Pick a Number! – The Enemy at the Gate

Rapid Sequence Intubation beim Kind Martin Jöhr, Luzern, CH - KATZ'08

Rapid Sequence Intubation beim Kind
Martin Jöhr, Luzern, CH – KATZ’08

Nicholas Chrimes and I were chatting on twitter the other day about airway attempts before surgical airway . IN the VORTEX Approach, it is cited that 3 optimal attempts at each of the Non Surgical Airways ( LMA, Face Mask & Endotracheal Intubation) should be made before proceeding to Emergency Surgical AIrway (ESA).

It got me thinking on why 3 attempts maximum is cited. Why not 2? why not 1?

The point Nick was making was that by 3 attempts , almost all further attempts are unlikely to succeed and time should not be wasted in repeating attempts.

My point though in our debate on Twitter was that if we are truly focussed on patient safety then further limiting the maximum number of attempts would be safer. Hence my suggestion of 2.

Another friend of PHARM, Dr Bill Hinckley actually has spoken on this previously

Anyway I delved into the airway literature to see if we could find other data to guide what might be the safest threshold to limit airway attempts, at least for education and training purposes.

Turns out there are several studies indicating the association of complications with repeated intubation attempts.

Emergency Tracheal Intubation: Complications Associated with Repeated Laryngoscopic Attempts, Mort 2004

This landmark paper set the benchmark , indicating association of 2 or less intubation attempts with 0.7% cardiac arrest rate vs 11% rate with 3 or More intubation attempts! However the author concludes that his data support the ASA taskforce recommendation of maximum 3 attempts! A caveat is provided though here:

The considerable increase of complications between two and three attempts may warrant further refinement of the recommendation of limiting attempts to three, and perhaps emphasize that alternative airway techniques and the use of accessory devices may better serve the patient if considered even earlier in the process of securing the airway

What about Airway Society Guidelines like Difficult Airway Society of UK? What do they say?

DAS UK Intubation guidelines 

With failed direct laryngoscopy, up to 4 attempts at intubation is advised but only 2 LMA rescue attempts!

Here are the American Guidelines 2013 update

Practice Guidelines for Management of the Difficult Airway
An Updated Report by the American Society of Anesthesiologists
Task Force on Management of the Difficult Airway

They are much less proscriptive! They just advise to proceed after “Failed Multiple attempts”! No number is given!

Now you must realise that elective anaesthesia patients are generally more stable patients and so can tolerate more attempts at intubation than say the polytrauma patient that has been run over by a truck. So lets look for a study of critically unwell patients …oh here is one from Scotland!

Tracheal intubation in the critically ill: a multi-centre national study of practice and complications

Note here 100% patients were intubated by 3rd attempt or had surgical airway ( 1 only). So in fact Nick’s assertion of 3 maximal attempts holds credence ..at least in Scotland!

When it comes to paediatric emergency intubation then its clear that safety lies in minimising attempts as much as possible. Between 2-4 attempts in this study there was a dramatic rise in incidence of hypoxia and bradycardia.

Complications of tracheal intubation in pediatrics

So in conclusion Nick and I seem to both be right! 2-3 attempts then move on! Personally I will teach 2 attempts maximum then try something else. I think the challenge is in the occasional intubator who is not as experienced as someone like Nick. In that Scottish ICU study it was clear that the more experienced the anaesthetist, the better the success of intubation as more attempts occurred. We cannot translate to the occasional intubator and assume the more things they try in stressful situation , the more success likely. In fact the exact opposite may occur as the airway gets traumatised. Remember when you are in the VORTEX of a CICV, I would suggest that limiting your attempts is prudent. If 2 intubation attempts have not worked and Desaturation is occurring then moving to Face Mask or LMA should really be the safest next step. If neither of those techniques work then it should be surgical airway time!

I think 2 is safer than 3 but the evidence suggests 3 is okay if the operator is experienced. Thats the caveat!

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