Awake fibreoptic intubation (AFOI)





Clinical

Indications:

  • Difficult B&M
    • Expected or previous history
  • Difficult intubation
    • Expected or previous history
    • Suspected or known cervical spine injury

Contraindication:

  • Severe upper airway obstruction
    • e.g. Upper airway tumours with stridor
    • Instrumentation can lead to bleeding and oemeda ... thus acute complete obstruction
  • Lack of consent / cooperation
  • Severe bleeding in upper airway
  • High-grade stenosis in airway
  • Allergy to local anaesthetics

Pros and cons

Pros:

  • Easier to back out
  • Spontaneous ventilation is maintained
  • Muscle tone is maintained
    • By extension, patient airway should be maintained (but not always)
  • Less CVS response (compared to laryngoscopy)

Goal

  • Maintain oxygenation, via...
    • Maintain spontaneous ventilation
    • Maintain airway muscle tone
  • Blunt cough reflex
  • Minimise trauma and bleeding
  • Allow time for topical anaesthesia to work

Preparation

Decisions to be made:

  • Oral or nasal approach
  • Conscious sedation or not
  • Topical anaesthesia
    • Choice of LA agent
    • Choice of application
  • Anti-sialogogue or not
  • Escape plan

Oral or nasal approach?

➤ Oral

  • May be harder due to sharper bend at oropharynx
  • Patient can bite on the ETT
  • Requires
    • Topical anaesthesia
    • Bite block

No need for lubrication and vasoconstriction

➤ Nasal

  • Bleeding may significantly impair view
  • Requires
    • Topical anaesthesia
    • Lubrication
    • Vasoconstriction

Conscious sedation

  • Advantage

    • Decreased patient anxiety

  • Disadvantage

    • Variable effect
    • Decreased cooperation
    • Decreased muscle tone → Smaller lumen
    • Risk of
      • Resp depression
      • Airway obstruction

Choice of sedation

Options:

Any combinations of the following:

  • Midazolam
  • Fentanyl / ketamine
  • Remifentanil
  • Dexmedetomidine
  • Propofol

➤ Remifentanil ± midazolam

  • Start at 0.05 mcg/kg/hr
    • Will maintain respiration at this dosage
  • Titrate slowly to effect

NB:

  • Remifentanil is better than propofol
    • Better tolerance
    • More cooperation
    • Faster time to intubation

Topical anaesthesia

Choice of topical LA agents

  • 4% lignocaine
    • Nebulised
      • More effective
      • Risk of higher plasma level
    • Atomised
  • Co-phenylcaine
    • 5% lignocaine + 0.5% phenylephrine
  • Cocaine

Choice of LA application

  • Nebuliser
  • Mixed with gel / lubrication
  • Direct spray
  • Spray through bronchoscopy ± epidural catheter
  • Recurrent laryngeal nerve block

Other drugs

Anti-sialogogue

  • Glycopyrrolate 0.2 to 0.4 mg IV or IM
  • Hyoscine 0.2 mg IV
  • Atropine 0.3 to 0.6 mg IM

Vasoconstrictor

  • Cocaine (for nasal mucous membrane)
  • Co-phenylcaine spray

Escape plan?

  • Must always have escape plan

MADE

  • Monitoring

    • Standard monitoring
    • CO2 monitoring if possible
    • Supplemental O2

  • Assistants / access

    • Have more than one assistant if possible
    • IV access

  • Drugs (VAST)

    • Vasoconstrictor
    • Antisialogogue
    • Sedation drugs
    • Topical anaesthetics

  • Equipment

    • Working fibreoptic bronchoscope
      • with a 10 mL syringe of 4% lignocaine
    • ETT
      • Use 1 to 1.5 size smaller
      • Consider using reinforced ETT
      • Different ETT sizes available
    • Intubating equipments
    • Cricothyroidotomy kit immediately available
    • Suction

Communication with patient and team

Patient

  • Psychologically prepare patient
  • Communicate with patient throughout procedure

Team

  • Communicate with team re:
    • Steps
    • Backup plan
  • Have ENT surgeon on standby if possible

Patient setup

  • O2 supplement
  • IV access
  • Sitting position if possible

Technique

"Spray as you go" application of LA

  • When vocal cord is in view
    • Spray vocal cord with LA ... through FOB
    • Wait 2 to 3 minutes before advancing
  • Advance through cord
    • Spray trachea and carina with LA

NB:

  • Spraying LA to infant can potentially worsen airway due to bronchospasm

Retrograde application of LA

  • Cricothyroid membrane is identified and punctured with a needle or cannula
  • LA is injected through the cricothyroid membrane
  • Patient will cough and spread the LA around