The latest CGD saw us look at all things airway. With some scary case-based discussions, excellent debate, a great presentation on the NAP4 findings and a simulation that would make the most senior anaesthetist experience code brown moments, the Sydney HEMS team came away from the education day more prepared and equipped to handle airway difficulties.
The Bleeding Airway
This is something that scares all clinicians. Our armamentarium that usually bails us out of trouble is no longer of use: forget video laryngoscopes or a fibre/flexible optic scopes… The two tools required are:
- Powerful suction
- Good laryngoscopy
Scott Weingarts ingenuity demonstrated how the use of a meconium aspirator can take away the need to have three hands! By attaching a meconium aspirator to your ETT, a suction device is created that obviates the need for further suction and allows you to perform laryngoscopy, suction and intubation simultaneously- making those moments where you lose your awesome view from suctioning just as you reach for your endotracheal tube a thing of the past.
Tips for Managing the Predicted Difficult Airway
In awake patients without an airway:
- Topicalise, topicalise, topicalise
- Good topicalisation might even allow you to get a good view with a videolarygoscope like our King Vision
Above is a video demonstrating the use of the King Vision videolaryngoscope to assess airway difficulty.
In unconscious patients not self-ventilating:
- Use your LMA as a rescue device
- Insert the Ambu ® aScope through the LMA
- Once the cords are in view cut the Ambu ® aScope and use as a bougie, rail road your ETT over the scope!
- Remember the formula for which size tube will fit through an iGel:
iGel size + 3 = Size of ETT you can pass
→ Size 7 is the largest ETT that will fit through a size 4 iGel but it will be a tight fit so consider using size 6 reinforced
→ The smallest tracheal tube that will fit over the Ambu ® aScope is a size 6.0
Tips for Using the King Vision Videolaryngoscope
- Keep the blade midline and do not sweep the tongue out of the way
- Do not advance the King Vision in to completely get a view of the larynx, once you get your initial view of the cords keep the blade there and advance the tube. Advancing the scope further will just result in the tube hitting the back of the cords and immense frustration!
- Secretions can be a pest, avoid if you can
- The King vision has an anti-fogging device
NAP4 Review – Frank Schneider
Frank gave us an excellent review of NAP4, the largest collection of data ever performed of major complications leading to death, brain damage, emergency surgical airway or ICU admission/prolongation.
Oversimplifying the numbers allowed NAP4 to show the relative safety of airway management in the anaesthetic population, with at least one in four major airway events reported to NAP4 being from ICU or ED. This makes it all the more relevant to GSA HEMS pre-hospital and inter-hospital practice.
Of the 219 page full report, there were 8 pages of recommendations, many of which were already integral and included in GSA HEMS HOPs. The executive summary is certainly worth reading. We discussed some of the more relevant learning points:
- Generally, there was poor airway assessment at times combined with poor judgement
- A fallback “strategy” (co-ordinated, logical sequence of plans aiming to achieve good gas exchange and prevent aspiration) rather than “plan” (single approach) was required
- “Failure to Plan for Failure” – probably the most quoted finding! The response to failed airways was unstructured and led to poor outcomes. Many institutions already rely on DAS guidelines or similar adapted guidelines, such as our own.
- Awake Fibre-optic Intubation (AFOI) was under-utilised: due to a combination of lack of skill, confidence, judgement or equipment being immediately available. This was more apparent in the ICU setting, AFOI was also not considered for airway rescue with a SAD in situ, leading to a surgical airway and poor outcome in one case.
- Multiple repeat attempts at intubation regularly deteriorated to CICV situations. A change in approach is required, rather than repeat attempts of a failed technique.
- Obesity was identified as an independent risk factor for difficult airways and plans should be modified accordingly, including the optimisation of positioning by ramping. Obese patients had an increased frequency of aspiration, SAD complications, difficult tracheal intubations and airway obstruction; rescue techniques failed more often.
- High failure rate of cannula cricothyroidotomy (60%) for numerous reasons including equipment, training, insertion and ventilation techniques. A surgical technique was almost universally successful and many institutions have resorted to teaching this exclusively
- “Capnography Fails” – both failure to use waveform capnography which led to unrecognised oesophageal intubations, as well as failure to recognise its waveform pattern and value during CPR
Once again, a fantastic show of enthusiasm for our simulations, bear in mind the following when applying it in your clinical practice:
- In obese patients positioning is the key- correct ear to sternal notch positioning will often get you a grade 1 view
- Management of neuro patient who is a difficult intubation you still need to consider principles of blood pressure management, avoiding hypoxia/hypercarbia and avoiding bucking/straining on the tube
Special thank you Drs Natalie Kruit and Frank Schneider for their contribution to this post!