Difficult Airway Society Guidelines on Awake Intubation

I have written a lot about airway management on this blog. You can find the main 5 part series on emergency airway management starting here. I have also covered a prior Difficult Airway Society guideline on the intubation of critically ill patients here. One topic I have not spent a lot of time covering is awake intubation. It has been covered extensively by experts like Scott Weingart and George Kovacs, both of whom have a lot more experience that I do. (There are multiple links at the end of this post.) However, the Difficult Airway Society has a new guideline on awake intubation, and I wanted to cover some of my key takeaways from that document. (It is worth reading the whole article and it is open access.)

The article

Ahmad I, El-Boghdadly K, Bhagrath R, et al. Difficult Airway Society guidelines for awake tracheal intubation (ATI) in adults. Anaesthesia. 2019; PMID: 31729018 [free full text]

My key takeaways

Indications

• “Awake tracheal intubation must be considered in the presence of predictors of difficult airway management (Grade D).”
• They only really talk about awake intubation for anatomically difficult airways, but I actually think that the physiologically difficult airway will be a more common indication in emergency medicine.
• “There are few relative contra-indications to awake tracheal intubation (e.g. local anaesthetic allergy, airway bleeding, uncooperative patients) but the only absolute contra-indication is patient refusal.” (Personally, I wouldn’t be trying an awake approach in the emergency department with an uncooperative patient.)

Set Up

• They make the controversial and probably incorrect statement that “awake tracheal intubation should ideally be performed in the operating theatre environment (Grade D). This setting has ready access to skilled assistance, drugs, equipment and space.” (We have plenty of skilled assistance, drugs, and equipment in the ED, although I will admit space is sometimes a little short.)
• We need to monitor for airway obstruction, hypoventilation, arrhythmias and hypotension. “It is recommended that ECG, non-invasive blood pressure, pulse oximetry and continuous end-tidal carbon dioxide monitoring are used throughout the process of awake tracheal intubation (Grade C).” Most of that is obvious, but the use of end tidal is an important recommendation, in my mind. 
• “Workspace ergonomics have an impact on performance and safety, and should be considered before starting the procedure (Grade D)”
• “A plan for unsuccessful awake intubation, including possible postponement, front of neck access or high-risk general anaesthesia, should be discussed explicitly and agreed on by all team members before beginning the procedure (Grade D).”
• “In the peri-operative setting the use of cognitive aids, such as checklists, improves inter-professional communication, teamwork and patient outcomes… Given the potential benefits, we recommend a cognitive aid such as a checklist before and during performance of ATI (Grade D).”

The Procedure

• Oxygen is important. “The administration of supplemental oxygen during awake intubation is recommended (Grade B). This should be started on patient arrival for the procedure and continued throughout (Grade D). If available, high-flow nasal oxygen should be the technique of choice (Grade C).”
• “Lidocaine has theoretical safety benefits over other local anaesthetic agents due to a favourable cardiovascular and systemic toxicity risk profile.” 
• “The dose of topical lidocaine should not exceed 9 mg/kg lean body weight (Grade C)… Practitioners should recognise that this is not a target but a maximum dose, and in practice this is rarely required.”
• “As with all local techniques, a high index of suspicion of the rare possibility of local anaesthetic toxicity with appropriate training, procedures and emergency drug provision (including lipid emulsion) should be in place (Grade D).”
• “Regardless of technique used, the adequacy of topicalisation should be tested in an atraumatic manner before airway instrumentation (Grade D), for example, with a soft suction catheter or Yankauer sucker.”
• You don’t necessarily need an intubating fiber-optic scope. “Awake tracheal intubation using videolaryngoscopy has a comparable success rate and safety profile to flexible bronchoscopy (98.3% each). Choosing between techniques is based on patient factors, operator skills and availability of equipment (Grade A).”
• The use of a standard PVC endotracheal tube is not recommended for flexible bronchoscopy (Grade A). I think this is probably obvious in a well stocked operating room, but in the emergency department where scopes are rare, the fancy tubes are not always stocked, so I have definitely seen normal tubes used. 

Sedation

• Awake intubation implies forgoing sedatives. They say “awake tracheal intubation may be safely and effectively performed without sedation.”
• However, awake intubation is an anxiety producing procedure (not just for the doctor), and sedation might improve patient tolerance and cooperation (and therefore success). Therefore, if it is required, they suggest “the cautious use of minimal sedation (Grade D).” They define minimal sedation as: “a drug-induced state during which the patient responds normally to verbal commands, whilst the airway, spontaneous ventilation and cardiovascular function are unaffected.”
• “The risk of over-sedation and its sequelae, including respiratory depression, airway loss, hypoxia, aspiration and cardiovascular instability, make the presence of an independent [physician] delivering, monitoring and titrating sedation desirable (Grade D).” (They actually say “anaesthetist”, but clearly an emergency doctor is also a great option.)
• They suggest remifentanil or dexmedetomidine as the ideal sedative agents. Those agents aren’t available in most emergency departments. I think ketamine is a good option, and given that they are reversible, fentanyl OR midazolam may also be reasonable. Whatever you choose (if it is required) it is best to stick with one agent.

Tube Confirmation

• Of course, you are already checking tube placement using end tidal CO2 on every intubation, right? Unfortunately, you could run into a problem with spontaneously breathing patients, because a detectable waveform can be present even when the tube is in the supraglottic area. Therefore, they suggest a two point check:
  • Everyone should get waveform end tidal CO2.
  • Additionally, tube position should be confirmed by either visualizing the carina (when using a fiberoptic scope) or visualizing the tube between the cords (when using laryngoscopy). (Grade C)
• “Anaesthesia should be induced only when the two point check has confirmed correct tracheal tube placement (Grade D).”

Complications and Failure

• Treat this like any attempt at intubation – you get three attempts, then stop. (You can have a fourth attempt ONLY if it is done by a more experienced operator.)
• If you are not successful, “immediate actions should include a call for help, ensuring 100% oxygen is applied and stopping (if necessary, reversing) any sedative drugs (Grade D). Operators should ‘stop and think’ to determine subsequent airway management, while also ‘priming’ for emergency front of neck access (Grade D).” 
• If airway management is essential (which will almost always be the case in the emergency department, as we can’t just “cancel the case”), the preferred option for securing the airway is awake front of neck access with either cricothyroidotomy or tracheostomy (Grade D). “The most appropriately skilled clinician available should perform this (Grade C).”

Training

• “Successful performance of awake intubation has been shown to be independent of seniority, but related to experience.” Therefore regular training is essential.

Other Awake Intubation FOAMed

EMCRIT: Emergency Awake Topicalized (EAT) Intubation – An Awake Intubation Update

EMCRIT: EMCrit Podcast 247 – The Dissociated Awake Intubation with my buddy, Ketamine

EMCRIT: Podcast 194 – Definitive Emergent Awake Intubation with George Kovacs

AIME Airway Management in Emergencies: Awake Airway Management and Flexible Endoscopic Intubation

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References

Ahmad I, El-Boghdadly K, Bhagrath R, et al. Difficult Airway Society guidelines for awake tracheal intubation (ATI) in adults. Anaesthesia. 2019; PMID: 31729018