Blunt Blows to Small Necks

It might not be that common but it would definitely be memorable. Paediatric airway trauma would make us all sweat. Here’s some quick thoughts from Dr Andrew Weatherall after working through a recent review.

When I was about 14, I was struck at very close range at the front of the neck. It was the work of a football recently departed from a foot. It wasn’t the result of any malice. Well I’m pretty sure it wasn’t. It felt bad. Straight away.

I am a little hazy about the details, though not from catastrophic loss of the ability to breathe. But I do remember pain, coughing and a feeling that things were tight. I seem to recall my voice feeling a little strained. I still got on public transport to get home.

I probably wasn’t destined for a glorious singing career by that stage with my boy soprano days somewhere in the past. And I didn’t end up with a rasp that would make people think I might do a sideline in underworld hits. When I remember this episode though I sometimes think about the benefits of ignorance. Because if I saw that happen now, I doubt I’d check the train timetable and get on with the day.

Rare Beasts

If you were the sort of clinician who promised to get a tattoo to commemorate rare things, you’d have a good chance of not needing the one of a fist hitting a tiny trachea. Also you would need counselling because honestly that would be very weird.

The most recent review I could find on blunt airway trauma stats in kids was put out in 2011 and involved a look at the US National Trauma Databank over the 5 years between 2002 and 2006. Out of a total of 2.7 million recorded cases across 900 centres (that headline figure includes adults) they identified 69 paeds laryngeal injuries. 69 in 5 years. You probably have a higher chance of seeing the Public Holiday Numbat wearing a ceremonial cape* than actually coming across one of these injuries.

dilettantiquity-numbat

Or boots. Boots on a numbat would also be unusual.

Of course just because something is rare doesn’t mean you don’t need to prepare if critical care in kids is your thing.

This all came to mind because Chatterjee et al took the trouble of sharing one such horrifying paeds airway trauma case as a trigger for a discussion of managing this sort of blunt trauma not that long ago. And it turns out that there is not that much out there. A total reference listing of 14 papers includes a few case reports and a degree of consensus and common sense.

You can find that paper at that link above but once you’ve got through the popcorn while reading that account, the key thing it offers is some practical thoughts about what to do. It seems to me that a few key questions determine how things proceed.

1. Is airway trauma even a thing? 

In the Sidell paper they point out that the majority of their cases were in blunt trauma cases. They further point out that isolated laryngeal injury was not the common story, with 76.8% of their patients having multiple systems injured.

Perhaps the multi-trauma aspect should be taken as a wake up call to seriously consider airway trauma in kids though. It might be very rare but if you’re talking about patients with lots of other injuries that you see more often then the risk of getting distracted by the stuff you expect to see goes up.

So beyond the slightly more obvious ones, such as those with an obvious history of trauma to the neck, cases of strangulation or the old wire across the neck while on some form of bi-wheeled locomotive device, a high index of suspicion seems worthwhile. That includes in motor vehicle collisions, falls and even in chest trauma where sudden compression can still rupture an airway higher up via a lateral tear.

Things to look for? Well the papers describe a huge array of symptoms including pain, haemoptysis, cough, dysphagia, hoarseness, stridor and shortness of breath. It’s worth remembering two points though:

  • It seems like only respiratory distress has been demonstrated to correlate with injury severity (again this is described in the Sidell paper as being from case reports);
  • You can also have a significant injury with almost no symptoms.

Well that makes it easy. I guess all we can do is remember that it could be a thing even without direct obvious injury, particularly if multiple systems are involved. Plus, repeating the primary survey shouldn’t just mean “A was cleared earlier/A is sorted because of the endotracheal tube”.

2. Now or later?

Let’s say you think there’s an injury. The next key question is about time. Does the patient have an injury without compromise or do they have any of the nasty factors? Respiratory distress or any degree of hypoxia or hypoventilation should be enough to make you move quickly. That’s the point at which the timeframe shuffle commences. How much time do I have to get support from ENT or move to theatres?

The patient with no compromise has time for assessment, consultation and thought. The world is the airway’s still slightly nervous oyster and options like nasendoscopy and other airway assessment are on the table. The patient with compromise does not have this time.

3. Here or there?

Let’s assume now that you’ve decided the patient doesn’t have the luxury of more time. The focus becomes even more acute. Can we get to theatres? Do I have time for ENT to get there as part of the team? Or do I have to step in right now in this spot without any further delay?

When I think through this one I think physiological compromise would be the point of difference. If it’s just respiratory distress on show, I’d beat a path to the operating room most times. If they are already hypoxic or otherwise displaying end organ effects (particularly change in neurological status) then I guess we’d set up camp right where they are.

4. Up or down?

On the way past it’s worth thinking about positioning. This is more of an issue in the patient who is conscious, rather than the patient who has already come in unconscious. Most patients with an airway injury instinctively get into a position which allows breathing. They seem to like breathing for some reason.

The last thing you want to keep a patient in a relatively happy and cooperative space is shift their position in any way that might worsen their symptoms. I can’t think of a good reason to try and change stuff that is kind of working and even if they’re starting to develop an oxygen need, I struggle to see how repositioning them to flat would make it better.

At the same time if we’ve inflicted a position on them (which is most likely to be flat) maybe we should think about asking if they’d like to sit up. And listen.

5. Breathing or not?

When it comes to the induction, there’s plenty to be said for maintaining spontaneous ventilation. Three key points with this though:

  • Any application of pressure (CPAP etc) has to be minimal. You don’t really want to convert a threatened airway into an airway disconnected like Picasso painted it on a bad cubist day.
  • Any instrumentation of the airway must be when the patient is definitely deeply anaesthetised.
  • Good topicalisation of the airway makes a whole lot of sense.

Oh, and of course the ideal set-up is to have ENT there and ready to help with access via the front of the neck if things shift sideways.

Meanwhile, the thoughts on spontaneous ventilation during airway work over at this post probably apply here too.

Now in the middle of all this planning, it should be said that the ideal result in the compromised patient is to go asleep safety and have ENT examine the airway (via rigid or flexible bronchoscopy) and then plan from there. Or maybe your friendly ENT surgeon has a different plan for the best airway option (maybe even starting with tracheostomy). They’re there for a reason so you best use them. This is where you get to deploy your own airway to help with phonation so you can communicate with that surgeon.

6. Knife in Hand

Again the recommended option is to embark on this with an ENT surgeon right there. If you can’t make that happen, then at least plan through how you’d perform front of neck access if it really came to that. There are arguments for cannula techniques in smaller kids and scalpel-bougie-tube options in bigger kids. (Keep in mind that from the Sidell paper the average age was around 12, so it’s more likely to be older kids we’re talking about here.) Most important is having a plan beforehand which is communicated to everyone as well as a continuing focus on maintaining oxygenation.

What would make you think of committing to front of neck access? If you’d tried all basic manoeuvres after not feeling it safe to pass an endotracheal tube but those basic manoeuvres (even up to supraglottic airway) weren’t managing to provide oxygenation, then it needs a serious thought. The other group for consideration would be those where you think you’ve passed a tube OK but ventilation doesn’t produce chest movement or a pattern on the capnograph you’d happily frame. In these settings front of neck access becomes a whole lot more important .

But What if There’s No Time?

This is quite a bit different. Practitioners in the prehospital environment have the same issue because it turns out there aren’t many ENT surgeons riding shotgun in any ambulance service I’ve heard of.

In the setting where ENT aren’t quite there, safely providing induction of anaesthesia followed by gentle endotracheal intubation seems to be the consensus. That might well mean volatile anaesthesia is your best bet. It’s worth noting that the passage of the endotracheal tube needs to be as gentle as possible. Choose an endotracheal tube at least half a size smaller than usual. Plan to intubate with a grade II view at most (or maybe there’s a role for videolaryngoscopy in these patients) and don’t use a bougie without a very clear reason.

It also seems to make sense to have a low threshold for not proceeding with intubation and manage the airway another way if it seems safer (e.g. a supraglottic airway used gently or even ongoing bag-mask work until ENT arrive to secure that airway).

In either situation, it’s fair to say it’ll be a slightly stressful day in the office.

 

Sound and Light

What would be really good of course is to know more about the airway before you get there with the plastic snorkel. A CT scan will always take time and a transfer. Could this be a point where ultrasound comes to the fore? After all, if you can see where the level of an injury is, that might alter your plans.

Well people are trying that. There’s at least this paper out there and it has a pretty comprehensive look at sonoanatomy and potential uses. It also says that you shouldn’t consider ultrasound in the unanticipated difficult airway.

Oh. I see.

us-copy

Let’s never forget that the images in a journal article on ultrasound almost always have pictures better than you’ll probably ever manage.

This isn’t entirely an unanticipated difficult airway though. It’s not hard to foresee a world where you use your ultrasound to get a sense of the anatomy. So perhaps it’s time we started training in this in paeds anaesthesia. Once familiar with airway ultrasound you could take the time to mark the level of key landmarks like the thyroid and cricoid cartilages, the cricothyroid membrane and those first tracheal rings.

It might also be useful is in excluding other serious things. Are you trying to figure out if there is a pneumothorax or something else leading to the poor oxygenation? An ultrasound will probably give you the answers you seek. Do you want to double check the carotid arteries? There’s a probe for that too.

For now though there’s not a lot of work to recommend an ultrasound machine because it’s early days. For now maybe it should be seen but not heard whirring into action unless you’re really clear what you want to ask of it and you’ve spent the time learning the skills. It’s not the mainstay here.

 

Is this an extensive list? No, probably not. But at the moment the literature pretty much amounts to case reports and a bit of consensus thinking. Cases like this are rare enough that all we can share is our best thoughts on the topic and hope to hear back from other clever people. Maybe other clever people like you. Because at least clever people are more common than cape-wearing numbats.

 

Notes:

* The eagle-eyed amongst you will note that the idea of the Public Holiday Numbat wearing a ceremonial cape is absurd. Ceremonial attire would be far too much effort on a public holiday for the numbat to endorse such behaviour.

In the future there will probably be a post about penetrating trauma. In the meantime you might like to reread this review of CICO in kids that was first mentioned in this post:

Sabato SC, Long E. An institutional approach to the management of the ‘Can’t Intubate, Can’t Oxygenate’ emergency in children. Pediatr Anesth. 2016;26:784-93.

There really isn’t much out there about kiddy airway trauma. Here’s the reference for that NTDB paper:

Sidell D, Mendelssohn AH, Shapiro NL, St. John M. Management and Outcomes of Laryngeal Injuries in the Pediatric Population. Ann Otol Rhinol Laryngol. 2011;120:787-95.

and here’s the review of blunt laryngotracheal injuries from an anaesthetic angle:

Chatterjee R, Agarwal R, Bajaj L, et al. Airway management in laryngotracheal injuries from blunt neck trauma in children. Pediatr Anesth.2016;26:132-8.

And here’s that review about ultrasound.

Stafrace S, Engelhardt T, Teoh WH, Kristensen MS. Essential ultrasound techniques of the pediatric airway. Pediatr Anesth. 2016;26:122-31. 

The numbat image is from flickr’s Creative Commons area and is unchanged from the post by dilettantiquity.

 

 

 

 

 

 

 

 

 

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