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Guidelines and Algorithms, Why Are They Important?

In this article Prof Chris Frerk, Consultant Anaesthetist at Northampton General Hospital and author of the Difficult Airway Society 2015 guidelines for the management of the unanticipated difficult airway in adults, explains how guidelines, algorithms and cognitive aids are helpful in challenging situations.

Looking after airways is usually easy once you have had some training. Anaesthetists place supraglottic airway devices every day without difficulty. We place tubes in tracheas safely and correctly every day. It is easy to do these things 99 times out of 100.

But 1 time in 100 it is difficult to place a supraglottic airway. And 1 time in 100 it is difficult to place a tube in the trachea. This happens because of the patient’s anatomy. It happens to very experienced clinicians as well as to newly trained healthcare workers. It happens about once a year. It happens when you least expect it.

Imagine what it might feel like when something that you usually do well goes wrong one day. Imagine what it might feel like when the patient’s life is at risk because you cannot get oxygen to their lungs.

The most common reaction is to feel anxious. You might feel your pulse begin to speed up. You might feel your mouth go dry. You might notice your hands begin to shake.

Another thing that happens is that it gets difficult to think clearly. And it gets very difficult to make good decisions about what to do.

This is where guidelines are helpful. Someone else has already done the thinking for you. There is a plan of what to do if things go wrong. It is the same plan every day in every hospital. Most days you don’t need to use the plan because most days everything goes well.

But the day will come when you realise that things are not going well and the airway is difficult. If you have learned the guidelines they will help you do the right thing.

Guidelines also promote good teamwork:

  • If you work with an assistant they will know the guidelines too. You can work well together better because you have both learned the same plan.
  • When another person arrives to help they will also know the guidelines. You can work well together because you have all learned the same plan.
  • All the equipment you want will be there because the hospital has prepared for the plan.

There are three techniques that we use every day to get oxygen into patients lungs when they are unconscious or when they are having an anaesthetic:

  1. Bag and mask ventilation
  2. Ventilation through a supraglottic airway
  3. Ventilation through a tracheal tube

©Difficult Airway Society

The DAS guidelines [1] give us a series of plans to help us use these three techniques as safely and effectively as possible. They help us to be prepare for unexpected difficulty. They give us rules about how many times we can try a technique before we accept that it is not working.

Look at Plan A in the DAS guideline diagram:

©Difficult Airway Society

Plan A includes facemask ventilation and intubation. Following the detail in the blue box of Plan A gives you the best chance of successful tracheal intubation. Failed attempts at tracheal intubation cause trauma and make bag and mask ventilation more difficult. Call for help straight away if you fail. Do not have more than three attempts at tracheal intubation before help arrives.

If you cannot intubate the trachea do not worry.
If you cannot intubate the trachea follow the guidelines.
Even if bag and mask ventilation is easy it is time to move on to plan B.

Look at Plan B in the DAS guideline diagram:

©Difficult Airway Society

Plan B uses a second generation supraglottic airway to maintain oxygenation. When you put in a supraglottic airway it frees up your hands When you put in a supraglottic airway it also frees up your brain to think more clearly. If you look at the pink box in the diagram on the right hand side it actually says

“STOP AND THINK”

You can start to relax. You can wait for help to arrive. The most sensible thing to do next is to wake the patient up. Only in very rare situations with very experienced staff is it sensible to choose one of the other options.

It is extremely rare for both Plan A and Plan B to fail. It probably happens less than one time in 20,000. But if it happens to you with a patient next week there is no need to worry as long as you follow the guidelines. It is as easy as “ABC”. If Plan A and Plan B have not worked then we use Plan C.

Look at Plan C in the DAS guidelines diagram:

©Difficult Airway Society

You can deliver oxygen to your patient using facemask ventilation. It might not be easy. You might need to use an oropharyngeal airway. And you might need to ask someone else to squeeze the bag while you use both your hands to hold the airway. But that is OK. Plan C will help you get oxygen into the patients lungs.

There is one other plan in the guidelines. That is Plan D:

Plan D is an emergency front of neck airway (eFONA), performed with a scalpel cricothyroidotomy. This is like an emergency tracheostomy but it is faster.
Because Plan A, B and C work so well you will probably never need to use Plan D. Most anaesthetists will never need to use Plan D.

But if bag and mask ventilation fails, tracheal intubation fails, supraglottic airway fails and your patient is becoming hypoxic then you have to use Plan D. Needing to do an emergency scalpel cricothyroidotomy is quite a scary thing to think about. That is why we need to practice it. Make sure you practice scalpel cricothyroidotomy. It is worth practising once a year to make sure you can remember how to do it.

Now have a look at the first sentence of this article again. It says “Looking after airways is usually easy once you have had some training”. This is true.

If you are able to use Plan A, B and C you will be able to look after patients airways safely. And you need to practice Plan D, just in case you need to use it one day in the future. If bag and mask ventilation fails, tracheal intubation fails, supraglottic airway fails and the patient is becoming hypoxic then you have to go to Plan D.

Plan D will be covered in more details later in Week 2.

Which difficult airway guidelines are used in your workplace? Are they similar to the DAS Difficult Intubation 2015 Guidelines?

References

1.Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults

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This article is from the free online course:

Airway Matters

UCL (University College London)