intubation cannot be accomplished:
    • A laryngeal mask can be inserted if obstruction is from a swollen tongue.
    • Emergent cricothyroidotomy or tracheostomy
    • Rigid bronchoscopy and retrograde intubation may be needed in case of bronchial obstruction.
Heimlich maneuver

The abdominal thrusts (Heimlich) anti-choking maneuver

Image: “The abdominal thrusts (Heimlich) anti-choking maneuver” by US ARMY MEDICAL DEPARTMENT CENTER AND SCHOOL FORT SAM HOUSTON. License: Public Domain

Not immediately life-threatening obstruction

  • History, laboratory, and imaging evaluations can be obtained.
  • Initial management:
    • Sit the patient up.
    • High-flow oxygen or heliox (a mixture of oxygen and helium) via a mask
    • Intravenous high-dose corticosteroids (reduce edema around the obstruction)
    • Nebulized salbutamol and adrenaline
    • Intravenous fluid replacement
  • Definitive management depends on the underlying cause.

Differential Diagnosis

  • Chronic obstructive pulmonary disease: chronic obstructive inflammation of the small airways and changes in the lung parenchyma and pulmonary vasculature. Patients usually present with dyspnea and chronic cough. COPD is a progressive condition with acute flares. Management includes smoking cessation, pulmonary rehabilitation, and pharmacotherapy.
  • Asthma: chronic inflammatory respiratory condition characterized by bronchial hyperresponsiveness and airflow obstruction. Patients typically present with wheezing, cough, and dyspnea. Diagnosis is confirmed with a PFT showing a reversible obstructive pattern. Treatment, based on symptom severity, includes bronchodilators and inhaled corticosteroids for control of inflammation.


  1. Aboussouan, L. S., & Stoller, J. K. (1994). Diagnosis and management of upper airway obstruction. Clinics in chest medicine, 15(1), 35–53.
  2. Herth F. JF. (2020).  Clinical presentation, diagnostic evaluation, and management of central airway obstruction in adults. Retrieved 25 January 2021, from
  3. Loftis L.L. (2019). Emergency evaluation of acute upper airway obstruction in children. Retrieved 25 January 2021, from
  4. Wittels K. (2019). Basic airway management in adults. Retrieved 26 January 2021, from

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