The CRUX & VORTEX compared by Dr Nicholas Chrimes

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Interesting. I like it but I think it is depicting something slightly different from the Vortex though.
The CRUX more closely follows the temporal sequence of interventions as the airway operator attempts at having an optimal attempt to establish a patent airway. The VORTEX is more broadly goal directed and simply “ticks off” whether optimal attempts at each NSA have been had and where to go to next in response to the outcome of that. As the VORTEX videos illustrate, an “optimal attempt at intubation” may indeed be broken up into a couple of tries, with the first try at an “optimal attempt at mask ventilation” occurring in the intervening period whilst preparations for the second try at ETT are made. This is exactly what the CRUX depicts, so in a sense it is illustrating the mechanics of what is going on “behind” the VORTEX. To me the CRUX is not a “high stakes cognitive aid” for use in a real time during a crisis but a way to explain how one might go about achieving the goals of the VORTEX.
The decision to put this emphasis on the VORTEX was a deliberate one on our part and a diagram not dissimilar to the CRUX was the immediate precursor to the VORTEX. What I believe the Vortex adds is this:
1. Simplicity: by avoiding depiciting the individual steps in achieving an optimal attempt and sticking with just the end goals of an optimal attempt at each NSA technique, it produces an overall “cleaner” look.
2. Clarity: from any NSA technique in the CRUX there are multiple directions in which the airway operator can proceed – and which of these to choose is not necessarily determined by success or failure at that technique. Whether from any technique you move back to another NSA or down to ESA is influenced by whether you have already failed at the others. Additionally you might move back and forth between two or three NSA techniques multiple times. I understand the concept of an NSA technique being “blocked” by a failed optimal attempt but given that the arrows themselves don’t lead you in a definite direction with success/failure this requires a change in how you visualise the pathway (almost a change in each circle from green to red as an optimal attempt fails) illustrate this. In contrast the VORTEX offers a smooth, definite progression from one NSA to the next as optimal attempts are completed – either upwards into the green zone with success, or downwards into the funnel with failure – without need to visualise changes/blockades in the cognitive aid. It is the spiral nature of the pathway that allows simultaneous visualisation of movement between NSA techniques and progression towards surgical airway. In this way think the VORTEX conveys more clearly the sequential elimination of NSA options and the inexorable approach of ESA that this implies. The “blockade” element is able to be represented by the fact that you are now further down the funnel. I suppose whereas the CRUX operates on two sequential axes – first the horizontal (to achieve optimal attempts at NSA), then the vertical (to move to ESA) if this fails – the VORTEX combines this by having a spiral pathway which can plot progress on both these axes simultaneously. Thus the VORTEX makes it very clear that ESA is getting closer as NSA options are being eliminated. It is harder for the team to keep track of progress through NSA techniques and proximity to ESA with the CRUX.
3. Flexibility: whilst I completely agree regarding the importance of attempting FM ventilation between attempts at LMA/ETT (and the VORTEX allows you to do this), the reality is that this will not always be appropriate or desirable. Since FM attempts don’t traumatise and risk further compromising the airway, there is more freedom to have multiple attempts at FM ventilation than can be done at LMA/ETT. The “no harm” aspect of always returning to FM ventilation is only true if FM is not also wasting time. Thus there is no harm in having “just one more” attempt at FM if it takes place while equipment is being prepared for 2nd attempt at ETT. On the other hand, if an “optimal attempt” at FM & ETT has already been had, and an LMA is immediately available, it would not be reasonable to delay attempting LMA insertion and potentially letting sats fall further to have one more attempt at FM. This would almost constitute a fixation on FM ventilation! Additionally rightly or wrongly many clinicians would not FM ventilate initially during RSI. Also as we’ve been discussing recently re RSA, some clinicians might prefer to go to LMA initially. These two options would be relatively easily overcome in the CRUX by allowing entry at any of the NSA techniques. What is less easily accomodated is that because FM is a more difficult & nuanced technique, I imagine that many clinicians who had attempted RSI/ETT first might next jump immediately to LMA (for the same reasons as advocated for using RSA in the first place). Scott Weingart has told me he would almost never FM ventilate during RSI for fear of inflating the stomach. Whether you agree with these rationales or not, the VORTEX allows the clinician to use their individual expertise to make these decisions in any particular context and then supports them equally in managing a difficult airway regardless of what their underlying preferences are in this regard. This is crucial in allowing the universal application of the VORTEX cognitive tool to any airway situation and allowing all clinicians involved in airway management, regardless of discipline, to have a unified approach.
4. Equality: central to the concept of the VORTEX is the equality of all 3 NSA techniques in terms of achieving AOD (though not necessarily in terms of other secondary airway management goals. The inequality in terms of secondary goals is addressed by the sequence the airway expert chooses to spiral through the funnel). The central premise of the CRUX (? the crux of the crux) seems to be that FM is more important somehow. I can’t quite follow why, as the author suggests, the decision as to how many attempts to have at alternate NSA techniques should be influenced by whether an optimal attempt at FM ventilation succeeds or not (more so than if an optimal attempt at another NSA technique fails). Why is failure at FM more significant than failure at ETT or NSA? The VORTEX approach advocates an optimal attempt at each NSA using the minimal number of tries possible. Certainly the sequential failure of optimal attempts at NSA techniques means time & options are running out but I can’t see why the sense of urgency should be greater because one of the techniques that has failed is FM. I would agree, however, that the often progressive nature of the deterioration of FM ventilation does provide an indication of the overall difficulty of the airway. Regardless, I would still be prepared to devote the same amount of time to PRODUCTIVE optimisation strategies for the remaining NSA techniques, whether ┬áthe initial one to fail was FM or one of the others.
5. Green Zone: one of the most important aspects of the VORTEX is the “green zone” concept, which is absent in the CRUX.
6. Concept: I believe the VORTEX 3D funnel concept is very important in reinforcing to staff the inherent dangers of not achieving AOD in the “slippery slope” of the funnel, and the significance of being on “level ground” in the green zone.
7. Optimisation Strategies: whilst the focus of the VORTEX inevitably falls to the colourful green diagram, equally important are the 5 universal optimisation strategies that tell you HOW to have an optimal attempt. This is key to both efficient/rigorous progression through interventions to improve attempts at each NSA as well to maintaining situational awareness that an optimal attempt has been completed and that further attempts at that NSA technique are wasting time/oxygenation as well as potentially further traumatising the airway (for LMA/ETT).
Overall, whilst I think it is a major improvement on traditional algorithms, my concern is that the CRUX is a bit less clear than the VORTEX and might risk clinicians bouncing between NSA techniques without a clear endpoint. In particular the idea of going around UNTIL you lose the ability to mask ventilate could be a real worry.
Of course all of this is said without having seen the education program that goes with this tool which would clearly be important.
In any case I think the VORTEX allows clinicians to apply the same emphasis on FM that the CRUX does whilst giving others, who do not share this philosophy, the freedom to prioritise differently – whilst still using the same tool. It is this context independence that is the really important thing about the VORTEX approach.
Thanks for sharing this.
Nick

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