How to manage the Expected Difficult Airway
Common Causes

* Anatomical problems
* Pathological obstruction of periglottic area
* Facio-Maxillary trauma
* Laryngeal trauma

Anatomical problems - (resulting in grade III or IV view)

Awake FOB (fibreoptic bronchoscopy)

* Use a drying agent and a vasoconstrictor to nasal mucosa
* Unrushed LA by method of your choice
* Nasal FOB easier than Oral route
* Sedatives + / - midazolam / remifentanil 0.05 ug / kg /min

General anaesthesia

* Don’t consider if difficult mask ventilation likely
* Don’t give muscle relaxant until confirmed adequate mask ventilation
* Confirm view with laryngoscope and choose an appropriate intubation method
* Consider non intubation

Intubation choices

* Right-angled intubaton devices: ILM, Bullard, Upsure. Useful when the reason for a poor view of the larynx is that the airway axes are not aligned
* FOB. NB 2 person technique, with one person using a laryngoscope to position the FOB behind the epiglottis
* LMA and FOB. LM opens up the posterior pharyngeal space and keeps FOB midline. Railroad a size 6 reinforced ETT over the FOB
* ILM ± FOB. Need to choose correct size or inlet will not lie over the larynx.
* Light wand -requires expertise
* Straight blade - useful in patients with a large tongue, epiglottis or prominent incisors
* Macintosh blade - useful in patients with a small oropharynx
* Tubular scopes - useful where there is pharyngeal oedema or tumour, as they push the tissues apart
* McCoy blade - moves fulcrum from teeth to hyoepiglottic ligament, decreasing dental damage

Pathological obstruction of periglottic area

* Awake tracheostomy
* Gas induction if you think the patient is intubatable
* Do not use an awake FOB in periglottic tumour or epiglottitis, as the FOB will further narrow an already compromised airway in a patient struggling to breathe. Lignocaine spray to the cords or FOB irritating the larynx will induce an IRREVERSIBLE LARYNGOSPASM

Trauma - Faciomaxillary fractures

Problems

* Stridor may be present because of blood or debris, or the fracture itself.
* An unstable bilateral fracture can push the tongue and paraglottic soft tissue into the upper airway.
* A mobile maxilla can cause obstruction of the posterior pharynx.
* Face-mask ventilation can move fractures posteriorly, causing obstruction.
* Impaired mouth opening due to trismus or mechanical reasons
* Avoid nasal intubation in Le Fort III fractures as tube can pass into skull
* Nasal intubation in maxillary fractures can cause haemorrhage obstructing a view of the larynx. Should secure the airway with an oral ETT first.
* NB Always consider associated head and cervical spine injury

Intubation choices

* Simple unilateral mandibular fracture with trismus, RSI is reasonable, otherwise consider gas induction or awake FOB.
* Le Fort III fractures - awake tracheostomy is the safest option.
* Retrograde intubation - does not require a direct view of the larynx.

Laryngeal trauma

* Difficult to diagnose, requires a high degree of suspicion.
* Dynamic situation which can worsen quickly
* Safest approach is an AWAKE TRACHEOSTOMY, especially if complete disruption of the trachea is present