This post is the written version of a talk by Dr Andrew Weatherall for the South African Society of Anaesthesiologists Congress 2017 in Johannesburg. The organising committee extended the invitation to be part of the faculty and paid for travel, accommodation and registration.
This thing has the working title “The Tao of Better Takeaway Options for Kids”. Why that title? Well my not at well informed understanding of the tao as a concept is that it is also known as “the way” and navigating a good path to get this done in challenging kids sounds like a worthwhile enterprise.
Plus you never know how this anaesthesia thing will work out and if I can figure out how to harness vague notions of ancient philosophies to package things for a modern audience maybe I can fall back on late night infomercials and self-help manuals. You have to have dreams.
If you have a chat with anaesthetists there is a good chance they’ll describe the most challenging bits of an anaesthetic as being the beginning and the end. Both bits. They don’t tend to think only about the start and assume the rest will work out.
That’s not what you’d think if you go for a search of the literature. If you look at the literature you’ll hear the cries of trees lost to explorations of very particular idiosyncrasies in use of induction agents, commentaries on airway devices, ventilation techniques, muscle relaxant choices, laryngospasm prevention at the commencement, straight blades and curved blades, videolaryngoscopes and not so media-dependent options. The lack of interest in the removal of the snorkel is sort of weird.
It’s a bit like reading movie reviews from the critic who only bothers with the first third of the movie.
“Top Gun? Yep, good film. It’s about a guy who flies planes, hits on women at bars with not great songs, spends a bunch of time playing volleyball with his shirt off with a guy called Goose and actually he seems to really like Goose so I assume they get married in the end and he and Goose live happily ever after.”
Perhaps it’s time we paid attention to the end.
What, me worry?
Well, yes. The patient who fails extubation (used interchangeably here with needs reintubation unless explicitly written as otherwise) is a patient who is going to have complications. If you look at the intensive care experience you can find papers quoting failed extubation rates anywhere between 4.1% (Baisch et al.) to 5.8% (Gaies et al.) right up to 17.5% in some cardiac series (Laudato et al.)
When Ing and crew looked they found in a pretty big series that around 1:1000 anaesthetic patients required reintubation. Not huge numbers for the straight anaesthetic ones although that included the general paeds anaesthesia population. Jagannathan et al. showed a 5% extubation failure rate in those with known difficult airways (although again the absolute numbers are pretty small as you’d expect – that 5% was a total of 7 kids they looked at).
Failed extubation is associated with bad outcomes though. These patients are more likely (again particularly in ICU patients) to have longer hospital and PICU stays, a longer time on the blowing machine and a higher rate of tracheostomy with all the associated problems.
Hiding in Plain Sight
The other feature of kids’ difficult airways is that they’re not subtle about being present. They hide right in the open. We know that kids who are smaller (say, under 10 kg), younger (infants and below), who have significant comorbid disease (particularly respiratory, neuromuscular and some heart issues), who have been on a ventilator for a long time (sometimes defined only by a few days but more commonly a few weeks) or who have required more airway interventions than the standard kid are all likely to cause trouble.
We can be pretty confident what will cause them issues too. In the paper by Ing they describe laryngospasm, airway obstruction and apnoea as the biggest issues leading to a reintubation. In the 7 kids failing extubation in Jagannathan’s paper 6 of them had evidence of upper airway obstruction. We’re supposed to be good at that, right?
Big People Make All the Plans
The Difficult Airway Society already has guidelines that cover managing tracheal extubation for those groaning hulks of flesh they consider “patients”. It stresses a need to plan, prepare, perform and then provide post-extubation care.
Interestingly it also stresses the issue of airway reflexes sometimes being the root cause of the problem. Those would be the same airway reflexes probably more likely to cause a problem in kids. They also stress issues with oxygen delivery and consumption. Wait a minute, aren’t kids likely to drop their oxygen saturation quicker?
We should probably get on with a plan.
So let’s imagine we get a fairly typical sort of request. A 10 month old child with a diagnosis of Pierre-Robin sequence has been in the intensive care unit with a nasty lower respiratory tract infection. They’ve had these before but on this occasion they rolled straight past non-invasive support and required intubation.
That all happened a rural spot though and the only information you have is that apparently the intubation required an ENT surgeon who “never saw the cords”.
Oh. Oh, I see.
Let us seek then to find the way, and get rid of this snorkel.
The 4 Stages
Let’s work through these 4 stages:
- The State of Understanding (Planning).
- The Questions of Readiness (Preparation).
- The Circle of the End and the Beginning (Practical stuff).
- The Preparation of the Next House (Post-extubation care).
The State of Understanding.
Before we get going we need to know what we mean when we talk about a difficult airway. From the Jagannathan paper they incorporated the following elements:
- Cormack and Lehane laryngoscopic view grading of 3 or 4.
- A need for an alternate device or video laryngoscope for intubation.
- 3 or more attempts required for intubation.
- A note of “difficult face-mask ventilation” recorded somewhere.
To this I think it’s worth adding:
- Prior failed extubation.
- Admitted with airway pathology (either because that’s something they picked up themselves or because we created it iatrogenically).
- A background of requiring noninvasive support.
- Airway access issues (meaning things that get in the way of you accessing the airway).
It’s then time to get into some yes/no questions to make sure we understand what we’re dealing with.
First up, do we need more information about the airway? If the answer is no then we can move on. However if we could use more information then we can seek that from old notes, other practitioners who know about the patient and any available imaging. We may be benefited by some form of airway endoscopy or bronchoscopy happening so we know what we’re dealing with. Or if the patient had acute airway issues above the level of the cords you might be well served by having a look yourself with direct or videolaryngoscopy.
The more you know, the better you can prepare.
Next question – is there acute pathology causing problems? If the answer is yes then it is worth having a discussion about whether waiting a little bit longer would increase your chances of extubation success. If the answer is “no, this is just the airway how it is, waiting won’t change that” then it’s time to move on again.
The final questions for understanding where we are relate to whether everything is polished and looking tidy. Is the patient as ready as possible? Are they neuromuscularly as strong as can be expected? Are they neurologically in a good place (meaning will their conscious level compromise your efforts or are they really ready to get rid of that tube)? Of course this is more challenging where they also want a look at the airway under anaesthesia first.
Are there other systems that need to be buffed up (think respiratory and cardiac)?
Then most crucially is there anything that can be done to improve the airway? Would steroids be useful? Though there is some uncertainty as to how effective they are it does seem that they might have clinical effects on the airway particularly if given over the full 24 hours prior to extubation.
Should you do a leak test? Actually probably not. It’s not a particularly useful test, seeing as it was designed probably mostly for cases of epiglottitis or croup in a day of uncuffed endotracheal tubes. The sensitivity for picking up issues is around the 60s so what will you do with either result, leaky or non-leaky?
Anyway, let’s assume our patient seems as ready as they’ll be soon.
The Questions of Readiness
These are the questions about whether you are ready.
- Who do you need?
How many anaesthetists and what levels of experience? How many nurses would you like handy? Do you want ENT lurking nearby?
- Where should you do it?
It’s worth being explicit with this in the planning. If you’re comfortable working in your PICU with their patients then fine. It’s a fair bet most of us would prefer to be in the theatre complex with the usual stuff around.
- When should you do it?
If you have a difficult extubation to undertake then why would you do it late or when people aren’t around? Why would you make the chances of an after hours deterioration just that little bit higher. On reviewing this question we’re planning to try and make these all happen before midday so any funny business is hopefully within hours.
- What equipment do you need?
Finally we get to the gear. It’s probably an easy list to contemplate. I’d have handy suction, an appropriate face-mask and circuit as well as airway adjuncts. I’d want working IV access. I’d have a nebuliser mask handy with the right drugs in case there is a need for nebulised adrenaline to manage airway swelling. I’d make a plan for noninvasive support if I thought this was a possibility.
And although I wouldn’t have thought about it before looking through the literature there are reports of the use of exchange catheters to be left behind as a means of rapidly rescuing the airway. The particular report by Faberowski and Nargozian indicated that the catheter stayed in place for a median of 64 minutes in their 20 patients and was “well tolerated”. There’s even a report of the use of the sheath for a ureteral stent.
Oh, and a quick note on noninvasive support. There is an increasing use of humidified high flow nasal cannulae to deliver a version of this. There are at least some studies in neonates suggesting it’s not inferior as an option to the more traditional version so this option should be more and more available in theatres.
Of course the equipment is nothing without the team knowing what you plan to do with it. So the brief of that carefully selected team also needs to be a focal point.
The Circle of the End and the Beginning
This stage is really just a reminder that if you’re going to prepare for the extubation of a challenging patient, then you need to be ready for the intubation of that same difficult patient. A full discussion of planning for that is a little beyond the scope right here, but you do need set-up ready and briefed for a potential re-snorkelling just as much as the plan for the de-snorkelling.
The Preparation of the Next House
So you set up a beautiful plan for extubation of this 10 month old after an airway endoscopy to confirm there is no compression of the lower airway anatomy to explain all those infections. You brief things well and you have a plan. And everything goes brilliantly.
Hit those hands up high in the air with all 5 fingers available people. (There must be a shorter way of saying that, right?) Great job.
Except it’s not. The post-extubation care matters. Which ward will the patient go to and what sort of monitoring will you plan? Will you keep them in the recovery area for longer? When will they get reviewed?
Speaking of reviews, what if that review gets inflicted on a colleague because it happens later? Thorough documentation and a good handover to colleagues around for the later hours are really important before you stride off into the sunset.
So there it is. A suggestion for finding a path for you and the patient to achieve safe extubation. Does it have all the answers? Well clearly not and I bet lots of clever people will come up with things I haven’t even considered yet. We’re still developing it at the joint I work in.
We’re confident though that when the request comes if we focus on understanding the airway, optimising everything, asking ourselves the preparation questions, preparing for the end and the beginning and remember to consider the bit that comes after, we’ll end up with some pretty great takeaway options.
Maybe good enough I don’t need to book that infomercial slot.
I owe a big thanks to colleagues at The Children’s Hospital at Westmead who have helped me bounce ideas around on extubation. A particular thanks to Dr Michael Cooper, present Chair of the Pediatric Committee of the World Federation of Societies of Anaesthesiologists and all round inspirational guy.
The images here are unchanged from their appearance under Creative Commons at flickr.com and are, in order by Todd Petersen, Véronique Dabord-Lazaro and ch@Os.
Now the background reading and references which of course are worth going to as the original source.
Here’s some of the ones about extubation failure rates:
Now some anaesthetic stuff:
Here’s the link to those DAS guidelines in publication form:
Now here is a thing on use of steroids:
Baranwal AK, et al. Dexamethasone pretreatment for 24 h versus 6 h for prevention of postextubation airway obstruction in children: a randomised double-blind trial. Intensive Care Med. 2014;40:1285-94.
Here are a couple of things on the leak test:
And here are two things on different techniques for exchange catheters as an option: