Airway Obstruction

Airway obstruction can be incomplete or complete

• Complete obstruction of the upper airway occurs when there is inability to talk, cough or breath. Apnea and cyanosis are present and paradoxical respirations may be noted.
• Incomplete obstruction occurs when there is partial upper airway obstruction and ability to breath is maintained. Inspiratory stridor and increased work of breathing are the hallmarks.

Upper airway obstruction can be due to the following factors:

• luminal (e.g. foreign body)
• intramural (e.g. tumour, neuromuscular diseases)
• extramural (e.g. thyroid mass)

CAUSES

• Foreign body
• Infection
  • Epiglottis
  • Retropharyngeal abscess
  • Bacterial tracheitis
  • Ludwig’s angina
  • Laryngotracheitis
  • Diptheria
  • Tetanus
• Immune
  • Angioedema
  • Anaphylaxis
• Tumor
• Trauma
  • Neck hematoma, e.g. trauma, bleeding diathesis, anticoagulants
  • laryngeal fracture
  • Burns
  • Postoperative complications
• Poisoning and toxic exposures
  • Smoke inhalation
  • Caustic ingestion
  • Strychnine poisoning
• Laryngospasm
  • Physical or chemical stimuli
  • Druginduced e.g. acute dystonic reaction, ketamine
• Congenital
  • Vascular rings
  • Laryngeal webs
• Other
  • Paradoxical motion of the vocal cords
  • Altered level of consciousness
  • Cranial nerve palsies
  • Paralysis
  • Hysterical stridor
  • Myoedema

ASSESSMENT

History

• Partial obstruction can be recognised where:
  • breathing is labored
  • breathing may be noisy
  • some escape of air can be felt from the mouth
• Complete obstruction can be recognised where:
  • there may be efforts at breathing
  • there is no sound of breathing
  • there is no escape of air from nose and/or mouth
• Stridor = sound on inspiration associated with airway narrowing
• stridor @ rest implies a reduction in airway diameter of >50%
• progression of symptoms
• positional exacerbation
• whether patient wakes @ night having difficulty breathing
• dysphagia
• drooling
• severe obstruction > coughing becomes difficult > chest infections

• Airway obstruction may not be apparent in the nonbreathing unconscious person until rescue breathing is attempted. 

Examination

• Airway assessment
• Neck examination
• Nasal endoscopy – photos helpful, doesn’t involve LA to cords which could precipitate total airway obstruction, beaware that a nice view in the sitting position doesn’t mean the same in the supine position.

Investigation

• CT – more helpful in subglottic assessmen
  • Define site of obstruction

• Supraglottic
• Laryngeal
• Subglottic – mid tracheal & lower tracheal/bronchial

MANAGEMENT

Basic life support

• If a foreign body is easily visible and accessible in the mouth then remove it taking care not to push it further into the airway. 
• DO NOT perform a blind finger sweep of the mouth as this may further impact a foreign body and damage tissues without removing the object.
• physical methods of clearing the airway should only be performed if
  • The diagnosis of foreign body aspiration is clear
  • ineffective coughing
  • increased shortness of breath
  • loss of consciousness or apnoea have occurred
  • Head tilt/chin lift have failed to open the airway of an apnoeic child

Assess Severity

• The simplest way to assess severity of a FBAO is to assess for effective cough. 

Effective Cough (Mild Airway Obstruction)

• Reassure and encourage the individual to keep coughing to expel the foreign material.

Ineffective Cough (Severe Airway Obstruction)

Conscious Person

1. 5 Back Blows–>
   • General:
     • Use the heel of one hand in the middle of the back between the shoulder blades.
   • Infants:
     • Support them in a head-downwards, prone position to enable gravity to assist in removing the foreign body.
     • A seated or kneeling rescuer should be able to support the infant safely across their lap.
     • Support the infant’s jaw to keep the airway open in a neutral position.
     • Deliver up to five sharp back blows with the heel of one hand in the middle of the back between the shoulder blades.
     • Check to see if each back blow has relieved the airway obstruction.
   • Children Over 1 Year of Age:
     • Back blows are more effective if the child is positioned head down.
     • A small child may be placed across the rescuer’s lap as with the infant.
     • If this is not possible, support the child in a forward-leaning position.
     • Deliver up to five sharp back blows with the heel of one hand in the middle of the back between the shoulder blades.
     • Check to see if each back blow has relieved the airway obstruction.
2. If Back Blows Are Unsuccessful–>
3. 5 Chest Thrusts:
   • Use the same compression point as for CPR and give up to five chest thrusts.
   • Chest thrusts are similar to chest compressions but sharper and delivered at a slower rate.
   • Infants:
     • The infant should be in a head-downwards supine position across the rescuer’s thigh.
   • Children Over 1 Year of Age:
     • Children may be treated in the sitting or standing position.
   • If the obstruction is not relieved, continue alternating five back blows with five chest thrusts.

Unconscious Person

• If unresponsive, a finger sweep can be used if solid material is visible in the airway.
• Start CPR.

Supraglottic & Laryngeal Lesions

• Awake tracheostomy
  • Indicated if: severe stridor, large tumour, gross anatomical distortion, larynx not visible on nasal endoscope
  • prepare in sitting position
  • once in place > confirm with CO2
• Inhalational induction
  • 2 anaesthetists

• experienced assistance
• surgeon in theatre scrubbed for emergency tracheostomy
• sudden complete airway obstruction > immediate tracheostomy or single attempt @ rigid bronchoscope