85. Unexpected difficult intubation Flashcards
You are asked to anaesthetise a 35-year-old, 110 kg man who has been
involved in a road traffic accident. He sustained mild facial trauma when he hit
the steering wheel and has a bruised chest. He has a fracture–dislocation of
the ankle that the surgeons want to operate on urgently as the foot is dusky.
Primary and secondary surveys did not reveal anything else of concern.
How would you assess his airway?
Bedside tests should be used in combination with each other and include
Mallampati score of the view of the pharynx
Calder scale looking at the mobility of the lower jaw
Thyromental or sternomental distance indicating mandibular space
compliance, mouth opening and neck movements
His weight of 110 kg can contribute to a difficult airway.
What else would you want to know prior to anaesthetising him?
A full medical and anaesthetic history
Clinical examination
Chest x-ray and ECG – he has sustained blunt chest trauma
Timing of his last meal prior to the RTA is important.
Any opioids in A&E
Spinal anaesthesia could be considered provided there are no contraindications.
If regional anaesthesia is contraindicated, then the method of securing the
airway would be influenced by the predicted difficulty of laryngoscopy and
intubation.
If a difficult airway is predicted, then awake fibre-optic intubation would be
an appropriate technique.
If the airway looks OK, then i.v. induction would be reasonable. If there is
any doubt about his stomach being empty, a rapid sequence induction
should be performed.
What drugs would you use for a rapid sequence induction?
Keep it simple!
Thiopentone 5–7 mg/kg and suxamethonium 1.5 mg/kg
He refuses a spinal and awake fibre-optic intubation.
Unfortunately, you cannot see the epiglottis at your first attempt.
What do you do?
Check that the head is extended and the neck is flexed (should be optimally
positioned prior to induction!).
Check that the larynx position is not distorted by the cricoid pressure.
No more than three attempts
Use an alternative blade such as straight or McCoy or use a bougie.
What would you do if the oxygen saturation starts to fall?
Call for help.
It is essential to maintain oxygenation.
This should be done with a bag and mask initially.
Ensure that cricoid pressure remains applied.
Would you give any other drugs?
No. Further doses of muscle relaxant or induction agent are
contra-indicated in a rapid sequence induction.
There is no ‘Plan B’ for alternative intubation techniques during RSI.
The patient should be woken up with oxygenation maintained until the
effects of the anaesthetic and muscle relaxant have worn off.
What would you do if you could not ventilate him?
Standard airway manoeuvres such as head tilt and jaw thrust.
Try two hand technique.
Reduce the cricoid pressure slightly.
Oropharyngeal and/or nasopharyngeal airway.
LMA.
What if you couldn’t ventilate through an LMA and the saturation
continued to fall?
This is a ‘Can’t intubate, can’t ventilate’ scenario.
Rescue techniques are needed.
Laryngospasm should not be a problem after an adequate dose of muscle
relaxant and induction agent but should be considered.
If you cannot ventilate through a facemask or LMA, the saturation
continues to fall beyond 85% and the patient is not waking up, then an
emergency cricothyroidotomy needs to be performed.
Describe to me how you would do that?
There are pre-packed kits for cricothyroidotomy.
It is essential that you are familiar with the one in your theatre suite.
There are many different types available on the market.
A stab incision is made in the membrane.
Enlarged by blunt dissection.
A small 5 or 6 mm cuffed endotracheal tube is inserted.
Assuming the patient was successfully woken up from this, how would
you proceed with his anaesthetic for his operation?
The surgery cannot be delayed.
An alternative technique to RSI is needed.
Regional anaesthesia such as a spinal should be reconsidered.
Awake fibre-optic intubation.
Any other regional techniques that you could use?
Combined spinal epidural
Femoral and sciatic nerve blocks
This would need to be discussed with the surgeon to take account of
Nature and extent of the proposed surgery
Potential for a compartment syndrome post-operatively
(May be masked by a block.)
Combined femoral and sciatic blocks alone may prove to be inadequate for
surgical anaesthesia
What about an awake fibre-optic intubation?
This is an option for the patient with a known or suspected difficulty airway,
especially if there is a risk of reflux.
If this patient had just undergone a cricothyroidotomy and extensive airway
manipulation, then this might prove difficult.
