Fibreoptic Intubation

Technique to secure a a (relatively) non-emergent definitive airway in a patient who has expected difficult laryngoscopy. May be:

Indications

  • Difficult intubation
    • Known
    • Suspected
    • Rescue
  • Difficult ventilation
    • Facemask
    • LMA
  • Cervical spine instability

Contraindications

  • Absolute
    • Lack of skill, assistance, or equipment
    • Near-total upper airway obstruction
    • Patient refusal
      For AFOI.
    • Uncooperative patient
      For AFOI.
  • Relative contraindications
    • Inability to tolerate apnoea
    • Contaminated airway
      Blood or soiling may:
      • Limit efficacy of topicalisation
      • Reduce visualisation of normal structures
      • Cover the camera lens

Equipment

Key equipment:

  • Bronchoscope
    Sized appropriately. An ‘adult’ bronchoscope will fit inside a 6.0 ETT
  • ETT
    • Sizing
      • Big enough to:
        • Allow adequate ventilation
        • Fit the scope
      • Small enough to:
        • Fit through the nose (if nasal)
        • Minimise the gap between tube and scope
    • PVC tubes
      • Appropriate for ICU/ intubation
      • Not appropriate for nasal intubation
    • Reinforced
      • Easier to negotiate
      • Not recommended for long-term use
      • May not have a Murphy eye
    • iLMA ETT
      • Soft tip
      • Snug tip fits scope well
      • Flexible allows it to negotiate corners
      • Length may be an issue
    • Parker Flex ETT
      • Flexes and curves past protruding airway structures, smoothing passage
      • Not as good as iLMA for railroading
    • Nasal RAE
      • Long enough even if using small tubes
      • Pre-formed curve makes it harder to manipulate during railroading
  • Oral intubation aids
    • Ovassapian
      Keeps scope in midline.
      • Single size
      • ↑ failure rate compared to Berman
    • Berman
      Keeps scope in midline and flange allows adjustment of view.
      • Multiple sizes

Generally, use a Parker Flex-Tip or Fast-track ETT. If planning nasal intubation, use a 6.0 for females and a 6.5 for males.

Technique

Supplemental oxygen should always be provided.

Sedation is not a substitute for topicalisation, but sedation is not required if good topicalisation is performed. (Still nice though).

Preparation

  • Positioning
    Two options
    • Patient supine with operator in normal intubating position
    • Patient sitting upright and facing the operator
  • Drugs and Equipment
    • Glycopyrrolate
    • Lignocaine
      • Have additional syringes to topicalise cords under vision
        • 2× 10mL syringes containing 2mL 2% lignocaine and 8mL air
  • Oxygenate
    • High flow nasal prongs
      If oral FOI.
    • Nasal cannula
      Through opposite nostril if nasal FOI.
    • Through suction port of bronchoscope
      1-2L/min assists oxygenation and clears blood and secretions from view.
    • Through a paediatric ETT in opposite nostril
      Allows gas monitoring.

Silicone or lignocaine spray are excellent lubricants for the bronchoscope and ETT.

Sedation

  • Aim for conscious sedation. Consider:
    • Midazolam and a small dose of fentanyl
      Familiar and reversible.
    • Remifentanil TCI (Minto) Ce 1-3ng/mL
    • Ketamine
      Minimises respiratory depression, but oral secretions may be problematic.
  • Risk of oversedation is high
    • Second anaesthetist for sedation is desirable
    • Use sedation cautiously and minimalistically
    • Propofol is not recommended
    • Avoid in the critically ill

Topicalisation

Many different topicalisation recipes exist; many are equally good. All require good explanation. Set expectations.

  • Antisialagogue (Glycopyrrolate 200-400μg)
    • Aids visualisation and improves local anaesthetic efficacy
    • Aim to give >5 minutes before topicalisation
  • For nasal intubation:
    • Vasoconstriction
      5× cophenylcaine sprays to nose
    • Topicalise:
      • Using EZ atomiser:
        • O2 at 10L/min
        • Give 1/3rd of lignocaine dose to the nostril to be intubated
      • Using serial dilation of nostril:
        • Use a selection of NPAs well lubricated with 2% viscous lignocaine gel
        • Dilate every 3-5 minutes in 0.5 size increments up to intended tube size
    • Topicalise airway as below
  • For oral intubation:
    • Using MAD:
      • Spray with 10% lignocaine via MAD over 5 minutes
        Up to 9mg/kg. Spray:
        • Oropharynx
        • Tonsillar pillars
        • Base of tongue
      • Have 2% lignocaine available for top-up spray-as-you-go
    • Using EZ atomiser:
      • O2 at 10L/min
      • Spray tonsillar pillars, posterior tongue, posterior pharynx
      • Turn nozzle down, and spray epiglottis and cords
    • Using high-flow nasal oxygen:
      • Inject 10-15mL of 2% lignocaine via a 27G or 30G needle into the distal portion of the oxygen tubing, synchronised with respiration

2% lignocaine is as effective as higher concentrations of lignocaine, provided the dose is correct.

Dose (mg) and volume (mL) of 2% lignocaine for administration via EZ Atomiser or High Flow Oxygen
LBW (kg) Maximum total dose Volume for atomiser Volume available for top up
40 230 10 1.5
45 275 10 3.75
50 320 12 4
55 365 13 5.25
60 410 14 6.5
65 455 15 7.75
70 500 15 10
75 545 15 12.25
80 590 15 14.75
85 635 15 16.75
90 680 15 19
95 725 15 21.25
100 770 15 23.5
Injection site for lignocaine into HFNO

Nasal Intubation

  • Pass scope through nose
  • Identify:
    • Inferior turbinate
    • Middle turbinate
    • Nasal septum
  • Patient may swallow at this point
    This will close the nasopharynx; sniffing will re-open.
  • Pass infero-medially to the inferior turbinate

If difficult, consider using an NPA to traverse nares:

  • Cut NPA along one side so it can be split open
  • Insert NPA
  • Pass bronchoscope through NPA
  • Remove NPA over bronchoscope

Oral Intubation

In the asleep patient, jaw thrust and pulling the tongue forward (have assistant use gauze-wrapped forceps) significantly increases space in the back of the oropharynx.

  • Protect the scope
    • Bite block
    • Berman Airway
    • Place ETT through teeth
  • Identify the uvula and continue into the oropharynx
  • (Remember to spray-as-you-go with 2% lignocaine from here)
  • Identify the larynx
    Slight anterior flexion smooths passage through.
  • Identify the carina
    Posterior flexion is required to negotiate the secondary curve of the trachea.
  • Advance tube over bronchoscope
  • Confirm position with two-point check
    Capnography and visualisation.
  • Induce anaesthesia

Emergency Fibreoptic

If time-critical but laryngoscopy not feasible:

  • Cophenylcaine
  • Lubricated nasal tube into nasopharynx
  • Fibreoptic through nasal tube and drop into cords

References

  1. Ahmad I, El‐Boghdadly K, Bhagrath R, et al. Difficult Airway Society guidelines for awake tracheal intubation (ATI) in adults. Anaesthesia. n/a(n/a). doi:10.1111/anae.14904
  2. Zhong G, Downey RG. Airway topicalisation via direct injection of local anaesthetic into the lumen of high flow oxygenation devices. Anaesth Intensive Care. 2020 Sep;48(5):409–10. doi:10.1177/0310057X20946049
  3. St Vincents FOI training manual