At the recent Student Paramedics Australasia International Conference 2016 held in Sydney, Dr Andrew Weatherall was given the topic of “things paramedics can do to produce better long-term outcomes after traumatic brain injury”. This is a version of that talk modified for the blog.
This topic, that someone else came up with, gets it.
So much of the time in prehospital medicine we focus on things we measure in the first hour or so. The stuff we do before we hit the doors of the hospital. That fairly bogus ‘golden hour’.
Those things matter. But the big picture of trauma care isn’t the first hour. It’s the rest of the patient’s life.
Everything we do in the prehospital setting is really about whether they get back to what they were dreaming of doing. It’s not up to us what those dreams are. Your patient might dream of playing big time sport. They might dream of creating the world’s great collection of corn chips that look like ex-Prime Ministers. They might want to fly on the first trip to Mars (and almost certainly die of cancer because everyone seems to be forgetting about deep space radiation). When we care for them we sort of have to want their dream to happen for them.
So on the days when I get to hang out with paramedics instead of getting paid by the government to wear pyjamas and give drugs to kids, this is the aim. And traumatic brain injury is worth looking after well.
We could dive into traumatic brain injury by starting with a bunch of graphs from a physiology text. Let’s dive into something to make it relevant.
This is the scene we’ll be going to. You’ll end up looking mostly at the patient who was driving the SUV. It looks like they had an initial collision, rolled over and then nudged up against the hatch that was veering off the road. Emergency services have been called by a passing pharmacy student who has done a First Aid course. They tried shaking and shouting and got no response. They thought about feeling for a pulse and they’ve found one.
This patient is clearly one who might have a traumatic brain injury (TBI). They could end up as one of the patients with moderate or severe TBI who lead to a cost to the system of around $8.6 billion each year. That comes from a report prepared for the Victorian Neurotrauma Initiative released in 2009. It estimated that for 2008 Australia would have around 1400 in the moderate TBI group and 1000 in the severely injured group.
And each one of those people doesn’t get back to their planned life. Some of them end up needing help with simple things for their whole life.
So this is the job and the clock started 5 minutes ago. What should we focus on? Is it all about RSI? Is it about early TXA? Is about the sort of stuff you need an advanced medical team for?
Well that could be the basis of discussion but we should start with a reality check.
If you look at the NSW Institute of Trauma and Injury Management report of the 2014 trauma database stats, there were 3458 severely injured trauma patients. 66% of the patients had an injury to the head. 3 of the top 5 severe injuries were subdivisions of subdural haematomas.
Of those arriving straight to a trauma centre, 80.4% arrived in an ambulance (vs 12.6% in a helicopter).
Even allowing for some of those ambulances having an accompanying advanced prehospital team, I think this grouping of numbers says something pretty significant: the vast majority of “big” trauma patients will get their care from paramedics.
This also means that if we want to save the most brain cells we should focus on making sure the patients getting those transports have the best possible care that those paramedics’ training can make happen. That’s more important across the population than the advanced team’s contribution.
There is a separate chat to have some day about trying to get advanced teams to the jobs where they might really help or the best way to do pointy end stuff. That’s just not the focus for this particular bit.
It does brings us to the first key thing that trained paramedics can do to improve long-term neurological outcomes – be there.
The nature of their training and their ability to focus on getting the vital things done and get moving means that paramedics will invariably lift the standard of care of the patient when they turn up and do their job.
Now exactly what they should do we’ll get onto in a bit but there will only ever be a small number of meaningful interventions to do for the patient so it makes sense to get it done as efficiently as possible and get moving. And of course while neurosurgery is mostly not an urgent requirement, about 1 in 5 patients will need some form of early head-cutter work. That 20% of patients really want professionals who are trained to make things move.
So it might seem like there’s not much meat on just saying “be there”, but I think it’s worth noting as we go that the standard way professional paramedics go about their business represents a step up compared to what was managed in the past.
Now that you’re there …
Back to the patient. When you get there, the patient looks to be in their mid-30s, is making breathing efforts and there is some air moving but it is fairly noisy respiration. Initial peripheral saturations read at 85% and the measured blood pressure of 95 mmHg is somewhere near what you would have guessed by palpating the radial pulse. The patient’s GCS is 7, the pupils are equal and reactive. A quick glance suggests the right femur looks like it’s adopting a more meandering course than usual on the way down to the knee.
So what should our aim be for these patients? What targets do we have that are the best evidence-based ones available?
Somewhat disappointingly we don’t have that much evidence for discrete targets. What evidence there is hasn’t really shifted much over the last couple of decades. Most of the stuff we do leans heavily on a general understanding of physiology as much as firm numbers.
But let’s focus on the numbers we do have. They’re based mostly on retrospective looks at info from big data banks. And the number to remember is 90. That’s the breakpoint because:
- 90% saturations is around 60 mmHg pO2 and we know that patients who have a reading below that value have worse long-term neurological outcomes.
- 90 mmHg is the magic BP number for adults – a measurement below this is associated with worse outcomes.
So we want to stay above 90 on both counts. That’s what we can all target right now.
And these markers kind of make sense. We often think about the primary injury already having happened when we get to the patient and focus on avoiding secondary injuries which we view as discrete and separate extra insults. Add new injuries and you make the outcome worse.
It’s probably more accurate to say that the primary injury evolves over a number of hours. In that traumatised brain there will be excitatory neurotransmitters looking to party way too much for the cells to recover. There will be inappropriate triggering of cell death. Calcium will be getting places it shouldn’t and generally grabbing onto cell elements it should leave alone. Each secondary injury ramps up processes like these as they continue to evolve. It’s one of those times all evidence-based practitioners need to try and stop evolution from being a thing.
There are a few other things worth keeping in mind:
- The brain is pretty simple in its demands. It wants oxygen and nutrients delivered.
- Things that make blood flow decrease aren’t good (remember that the injury itself is quite likely to drop blood flow well below normal).
- Intracranial pressure that is high isn’t great. It compromises blood flow.
Oh, and it’s also worth mentioning that there aren’t many things inside the head that we influence the volume of prehospitally:
- There’s the brain tissue (and the associated fluid that goes with it).
- There’s blood. Blood can be inside vessels which gives us some scope to manipulate how much flow is occurring. Occasionally it will be outside vessels and the vast majority of times that patient will get their definitive care at the hands of a neurosurgeon.
- There’s CSF (which we have less influence over).
So if our aims are basic do we have to wait for advanced techniques to try and reach this target? Of course not.
This brings us to the second important “thing that we can do right now” – be basic.
Consistent delivery of basic measures has the potential to save huge numbers of brain cells. It’s more meaningful than waiting to try and develop the infrastructure and expertise to get more people doing advanced things like RSI.
The perfect example is impact brain apnoea. This has really only been described in any detail fairly recently by Wilson et al but there are accounts throughout medical history and the animal literature that describes a phenomenon of subjects forgetting that whole breathing malarkey in the immediate aftermath of trauma.
The suggested treatment? Open the airway and support ventilation. Those simple steps are meaningful.
They’re meaningful for all patients with TBI too. Which is why it’s worth getting back to the simple message of “A-B-C” which some sage once told us was as easy as “1-2-3”. Simpler than the transition to adulthood from child stardom if you were that individual anyway.
So let’s work through those simple little letters.
1. How’s your “A” game?
Failure to do the basic bit of airway well is one of the commonest issues we see when welcome people training at the kids’ hospital. It’s such an important foundation though. So ask yourself whether you do the basic version of “A” well. Is your jaw thrust good enough to get those bottom teeth in front of the top teeth? Do you reach for adjuncts like oropharyngeal or nasopharyngeal airways as an aid? Are you quick enough to move to a two hand technique?
Most importantly do you make sure that you create a good seal with your mask? The value of a good seal is actually highlighted by work looking at pre oxygenation techniques. A colleague from CareFlight, Dr Chris Groombridge, did a nifty study with volunteers evaluating the maximum expired oxygen level you could achieve with different techniques. Anaesthetic circuit vs bag-valve mask (either alone or with nasal cannulae or PEEP valve or both) vs non-rebreather mask (with and without nasal cannulae).
And at the end of 3 minutes you still couldn’t beat either the anaesthetic circuit or the bag-valve mask with a well-maintained seal.
Hayes-Bradley et al did some work with a slightly different focus, evaluating the impact of nasal cannulae on pre-oxygenation with a bag-valve mask set-up or non-rebreather. Nasal cannulae helped only where there was a deliberately created leak in the seal.
Now you could take the line that it’s just pragmatic to assume you’ll end up with a leak. But why should we accept doing the technique anyway other than perfectly? Let’s focus on getting the seal right.
We’ve really taken that to heart at work, making the effort to maintain that seal throughout pre-oxygenation. It’s all part of ensuring that our focus on is on the main game – maximising oxygenation throughout the RSI rather than pushing on to the laryngoscopy and intubation step without optimising things up front. The brain wants oxygen more than it wants laryngoscopy.
That some prioritisation of the basic step of managing “A” well – perfect performance of basic airway manoeuvres, suction and use of adjuncts – can apply to all of us, whether we intubate or not. It’s the first step to delivering on our first aim – get those peripheral saturations above 90.
It also feeds seamlessly onto …
“How good are your “B” moves?”
What about those patients who need support for the breathing part of the equation. That might be via that bag-valve mask set-up or you might have supraglottic airways as an option you’ve been trained to use.
The question here is not just how well do you do it but do you take steps to make sure you’re using that skill set in the best interests of the patient?
So if you think a supraglottic airway might be appropriate for a patient do you quickly assess if they’re ready for it with a firm jaw thrust and a deep suction before placing it? Do you check what the seal is like once it’s in?
And how do you measure your effort with the bag you hook up to that SGA? Because it’s easy to puff away like your hand is a talking sock puppet. We should really all be hooking up capnography wherever we can (for bag-valve mask work too). It might not provide a trace like the intubated patient but it will be more accurate than a guesstimate. And without having a sense of where you’re at with the CO2, how do you know if you’re not creating hypocapnoea when hypocapnoea is associated with reduced cerebral blood flow (and of course hypercapnoea could cause raised ICP)?
Doing the “basics” well requires a bit of attention. Who knew?
But you might well say, what about RSI? Shouldn’t we be figuring out how to train people to do that? Well while there is a probable role for RSI it is really hard to demonstrate the positive benefit. That is probably partly because prospective research in prehospital medicine is very hard. But the evolution of the research that’s out there suggests that getting that high stakes procedure done well enough to have the benefit outweigh the potential complications will take a very long and concerted effort.
Take for example just 3 studies:
- The San Diego RSI paper – this suggested worse outcomes but subsequent analysis revealed performance of the procedure with significant periods of hypoxia (57% of those analysed had a desaturation with an average time of 160 seconds and a median fall in saturations of 22%).
- HIRT – which took long enough in recruitment that the system changed all around it, rendering it very difficult to keep arms of the study in their planned arms. Those that received the advanced interventions team as intended did have a 14% reduction in mortality but it’s not robust enough to bank your house on.
- The Victorian paramedic RSI paper – this showed benefit but there were more patients in the control group lost to follow-up and you’d think that those who did better would be the ones you’d lose. Just one different outcome in the control group would have made the findings insignificant. So it’s not robust enough but for different reasons.
So RSI makes physiological sense and most would still say it has a role. But it’s hard to make it pay off. We can all do the basics right every day from today.
What should we see when people are doing “C”?
It’s not like there’s some study out there saying “this particular prehospital intervention related to circulation and haemorrhage leads to better TBI outcomes” but we can focus on maintaining that blood pressure above 90 mmHg. So things that cause catastrophic hypotension (say, pneumothorax with haemodynamic consequences) need treatment with whatever the provider is trained for.
If there is external haemorrhage that has to be controlled so we can focus on doing that particularly excellently. If you’re putting on a tourniquet, think about providing proximal occlusion of flow first with your whole weight (e.g. a knee not just into the groin but leaning in and twisting a bit to really slow down flow before the tourniquet goes on). Really provide pressure to stop bleeding if pressure is the treatment you’ve chosen. Splint that femoral fracture to reduce loss of blood volume.
At the same time it’s worth noting that some of the evidence base for things we do is less strong than we might assume. As covered by Dr Alan Garner in the series starting here, the evidence base for pelvic splints improving haemodynamics isn’t based on huge reams of work.
Other options will probably come through for lots of practitioners soon. Haemostatic dressings or granules are likely to make a difference for some patients. With a little more evidence TXA might roll out across the land. And while there are very interesting concepts like prehospital REBOA out there to be wielded by a select few, something like the Abdominal Aortic Junctional Tourniquet might be a far more significant option on a population level. Judicious use in the exsanguinating patient with due regard to the potential downsides (particularly if it might take a while to get to somewhere else) could be an option for an awful lot more practitioners.
The Other Simple Things
That’s not the end of the simple things of course. Think about whether you can sit your patient up to drop the ICP. Is there a better way to maintain C-spine stability then a rigid collar? Is there anything constricting the neck?
Add a lot of simple steps together and you have pretty comprehensive efforts for those brain cells that just want blood to flow and nutrients to turn up.
The Group Who Doesn’t Get the Simple Things
And while we’re at it, there is one group who tend to get much less of all of the things, including the basics.
Which is not great if you’re trying to think about how to provide better long-term outcomes. Their long-term is even more long-term.
Bankole et al provide just one example of a study demonstrating this. They looked at prehospital care around a New Jersey centre and compared the care received by kids with TBI to that received by adults. The numbers are pretty stark (though some of the headline items relate to interventions like intubation).
69.2% of the kids intubated had complications at intubation. 20% of kids with a GCS under 8 had no attempt at intubation. Failed intubation rates were 29.03% (vs 2.27% in adults). Kids also had higher rates of the dislodgement, oesophageal intubation, wrong size of tube choice and a requirement for multiple attempts.
Even intravenous access was placed less (adults had a prehospital cannula 85.9% of the time whereas in kids with the same spectrum of pretty severe injuries it was 65.7%).
More recently advanced practitioners in Switzerland published around the topic of advanced airway management in kids and while they did well initially, wrong tube sizes and wrong depth of the tube turned up again.
There are lots of reasons we do less well with kids. We see them less for a start and there can be additional scene distractions. But ultimately we need to recognise this and figure out a way to make sure we step up to the mark.
Back to the Scene
The patient has been making respiratory efforts but you can see the chest see-sawing a bit with diaphragmatic effort with an added breathing buzzsaw soundtrack. You jaw thrust and the airway improves. A suction improves the airway still further. You add a bag-mask set-up and really focus on a great seal. The saturations rise above 95%. The femur looks like it’s taking a meandering the scenic route towards the knee but it’s soon splinted and a big wound in the calf gets pressure to slow the bleeding. You’re on your way…
Now that sounds pretty easy. When you’re in a lecture theatre or reading a lesser known blog it sounds even easier. But we all know that the scene isn’t actually that easy. We’re assailed by all sorts of things and there is plenty of work in simulation sessions (like here) showing that when faced with high stress situations we tend to omit things we ordinarily wouldn’t, do things we’d normally not contemplate and remember all of it less.
This touches on the next thing prehospital practitioners have to do to provide better care for the brain – be the same with your care, everywhere. (The astute reader will notice that not only did I match the formatting to the other “be” statements, I made it internally rhyme. I’m really trying to make it seem meaningful.)
Beyond starting by acknowledging the risks of a deterioration in performance depending on the day or the job or the other stuff in our lives, we have to figure out how to be consistently excellent with our care. That’s what the patient expects. Their brain cells aren’t very interested in your back story or your motivation. They’d like you to do your job.
The strategies to try and make sure you always step up are way too many to go in right here, so it’s worth looking around. But use the team, communicate well, share your plans with those around you, use checklists or practice tactical breathing or other focus techniques or whatever it is that works for your good self.
Just don’t accept that you have to be a hostage to all those other factors.
And part of not accepting the status quo is striving to always provide better than we can do right now. That requires all of us to be a leader.
If we want to be able to provide capnography for all those patients whose A and B we’re managing then we might need to advocate for that. If we want to be able to look back in detail at how well we did, then monitors that only store information every 2 minutes (which is so often the case with prehospital monitors) aren’t up to scratch and we need to lead those demands. We need to provide leadership in governance and education to keep our standards constantly improving. We might even need to advocate solutions to issues in other areas of health that would free up paramedics to be out on the roads so they can work on that being there bit.
While this topic is mostly about what we can do right now we obviously have to keep an eye out for what comes next. And I could well be wrong but my guess is that the thing that comes next that makes a big difference across the population to those who suffer a TBI won’t be one of the magic bullets being tried like progesterone, or EPO, or even TXA.
What would be really great is to actually know what the brain wants right now. Is the blood pressure of 100 mmHg actually adequate for this person’s brain or are they usually hypertensive and critical cerebral ischaemia is being added to your mix?
Does this patient actually need their CO2 a little higher than you might have thought because blood flow isn’t so great? Is their evidence of haematoma developing on one side that hasn’t shown up clinically?
That’s part of why we’re researching tech like near-infrared spectroscopy tissue oximetry. Now I’m not convinced that particular technology will provide that information reliably enough, but I do think that the most meaningful thing we could add to prehospital TBI care is more info about what this patient’s individual brain would like, rather than being stuck with population-based gross numbers.
And if we find that device the ultimate result will probably be that it tells us how to do the basics just that little bit better for this particular patient.
Because they might have big plans for corn chips that look like ex-Prime Ministers.
OK, this was a really long post, but when you put a talk into post form it can be like that.
Here are just a few things from along the way you might like to go and look at.
Here’s a link to that Access Economics report with the alarming costs stuff.
Here’s the 2014 Trauma Registry report from ITIM in NSW.
The “90” numbers are part of the prehospital TBI guidelines.
The first of the “seal” papers:
and the other one …
The San Diego paper:
Garner AA, Mann KP, Fearnside M, et al. The Head Injury Retrieval Trial (HIRT): a single-centre randomised controlled trial of physician prehospital management of severe blunt head injury compared with management by paramedics only. Emerge Med J. 2015;32:869-75.
The Victorian paper:
Bernard SA, Nguyen V, Cameron P, et al. Prehospital rapid sequence intubation improves functional outcome for patients with severe traumatic brain injury: a randomised controlled trial. Ann. Sure. 2010;252:959-65.
That Bankole thing:
That sim paper:
Oh, and I put stuff over on the blog site at www.songsorstories.com relating to kids anaesthesia. If you look at the categories “airway” and “tips and tricks” and “cannulation” you’ll find some basic tips for working on things.
All the images here are from flickr creative commons and unaltered.
Did you scroll this far? Well you will inherit the earth that is constructed where scrolling is rewarded. Here, have this porcupine reviewing pumpkins as payback.