COVID airway management: SAS consensus statement

I have spent a lot of time talking about airway on this blog. Most of the core knowledge is encompassed in the 5 part airway series that starts here. Even in the era of COVID, this basic airway teaching is still essential. We still need to be masters. However, there are some significant changes that we are all going to be making. These changes are a moving target, so I anticipate this post will be updated significantly over time. However, the Safe Airway Society published the most comprehensive and logical document I have encountered on COVID airway management, so I thought I would pick out some of the key highlights. (This document is free to read online)

The article

David J Brewster, Nicholas C Chrimes, Thy BT Do, et al. Consensus statement: Safe Airway Society principles of airway management and tracheal intubation specific to the COVID-19 adult patient group. The Medical Journal of Australia. 2020. [free open access article]

My takeaways

We absolutely must keep staff safe throughout this pandemic. This is both for our own benefit, but also so we are available to look after patients. They state that “the process of airway management is a high-risk period for aerosol-based transmission for the following reasons:

• Patient may become agitated or combative due to hypoxia
• Patient PPE must be removed.
• Clinicians are in close proximity to the patient’s airway.
• Laryngoscopy and intubation are vulnerable to aerosol generation.
• Aerosol generating events are more likely.”

They make a distinction between aerosol generating events (which inevitably involve to occurence of high-velocity gas flow), and procedures which are vulnerable to aerosol generation. The latter do not inevitably involve airflow. For example, laryngoscopy will only generate aerosols if the patient coughs, which can be prevented by using an adequate dose of paralytic and giving the paralytic adequate time to work. This is their list:

Aerosol generating events

• Coughing/sneezing • NIV or positive pressure ventilation with inadequate seal • High flow nasal oxygen (HFNO) • Delivery of nebulised/atomised medications via simple face mask • Cardiopulmonary resuscitation (prior to intubation) • Tracheal suction (without a closed system) • Tracheal extubation

Procedures vulnerable to aerosol generation

• Laryngoscopy • Tracheal intubation • Bronchoscopy/Gastroscopy • Front-of-neck airway (FONA) procedures (including tracheostomy, cricothyroidotomy)

What factors increase risk for ED staff and what can we do about it?

Coughing: Ensuring all patients with respiratory complaints are wearing masks; Wear appropriate PPE whenever managing these patients; Minimize the time that a patient does not have a mask on; Ensure the patient has a well fitting mask with a viral filter; Ensure paralysis before laryngoscopy.

Inadequate face-mask seal during pre-oxygenation: Use a two hand vice (V-E) grip on a well fitting mask, ensure the appropriate viral filter is in place between the mask and the BVM bag, and use waveform capnography to help monitor for a mask leak.

Positive pressure ventilation with an inadequate seal: Avoid positive pressure ventilation; prioritize intubation with a cuffed endotracheal tube; if a supraglottic airway is required, ensure it is the adequate size, at the adequate depth, and the cuff is full inflated (if your model has an inflatable cuff).

High gas flows: Avoid high flow nasal oxygen (although I think there is more science coming on this soon), nebulizers, and open airway suction. (The Canadian consensus seems to be to treat any oxygen flows greater than 6 L/minute as high risk for aerosolization.)

Non-invasive ventilation and high flow humidified nasal oxygen

Don’t use them. Assume they are aerosol generating. More importantly, they have a high rate of failure in severe ARDS and viral pneumonia, so you are likely going to have to intubate anyway.

This gets a little more complicated. They have been used around the world, and as we get short of resources, we may be forced to use them (hopefully prioritized to negative pressure rooms). There is also new data arriving almost daily. I expect this recommendation may be changed with time, and we may need to break it out of necessity, but for now I am sticking to it.

General principles

Follow your usual airway algorithms and guidelines, unless there are specific recommendations to change because of COVID. (We are very good at resuscitation. We don’t want to abandon that skill in the face of COVID. We just want to adapt that still to ensure that resuscitation is safe for everyone involved.)

If in doubt, intubate early. We have spent years staving off intubation with tools like non-invasive ventilation. We are used to postponing intubation to see how the patient will progress. In the face of COVID, that just increases the chance of high risk crash intubations, and increases the use of open oxygen systems. Furthermore, once these patients require a high FiO2 (more than 50%), a very large percentage need to be intubated.

Significant institutional preparation is necessary to optimize staff and patient safety. 

Each hospital will have to adapt the general guidelines to their own equipment, teams, and expertise. I like the criteria they provide for standardized practice:

• Safe: choose options that will not expose patient or staff to unnecessary risk
• Simple: straightforward solutions that can be executed efficiently
• Familiar: where possible rely on existing techniques that are familiar to the relevant clinicians
• Reliable: choose options that are known to be successful in the hands of the relevant clinicians
• Robust: choose options that will continue to fulfil the above criteria in the face of foreseeable variations in patient characteristics, environment and the availability of personnel and resources

Environment

The ideal environment is a negative pressure room with an antechamber. If not available, use a normal pressure room with the doors closed.

I anticipate that one of the more complex decisions for emergency providers is deciding what to do with semi-stable patients, especially in hospitals where the ICU environment is far more conducive to infection control practices than the emergency department. They say: “the decision to move a clinically stable patient between two clinical areas prior to airway management should primarily be based on whether the destination environment will provide a more controlled situation, better equipment and/or more experienced staff to make the process of airway management safer (including less likely to generate aerosolized virus).”

Equipment

Use a standard BVM, with a good 2 hand seal, a viral filter, and a PEEP valve for pre-oxygenation, but do not provide ventilations. 

• “Pre-oxygenation should be performed using a well-fitting occlusive face mask attached to a manual ventilation device with an oxygen source.”
• “A viral filter MUST be inserted between the face mask and manual ventilation device to minimise aerosolization.”

• “Non-rebreather masks provide sub-optimal pre-oxygenation and promote aerosolization and are not recommended for this purpose.”
• “Nasal oxygen therapy (via standard or high flow nasal cannulae) should not be used during pre-oxygenation or for apnoeic oxygenation due to the risk of virus aerosolization to the intubation team.”

Play with your equipment before you need it. The general schematic of what your setup should look like is:

The specific equipment used for intubation will vary a lot depending on your department, but I will make two notes. Video laryngoscopy is specifically recommended, with both standard geometry and hyperangulated blades available. They say that if a supraglottic is indicated, we should use a second-generation device, as it has a higher seal pressure which should decrease the risk of aerosolization. 

Team

Follow all your usual best practices, including ensuring team members have clearly defined roles. Limit the number of people in the room, and have the most experienced staff manage the airway.
They specifically note that we might want to excuse staff at high risk from infection from airways teams (staff over 60 years of age, immunosuppressed, pregnant, or with serious comorbidities).

Some CRM

Communication will be more difficult than usual. Voices need to be raised to hear through the masks. Communication between people inside and outside the room will be difficult. Both high tech (speaker phones) and low tech (white boards) solutions are reasonable. Ensure clear concise language is used, and focus on closed loop communication. 

These will be very high stress situations. Use cognitive aids to your advantage (eg. airway checklists).

Teamwork also applies to PPE. Buddy up to make sure everyone on the team is donning and doffing (yes I am also sick of those words) correctly.

Education is also emphasized. Every department needs education on all new procedures, and also practice to ensure we remain strong in the resuscitation basics. We love practicing airway stuff, but it is probably even more important to practice the appropriate use of PPE.

Intubation

Anticipate that the patient will desaturate faster than we are used to, and that we do not have our usual full complement of tools. Therefore, treat every airway as a difficult airway.

Rapid sequence intubation should be the technique of choice for most patients. Ensure you wait long enough for the paralytic to work, because we don’t want to provoke coughing. Use video. Ensure the cuff is inflated before providing any positive pressure breaths, and be extra careful about tube depth, because you don’t want to have to go back into the room just to readjust it. A viral filter should be attached directly to the ETT. Otherwise, proceed mostly as you normally would. An NG tube should also probably be placed right away, to prevent other providers from having to come back and do it later. (In general this is key. Plan ahead so you can do everything you need for a patient in a single visit, rather than having to don and doff multiple times to accomplish the same things.)

Backup plans

The one area that this document does not give me as much detail as I want is in the best ways to re-oxygenate, and the best sequence of backup airway maneuvers. They do note that in a can’t intubate can’t oxygenate situation, we should proceed with front of neck access using the scalpel-bougie technique. 

The Safe Airway Society Checklist

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There is a ton more in this document. Again, I recommend you read it yourself. 

That’s it for now. I expect to be back with many COVID updates. (I think a quick post addressing the ibuprofen thing needs to be put together. Yes, I would still take ibuprofen myself.)

Stay safe out there, and look after your colleagues in these stressful times.

References

David J Brewster, Nicholas C Chrimes, Thy BT Do, et al. Consensus statement: Safe Airway Society principles of airway management and tracheal intubation specific to the COVID-19 adult patient group. The Medical Journal of Australia. 2020. [free open access article]