3.1 AFOI Flashcards
a) Which nerves supply sensation to i) the nasal air passages (10%), ii) the oropharynx (10%) iii) the
larynx? (10%)
i
Facial Nerve
maxillary branches
ii
Oropharynx
Glossopharyngeal and hypoglossal
iii
Superior and recurrent laryngeal nerves
a) Which nerves supply sensation
to: i) the nasal air passages (10%),
ii) the oropharynx (10%) iii) the
larynx? (10%)
Nasal air passages = ophthalmic and maxillary divisions of facial nerve:
> > Anterior septum and nares: anterior ethmoidal nerve (V1).
> > Elsewhere: greater and lesser palatine nerves (V2).
Oropharynx = glossopharyngeal nerve.
Larynx = vagus:
> > Above vocal folds: internal laryngeal branch of superior laryngeal nerve.
> > Below vocal folds:
recurrent laryngeal nerve.
c) What are the indications (15%) for awake fibreoptic intubation?
> > Previous difficult airway for intubation or face mask ventilation.
> > Predicted difficult airway:
> > Need for intubation but requirement to stay awake,
e.g. need for
neurological examination following intubation.
contraindications (15%) for awake fibreoptic intubation?
> > Patient refusal.
> > Patient not able to comply (confusion, young age etc.).
> > Local anaesthetic allergy.
> > Operator inexperience.
> > Subglottic airway issue (i.e. if the predicted difficulty in the airway is below
the glottis, it won’t be overcome by fibreoptic intubation).
> > Significant laryngeal stenosis.
> > Threat of airway obstruction.
> > Airway bleeding or risk of airway bleeding due to e.g. vascular tumour
d) List the complications of awake fibreoptic intubation. (25%)
Drugs related:
» Failure to achieve adequate anaesthesia of airway resulting in patient
discomfort.
> > Local anaesthetic toxicity.
> > Nerve damage secondary to nerve blocks if used.
> > Apnoea, loss of consciousness and loss of airway due to sedation,
if used.
d) List the complications of awake fibreoptic intubation. (25%)
> > Trauma to any of the structures en route.
> > Airway obstruction due to fibreoptic scope and tube, airway oedema,
bleeding, laryngospasm.
> > Failure to achieve secure airway due to operator inexperience, patient
noncompliance, airway more problematic than anticipated.
> > Aspiration of blood from trauma of procedure or pre-existing bleeding,
or secondary to full stomach. Consequent risk of lower respiratory tract
infection etc.
> > Bronchospasm.
b) Outline the techniques for achieving local anaesthesia of these areas? (15%)
> > Spray as you go. Co-phenylcaine mucosal atomisation device to nostrils, 1% lignocaine spray to tongue and oropharynx, 2% lignocaine via
epidural catheter to larynx above and below the cords.
> > Topicalisation with local anaesthetic soaked pledgets in nasal passages
(disadvantages: does not reduce sensation of any other area).
> > Nebulised local anaesthetic
(disadvantages: easy to exceed maximum
local anaesthetic doses, does not work for larynx, requires the patient
to take good breaths, which is often not possible in patients requiring
awake intubation).
b) Outline the techniques for achieving local anaesthesia of these areas? (15%)
> > Individual nerve blocks: glossopharyngeal nerve, superior laryngeal
nerve block, recurrent laryngeal nerve block etc.
(disadvantages: patient
discomfort, especially in a patient who already has airway compromise;
multiple blocks needed; and expertise in unusually performed blocks required).
> > Cricothyroid puncture for translaryngeal block (disadvantages:
anaesthetises larynx only, patient discomfort).
b) Outline the techniques for achieving local anaesthesia of these areas? (15%)
> > Individual nerve blocks: glossopharyngeal nerve, superior laryngeal
nerve block, recurrent laryngeal nerve block etc.
(disadvantages: patient
discomfort, especially in a patient who already has airway compromise;
multiple blocks needed; and expertise in unusually performed blocks required).
> > Cricothyroid puncture for translaryngeal block (disadvantages:
anaesthetises larynx only, patient discomfort).
> > Predicted difficult airway:
Dentition.
• Limited mouth opening (facial fractures, rheumatoid arthritis, dental
abscess, scleroderma).
• Limited neck movement
(rheumatoid arthritis, ankylosing spondylitis,
previous cervical spine surgery or trauma)
•Airway anatomy abnormality
(thyroid, tongue, tonsillar or laryngeal
tumours, epiglottitis, Ludwig’s angina, airway oedema or burns,
obesity, retrognathia, previous neck radiotherapy).
• Syndromes associated with difficult airway (Pierre-Robin,
Treacher-Collins).
