The Bind When It Comes to a Binder (Part 3)

There’s been a lot of stimulating discussion after parts 1 and 2 of this series from Dr Alan Garner (you can check those here and here). Here’s part 3. 

Thanks for sticking with the discussion so far. In part 2 we had a look at AP compression injuries and lateral compression injuries. Short summary is binders make sense and there is some observational evidence of benefit in AP compression injuries. However in lateral compression, binders make no biomechanical sense and there is definite evidence they increase fracture displacement both in cadavers and real live trauma patients.

The final group that we have not yet considered in the Young and Burgess classification is the vertical shear group. These patients are complex because the injuries are both horizontally and vertically unstable. You will see what I mean if you have a look at this Xray:

Pelvic Xray copy

Is putting a binder around the greater trochanters and pulling going to help? Will it produce anatomical realignment? I think you will agree that it is hard to know. In this case it might rotate the left hemipelvis inward and create even more distortion. You might also guess that some traction on the left leg before you apply the binder might get a better result too. More on this later.

Is there any actual evidence that things can get worse with a binder in vertical shear? Tan’s paper had six of this injury type. Two of the six had a fall in MAP immediately after the binder was applied, one by 20mmHg! It is a bit crazy that we are discussing studies with six patients but this is the level of published evidence to date. Such as it is, the evidence is that one in three vertical shear injuries deteriorated immediately after the binder was placed. Toth’s paper found that 14/17 patients had improved alignment post binder in this group so it often does some good. Unfortunately you have to think really carefully about this group, and be prepared to loosen it off again if you don’t get the response you were hoping for.

Yes, loosen it if the patient deteriorates! Primum non nocere. Remember there is as yet no study that has shown significant mortality improvement with pelvic binders. They are not a standard of care. If what you do makes thing worse then backing off is the right thing to do. I try not to let my own psychological need to do everything I can for the critically injured patient in front of me drive me to do things that might actually harm the patient. Sometimes less is more.

So what are we left to conclude?

  • AP compression – makes biomechanical sense and low level evidence binders help
  • Lateral compression – makes no biomechanical sense and real world evidence binders increase fracture displacement. Is “just holding it still” enough?
  • Vertical shear – a really difficult group; evidence of haemodynamic and anatomical improvement in the majority but clinically significant deterioration has also been documented
  • The real world as always is a bit more complex than this and mixed injury types happen
  • And of course, no evidence yet overall that binders have a significant effect on the outcome that matters in this case –mortality.

It should be pretty obvious that the type of fracture should be the guide to whether or not a binder might help. This is great if you are doing an interhospital transport and have an Xray. Not really helpful though if you are at the roadside, on an oil rig, or at a remote clinic 1000kms from the nearest trauma centre with no imaging (as our teams frequently are). So how can you work out whether a binder will help?

First thing is reading the injury mechanism. If you are at the scene you may get a lot of clues about the force vector, particularly in motor vehicle trauma. This is a photo of an incident I attended a few months ago.

Powerpole copy

In this case the car had slid sideways into the power pole striking the driver directly in the right side with such force that she had broken the centre console with the left side of her pelvis and was partially in the passenger seat. This can only be a lateral compression injury and there is no way a binder can help. Direct frontal injuries are also pretty obvious and the injury type is going to be an AP compression if a pelvic ring fracture is present.

This is good as far as it goes. It really does not help much with other mechanisms like pedestrians and motor cyclists. Were they side-on or front-on when they were hit by the truck? Motor cyclists can have a significant rotational component to their flight before they hit something which can make prediction of injury patterns really problematic.

There is one other trick which can give you a really valuable clue. Symphyseal diastasis is the hall mark of the AP compression injury. This is the sign that the “book is open”. If you can identify this then you can identify the group that is likely to benefit from a binder to “close the book” (although some will have vertical shear so care is still required). This is yet another use for my trusty companion, the handheld ultrasound.

The width of the pubic symphysis can easily be measured with the same high frequency linear probe that you use to exclude a pneumothorax. The upper limit of normal width measured at the point shown in the image is <25mm in adults (Bauman). I am not aware of any published data on children. As with all things there is a bit of variation here and cadaver studies have shown that anterior sacroiliac ligament disruption is likely for displacement greater than 45 mm and unlikely for values less than 18mm. So if the symphysis is less than 18mm you can be very confident the pelvis is not “open”.

Ultrasound copy

Clinical ultrasound copy

Note that in the source study for the reference range they failed to achieve a measurement in one case because the symphysis was wider than the width of their probe. You may have to move the probe from side to side to pick up both sides of a really wide symphysis.

If the patient does not have symphyseal widening on the other hand there is no reason to believe that a binder will help and they may well have an injury type that will be worsened by a binder (the symphysis does not open in lateral compression). Ultrasound is likely to be our best guide as to which patients have the possibility of benefitting from a binder whilst avoiding those where harm is the more likely outcome.   Some patients with vertical shear and an open symphysis may still deteriorate so there is no guarantee, but ultrasound will at least allow you to identify the group who have the possibility of benefit rather than harm.

As with so many things in prehospital care we need some good studies in this area. In the meantime, read the mechanism, read your ultrasound screen and be judicious in applying binders. Harm has occurred with these devices – they are not a universal panacea. Much of the art of medicine is picking the right patient for the intervention so you maximise benefit and minimise harm. This patient group is no different.

And thanks for the comments. Julian Cooper’s thoughts helped me work through my own theories on the issues and I have realised that our theories and the observational evidence don’t seem to align. There is also some potential new approaches to the massively haemorrhaging pelvis that are easily applicable in the prehospital environment and those are worth looking at too.

So looks like I am doing part 4. Stay tuned folks.

Bauman M et al. Ultrasonographic determination of pubic symphyseal widening in trauma: the FAST-PS study. The Journal of Emergency Medicine, Vol. 40, No. 5, pp. 528-–533, 2011.

Doro CJ et al. Does 2.5 cm of symphyseal widening differentiate anteroposterior compression I from anteroposterior compression II pelvic ring injuries? J Orthop Trauma. 2010 Oct;24(10):610-5. doi: 10.1097/BOT.0b013e3181cff42c.

Tan ECTH, et al. Effect of a new pelvic stabilizer (T-POD1) on reduction of pelvic volume and haemodynamic stability in unstable pelvic fractures. Injury (2010), doi:10.1016/j.injury.2010.03.013

Toth L, King KL, McGrath B, Balogh ZJ. Efficacy and safety of emergency non-invasive pelvic ring stabilisation. Injury, Int. J. Care Injured 43 (2012) 1330–1334

Scary Little Creatures

Dr Andrew Weatherall does prehospital doctor stuff but spends lots of time serving the somnolent god of anaesthesia  in a tertiary paediatric hospital. He has particular interests in cardiac, thoracic, trauma and liver transplant anaesthesia and is trying to be a PhD student in his spare time.  You can also find him as @doc_andy_w 

Little creatures have the potential to cause significant stress. It’s true of spiders. It’s true of parasites. And for many medicos, it’s true of paediatric patients. All too often, the experienced clinician confronted with the alien life-form of a kid goes through a rapid medical devolution, retreating to the almost foetal uselessness of a medical student confronted for the first time by having to do a procedure they’ve only read about.

Dance all you like tiny peacock spider, still wary. [via Jurgen Otto on Flickr under "Some Rights Reserved CC licence 2.0]
Dance all you like tiny peacock spider, still wary. [via Jurgen Otto on Flickr under “Some Rights Reserved CC licence 2.0]
It’s entirely reasonable to feel less comfortable with stuff you don’t do all the time. In fact, it’s healthy to step up a level of vigilance to make sure no little point in care is forgotten. The risk is that the heightened awareness can flip over to downright anxiety. Even experienced clinicians can sometimes forget that they are really good at what they are about to do and let little things compromise their success.

Managing the paediatric airway is a case in point. It is different. There are all those annoying calculations to remember. Everything feels the wrong size. The things that should be easy, like bag-mask ventilation, seem unusually clumsy. It’s as if someone managed to switch your shoes onto the wrong feet and then asked you to run.

When doing time in the paediatric theatres we frequently have experienced clinicians dropping by to brush up on their paediatric airway skills. From an observer’s point of view, there are little technical things that crop up repeatedly and cause grief. They are also the sort of technical hitches that distract from the mental process of getting the job done. If these little things were addressed, the prospect of the paediatric airway should be no more daunting than the prospect of participating in a yawning competition at the local retirement village lawn bowls competition.

So here, in no particular order, are the commonest practical things I see clever people forget:

  1. A Light Touch

True paediatric patients are not big. Unlike the momentarily moribund wildebeest of adult medicine, they do not require brute strength. Airway management starts with good bag-mask technique and that should be easy (I am making the assumption that they don’t have the sort of condition that makes people widen their eyes when flicking through the ‘big book of syndromes’).

All too often those who do medical stuff in big people seem to want to subdue the small scruff of a paediatric patient with the big unwieldy shovels they refer to as ‘hands’. In smaller kids, it is really hard to apply good bag-mask technique if you try as you would in an adult, with a digit behind the angle of the jaw and other fingers arranged along the mandible.

Try this one – lay your middle finger gently across the soft tissue just where the neckline starts to head up to the chin (yep, right in the midline). Gently stretch the skin up to the jaw line with that middle finger (almost like you’re pushing the little ridge of skin up to the chin). Now add the mask with your index finger and thumb holding it to the face as per normal. You should have an open airway. That’s all the effort it takes (if that’s as clear as mud, let me know and I’ll try to produce a better version).

  1. Puff

Smaller kids desaturate quickly. Whether or not you’ve done nasal prong oxygenation, you should feel at liberty to gently provide ventilations while waiting for the muscle relaxant to reach “apparent serenity now” efficacy.

  1. Know Your Equipment

If you are going to use different equipment it pays off to know the details of the kit. This seems really obvious, but all too often the occasional paediatric airway specialist gets so focussed on the other bits of getting the job done they take the equipment stuff for granted and things get messy at some point after everyone thinks crunch time has been and gone.

Here’s an example. Observe the photo of two different kids endotracheal tubes. The one on the bottom is a bit more custom-designed for kids. Another popular brand up top looks pretty much like a down-sized adult endotracheal tube.

Same, same. But different.
Same, same. But different.

When you look closer, you might notice that the one on the bottom has an obvious black line where the tube is intended to line up with the cords. If you place it there, the tip of the tube is usually in a good spot, and the distance between cuff and cords is actually a fair bit.

Seeing the difference yet?
Seeing the difference yet?

Now look at the one on the top by comparison. The cuff ends around where that black line is. So if you place this one with the cuff a bit beyond the cords, you have successfully achieved lung isolation (kudos to you). Sometimes in bringing it back to where both lungs benefit from the cool breeze generated by your relieved bagging, the cuff could be sitting in the cords. Bugger.

OK, I flipped them but you can still see the different cuff position (and other features).
OK, I flipped them but you can still see the different cuff position (and other features).

Knowing which one you carry (or should carry) matters. Same goes for choice of laryngoscope (and the resultant changes in positioning the patient). Speaking of which …

  1. Keep an eye on the forest

You get handed a straight-blade laryngoscope to intubate a child (the fact that I’d probably choose a curved blade in pretty much every paeds patient is an entirely separate rant). Your job is to get a view on laryngoscopy that permits successful intubation. Your job is not to pick up the epiglottis. Do not confuse a popular choice for during the intubation with your daily KPI.

If placing the tip of the blade in the vallecula is what works, do that and put the tube in.

  1. Use Cuffed Tubes

Shouldn’t we be choosing uncuffed tubes? Really? Just because you prefer harder to manage ventilation with a high chance of needing to change the tube entirely? Or are you a staunch supporter of tradition in medicine? Even where that tradition was established because the perished rubber endotracheal tubes with their low volume high pressure cuffs made of rubberised sandpaper were causing complications?

Seriously, just use cuffed tubes (and check the cuff pressure regularly). That way you get to do it just the once before the high fives rather than trying to figure out how to calibrate the ‘leak’.

  1. Noses are for other doctors

There is no need for all endotracheal tubes in paediatric patients to be nose snorkels. A secure airway is the goal, and that is best done with a quick oral intubation. The number of doctors I see who seem to have the impression that neophyte airways means nasal airways in all circumstances never ceases to astonish.

So there’s just 6 quick tips to get the practical bits sorted. Is it absolutely exhaustive? No, but these are things I keep seeing (so you can grade the level of evidence as “stuff I see heaps and heaps that I thought I’d mention”). If you’ve got others (or disagree) I’m always all ears.

The aim is to help anyone get to the natural state of things – where ill kids needing intubation aren’t the scary ones. It’s healthy 3 year olds drinking red cordial at a party that inspire true fear.

Note:

This post is meant as a chance to share stuff seen through observation. If anyone is keen, I can follow up with the broader rant with the working title of “the variety of ways all that stuff about paediatric airways turns out to be kind of rubbish”, or the “choose the cuffed tube” rant in full.