Awake Fiberoptic Intubation

Question 1

What structures are encountered during awake nasal fiberoptic intubation and what is their sensory innervation

Answer 1

Nasal Air passages, innervated by the Trigeminal Nerve

Oropharynx, innervated by the Glossopharyngeal nerve

Larynx, innervated by the Vagus Nerve

Question 2

What techniques could be employed as part of an overall strategy for airway topicalisation prior to awake nasal fibre-optic intubation

Answer 2

Mucosal Atomisation Device:
To administer lidocaine to the pharynx, larynx, trachea and or co-phenylcaine to the nostrils

“Spray as you go”
Lidocaine spray to the oropharyngeal structures followed by spray above and below the vocal cords via an epidural catheter inserted down a channel in the fibreoptic bronchoscope

Topicalisation with local anaesthetic soaked pledgets in the nasal passages:
This would still require another topicalisation technique for the rest of the airway structures

Nebulised Local Anaesthetic
This can be difficult to keep within safe limits of local anaesthetic dose, it also requires the patient to take good breaths which is not guaranteed in a patient who requires a awake fibre-optic intubation

Individual Nerve Blocks
For example glossopharyngeal nerve block, superior laryngeal nerve block, these do risk patient discomfort especially in a patient who already has airway compromise, also multiple blocks would be required, it also requires the expertise to perform the blocks and there is also an association with high plasma concentration of local anaesthetic with this technique

Cricothyroid Puncture
This provides a trans-laryngeal block and hence anaesthetises the larynx only, there is a risk of patient discomfort however if a cannula is used it can be employed as a rescue oxygenation technique if required

Question 3

What is the maximum dose of lidocaine in mg/kg that can be used for topicalisation of the airway prior to awake nasal fibre-optic intubation

Answer 3

9mg/kg lean body weight

Question 4

What are the predictors of a difficult airway that may indicate the need for an awake fibre optic intubation

Answer 4

Previous difficult airway for oxygenation OR intubation

Head and Neck Pathology
e.g. malignancy or previous surgery / radiotherapy

Limited mouth opening
As seen in Rheumatoid Arthritis, facial fractures, dental abscess, scleroderma

Limited Neck Movement
As seen in Rheumatoid Arthritis, Ankylosing Spondylitis, Previous Cervical Spine Surgery or Trauma

Obstructive Sleep Aponea

Morbid Obesity

Airway anatomy abnormality
e.g. Thyroid, Tongue, Tonsillar or Laryngeal Tumours, Ludwig’s Angina, Airway oedema, Burns or Retrognathia

Syndromes associated with difficult airways
e.g. Treacher-Collins or Pierre-Robin

Question 5

How should tracheal placement be confirmed prior to commencement of anaesthesia in a patient having an awake nasal fibre-optic intubation

Answer 5

Visualisation of the tracheal lumen

Capnography trace consistent with tracheal intubation

Question 6

What are the contraindications to awake fibre optic intubation

Answer 6

Patient not able to comply with instruction (e.g. confusion or young age)
Local anaesthetic allergy
Operator inexperience
Significant laryngeal or subglottic stenosis or narrowing (hence it is not possible to bypass the area of concern)
Threat of airway obstruction
Airway bleeding or risk of significant airway bleeding due to for example a vascular tumour
Patient Refusal