Airway Obstruction

OVERVIEW

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 respiration 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
    • Post-operative complications
  • Poisoning and toxic exposures
    • Smoke inhalation
    • Caustic ingestion
    • Strychnine poisoning
  • Laryngospasm
    • Physical or chemical stimuli
    • Drug-induced 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

  • 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

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 assessment

Define site of obstruction

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

MANAGEMENT

Supraglottic & Laryngeal Lesions

  1. Awake tracheostomy
  2. Inhalational induction

INHALATIONAL INDUCTION

  • 2 anaesthestists
  • experienced assistance
  • vasoconstrictor + LA to nose
  • surgeon in theatre scrubbed for emergency tracheostomy
  • sevo/O2 induction (may need halothane)
  • don’t bag if becomes apnoeic (allow CO2 rise)
  • insert N/P airway if required
  • wait for pupils to become small and central
  • laryngoscopy (long, McCoy)
  • assess whether can intubate
  1. attempt intubation only twice
  2. tracheostomy while breathing spontaneously
  • sudden complete airway obstruction -> immediate tracheostomy or single attempt @ rigid bronchoscope

AWAKE TRACHEOSTOMY

Indications

  • severe stridor
  • large tumour
  • gross anatomical distortion
  • larynx not visible on nasal endoscopy

Technique

  • no sedation
  • helium/O2 mix -> improves symptoms
  • beaware of giving high FiO2 -> can precipitate CO2 narcosis
  • prepare in sitting position
  • once in place -> confirm with CO2

Post op

  • Analgesia
  • Humidification
  • If intubated – leave Cook Airway catheter in place until patient fully awake
  • Dexamethasone
  • May need PEEP or IPPV post

Mid Tracheal Lesions

  • ie. thyroid mass
  • ensure that patient can be intubated to below level of obstruction
  • normal induction may be appropriate
  • any suggestion of malignant tracheal invasion -> AFOI

Lower Tracheal & Bronchial Obstruction

  • mediastinal masses (lymphoma, invasive carcinoma)
  • beaware of invading thyroid carcinomas -> tracheal collapse with muscle relaxation -> have a ridgid bronchoscope available.
  • if obstruction close to the carina or invading the bronchus -> can’t do tracheostomy or give muscle relaxation -> may need bypass.

References and Links

  • CEPD – October 2002 (Rees & Mason)
  • Obstructed Airway in ENT Surgery – Anaesthesia 1999, 54, page 625-628 (Mason & Fielder)

CCC 700 6

Critical Care

Compendium

Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also the Innovation Lead for the Australian Centre for Health Innovation at Alfred Health, a Clinical Adjunct Associate Professor at Monash University, and the Chair of the Australian and New Zealand Intensive Care Society (ANZICS) Education Committee. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.

After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.

He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE.  He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.

His one great achievement is being the father of two amazing children.

On Twitter, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.