an abominable airway…
the case.
a 28 year old male presents to your Emergency Department with a 2-3 week history of increasing neck swelling. He is now spitting out frank purulent discharge from his mouth and reports fevers and night sweats.
He reports a rapid increase in neck swelling which is now preventing him from eating a normal diet. His purulent secretions started about 10 days ago & also appear to be getting worse. He has had no associated cough, chest pain, haemoptysis, vomiting, headaches or photophobia.
PMHx:
- Squamous cell carcinoma of the tongue.
- Diagnosis made ~4 months ago.
- Declined initial treatment (both chemotherapy & local radiation therapy were recommended)
He currently takes no regular medications & has no known drug allergies.
He is a non-drinker & smokes ~15 cigarettes per day.
On examination:
A. Interesting & intimidating. Expectorating purulent secretions +++. Limiting mouth opening (~1.5cm). Significant bilateral submandibular neck swelling (L>>R) with mild overlying erythema.
B. Respiratory rate 22/min. SaO2 96% on room air. Clear chest on auscultation.
C. Tachycardic to 130/min. BP 126/70. Capillary refill <2 seconds. Dual heart sounds.
D. GCS 15. No focal deficits.
E. Febrile to 39*C. No rashes. Blood glucose 8.2 mmol/L.
[DDET Here is his venous blood gas…]
[DDET Describe & interpret…]
- Metabolic alkalosis
- HCO3 41, BE 14.
- Compensated pH 7.44, pCO2 61
- Expected pCO2:
- = (0.7 x 41) + 20
- = 28.7 + 20
- = 48.7
- Actual pCO2 = 61, ∴ likely concomitant respiratory acidosis.
- Moderate hypokalaemia
- Markedly elevated iCa: 1.81
- Lactate 1.7 (?sepsis driven)
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[DDET … & now the rest of his results]
[DDET Describe & interpret…]
- Hypokalaemic, hypochloraemic metabolic alkalosis
- ?secondary to vomiting, malignancy, endocrinopathy.
- Life threatening hypercalcaemia
- Likely a paraneoplastic process (PTH-related protein or ectopic Vitamin D production)
- Alternatively, from metastatic osteolysis
- Other differential diagnoses include:
- Primary hyperparathyroidism
- Medications (thiazides, lithium, oestrogens)
- Granulomatous diseases (sarcoidosis, tuberculosis, histoplasmosis)
- Milk-alkali syndrome
- Non-specific LFT derangement
- Elevated WCC with predominate neutrophilia
- Not unexpected given the presence of sepsis.
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[DDET What is your immediate management?]
- Intravenous access & volume replacement
- 0.9% Saline or Hartmann’s solution, empiric 500-1000mL
- Reassess pulse rate, blood pressure, capillary refill & urine output
- Empiric antibiotic therapy
- Clindamycin 600mg IV or Benzylpenicillin 2.4g IV
- ± Metronidazole 500mg
- Steroids
- 10mg IV dexamethasone
- Correction of electrolytes:
- Potassium:
- 10-20mmol KCl per hour & reassess
- Calcium:
- Restore intravascular volume (IV fluids)
- Maintain urine output ~ 100-150mL/hr
- Bisphosphonates (palmidronate or zolidronic acid)
- Potassium:
- Analgesia
- Antipyretics
- Supportive care
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[DDET You decide he requires advanced imaging…]
You feel that he is able to maintain his own airway at present & he is capable of lying flat.
Here is his CT neck:
[DDET … same CT, different angles…]
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[DDET The story continues…]
As your patient arrives back from radiology you notice he now looks unwell !!
He is in obvious respiratory distress with tachypnoea (respiratory rate of 34/minute) and moderate work of breathing. His room air oxygen saturations are now 68% !!
He is clammy & tachycardic but normotensive.
He is confused, but cooperative.
[DDET What do you do now?]
- Transfer to a resuscitation bay
- Full cardiorespiratory monitoring.
- Advanced airway equipment (including difficult airway trolley) moved to the bedside.
- Call for help.
- This will be dependent upon your facility & the experience of your available staff at hand.
- Anaesthetics & ENT surgery would be great allies in this scenario, especially if he doesn’t rapidly improve.
- Asking for an operating theatre to be on stand-by with fibre-optic equipment ready would also be a good idea.
- Maximise oxygenation.
- High-flow oxygen via non-rebreather mask ± high-flow nasal oxygen.
- Non-invasive ventilation may also be worth trying.
- Assess & treat reversible pathology.
- Trial of nebulised adrenaline (5mg).
- Consider a further dose of intravenous steroid acknowledging this takes time for effect.
[DDET and in a few minutes…]
- The ENT surgeon is “on their way“…
- Anaesthetics come to the bedside & quickly make a plan for an attempt at an awake fibre optic intubation in their theatre, with surgical backup.
- The patient improves somewhat. His oxygen saturations climb to 99% on oxygen & his work of breathing settles.
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[DDET But things don’t go to plan…]
5 minutes later, he rapidly deteriorates!!!
He continues to desaturate (to 80%) despite high-flow supplemental oxygenation and he develops significant increased work of breathing. He is now clammy, diaphoretic and very agitated. He is ripping off his oxygen mask, pulling off monitoring and tugging on his IV lines.
[DDET What do you do now…?]
- Get control.
- How? What agent(s)?
- We used Ketamine IV aliquots (10-20mg) & titrated cautiously to effect (wanting to maintain spontaneously respirations).
- Abort the plan to transfer to theatre.
- Prepare for a definitive airway.
- Difficult airway trolley at the bedside.
- Surgical airway kit opened.
- Cricothyroid membrane identified and marked (± infiltration to the site with local anaesthetic).
- Prepare the team.
- Role designation.
- Brief team (& patient) on likely sequence of events.
- Cognitive rehearsal.
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[DDET The discussion]
Unlike other ‘blunt dissections’, this discussion has been designed to encourage reflection and promote critical thinking about your preferred method of surgical airway. It is written as a stark reminder that these cases can present with little-to-no warning. The onus is on us, as critical care clinicians, to constantly revisit our practice, procedures and undertake cognitive rehearsal to allow for peak performance during intimidating and challenging scenarios.
Primary surgical airway
Indications.
- Restricted mouth opening (burns, facial trauma).
- Distorted anatomy (facial trauma, laryngeal injury, haemorrhage).
- Limited access to the upper airway due to entrapment in the prehospital environment.
NB – Surgical airways are indicated & the final step in a “cannot intubate, cannot oxygenate” (CICO) scenario.
Contraindications.
- ability to secure an airway via less invasive means
- airway trauma that renders access via the cricothyroid membrane futile
- e.g. laryngeal fracture, tracheal transection
Tracheostomy should be performed in these instances, or access can be achieved via the traumatic airway opening.
- e.g. laryngeal fracture, tracheal transection
- Children < 10 years of age
- young children are prone to laryngeal trauma and they have a higher incidence of postoperative complications
- needle cricothyroidotomy is generally advised, however life-saving surgical cricothyroidotomy has been successfully performed in children
The equipment.
What’s available?
There is a wide array of proprietary surgical airway sets available for use. These are typically made for insertion via the modified Seldinger technique and have a variety of needles, dilators, tracheal hooks, tubes, cannulae and wires (see below).
It is crucial that you know (1) what your facility has stocked & available & (2) what your preferred piece of equipment is prior to identifying a patient requiring its use.
What I prefer…
The theory.
A demonstration.
A real scenario.
This video demonstrates the method on a live patient (courtesy of EMCrit.org):
…and now it’s up to you!!
You must now decide:
- What equipment you will use?
- How will you position the patient? Do you extend the neck?
Who will do this when the decision is made? - What steps you will take in the procedure?
- What side of the bed you will perform this task?
- How you will coordinate your teams movement once the decision is made?
Once decided, incorporate them into your Difficult Airway Plan & announce it your team !!
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[DDET Case conclusion]
The team decides that a transfer to the operating theatre is unsafe. With his CT scan being interpreted as an ‘unintubatable’ oral airway, the decision is made to proceed with a primary surgical airway in the Emergency Department.
The patient receives 10-20mg aliquots of intravenous ketamine resulting in behavioural control and allows the team to commence an aggressive re-oxygenation (& preoxygenation) strategy.
Your anaesthetic colleagues take the head of the bed, providing two-handed bag-valve mask and intermittent positive pressure ventilation with the additional of 10 cmH2O of PEEP, two nasopharyngeal airways and an oropharyngeal airway. This results in an improvement in oxygen saturations back to 98%.
At this stage, you find out that your surgical colleagues are not onsite & are over 45 minutes away…
This procedure is yours.
The cricothyroid membrane is identified and marked. It is subsequently anaesthetised with subcutaneous lignocaine (+ adrenaline).
An open surgical cricothyroidotomy is performed…
Scalpel. Finger. Bougie. Size 6 endotracheal tube. End-tidal CO2.
Once the tube placement is confirmed & secured, the patient is muscle relaxed & his sedation is increased.
Following a night in the Intensive Care Unit he is taken to the Operating Theatre for a formal surgical tracheostomy. Whilst in theatre it is confirmed that his airway was truely unintubatable via both direct and fibreoptic means…
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[DDET References]
- Surgical Cricothyroidotomy – LITFL Critical Care Compendium
- Surgical Airway – Resus.me
- Greater Sydney Area HEMS. PREHOSPITAL EMERGENCY ANAESTHESIA MANUAL Version 2.2, January 2016.
- Hamaekers AE, Henderson JJ. Equipment and strategies for emergency tracheal access in the adult patient. Anaesthesia. 66 Suppl 2:65-80. 2011. [pubmed]
- Paix BR, Griggs WM. Emergency surgical cricothyroidotomy: 24 successful cases leading to a simple ‘scalpel-finger-tube’ method. Emergency medicine Australasia : EMA. 24(1):23-30. 2012. [pubmed]
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