Priming

The term 'priming' was coined for the Vortex Approach to refer to an escalation in readiness to perform Neck Rescue that occurs prior to recognition of a CICO situation. This includes activities that occur during an evolving airway crisis in parallel with attempts to enter the Green Zone via one of the upper airway lifelines, not just preparatory activities that only take place in the more static setting before the initiation of airway management. Priming is distinct from preparatory activities which only take place after a declaration of CICO. Priming is crucial to ensure that airway management teams are poised to perform Neck Rescue with zero latency when CICO is declared, without any additional delay during which patients may be exposed to ongoing hypoxia.

Priming represents a departure from the way in which clinical teams have typically approached readiness for Neck Rescue - which has been to wait until a CICO event is imminent or has already occurred before making any efforts towards getting ready to perform Neck Rescue. Effective priming presents two main challenges:

1. Trigger: the onset of an airway crisis is frequently insidious. Even during routine airway management, it is not uncommon for optimisations to be required before entering the Green Zone. The gradual evolution of these routine issues into an airway emergency makes it difficult for clinical teams to identify and declare a clear point of onset for a crisis and thus a trigger to initiate priming.

2. Outcome: initiation of priming in an appropriate timeframe will not usually culminate in a declaration of CICO or the need for Neck Rescue. To be effective, priming must be initiated early in the management of the challenging airway. Given that CICO events are so uncommon, it would be expected that in most cases the airway will subsequently be successfully managed by one of the upper airway lifelines. Thus initiation of priming will not usually culminate in a declaration of CICO or the need for Neck Rescue.

The lack of a clear trigger for early escalation and the fact that early escalation will almost always ultimately represent a 'false alarm', has the potential to create a barrier to effective priming. Clinicians may be reluctant to initiate priming early due to concerns about being seen to have panicked or overreacted. 

PRIMING STATUS TOOL

While the Vortex tool defines when performance of Neck Rescue is indicated, it does not in itself provide a clear trigger to initiate priming for Neck Rescue. To facilitate effective priming for Neck Rescue, the Vortex Approach uses the Priming Status tool as an adjunct. Inspired by Scott Weingart's CriCon concept, this tool helps to address the above issues by linking specific pre-defined priming actions to objective criteria in the management of the challenging airway in a manner that is integrated with the Vortex model. Using a three tiered Ready-Set-Go system, the Priming Status escalates with the declaration of a completed best effort at any lifeline that does not provide entry to the Green Zone. Visually this is conceptualised as descent further into the funnel of the Vortex. Adopting a structured and standardised approach to priming shares the responsibility for escalation with the team, removes the perceived focus on the 'anxiety' of an individual clinician for initiating priming and reduces the barriers to timely escalation towards Neck rescue. 

Priming Status to READY: In the situation where a best effort at one lifeline has been completed without providing entry into the Green Zone the Priming Status escalates to READY. This prompts the team to call for help, allocate someone to perform Neck Rescue (in case this ultimately becomes necessary) and confirm that the equipment to perform Neck Rescue is available at the bedside. These actions encourage the team the contemplate the possibility of Neck Rescue early, ensure that an appropriately skilled clinician is allocated to perform the procedure and allow the allocated proceduralist to begin preparing both practically and psychologically to perform this confronting intervention. It is not necessary to open the Neck Rescue kit as this stage. 

Priming Status to SET: In the situation where best efforts at two lifelines have both been unable to provide entry to the Green Zone, the Priming Status escalates to SET. This mandates the airway management team to take all steps towards Neck Rescue without actually initiating the procedure itself. This should include assembling equipment for the preferred initial technique, identifying and marking landmarks by palpation (or using ultrasound where this will not delay performance of Neck Rescue if Priming Status escalates to GO) and, time permitting, infiltrating with adrenaline containing local anaesthetic to reduce bleeding. At the completion of the SET phase, the team should be poised to perform Neck Rescue immediately if the Priming Status escalates to GO. The Priming Status should not escalate beyond SET unless best efforts at all three upper airway lifelines have been unable to secure entry into the Green Zone.

Priming Status to GO: In the rare situation where best efforts at all three lifelines have been unsuccessful, the Priming Status escalates to GO. At this stage the patient should be pulled towards the head of the bed to allow extension of the neck, and Neck Rescue initiated. The priming process encouraged by the Priming Status tool should enable Neck Rescue to be implemented with minimal delay once a CICO situation is declared. Where a cannula technique is intended and the oxygen saturations are still >90% it is sufficient to re-establish airway patency using a cannula (a relatively low-risk procedure) and delay insufflation of oxygen (the component of cannula oxygenation associated with most risk), secure in the knowledge this can be readily instituted if oxygen saturations begin to fall. 

As well as the mandatory escalations with completed best efforts at any one lifeline, additional discretionary escalations of the Priming Status may be suggested by members of the team according to other recommended criteria on the tool or their own clinical judgement. In order to facilitate early requests for assistance, escalation to READY is strongly recommended when consecutive individual attempts (not necessarily best efforts) at any two lifelines occur without achieving entry into the Green Zone (e.g. if 1st attempt at intubation and 1st attempt at face mask ventilation fail to achieve alveolar oxygen delivery). In an anticipated difficult airway, where there is perceived to be a high risk of needing to proceed rapidly to Neck Rescue, airway management may even begin with the Priming Status already at SET (the "double setup"). In such situations, particularly where a very short safe apnoea time is anticipated, it may sometimes also be prudent to allow only one maximally optimised attempt declaring a best effort at each lifeline (an attempt XYZ approach).

The declaration of a completed best effort at any lifeline should be accompanied by a request to escalate the Priming Status. If this is not made by the airway operator, other members of the team should feel empowered to insist on this. It is important to note that the Priming Status should not reach GO unless best efforts at all three lifelines have failed to provide entry into the Green Zone. Once the Priming Status reaches SET it should plateau here until a declaration is made that best efforts at all three upper airway lifelines has been unsuccessful.

If, following any escalation in the Priming Status, entry into the Green Zone is subsequently achieved by an attempt at an alternate lifeline, no further progression is warranted while access to the Green Zone is maintained. The Priming Status should remain at the escalated level, however, in case access to the Green Zone is inadvertently forfeited and a return to the funnel of the Vortex occurs. Only once a secure airway that is suitable for the context has been established, should the Priming Status 'stand down' to its default 'neutral' status.

It is appropriate to consider the need to reinstitute a previously elevated Priming Status in any circumstance where secure access to the Green Zone has the potential to become compromised, such as during extubation.