Tag Archives: prehospital

Prehospital Trauma, Research

Blood Warmers (Sort Of) In The Wild

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This post (after, let’s face it, a massive break) is the written version of a talk by Andrew Weatherall for the Aeromedical Society of Australasia Conference 2019, held in Perth.

 This is a thing that’s about blood. And the roadside. And the lab bench. Naturally it starts with a story because clinical research should start with a patient. That’s why we do it. It’s a really topic to talk about because the management of transfusion, and the questions it brings up might seem simple at first glance. But a transfusion in the prehospital environment is a particular example of people across a whole system working for a patient.

And the questions clinicians ask that start with something small are the sorts of questions that make a difference in simple ways to every single patient.

A Mountain Story

You have to cast yourself back to the late 90s. Back when the millennium bug was a spooky tale and not an impressively well managed systems vulnerability.

On a particular morning back then there was a car accident in the Blue Mountains, just outside of Sydney. It was serious. The driver had died.

These were the times when asking for a team with a few more options waited until the ambulance officers had got to the scene and started working very hard. So around 28 minutes after the accident, the CareFlight crew on that day got a call to attend to try and help a passenger. Around 52 minutes had passed by the time they reached the patient.

In that time a lot of difficult treatment and rescue work had already happened. The patient, a 15 year old was accessible but still a bit stuck. The paramedics had already started care. In this case this included a large bore cannulae and 6 litres of polygeline fluid resuscitation.

I should have mentioned it was 7 degrees Celsius this particular morning.

Over the course of the extrication all the crews on scene combined. The patient was intubated because the combination of their injuries, diminishing conscious level and the respiratory rate of 40/min suggested something was up.

They received the 4 units of red cells that the CareFlight crew was carrying. The heart rate of 140/min and blood pressure of 70 mmHg made it clear bleeding was an issue. It was an issue that needed more red cells. How does that happen on a cold day in the mountains in 1997? The local hospital, nothing like a trauma hospital sends O negative red cells when they receive a call. The police deliver it.

The patient had a chest drain inserted after their breath sounds changed unilaterally.

But it was clear they needed more fluid resuscitation. And more.

In total, by the time the patient reached their destination hospital a flight later and about 132 minutes after their injury, the combined teams had managed to find a total of 15 units for that patient. Which gave the hospital a chance to get working.

The receiving hospital that day was Nepean hospital, at the foot of the mountains (and these days not a major trauma centre). They received a critically unwell patient and had a long day in the operating theatres. A long day with a long list of injuries who received a further 56 units of red cells, 16 units of platelets and 19 units of FFP.

And survived.

I know they survived because they provided consent for the first case report of massive transfusion in the prehospital setting that Rob Bartolacci and Alan Garner wrote up in the MJA in 1999.

Questions

That story could be seen as an extraordinary success. It didn’t stop the crew asking questions though. This was of course before we knew nearly as much about trauma and bleeding and coagulopathy. I mean we knew it was an issue but Brohi et al hadn’t published that excellent work showing a rate of coagulopathy of 24.4% or the huge import of coagulopathy when it came to mortality.

We didn’t have nearly as much understanding of the ills of acidosis, coagulopathy and hypothermia. We didn’t even have as much evidence about how easy it is to cool patients with cooled fluids as we now do.

We knew hypothermia was bad though. So when that patient arrived to hospital with a temperature of 29.5 degrees Celsius and a heart rate of 80/min, the crew started thinking about ways to do it better.

These days of course we prioritise haemorrhage control. We have a different approach to administering massive transfusions. We’d be reaching for tranexamic acid. Along the way though the first question was ‘how do we try and make our fluids warm?’ Red cells come out of the esky at around 4 degrees Celsius. Patients are not designed to meet that temperature halfway.

Lots of things have been tried over the years. In the past we’d relied on the Australian sun. We’d relied on the toasty armpit of an emergency service worker probably wearing a non-breathable fabric blend that isn’t very flattering to the profile. We’d tried gel heat pads that you’d use to ease a muscle ache.

Fast forward a decade and a bit though and we finally had a portable fluid warming device small enough to help us out. We felt pretty good about the Belmont Buddy Lite too. It was a huge step up, we figured, from what we’d been doing.

Clinicians still ask questions though. This time it was another CareFlight specialist, James Milligan, who started asking questions. It was a pretty simple one really. ‘Maybe we should check how much better it is than all the other options we’ve tried?’

Simple, right?

 

Setting the Right Rules

Now one of the great challenges when you’re trying to do bench testing of a device for prehospital and retrieval medicine is getting the balance right. You want to produce measurements that are rigorous and reliable enough to give you real information. The risk when you do that is that you do things so differently to the environment that counts for us that it no longer represents something that still applies at the roadside.

So the natural choice if you want to bench test a prehospital blood warming device is this …

… a bespoke cardiopulmonary bypass circuit to deliver reliable flows, measure the temperature at multiple sites, measure pressure changes across the circuit, collect the first unit of red cells you administer, spin it down and cool it then recirculate that blood to deliver the equivalent of a second unit.

With a plan to fix the flow rates to 50 mL/min (the suggested rate for the Buddy Lite), randomise the sequence of runs and repeat each type of run 3 times to generate useful data. We standardised as much as we could, including the spine board we used for the ‘on a warmed spine board in the sun’ group and had the board heating for a standardised period of time. We used a single armpit to generate body heating. (Yes, I can confirm that sometimes you have to sacrifice a few frozen off armpit hairs for science.) You get those gel pads ready to go. You get the support in an entirely different setting from your blood bank.

Then it’s time to test how MacGyver works in real life.

 

Phase 1: A Warmer vs MacGyver.

This study turned out to be one of those ones where the results match pretty much what you thought. You can find the full paper here but the key table to pull out is this one.

Even with this simple study there are a few interesting points to note:

  • There is actually more warming than you might expect when you just run the fluid through an intravenous fluid line.
  • The Australian sun actually did pretty well.
  • My armpit is just an embarrassment. Only for this reason.
  • Gel pads just don’t have the contact time to count.
  • The thing specifically designed for warming turns out to be better than warming.

Phew. Done and dusted.

Except we had more questions.

The thing is as clinicians we knew that delivering at 50 mL/min is probably not what we do when a patient is really critically unwell. There’s every chance it’s quicker. It certainly was in 1997. Maybe even pulsed because someone is squeezing it in.

So to really make the benchtop more like the place we work, we wanted to test different flow rates. We also thought maybe we should double check that putting red cells through a rapid temperature change across a small area of space where at least some pressure changes happen inside the device was still OK for red cells. What if we haemolyse a bunch of hose bendy little discs.

Happily just as we got there, more devices hit the market.

 

Phase 2: Warmer vs Warmer

We had some more limits to set though. The devices we’re after for prehospital work need to be light enough to not be too annoying. They have to be free of an external power source. Ideally they’d be idiot proof. I mean folks like me just a little overloaded at the accident scene need to use them.

So we looked for devices that could do the job at a total weight under 1 kg and that operated as standalone units. We ended up with 4 to test:

  • The Thermal Angel.
  • The M0
  • The Hypotherm X LG.
  • The Buddy Lite.

This time with flow rates of 50 mL/min, 100 mL/min, and 200 mL/min (the maximum rating of any device was 150 mL/min but we also knew that with a pump set we can get up as high as those numbers). Still randomised. This time with fresh units of red cells so we could test for haemolysis on the first run through the circuit.

The testing circuit was a little different this time, mostly because it did things better and would reliably deliver the flow rate all the way to 200 mL/min. It was a bit quicker to cool the units too.

The results this time are best shown in a couple of the tables. At 50 mL/min there’s one warmer that’s clearly performing better than the others. The red cells reach the thermistor that reflects delivery to the patient at 36.60C. The best of the others only gets to 30.50C.

When you get to higher flow rates the difference is even more marked.

That same device gets the blood to 32.50C. The others? 23.7, 23.5 and 19.40C.

That is a heck of a difference.

Along the way we couldn’t pick up any evidence of haemolysis. We count that as the best sort of negative result.

Oh, that warmer was the M warmer. We switched.

The Deeper Bits

A study that started with a very simple question ended up being a pretty fun excursion into the lab. Except for that one thing where the clamp went on the wrong bit of the circuit.

For no reason at all I’m just going to mention that wearing PPE not your own clothes is something you should be glad you do at work. It pays off.

The other thing worth noting is that all of these devices go through a process before they become available for sale commercially. That is part of what the TGA does. And they all do kind of what they say on the box. They do warm things up. They are unlikely to cause problems. They’re not the same though. You could even argue that some of them performed so below the level of the most effective device we tested that it’s only marginally better than our next reference, my armpit.

Everything that goes to market has its own story, just like the little pig who goes to market I guess. The TGA is obviously very rigorous in applying its incredibly voluminous guidelines. And I wouldn’t suggest that the manufacturers or those sponsoring the devices t get into the market haven’t likewise followed every part of that process.

What is less clear to me is how you demonstrate ‘suitable for intended use’ which is one of the essential principles that must be shown to be met. Near as we can tell there wasn’t prior testing of these units that so rigorously reflected how we’re likely to use the units in our actual practice prehospitally.

There is a requirement to show that the design meets appropriate standards and that there is clinical evidence. However you are permitted to show that testing is similar enough to the area you reckon it can be used that it gets signed off. On my read of the guidelines you can even show good evidence for the principle of blood warming and that a similar device has been shown to do that well and say ‘our tech specs show we can do the same thing so tick here please’. Extrapolating practice from the hospital or other settings to prehospital and retrieval medicine is a thing we often have to do but that doesn’t mean we should just accept that.

So when you look at a design like, say, the Buddy Lite (a device that has served us really well and that was a huge step up from what we were doing) you can see that it would meet lots of essential principles about not exposing the patient to harm, being safe to handle and operate and warming the infusate. As long as it is delivered as suggested by the manufacturer at 50 mL/min.

And that’s the bit of evaluation that we can’t rely on the TGA to do for us. Is 50 mL/min what we’re after?

We need clinicians asking questions.

Slow Down

So we started with a question. Actually the questions have been happening since at least the 90s.

Simple questions asked by clinicians thinking about the patient in front of them are really useful. They take you in unexpected directions. They lead you to work in teams just like you do at the accident scene. It’s just that this team involves some doctors and a paediatric perfusionist and a haematologist and a lab technician and the blood bank and the Red Cross and a statistician in Hong Kong.

And we’ll keep asking questions. Along the way on this study we figured out that the Hypotherm was just a little challenging to use. In using the M warmer we’ve picked up ways we need to manage the battery recharging.

Clinical teams are vital to doing things better for our patients not just because we actually do the doing, but because the studies that get out there need to be interpreted by people who know the operating space. Or it needs to be clinical teams and patients inspiring studies in the first place.

Someone needs to keep an eye on the pigs when they’re trying to get to market.

 

The References Bit:

OK that’s quite long.

That case report is this one (and obviously the patient has given permission for its use in contexts like this):

Garner AA, Bartolacci RA. Massive prehospital transfusion in multiple blunt trauma. Med J Aust. 1999;170:23-5.

The first of the blood warming papers is this one:

Milligan J, Lee A, Gill M, Weatherall A, Tetlow C, Garner AA. Performance comparison of improved prehospital blood warming techniques and a commercial blood warmer. Injury. 2016;47:1824-7.

The more recent one comparing devices is this one:

Weatherall A, Gill M, Milligan J, Tetlow C, Harris C, Garner A, Lee A. Comparison of portable blood-warming devices under simulated prehospital conditions: a randomised in-vitro blood circuit study. Anaesthesia. 2019;8:1026-32.

If you want to read that Brohi et al paper again it’s here:

Brohi K, Singh J, Heron M, Coats T. Acute traumatic coagulopathy. J Trauma. 2003;54:1127-30.

You might like to reflect on just how quickly you can cool someone down with cold crystalloid:

Kämäräinen A, Virkkunen I, Tenhunen J, Ali-Hankala A, Silfvast T. Induction of therapeutic hypothermia during prehospital CPR using ice-cold intravenous fluid. Resuscitation. 2008;79:205-11.

If you have lots of spare time you might like to read the TGA regulations. (Note they are being updated.) I advise drinking coffee first.

And did you get all this way? Then you definitely need to watch this and relax.

 

Analgesia

Look Back at Analgesia

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It seems like a simple thing that’s a given – delivery of good analgesia. Except for the bit where good clinicians fail over and over at this. Here’s Dr Alan Garner checking out a recent study from the Swiss that looks at some of the holes. 

As prehospital clinicians I think we all aim to provide as technically sound and evidence-based management as we can.  This is a given but when I think about what I would like for my own family or myself I also want “care”.  This is what makes health care interactions more than just an exchange of services for money. And this is what sends me crazy when I hear patients described as “clients”.

But I am digressing.  A major component of care is the relief of suffering and the most common form of suffering we see in the prehospital world is pain.  Good pain relief early might not change the patient’s probability of death in the longer term but it might well change functional outcomes such as symptoms of post traumatic stress disorder.  But most of all we should do it, and do it well because we care.

There have been a lot of studies published about management of pain in emergency departments and it almost always looks bad.  People with obviously painful conditions either not getting analgesia, getting it late or not getting enough.  Given that the most common single presenting complaint to emergency departments is pain of some kind, I would argue that a fundamental KPI of good emergency care should be time to adequate pain relief and this should be reported above the 4 hour rule, access block and any other process indicator.  Waiting for a bed for hours is regrettable but waiting for hours in agony is simply barbaric.

If EDs are doing it badly you can be reasonably confident that prehospital is worse given all the additional constraints.  A new study has just been published by the guys from REGA (Swiss Air Ambulance) building on some work they have done previously around the prehospital analgesia question.  The work arose from a quality assurance project on analgesia that they have been conducting across their organisation to try and improve pain management and they are much to be commended for sharing their work on this.  They have allowed us a view into their struggle so we can learn from them.

And it has been a struggle.  In this new study they documented that one in six patients with moderate to severe pain (defined as >3 on a 0-10 numerical rating scale as reported by the patient) did not get any prehospital analgesia at all!  This is even more noteworthy given that the physician documented the pain score of >3 at the scene but apparently did not act on it for some reason.  One clue might be that a predictor of inadequate analgesia was shorter scene times and more severe injury (higher NACA score).  I was wondering if hypotension therefore might be one of the drivers for no analgesia but “circulation insufficient” was pretty uncommon being present in only 13 of the 778 conscious patients in this study (this stuff is in Table 1 in the paper).

 

Local Stories

Several years ago we audited the analgesia given to children by our own service.  In some cases we did not give analgesia for clearly painful injuries (like bent long bones) but there was evidence that the road paramedics who had been there ahead of us had done so.  There is no mention of this occurring in the Swiss study.  Perhaps this might partially explain the lack of analgesia given if this is also occurring in their system.  Although even if this did occur the physicians still documented pain scores >3 whilst the patient was in their care which you would have thought would prompt further analgesia.

I am not meaning to be too critical here.  In the audit of our own service that I mentioned we also found cases with clearly painful injuries and no record of analgesia given by road paramedics or our doctors.  This prompted a major rethink for us in our approach to analgesia in the field including formally recording pain scores on our observations chart to prompt our teams to keep this front of mind.  Analgesia is also included as an item in all our Carebundles for traumatic conditions, and for intubated patients regardless of the underlying pathology.  One of the risks for inadequate analgesia identified in this new study was that the patient had a non-trauma problem.  It might be timely for us to review our Carebundles for non-trauma conditions too.

Digging Deeper

Another risk factor for inadequate analgesia was severe pain from the outset (score 8 or more).  In this situation it seemed a single agent just was not enough.  Judicious use of small amounts of ketamine in addition to the opioid appeared really useful here.  And it appeared the combination was better in severe pain rather than just ketamine as a single agent.

I am also a little surprised about the narrow modes of delivery utilised with all analgesia given IV.  In our system the nasal route for fentanyl is used frequently particularly for children and it works a treat.  I also think that regional blocks have a place, particularly where the injury mechanism and your exam indicate that the injury is confined to a limb and the situation is not time critical (the time it takes is probably the major contraindication prehospital).

We have recently formally introduced fascia iliaca blocks to our service.  There are lots of other blocks you can utilise , particularly if your service carries an ultrasound machine with an appropriate probe for nerve localisation.  This is a skill you are unlikely to learn prehospital (except perhaps for femoral or fascia iliaca blocks) as you will never do enough of the other types to develop any skill.  If part of your practice is in the hospital context where you can get lots of practice however, these are well worth learning.  Done well they can completely remove the need for parenteral opiates.  The context that we have used regional blocks (other than femoral or fascia iliaca) is in limbs trapped in machinery.  Not a common circumstance but a useful tool to have in the box when it occurs.

The Other Bits We Rarely Look At…

I don’t think this was the aim of this study but it would also have been nice to see some attention paid to non-pharmacological methods of pain management.  Good splinting and packaging is the obvious first line for prehospital services and is one of the basics that is worth doing well.  We don’t carry hot or cold packs in our service due to the weight, but they are available from our local ground ambulances.  These can also help in the right patient.

Plus a Slightly Unexpected Elephant

And lastly they claim a slightly unexpected elephant is in the room.  Treatment by a female physician is reported as being associated with a higher likelihood of arriving at hospital with inadequate analgesia.  To be honest I’m not quite sure what made them look at the gender of the practitioner but there it is, written up. Before anyone assumes this was some situation induced by most of the patients being middle-aged blokes, it wasn’t about the patient gender at all.

IMG_5815
An actual elephant not in a room as opposed to the elephant in the study that is probably not an elephant. 

So what is going on? I can’t quite figure out why this would be the case although the Swiss group has documented this previously in their own system.  Is this a Swiss peculiarity or is it more wide spread?

Well to me it looks like there are a few holes in the information provided that make me wonder if it’s a blip rather than an actual pachyderm. For example non-trauma patients were more likely to arrive at hospital with insufficient analgesia than trauma patients. I can’t construct what proportion of those patients got a physician of a particular gender by chance from this report though. Could it be that the real issue is that clinicians interpret the significance of pain differently based on the context or mechanism? If it’s “medical” pain rather than traumatic pain do we tend to wait for the medicine to fix the medical, rather than treating pain separately? There’s at least one confounder for you without even trying so I’m not convinced a strong case is made that provider gender is a crucial determinant of analgesia efficacy.

A question the physician gender stat does raise that is beyond the scope of this study is the need to consider the particularities of the provider in the mix. Beyond breaking things into much larger groups (like physician vs paramedic) I don’t recall seeing much on what characteristics of a clinician make them more or less likely to provide the good juice. If we don’t understand biases that might be in play I’m not sure we can do the most effective job of changing practice.

 

The bottom line – be obsessed with good analgesia.  It’s easy to get obsessed with all those interventions we think of as advanced, but the long-term quality of life of patients will probably be equally influenced by getting this bit right. Use a multimodal approach rather than just the parenteral one.  Combine agents if severe pain requires it.  Consider local and regional blocks if you have the skill.

And if anyone can figure out if the physician gender difference in this study is a blip or a real thing of some other sort hidden somewhere in the unreported elements, I’d like to know.  It’d be good to show that elephant the door.

 

Notes:

Yes. That’s a real elephant and the photo is via @AndyDW_

Oberholzer N, Kaserer A, Albrecht R, et al. Factors Influencing Quality of Pain Management in a Physician Staffed Helicopter Emergency Medical Service. Anesth. Analg. 2017. 

 

Research

Getting to the Start Line

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We can debate the value of this advanced team model vs that advanced team model. We can debate videolaryngoscopy vs direct laryngoscopy for days. People do. Its all chump change compared to the real challenge. Getting that team where they need to be. Dr Alan Garner and Dr Andrew Weatherall have a bit reviewing a paper they’ve just had published trying to add to this discussion. 

You may just have noticed that there are things happening in Brazil. They are called Olympics and they are a curious mix of inspiring feats of athleticism and cynical marketing exercise inflicted upon cities that can probably barely afford them and which will be scarred for a generation afterwards. I’d hashtag that but it turns out the IOC will take you on if you mess with their precious sponsor money.

Now, you might think the obvious segue from a mention of the Olympics at the start there would be to mention drugs. The sort of drugs that enhance performance. It’s just that this feels too obvious. We’d rather make a very tangential link to kids. In particular, let’s talk about kids who are very, very injured.

 

The Teams

One of the bits of the Olympics that is a bit fascinating is the logistics of getting highly specialised teams into the right place at the right time in the sorts of cities that don’t usually get anything to the right place at the right time.

Maybe this is unfair but I don’t immediately think “super efficient transport infrastructure” when I think of Rio de Janeiro. And when I’m on a commute in the early hours of a Sydney workday, the fact that anyone was able to get a rowing team out of the stacking rack and to a patch of water in the hillock-shaded nirvana of Penrith during our local Olympics is astounding.

That’s kind of central to the whole circus though. Everyone is getting their right team to the right start line at the right time. It would probably be more entertaining if you dropped the table tennis team at the volleyball court but that’s not how it works when you’re trying to get the best of the best doing what they are built for.

Which is the cue to make this lumbering patchwork monster lurch back to the segue.

 

Right Place, Right Time

Advanced EMS needs to achieve the same goals of right place and right time. (Never said it would be a pretty link, but there it is.) Whatever your model of staff might be for delivering advanced prehospital care (paramedic/physician, paramedics across the board, St Bernard with an alcohol supply) there would be no one who doubts that the key to the whole thing is to get them to the right jobs at a time when those advanced skills have a role in making a difference.

You might be able to put one of those snorkels in the airway hanging upside down while drilling an intraosseous with particularly agile toes but if you’re back at base that’s not going to help the patient out there who is injured.

For a while now we’ve been really exercised by that problem. How do we make the tasking process better? Because tasking is not about the team at base. It’s not about which location the vehicle comes from. Tasking is always about the patient waiting for the care they need. They’re just wishing you’d been waiting there already, not still somewhere else.

The latest in a suite of papers which are ultimately about this question has gone online pretty recently. With the catchy title of “Physician staffed helicopter emergency medical service case identification – a before and after study in children” it builds a little bit from an earlier paper where two parallel tasking systems for sending advanced EMS (in this case physician staffed HEMS) to injured kids was compared.

That paper suggested that when you had a team actually delivering HEMS involved in identifying and tasking of cases, they were far more likely to identify cases where their skills might help (meaning they were more likely to identify cases of severely injured kids from the initial emergency call information in the system) than a single non-HEMS tasker working away in the office.

The involvement of the HEMS team got removed though, so it seemed timely to revisit this area to look at the time before the changes where the two systems worked together and the subsequent time period where it was just left to that one paramedic in the office.

Kids and the NSW System

It is going to help you to know a bit of background here. For a while now in New South Wales, there has been a stated goal in the trauma system to get kids straight to a paediatric trauma centre (PTC). Interest in this first came about because of overseas evidence that maybe this was the best option for kids. This was later followed by local work. This established that kids who went to other centres before the PTC tended to wait a long time in the first place they went to. Like 5 hours in that initial hospital before there was any movement.

Another study also suggested that kids who went to an adult trauma centre first had 3 to 6 times the risk of a bad outcome. And by bad outcome I mean a dying sort of outcome. Now, there are issues with being too firm on those numbers, particularly as not many kids die from traumatic injuries over any measured time period in our system so one or two kids surviving in the adult centre would make a big difference to those stats. But these were the sort of figures that made people keen to get kids straight to the specialist kids centres.

So the system is supposed to be designed to get kids to the kids’ hospitals as a priority. Do not pass go, do pass the adult centre.

Around the same time as that was becoming a talking point, the Head Injury Retrieval Trial was getting moving. As part of that trial, there was an agreed setup for the HEMS crew (including the aviators) to have access to the emergency call info on the ambulance computer screens on about a 90 second delay from when it hit the ambulance system.

For the trial (only adults), you’d look at the highest urgency trauma cases and look for specific trigger mechanisms which would lead to a protocolised response – either an immediate decision to randomize or a callback and interrogation step.

For kids, a different request was made. The request was just to respond to severely injured kids (where it seemed like the severity matched the initial call info or the mechanism was a super bad one; something like “kid vs train” for example). No randomisation as they were not in the trial; we just went.

So the crew screened for paediatric cases too, as requested. And went to paediatric cases. There was some real learning in that too, as the HEMS crews started making it to a much higher proportion of severe paeds trauma (and drowning) than had historically been the case.  This was partly due to the higher rate of recognition of cases, and partly due to the fact that the HEMS team was really fast getting to the patient, arriving before the road paramedics had already moved on.   You can read more about the kind of time intervals the HEMS team achieved here.  As far as we are aware from the published literature the whole end-to-end process was the fastest ever reported for a physician staffed HEMS system, while still offering the full range of interventions when indicated.

Mirror, Mirror

A third of the way through the HIRT thing happening, the ambulance service introduced a role within ambulance which hadn’t been there before. The Rapid Launch Trauma Coordinator. Their role? To look at the screens as jobs came in and try to identify cases where advanced EMS might help.

As it turned out they elected to include the trial area as well as other areas in the state in the roving brief for this paramedic sitting in at the control centre. While that was an issue for the trial, for kids it was just a bonus, right? Another set of eyes trying to find kids who might need help sounded perfect.

The bonus in kids was that there was no need to try and have the person doing the RLTC work blinded to whether the case had been randomised or not, so if the HIRT crew in their screening saw a case with a kid, they’d call quickly and see if the RLTC knew of a reason they shouldn’t go. It was a nice collegial cross-check.

This also ensured that only one advanced team went unless they thought there were multiple casualties (in the trial double tasking was common due to the blinding of the RLTC to the randomization allocation).  So the cross-check avoided double ups and maximized use of resources too.

OLYMPUS DIGITAL CAMERA
Well how close to being the same are they then?

It was in this context of the systems for screening cases operating alongside each other that the first bit of research was done [2]. Over a two year period cases with severely injured kids occurring while the HEMS was available were reviewed to see if either screening process picked them up.

There were 44 kids fitting that bill (again, the numbers are low in the Sydney metro area). 21 weren’t picked up by anyone. 20 were picked up by that HIRT crew and 3 were picked up by that person working on their lonesome in central control.

When you looked more broadly at times the HIRT system wasn’t available compared to those it was, the proportion of patients directly transferred to the PTC was much lower. This fits with other stuff showing that advanced EMS teams tend to be more comfortable bypassing other sites to make it to a PTC, while also performing more interventions.

Another thing this research threw up was to do with time of a different kind: when HIRT was available the median time to reach the PTC was 92 minutes, compared to 296 (nearly 5 hours again) when they weren’t available.

So on that first round of research the message seemed to be that there was something about that case screening process that picked the severely injured kids more often. Maybe it was the extra eyes and regular rotation. Maybe it was better familiarity with the nature of the operational work for advanced EMS on the ground. Either way that screening process seemed to support the goals of the trauma system pretty well.

Things You Take Away

Come March 2011, the screens were taken away from the HIRT set-up as the trial wrapped up. No more screening by the actual HEMS crew. Back to centralised control screening back in the office.

As the HIRT screening process seemed to have such a dramatic effect on the trauma system in Sydney we wanted to keep it going as did the trauma people in the Children’s Hospital at Westmead.  They had particularly noted the change as by virtue of geography they are the closest kids centre to most of the Sydney basin.  The increase in kids arriving straight to the ED even led them to revise their internal trauma systems. But away the screens went.

So the question for this subsequent bit of research was really pretty simple: did we lose anything going back to the centralised process alone? More crucially, do the patients lose anything?

Comparisons

This time the comparison wasn’t the two screening processes working alongside each other. It was before and after. What didn’t change was the sort of paeds patients being looked for. It was any kid with severe trauma. This might include head injury, trunk trauma, limb injuries, penetrating injuries, near drownings, burns and multi-casualty incidents with kids involved.

So in the ‘before’ epoch there were 71 cases of severely injured kids (covering 34 months) that fitted the bill. For the ‘after’ epoch there were 126 cases (over 54 months).

In the ‘before’ epoch with the systems working alongside each other, 62% of severely injured kids were picked up and had an advanced EMS team sent.

In the ‘after’ phase? It fell. To 31%.

And while the identification rate halved it also took kids longer to reach the PTC going from 69 to 97 mins. 28 minutes might seem small but then most of us have probably seen how much can change in a severely injured patient in less time than an episode of Playschool runs for.

Things that didn’t change? Well the overtriage rate for the CareFlight crew was pretty much the same. And whether advanced EMS teams or paramedic only teams reached the kids, their respective rates of transfer direct to PTC were pretty much the same as in the ‘before’ time. It seems that once crews get tasked they treat the patients much the same as their training sets them up to do.

It certainly seems that the right team in our system is a physician/paramedic crew (in NSW the doctor/paramedic mix is the advanced EMS set-up used across the board) as the kids get much more intensively treated at the scene and then get transported directly to a kids centre.  In other words faster access to advanced interventions and much faster access to the specialist kids trauma people.  Right team to the right patient at the right time.

 

The Washup

So we’re left with a few things to consider. There is an acceptance locally that severely injured kids are more likely to get time critical interventions if an advanced EMS team is sent (and advanced EMS teams could come from different backgrounds in different places, it just happens to be physician/paramedic here). There is a belief that those who’ve had that extra training and exposure will feel more comfortable with kids, who can be challenging.

The system has set a goal of getting those advanced teams to severely injured patients, and in this case we’re talking about kids. These two papers suggest that a model where those who are directly involved in advanced EMS are part of the screening process will identify more severely injured kids and get more of them straight to the PTC and definitive care.

Should this be a surprise? As the paper mentions this isn’t the only example of a model where clinicians who do advanced EMS work being part of the screening process seems to be a success above and beyond those who specialise in screening all calls. It may be that knowing the lay of the land when it comes to service capability counts for a whole lot. There is also work suggesting that telephone interrogation of the emergency caller by a flight paramedic is accurate when compared to assessment by on-ground ambulance crews when trying to figure out whether advanced care might help.

This was the experience with the HIRT screening process too, where structured callback was part of the game. The HIRT system also had some unique features.  It is the only one we have heard of where the crew sitting next to the helicopter identified the cases they responded to.  This seemed to create added benefits in shortening the time to getting airborne because parallel activities come to the fore (see the paper for more).  A very consistent six minutes from the beginning of the triple zero call (emergency call from the public) to airborne is pretty quick.

Does this have any implications for adults too?  Back in 2007 when the RLTC was introduced the local ambulance admin made the decision that sending advanced EMS teams to severely injured patients was the standard in Sydney and the RLTCs job was to make that happen.  From the time the RLTC started till the screens were removed in March 2011 the HIRT system identified 499 severely injured adults.  The RLTC also spotted 82 of these, or 16%.  So the HIRT spotting system appears to be even more effective for adults than in kids.

Right now there are a bunch of different advanced EMS teams in Sydney, all wanting to get to that right patient and offer top notch care. Those patients would be very happy to have teams with the full range of skills coming. And all those teams have the skills to add the sort of screening that involves protocols that operated during HIRT. They’re sitting waiting for someone else to look their way.

So let’s work it through again.

Let’s say you were trying to meet that thorny challenge of right team, right place, right time. Let’s say you had ended up trying out a screening system similar to some others around the world but with some tweaks that made it even better, particularly for local conditions.

Let’s say that system hugely improved the way that severely injured kids were cared for.  Let’s say that system was also even better at spotting severely injured adults too.  Let’s say that system was part of the fastest end-to-end physician HEMS system yet described in the world literature.

Let’s say when you moved away from that screening system you didn’t pick up as many of the severely injured kids as you wanted to so they missed out on early advanced care, the kids didn’t get to your preferred destination first up as often and they took longer to get there.

You might ask why such a hugely effective system was discontinued in the first place.

You might ask why it has not been reinstated given the subsequent evidence.

And they would be very good questions.

 

Notes:

The image of Charlie in his guises was on the Creative Commons area of flickr and posted by Kevin O’Mara. It’s unchanged here.

The papers mentioned again are:

Garner AA, Lee A, Weatherall A, Langcake M, Balogh ZJ. Physician staffed helicopter emergency medical service case identification – a before and after study in children. Scand J Trauma Resusc Emerg Med. 2016;24:92.

Garner AA, Lee A, Weatherall A. Physician staffed helicopter emergency medical service dispatch via centralised control or directly by crew – case identification rates and effect on the Sydney paediatric trauma system. Scand J Trauma, Resusc Emerg Med. 2012;20:82. 

Soundappan SVS, Holland AJA, Fahy F, et al. Transfer of Pediatric Trauma Patients to a Tertiary Pediatric Trauma Centre: Appropriateness and Timeliness. J. trauma. 2007;62:1229-33.

Mitchell RJ, Curtis K, Chong S, et al. Comparative analysis of trends in paediatric trauma outcomes in New South Wales, Australia. Injury. 2013;44:97-103.

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 brain injury compared with management by paramedics only. Emerg Med J. 2015;32:869-75.

Garner AA, Mann KP, Poynter E, et al. Prehospital response model and time to CT scan in blunt trauma patients; an exploratory analysis of data from the head injury retrieval trial. Scand J Trauma Resusc Emerg Med. 2015;23:28. 

Garner AA, Fearnside M, Gebski V. The study protocol for 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. Scand J Trauma Resusc Emerg Med. 2013;21:69. 

Wilmer I, Chalk G, Davies GE, et al. Air ambulance tasking: mechanism of injury, telephone interrogation or ambulance crew assessment? Emerg Med J. 2015;32:813-6. 

Did you check all of those out? Why not take a break from all of that and watch these French kids rock a club track?

 

 

carebundles, Prehospital Trauma

Things to Do When Blunt Things Happen

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Continuing the series of sharing Carebundles, Alan Garner moves on to go through the stuff to include in multiple blunt trauma. 

OK, part 2 in our Carebundle series.  This time we will take a look at our multiple blunt trauma bundle.  This excludes isolated head injury which we dealt with in the previous post.  Why that order you may ask? Our Sydney service started life as a trial evaluating the management of severe head injury so TBI is front if mind for us.  It is also more straightforward as there are not the competing priorities that occur in multiple trauma.  And in the end we don’t just want survivors but neurologically intact survivors so starting with TBI and brain resuscitation makes sense.  The multiple blunt trauma bundle has conditional targets that are modified by the presence or absence of brain injury acknowledging that brain resuscitation is our major goal.

So multiple blunt trauma is next. This has many bits of intrigue to it. It is multiple. We’re moving into the bits of the body where the pathology can be buried in the large splodgy bit in the middle. The diagnostic stuff can be pretty challenging at the side of the road. Oh, and because it’s multiple there’s always that threat of a new competitor emerging in the pathophysiology parade.

We won’t touch on penetrating trauma, burns and immersion all of which have their own bundles of joy for another time.

The Common Touch

All of the mandatory items overlap with the TBI bundle so we won’t waste any time on them here:

  • Venous access – yes we reckon that still makes sense.
  • Analgesia – opioids/ketamine – yes we’re really trying to stress that analgesia is a vital component of care, pretty much every time.
  • Monitoring: SpO2, NIBP, ECG
  • Spine immobilisation – note we’re just sticking with immobilisation.
  • SpO2 > 93% by ED arrival
  • Scene time < 25 min – again, this isn’t always possible which is part of why Carebundles provide guidance but need clinician judgment on each job. What we’re aiming for is a background enthusiasm for keeping momentum throughout the time we’re looking after patients so we can get them to the hospital with all those eager people waiting.
  • Transport direct to trauma centre – this would be the house for the eager people.

The conditional items however vary from the TBI bundle and we will now go through these.

 Checking the Terms and Conditions

Long bone fractures splinted

There is no evidence I am aware of that this changes outcome but it is standard ATLS teaching and makes pain control easier. We carry lots of excellent drugs and the Carebundle makes a point of mentioning them but everything is easier if you manage the physical elements contributing to the painful situation. Really this is the original multimodal analgesia. It’s just that one of the modes is “physical things that stop hurting things from exercising a right to freedom of movement”.

 Massive external haemorrhage controlled

There is strong cohort level data that this saves lives, although more so in the penetrating trauma context where it is more common.  Certainly data from recent conflicts supports this as a primary aim of prehospital care. So we’re carrying tourniquets, dressings, chitosan gauze and granules (though the latter are more for penetrating wounds).

5619821151_aec6b61856_o
Right here seems to be a point to salute the wondrous quality of the shells of prawns.

 TXA if episode of SBP < 90mmHg, or below normal for age

CRASH 2 inclusion criteria were felt to be a little vague to include in our bundle.  After all the inclusion criteria in this study was any trauma patient who was at risk of haemorrhage.  To make the bundle we felt the item needed to identify the cases where TXA really should have been given because the risk of life threatening haemorrhage is so high.  There is some evidence that just a single episode of documented hypotension is enough to identify a group of very high risk patients so we adopted this as our criteria. As another mental trigger point, some of our team have expressed a process when they consider packed cell transfusion – “If I’m reaching for blood, I should reach for that drug.”

 If shocked, SBP at ED arrival (refer fluid guideline)

  • No head injury: palpable central pulses/obeying command
  • With head injury: Palpable peripheral pulses, or SBP > 90mmHg / lower limit of normal for age

In setting our blood pressure targets we differentiated between those with and without head injuries.  Without a head injury permissive hypotension is our strategy.  With a head injury we adopted the lowest level identified in the Brain Trauma Foundation Guidelines i.e. SBP of 90mmHg as our target.  This is lower than our target for isolated severe TBI where our target is a MAP of 90mmHg or SBP of 110mmHg (see the TBI bundle post for further details). That last modification is obviously for paediatric patients where the guidelines are a little harder to attach specific numbers to.

 If GCS < 9:

  • Intubation and mechanical ventilation
  • EAM above JVP (head elevation)
  • ETCO2:
  • 30-35mmHg if no chest trauma/shock
  • 25-30mmHg if chest trauma/shock present

This is similar to our isolated severe TBI bundle but we finesse our etCO2 targets in the presence of other injuries that might affect the gradient between arterial and alveolar levels.  There is some evidence that adopting a lower prehospital etCO2 target in patients with chest trauma and/or shock is reasonable as these patients have predictably higher gradients.  My own personal experience is that in patients who have both chest trauma and shock the target needs to be even lower.  I have achieved an etCO2 by ED arrival in the mid-twenties in patients where both these factors are present only to find the first blood gas reveals an arterial level in the 50s.  I would certainly be interested in hearing other people’s experience on this one.  Of course in our rapid response urban trauma work we don’t carry a POC blood gas analyser like we do in our interfacility transport operations.  Actually measuring the arterial CO2 would be ideal but we don’t think this is practical for both time and weight reasons in our urban response service.

 Thoracic decompression if hypoxic/shocked & clinical or US suspicion of pneumothorax

I don’t think this one is rocket science.  Even if we know a pneumothorax is present on ultrasound we usually leave it alone if they are not compromised.  If compromise is present however then we expect it to be decompressed.

 If GCS <13, BSL documented

All patients with an altered level of consciousness get their blood glucose documented.

 Pelvic binder if shock and:

  • possible AP compression / Vertical Shear injury or signs of pelvic #

 We don’t expect pelvic binders to be placed prophylactically.  There is no evidence to support such a practice.  We do however think that binders are helpful on AP compression and possibly vertical shear type injuries and the patient is shocked.

So that is it for our multiple blunt trauma bundle.  It’s what we came up with on a review of the evidence but we’re always open to clever thoughts from others. If you have comments or suggestions we would love to hear from you.

And next time we return to the Carebundles it might just be time to get to the pointy end of penetrating trauma.

 

Notes: 

As always, we’re very happy to hear other people’s clever takes on things that are worth doing. It helps us re-examine our thinking.

Here’s the PubMed link again for the “a single low blood pressure” matters paper linked above:

Seamon MJ et al. Just One Drop: The Significance of a Single Hypotensive Blood Pressure Reading During Trauma Resuscitations. J Trauma. 2010;68(6(:1289-94.

And here’s the one on capnography and major trauma:

Helm M, et al.  Tight control of prehospital ventilation by capnography in major trauma victims. Br J Anaesth. 2003 Mar;90(3):327-32

 

The image for this post came from flickr’s Creative Commons area. It is unchanged from the original posting by “Peter”

 

If you made it this far a reminder that there are options, probably within this very page, to follow along so you get an email when a post turns up.

Governance, Retrieval

PHARM quality – how do you know when you’re doing it well?

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This post from Dr Alan Garner tackles a core problem for all practitioners who give a damn – how do you know you’re doing it well? A chat worth having and Alan has a pretty good summary of the Carebundle approach. 

How do we measure quality in prehospital and retrieval medicine?  Speed?  Number of procedures performed?  Number of twitter followers?

Seriously though, this is a question that vexed me for many years as a service director and trying to find metrics that measure things that mattered seemed an elusive task.  The major part of the problem stemmed from the heterogeneity of the patient population that we treat.  Even simple (but easily measured and therefore attractive to bean counters) things like timeliness are not straightforward.  Not because they are hard to measure but because sometimes time matters and other times it very clearly does not.  Indeed emphasising it as a measure could lead to perverse outcomes for some patients.

Let me give you a couple of examples to illustrate the problem:

Case 1.  Central abdominal stab wound with hypotension.

There is almost no prehospital intervention that matters in this patient except gasoline and perhaps tranexamic acid.  I don’t think anyone would argue that time is a reasonable quality measure in this patient.

Case 2.  COPD patient in a small hospital an hour flying time from the nearest intensive care unit.

Patient is eventually stabilised on non-invasive ventilation after three hours of effort by the transport team at the referring site. They are then safely transported.  Clearly for this patient time does not matter at all.  Reporting turnaround time at the referring site in this patient may place subtle pressure on the team to intubate the patient early and depart – a move that is very clearly not in the patient’s best interests and would have placed the patient at significantly increased risk of unnecessary morbidity and mortality.

This got me thinking that our measures of quality had to be disease process specific or we were never going to move forward.  Speaking with Erwin Stolpe was the turning point in my thinking.

You Should Really Try to Know Erwin

Many of you will not have heard of Erwin.  Sometimes when I talk to people or read things on social media I get the impression that physician staffed HEMS started in about 2005.  The reality of course is quite different.  Erwin is a trauma surgeon from Munich who began flying as a resident on the Christoph 1 service out of that city in 1968 (yes, not a typo – 1968).

Erwin Stolpe
Here he is, at AirMed 2014 in Rome.

These days he no longer flies but is chair of the ADAC medical committee.  For those unfamiliar with ADAC they run about 35 physician staffed HEMS bases in Germany and also operate several jets for longer range transports.  Their HEMS services alone conduct about 50,000 prehospital cases annually.  The breadth and depth of experience of this organisation is extraordinary and Erwin has been there from the beginning.  You would think there might by a few pearls of wisdom there and you would be right.

The Key Cases

Erwin described to me the “tracer diagnosis” process they use to track the quality of the care that they provide.  Analysis of their prehospital caseload indicated that four diagnoses made up 75% of the cases they attended.  For these four diagnoses they defined the treatments that they expected the teams to achieve (see pages 52 onwards of this presentation by Erwin for more detail).  They used national and international consensus guidelines as a base.  They then began reporting against those criteria and they have also started to publish that performance.

What Erwin was calling “tracer diagnoses” is probably better known to us in the English speaking worlds as a “Carebundle”.  Lots of people will be familiar with the ventilator Carebundle for intubated patients in the intensive care unit.   Adherence to the items in the bundle is associated with lower rates of ventilator associated pneumonia.  In NSW and Queensland, Health Departments have introduced bundles for central line insertion in order to tackle the rates of central line associated bacteraemia.  In this case the bundle applies to a procedure or process rather than a diagnosis.  Is there a place for this kind of methodology in the prehospital and retrieval world to improve quality too?

What are we talking about when it comes to PHARM?

Let’s start by looking at what a Carebundle is.

“A bundle is a structured way of improving the processes of care and patient outcomes: a small, straightforward set of evidence-based practices — generally three to five — that, when performed collectively and reliably, have been proven to improve patient outcomes.”

This definition is taken straight from the Institute for Healthcare Improvement (IHI) website.  There is a bit of controversy regarding whether the items in a Carebundle really need to all be completed for the bundle to be effective in some sort of synergistic way or whether they are in fact just a checklist of items that have been shown to be effective and you get as many done as you can.  I am not aware of any evidence for the synergistic effect multiplier that is implied on IHI website.  I think it is unarguable however that you should try and get as many of the things that are proven to make a difference to that condition completed as possible.  That is certainly the approach that we have taken.

Another quote from the IHI website describes for me what we are trying to achieve by using bundles:

“The power of a bundle comes from the body of science behind it and the method of execution: with complete consistency. It’s not that the changes in a bundle are new; they’re well established best practices, but they’re often not performed uniformly, making treatment unreliable, at times idiosyncratic. A bundle ties the changes together into a package of interventions that people know must be followed for every patient, every single time.”

Using Carebundles in hospitals is clearly not new.  Even in EMS it has been previously described for benchmarking purposes.  The attraction of the methodology for me was that we would know if our care for patients with severe head injury for example was following the best available evidence and we would know what proportion of our patients were receiving that care.  I did not want just some of our patients to get that care, I wanted all of them to get every item of care that we could identify matters for that disease process all of the time.

Making it Match What We Do

For our rapid response service in Sydney we then determined from our medical database the diagnoses that cover 75% of our caseload as ADAC had done.  For us this resulted in the following list:

  • Multiple blunt trauma
  • Isolated severe head injury (GCS<9)
  • Burns (>15% BSA)
  • Penetrating trauma
  • Immersion/drowning
  • Seizures (to which we were often being dispatched as they were mistaken for head injury or had caused a minor traumatic event)
  • ROSC post primary cardiac arrest (similar to seizures – trivial traumatic injury and patient in VF)
  • Traumatic cardiac arrest (for us this is the HOTTT Drill which I have described in a previous post, well podcast but which also includes the HOTTT Drill package to go with it).

We then turned to the evidence based consensus guidelines, Cochrane reviews and good quality RCTs to define the Carebundle items.  This is a sobering process as you realise just how few interventions there are that have good evidence to back them up.  This is particularly true for prehospital care where we are often operating in an evidence free zone.  In many cases we had no choice but to go with the consensus (or best guess as I like to call it).  We decided that we would include intubation for unconscious trauma patients for example despite the evidence not being all that strong and in many cases contradictory.

When we had defined the items for the specific diagnosis we printed them up on cards that team members carry in their pocket.  These serve as a checklist which teams use on site or in transit just to be sure that they have covered all the items.  Below is our isolated severe head injury card – the item I constantly forget is the blood glucose level (BSL).  Highly embarrassing if this is low when you arrive at the trauma centre!  I for one am glad to have the prompt.

BI copy

Some of these items are extrapolated from in-hospital care.  For example having the external auditory meatus (EAM) above the JVP makes sense in terms of managing raised ICP but there is no direct prehospital evidence that shows this changes outcome.  We have also set relatively conservative targets for things like oximetry and blood pressure.  Most of the evidence suggests SpO2 >90% is enough but we felt that desaturation happens very rapidly from this point so we would rather aim a little higher.

Aspirations and Signals

Some of the items we knew from the outset that we would never achieve in all cases.  Scene time of <25mins is the obvious example.  When a patient is trapped this is outside of our control.  We know however that one in five patients with a severe head injury will have a drainable haematoma that is time critical.  We therefore included this item in order to signal to the team that we expect them to treat severe head injury as a time critical disease in the prehospital phase.

Some of the bundles have conditional items as well.  For head injury this is the hypertonic saline which we only expect to be given if there are lateralising signs or neurological deterioration.

When the team returns to base they complete an audit form indicating if the bundle items were achieved and if not, the reason for the variance.  This both reinforces for our personnel the contents of the bundles and also allows us to report on compliance.  Below is an example of our report for severe head injuries showing the reasons of variance in the comments section.

Report copy

You can see that we don’t meet all the targets all the time, and there is usually a good reason when we don’t.  However the Carebundles allow us to be transparent about what we think good care is, and also about how successful we are in achieving it.  We include Carebundle compliance (along with a lot of other stuff) in our external reporting in NSW to the Ministry of Health, NSW Ambulance, The NSW Institute of Trauma and Injury Management and all the trauma centres to which we transport patients.  Transparency is a key component of good governance and this processes helps us to achieve that.

Those People Were Here First

The concept is not new.  I merely walk behind the giants of the industry and follow their lead in this.  It is also worth noting that Russell MacDonald from Ornge in Ontario is leading a similar project with an initial group of 10 “tracer diagnoses” amongst a small international collaboration of critical care transport providers.  It will be interesting to see how closely their bundle items accord with our own.  Aligning our bundle items would allow us to benchmark ourselves against similar organisations in other parts of the world and create opportunities for us to learn from organisations who manage specific conditions better than we do.  In the end this is about maximising the outcomes for our patients and I will gladly accept any help I can get in achieving that.

Notes: 

Here’s the stuff referred to along the way, because the originals remain a vital part of looking at the issue.

J. B. Myers, C. M. Slovis, M. Eckstein et al., “Evidence-based performance measures for emergency medical services systems: a model for expanded EMS benchmarking,” Prehospital Emergency Care, vol. 12, no. 2, pp. 141–151, 2008.

Here’s a link to the English version of the “tracer diagnosis” abstract.

Helm M et al.  [Extended medical quality management exemplified by the tracer diagnosis multiple trauma. Pilot study in the air rescue service] Anaesthesist 2012;61(2):106-115.

(Well, not all of us are clever enough to know German.)

Here’s the direct link to the IHI page.

The image of Erwin Stolpe comes from the Intercongress flickr account and is unaltered under the CC 2.0 licence.

 

Airway, Paediatrics

The Dangerous Little Details

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A new bit of research is out looking at paediatric intubation in the prehospital and retrieval setting. Picking it up and turning it this way, that way and all around, here’s Dr Andrew Weatherall. 

Advanced prehospital practitioners that I’ve met have some pretty common traits. They are pretty comfortable around things that other people might find chaotic. They often have pretty strong opinions on food and coffee. Not necessarily even on good food either. I’ve been given connoisseur-level education on various take away options. Most importantly, they are appropriately bananas about doing a good job for their patients.

That extends to paediatric patients which is obviously excellent. Except we tend not to do our most excellent work when it comes to kids. The reasons for that could fill many a blog post (and maybe we’ll get back to that another time) but kids tend to get less pain relief when faced with similarly painful situations, less interventions even when they’re indicated and we tend to do those procedural things less well.

In 2011 Bankole et al. compared interventions in kids (defined as < 12 years old) and adults with a head injury and a GCS < 15 in New Jersey (there was 102 patients in the kids group matched to 99 adults with equivalent injuries).  69.2% of the kids had some sort of problem with intubation. That was across failed intubation (29.03% vs 2.27% in adults), tube dislodgement (16.12% vs 2.27%), wrong-sized tube (7.45% vs 0%) and multiple attempts (as in over 3 tries) at intubation (6.45% vs 2.27%). A peripheral IV was there in 85.9% of adults but only 65.7% of kids.

In a paper that also commented on relative intubation rates in advanced EMS vs general EMS in the Netherlands, Gerritse et al also commented on analgesia. In their study 77% of kids who really needed some form of analgesia actually received nothing from the general EMS. No kid under the age of 4 received any form of analgesia from the EMS. Not one.

I’m not quoting those papers to say anything other than good practitioners (I have a predisposition to think most of those working at any level of EMS are people trying to do the best job their system and training allow) find kids extra difficult. This patient group provides an additional challenge on top of the storm you already deal with the scene. Like someone started blasting fairy floss into your eyes in the middle of that storm. OK I’m not sure that was the greatest analogy but it’s happened now so maybe we can just agree to move on while also remembering that when you’re a kid fairy floss is pretty great. Mmmm, fairy floss.

Enter the Swiss, purveyors of good chocolate and cheese with holes, with some interesting work that sheds a little extra light on things that even the most advanced practitioners find challenging about little people and airway management.

Let’s Stop and Check the Scenery

Not the mountains or lakes or Large Hadron Collider scenery, the other scenery.

Appearing in SJTREM, the paper comes from a  look at their database between June 2010 and December 2013. Across their 12 bases and one affiliate base they do around 11000 prehospital or interhospital missions per year with their paramedic-doctor teams. I should point out that these advanced teams really have had good training in airway management and specific paeds time. The study looks at any kid under the age of 17 requiring any airway manipulation (not just intubation or supraglottic airway or tracheostomy but bag-mask ventilation as well).

From their pool of 4505 paediatric patients over the 3.5ish years (which if they’re doing around 11000 jobs per year should be around 11-12% of their total workload) the ended up with 425 kids requiring some sort of airway care (9.4% of the paediatric group). A little over half (225) were prehospital cases. From here on in when we talk about intubation it’ll be about prehospital missions because those moving between buildings were already intubated and ventilated.

So what did these top operators find?

Actually It’s Not About the View

In the 215 patients for whom an attempt at endotracheal intubation was attempted, first-pass success was 95.3%. Now, if you’ve dropped by this blog before you might recall Dr Alan Garner discussing whether this is the most important measure. I think that’s a great post, but I don’t think it is meant to be interpreted as “first pass intubation tells us nothing” (Alan can always correct me).

What this number does say is that the challenges in kids aren’t necessarily about getting a view of the cords that is enough to achieve intubation. Only 10 patients (4.7%) were described as inflicting a difficult airway management scenario on the team. 98.6% eventually ended up with a support snorkel in their trachea.

There were 2 children who could not be intubated and ended up oxygenating very nicely with the aid of a supraglottic airway, while one patient with a known “airway issues syndrome” (Goldenhar’s syndrome) couldn’t be either intubated or ventilated but was already at the end of a prolonged arrest situation.

So for advanced EMS providers, maybe it’s not the getting a view/passing the tube part of the procedure that is really at issue. In our own research that touched on this, the intubation success rate was 98.7% of the paediatric patients were successfully intubated while one patient was managed with a laryngeal mask in the prehospital phase.

This fits with the overall truth of paediatric airways: unanticipated difficult laryngoscopy is less common in kids than adults.

So Where’s the Problem?

The problems with paeds airway intervention here are about the details. You may have noticed that people who do subspecialty work in paeds can be a little bit fanatical about details. There’s a reason for this. A smaller airway is less forgiving of the tube that is the wrong size, be it too big or too small. An endotracheal tube that is 1 cm too far in on your 1 year old is proportionally a lot closer to the carina than when the same situation applies to an adult. Add a little flexion or extension and that whole tube can end up visiting new pockets of the bronchial tree.

This is the part that is really well covered in the Swiss study. In the 82.7% where intubation was noted, 82.5% got an adequately sized tube. It was too shrunken to be appropriate in 2.9% and too gargantuan in 14.6% (in the under 1s that rose to 57.5%). Rates were higher if that tube was placed during a CPR scenario.

The depth? Well, if you went off the formulae often mentioned in dispatches, most insertions were deeper than that. And while I can’t seem to find the bit in the results that clarifies this statement, the authors say in the discussion that “Only the placement of the depth marking of the correct Microcuff ET tube … for age between the vocal cords was accurate for all paediatric patients …” (Not familiar with the markings? You could look at an earlier post on this site, here.)

 

Details, Details

I think this is the key message of this study. Lots of things might make you sweat about paediatric airways. I suspect that for most practitioners it is the view and “plastic through the cords” components that cause the stress.

That bit is important, of course, and everyone wants to do that bit well. This study supports the argument that advanced practitioners already do that bit really well. Perhaps in thinking keenly about that bit it’s attention to some details, the sort of details that kids are pretty unforgiving about, that gets in the way of safer paeds airway management.

Stavros Markopoulos
Look at this butterfly. Gets fuzzy on the last few details of the right wing and can’t even butterfly properly.

Things to Take Away

Any research only reveals a very particular part of a story. There are questions left unanswered or things that don’t quite apply to your practice. That doesn’t mean we can’t use those results to reflect on things we do when we deliver our variant of advanced care.

So I’d say there are a few key things suggested by this study:

  • If you’ve trained in paediatric airway management, chances are the intubation itself (at least the getting a view and passing the tube bit) will go well.
  • Really well trained people still find the details challenging. The wrong tube size and the wrong depth of insertion matter in these patients.
  • It might be time to review whether those old formulae are the best option.
  • Knowing your equipment (like where the line on the tube goes) is pretty worthwhile.
  • The tube through the cords isn’t where attention to detail stops. That’s not the moment to ease up.

So we can all get out there, push through the fairy floss, be confident that we’ll get those endotracheal tubes in and start remembering the little details that will produce perfection.

No more fuzzy butterflies.

Notes:

Of course it’s not the fault of the butterfly it’s right wing looks fuzzy. It’s the photographer. Well, actually it’s an amazing photo where the wing is a tiny bit in a different alignment. It’s from flickr Creative Commons via Stavros Markopoulos and is  unaltered.

The source paper link is right here and it’s open access:

Schmidt AR, Ulrich L, Seifert B, Albrecht R ,Spahn DR, Stein P. Ease and difficulty of pre-hospital airway management in 425 paediatric patients treated by a helicopter emergency medical service: a retrospective analysis. Stand J Trauma Resusc Emerg Med. 2016; 24:22. 

I also mentioned a paper we put out there:

Barker CL, Weatherall AD. Prehospital paediatric emergencies treated by an Australian helicopter emergency medical service. 2014; 21:130-5. 

Then there’s the Bankole et al. paper:

Bankole S, Asuncion A, Ross S, et al. First responder performance in pediatric trauma: A comparison with an adult cohort. Pediatr Crit Care Med. 2011;12:e166-70. 

And finally the Gerritse et al. paper which is also open access:

Gerritse BM, Schalkwijk A, Pelzer BJ, Scheffer GJ, Draaisma JM. Advanced medical life support procedures in vitally compromised children by a helicopter emergency medical service. BMC Emerg Med. 2010;10:6.

Addit: After a really helpful comment from Paramedidad the line “In their study 77% of kids who really needed some form of analgesia.” was fixed to read “In their study 77% of kids who really needed some form of analgesia actually received nothing from the general EMS.” 

 

Drowning, Research

Summers Past – A Look Back at Drowning Cases

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A quick post on a recent paper from one of the authors, Andrew Weatherall. You can get the full text over here and it might be worth having a quick look at a quick review of a study from the Netherlands that Alan Garner did previously. 

Every summer, for too many summers, prehospital teams at CareFlight go to drownings. Too many drownings. This isn’t to say it’s only summer, but that is definitely when most of the work happens. Sometimes they’re clustered in a way that makes you think there’s some malevolent purpose to it, some malign manipulation of chance striking at families.

And also at our teams, particularly the paramedics, backing up day after day.

So drowning is something we want to understand better. What are we offering? What are our longer term outcomes?

And surprisingly given that drowning has been a long-term feature of preventable tragedy, particularly in Australia, there’s not really that much research out there. In fact it was only in 2002 that clever people at the World Congress on Drowning sat down and agreed on definitions for what was really drowning.

So we set about trying to add at least a little bit to the discussion.

Looking Back

Retrospective research has a bunch of issues. It has a place though when you’re trying to understand your current practice and what you’re actually seeing, rather than just what you think you’re seeing.

We went back and looked at a 5 year period between April 2007 and 2012 (and full credit to co-author Claire Barker who did the majority of that grunt work). For most of this time the tasking system included the HEMS crew observing the computer assisted dispatch system screens. For some of the time there was also a central control person doing this while from March 2011 on there was only the central control person. The aim of the game was to pick up cases where there was an immersion mechanism and either reduced conscious state or CPR and get a team with advanced medical skills moving.

Key points of interest were whether the cases were picked up, what interventions the HEMS team undertook and, if possible, what were the outcomes for those patients? In particular was it possible to glean what their longer term outcomes were?

Things We Found

Up until the move to solely central tasking, all of those at the severe end of the scale (ISS > 15 meaning they had an altered level of consciousness of documented cardiac arrest) were identified for a HEMS team response. Once it went to central control alone, 3 of the relevant 7 were not identified (obviously not super big numbers).

Of the 42 patients transported, 29 of them could be fairly had an ISS > 15 and you can see the interventions in the prehospital setting here:

Table 2 copy

So what were our other findings?

Those who present with GCS 3

This group did not do well. Of the 14 in this group, 10 died within 2 weeks. Of the other 4, one died at 17 months, having had significant neurological impairment after their drowning.

But there was one patient with GCS 3 and a first reported rhythm of asystole that was rated as having normal neurological development on follow-up by the hospital system.

What was different about this kid? How do we make that outlier fit right in the middle?

That’s a nagging question from this study.

9 and above, 8 and below

In our patients, if you had an initial GCS over 8 there was no evidence of new neurological deficit. All the patients with GCS 8 or below were intubated and ventilated by the teams. Every patient with a GCS over 3 when the team arrived survived. All of the survivors (with any initial GCS) had return of spontaneous circulation by the time they were in ED.

Another feature was the neurological outcome for those with an initial GCS between 4 and 7 – 7 of the 8 kids in this group had a good neurological outcome. (One patient had pre-existing neurological impairment but returned to baseline.)

Figure copy

The Bystanders

An observation along the way that is a real highlight. All but one child with a GCS less than 8 on arrival of the HEMS team had received bystander CPR (and that included all of them for those who were systolic). Here’s hoping that marks good community knowledge of what has to be done.

The Stuff We Just Can’t Say

There are the usual issues with retrospective studies here. Some patient may have moved out of area and not had subsequent follow-up. There’s also those three cases of severe drowning not picked up after the change in tasking options after March 2011. As those patients weren’t managed by the reporting HEMS team they don’t make up part of the 42 in this data set. As mentioned in the results, two of those cases went to adult trauma centres first, then were transferred more than 4 hours after the incident to a paeds specialist centre, where they unfortunately passed away. The other case did get a HEMS response by another organisation but we didn’t have detailed access to the treatments undertaken.

Another really important point about the follow-up. The follow-up here is short-term, as it was what is available from the hospitals. It may well be that more subtle neurological impairment only becomes evident as kids get older, particularly when they hit school age. I happen to know that The Children’s Hospital at Westmead has done some work on longer term neurological outcomes which should hopefully hit the public airwaves soon. Intriguingly they’ve looked at kids thought to be entirely neurologically normal and followed them in detail over the longer term. No spoilers in this post but I’ll definitely follow up when it breaks.

It’s also the case that when you’re looking at those who get a HEMS response, you’re not catching the denominator of all drownings. This study doesn’t help us understand what proportion of total drownings end up at this more severe end of the spectrum.

With those provisos, retrospective research still has a key role. It’s still a brick of knowledge. A small brick maybe, but a brick. It’s certainly a better brick to build with than you end up with if you don’t look.

What do we need?

More. Always more data. There is a bit here that suggests things similar to other series, some of which are a good deal bigger. Outcomes after arrest from drowning are better than is generally the case. Our impression is that, as suggested by that Netherlands paper, time does matter and that once you get beyond 30 minutes of resuscitation further efforts are unlikely to help.

The other factor that would appear to make sense (but clearly needs lots of robust research) is that earlier delivery of interventions that should make a difference to outcomes would be good. That surely starts with a big focus on bystander CPR. But that should also be backed up by accurate, early triage of teams with the skills to extend that care. The right teams in the right place at the right time remains the challenge.

 

Notes:

There’s a comprehensive bit on the tasking stuff in this earlier paper relating to tasking and paeds trauma. It should clarify the different systems used, which can be a bit hard to get your head around.

After the paper came out, @LifeguardsWB asked a pretty reasonable question “What were the average response and transport times?”

So as described in the subsequent tweet, the median times were:

  • Start of emergency call to team on scene = 17 minutes.
  • Time on the scene = 17 minutes.
  • Total prehospital time = 54 minutes.

 

 

 

Prehospital Trauma, Research

Studies in Blood from Iran – A Quick Review

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We all want to stop bleeding. Here’s a quick review from Dr Alan Garner of a paper coming out of Iran that looks at haemostatic dressings. 

Hatamabadi HR et al. Celox-Coated Gauze for the Treatment of Civilian Penetrating Trauma: A Randomized Clinical Trial. Trauma Monthly. 2014;20:e23862. dii: 10.5812/traumamon.23862

There is not a lot of data on haemostatic dressings in the civilian context and human data from the military context is not randomised for obvious reasons. It is therefore nice to see a RCT on this subject in humans. In the study they compare the time to haemorrhage control and amount of haemorrhage in stab wounds to the limbs between 80 patients treated with Celox gauze versus 80 patients treated with normal gauze.

The study is from an emergency department in Tehran and is pragmatic in design. There are some limitations of the study worth mentioning. It was open label, and the amount of bleeding was measured simply by the number of gauze squares used. Weighing the gauze would have been a more accurate way to estimate ongoing blood loss.

The details of how the gauze was applied isn’t that clear. To be effective the gauze needs to be packed into the wound against the bleeding vessel. Was the Celox used in this way to maximise the chances it would work? I can’t tell from the paper. Oh, and the company provided the product for the trial.

Perhaps the biggest puzzle in the design is that patients with really significant haemorrhage (those requiring transfusion) were excluded from the trial. This is the group where you really want to know if the stuff works. You could theorise that this group of patients may have trauma coagulopathy and the method of action of Celox (being by electrostatic attraction and independent of clotting factors) might be particularly useful and a bigger difference between groups may have been found. I guess that will have to wait for another day and another trial that someone works through ethics.

Acknowledging all of this, there was a significant difference in the time taken to achieve haemostasis and the amount of ongoing bleeding with the Celox gauze looked superior by both measures.

This suggests that it remains reasonable to use these products as evidence continues to point to efficacy. Of course these agents are not a magic bullet and all the other principles of haemostasis need to be applied as a package, including urgent transport to a surgical facility.

Prehospital Trauma, Research

Examining the Hairs on the Yak – A Good Chance for More Chat

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One of the good things about research that has its own issues, is that there is lots of scope to learn from the things about it that are good, as well as those that aren’t so great. The nice thing about ongoing comment is it gives even more chances to explain why a researcher might make certain choices along the way. Every question in research has more than one way of approaching some answers. Dr Alan Garner returns to provide even more background on this particular study, which has already generated some interesting conversation and a follow-up post. 

It’s an excellent thing to be able to keep having discussion around the challenges related to both conducting and interpreting a trial.  These things always bring up so many valuable questions, which deserve a response. So this is not going to be quick, but I hope you’ll have a read.

Lots of things changed between the time this trial was designed and now. Standards of care change. Systems, processes and governance models change. Indeed, in this trial standard care changed underneath us. We completed the protocol and gained ethical and scientific committee approval for this study during 2003.

The world was a different place then – at the start of 2003 George W Bush was US President and Saddam Hussein was still running Iraq. There is no keener instrument in medicine than the retrospectoscope particularly when focused 12 years back. Would I have done things differently if I knew then what I knew now – absolutely. Does the trial have hairs? Looks like a yak to me and I don’t think we are pretending otherwise.

Asking Questions

Did we ask the right question? The question was pragmatic. Add a doctor and with them comes a package of critical care interventions that were not routinely otherwise available in our standard EMS system. A number of cohort studies had previously looked at exactly this question and more studies have asked it since. Even papers published this month  have examined this question although the issue often overlaps with HEMS as that is how the doctors are frequently deployed.

I might segue slightly to address dp’s question as well which overlaps here. Is it the procedures that the team performs or the person performing the procedures that matter? Dp suggests that a better study design would be to have them all use the same protocols then we compare doctors with non-doctors. Such a randomised trial has actually been done although it is a long time ago now – 1987. It is one of the classic Baxt and Moody papers and was published in JAMA.

Patients were randomly assigned to a helicopter staffed by a flight nurse/paramedic or a flight nurse/emergency physician. The flight nurse and emergency physicians could perform the same procedures under the same protocols including intubation, chest tubes, surgical airways and pericardiocentesis. By TRISS methodology there was lower mortality in the group that included the doctor and the suggestion was this might be related to how they judged the necessity for intervention, rather than technical skill. This study is well worth a read. They note that the outcome difference might have been removed if the nurse/paramedic team was more highly trained but where does this end? We then move into the question of how much training is enough training and this is an area that I think is still in its infancy. Each time you do some research your prompt a whole lot of extra, usually interesting questions.

All That Methods Stuff

Anyway, back to this paper. All analyses presented in this paper were pre-specified in the statistical analysis plan. Although the protocol paper was not published till 2013, the statistical analysis plan (SAP) was finalised by the NHMRC Clinical Trials Centre in August 2010, more than a year prior to follow up of the last recruited patients. Copies of the SAP were then provided to the trial funders and NSW Ambulance at the time it was finalised in 2010. Along the way we have presented data in other settings, mostly at the request of interested parties (such as the Motor Accidents Authority who specifically requested analyses of road trauma cases) and in retrieval reviews. This is why there has been the opportunity for extra public scrutiny by experts like Belinda Gabbe. And public scrutiny is a good thing.

And Standard Treatments?

I’m very happy to provide some reassurance that this study did not rely on junior doctors being put through EMST/ATLS and then sent out to manage severe prehospital trauma patients. Rather the trial protocol states that treatment was according to ATLS principles. In 2003 there was no other external standard of care that we could cite for trauma patient management that was widely and internationally recognised.

The specialists had of course all completed EMST/ATLS but they were also all critical care specialists in active practice in major trauma centres in Sydney with ongoing exposure to severe trauma patients. The average years of prehospital trauma management experience held by this group of doctors at the beginning of the trial was more than 12 years each. They operated to those high level of treatment standards, with regular reviews of management to make sure this was current best practice over the life of a trial that ended up being longer than we hoped.

Other Dimensions of Time

And time wasn’t a friend. Recruitment was indeed slower than planned. This is a common problem in prospective trials. Our estimates of how long it would take to recruit the required sample size were based on a written survey of the major trauma centres in Sydney in 2003 to determine how many unconscious adult blunt trauma patients they were seeing each year. This was reduced to 60% to reflect the fact the trial would recruit for only 12 hours each day (although during the busiest part of the day) and the time needed to recruit was then estimated at 3 years. We in fact planned for 4 years to allow for the fact that patients usually disappear when you go looking for them prospectively. This of course is exactly what happened but to a greater degree than we planned.

I agree it would have been nice to have the results formally published earlier. We did present some results at the ICEM in Dublin in June 2012. It is interesting to note that Lars Wik spoke immediately before me at this conference presenting the results of the CIRC trial on the Autopulse device. This study was finally published online in Resuscitation in March 2014, more than three years from recruitment of their last patient and this trial did not include a six month neurological assessment as HIRT did.   Getting RCTs published takes time. Given we did have to perform six month outcome assessments I don’t think we were too far out of the ball park.

Quokka copy 2
To keep you going, here’s a quokka who looks like he’d be up for a chat too. [Via Craig Siczak and unchanged under Creative Commons.]

Randomising in Time Critical Systems

Just to be sure that I really have the right end of the stick on the question of excluding patients after randomisation I ascended the methodology mountain to consult the guru. For those that don’t know Val Gebski he is Professor and Director, Biostatistics and Research Methodology at the NH&MRC Clinical Trials Centre in Sydney. He was our methodology expert from the beginning of planning for the trial.

When I reached the mountain top I had to leave a voice message but Val did eventually get back to me. He tells me excluding patients post randomisation is completely legit as long as they are not excluded on the basis of either treatment received or their outcome. This is why he put it in the study design.

These are essentially patients that you would have excluded prior to randomisation had you been able to assess them properly and of course in our study context that was not possible. The CIRC study that I have already discussed also adopted this approach and excluded patients that did not meet inclusion criteria after enrolment.

Prehospital studies where you have to allocate patients before you have been able to properly assess them are always going to have these kind of difficulties. The alternative for a prehospital RCT would be to wait until you know every element of history that might make you exclude a patient. How many of us have that sort of detail even when we arrive at the hospital?

Extra Details to Help Along the Discussion

The newly met reader might also like to know that the call off rate was about 45% during the trial, not 75%. This is not different to many European systems. If you don’t have a reasonably high call off rate then you will arrive late for many severely injured patients.

And of course the HIRT study didn’t involve “self-tasking”. The system randomised cases on a strict set of dispatch guidelines, not on the feelings of the team on the day. This process was followed for nearly 6 years. There was not a single safety report of even a minor nature during that time. Compliance with the tasking guidelines was audited and found to be very high. Such protocolised tasking isn’t inherently dangerous and I’m not aware of any evidence suggesting it is.

It’s reassuring to know that other systems essentially do the same thing though perhaps with different logistics. For example in London HEMS a member of the clinical crew rotates into the central control room and tasks the helicopter using an agreed set of dispatch criteria. This started in 1990 when it was found that the central control room was so poor at selecting cases, and it resulted in the call off rate falling from 80% to 50%. The tasking is still by a member of the HEMS team, they just happen to be in the central control room for the day rather than sitting by the helicopter.

A more recent study from last year of the London system found that a flight paramedic from the HEMS service interrogating the emergency call was as accurate as a road crew assessing the patient on scene. This mirrors our experience of incorporating callbacks for HIRT.

The great advantage of visualising the ambulance Computer Assisted Dispatch system from the HIRT operations base by weblink was the duty crew could work in parallel in real time to discuss additional safety checks and advise immediately on potential aviation risks that might be a factor.

To consider it another way, why is the model safe if the flight paramedic is sitting at one location screening the calls but dangerous if he is sitting at another? What is the real difference between these models and why is one presumably a safe mature system and the other inherently dangerous?

More Mirrors

I agree that the introduction of the RLTC to mirror the HIRT approach of monitoring screens and activating advanced care resources (with extension to a broader range) was a good thing for rural NSW. However they did activate medical teams into what are very urban areas of Sydney who were neither a long way from a trauma centre nor was there any suggestion they were trapped. Prior to the RLTC the Ambulance dispatch policy for medical teams was specifically circumstances where it would take the patient more than 30 mins to reach a trauma centre due to geography or entrapment. Crossover cases obviously didn’t explain the whole of our frustrating experience of recruitment, but it was one extra hurdle that finally led us to wrap recruitment up.

You can’t bite it all off at once

In a study where you collect lots of data, there’s no publication that will let you cram it all into a single paper. So there are definitely more issues to cover from the data we have. This includes other aspects of patient treatment. So I will be working with the other authors to get it out there. It might just require a little bit of time while we get more bits ready to contribute to the whole picture.

Of course, if you made it to the end of this post, I’m hoping you might just have the patience for that.

Here’s those reference links again: 

That Swiss paper (best appreciated with a German speaker). 

The Baxt and Moody paper.

CIRC.

The earlier London HEMS tasking paper.

The latter London HEMS tasking paper. 

Prehospital Trauma, Research, Uncategorized

Same, same? Actually different

5 Comments

More of the operational data from the Head Injury Retrieval Trial has just been published. By luck more than anything else this has occurred within 24 hours of the publication of the main trial results which you can find here.

Some operational data about systems used in the trial has already been published. A key part of HIRT was a dispatch system where the operational crew were able to view screens with case information as they were logged to spot patients who may have severe enough injuries to warrant advanced care. They could then use the available information or call the initiating number for further details. If the available information matched the criteria for consideration of an advanced care team, the randomisation process then swung into action. The whole idea was to streamline the process of activation of an advanced care team to severely injured patients.

A study looking at this dispatch system in the context of identifying severely injured children has already been published here. This study compared the trial case identification system with the Rapid Launch Trauma Coordinator (RLTC) system in NSW. When the trial dispatch system was operating the paediatric trauma system in Sydney performed significantly better than when the trial system was not available. This was a combination of the dispatch system and the rapid response capability of the trial HEMS. The speed and accuracy of dispatch was a key component however.

So what’s this new paper about?

In this new paper we had the opportunity to explore the HIRT data set to look at the times it took various team models to treat patients and get them to the hospital, and then through the ED to CT. The data is unique as far as I know as we had the unusual situation of two physician staffed services operating in parallel sometimes being dispatched to the same patients.

You can find the paper here.

Getting to a CT scanner in a more timely fashion than this was a way of tracking patient progress through their care. [via telegraph.co.uk]
Getting to a CT scanner in a more timely fashion than this was a way of tracking patient progress through their care. [via telegraph.co.uk]
First comment is that this appears to confirm some European data that physician teams do not significantly affect prehospital times when compared with paramedics although the intubation rate is much greater. Papers such as that by Franschman from the Netherlands make interesting comparisons with this paper. The Dutch Physician staffed HEMS system closely mirrors the HIRT rapid response system in time intervals (and many other factors too). The fact that we have such similar results half a world apart suggests some generalisability of the data.

So are there some differences?

This study did show some differences between the physician teams in those time markers through the patient pathway. It’s worth making a couple of comments that might help to interpret that data.

This is not about individual performance but about systems. There were doctors and paramedics who worked across both systems. Their times followed the pattern of the system they were operating in on any given day.

If you look in the study discussion, the two physician HEMS systems are quite different. The Greater Sydney Area (GSA) HEMS forms part of the State ambulance helicopter system. It has to be all things to all people all the time. They have a wide range of tasks including interfacility transports, hoisting operations, ECMO and IABP transfers etc and they may potentially be tasked anywhere in NSW and perhaps up to 100nm off the coast. By necessity they are multirole and they have to be able to respond to any of these mission types when the phone rings without any notice.

The rapid response HEMS system that was set up for the trial is not constrained in the same way. It is a specialist service where every mission follows the same basic pattern. This data indicates that it is very, very good at doing one thing. Indeed as far as I am aware the scene times for intubated patients are the fastest achieved for a physician staffed HEMS anywhere in the world, even slightly faster than the published data from the Netherlands. The price of specialisation however is that this service cannot perform the range of tasks that the multirole GSA HEMS undertake.

Put simply the services are not interchangeable. The data indicates that the specialist rapid response model will arrive at patients first compared with the multirole GSA HEMS model anywhere in the greater Sydney area, except at the extreme edges of their operating range where rural bases may be faster, or within a couple of km of the GSA HEMS Sydney base.

The differences also apply to scene times where the HIRT rapid response system had scene times of half that or less observed in the GSA HEMS teams, even when confounders such as entrapment and requirement for intubation were considered. We speculate on some reasons for this such as the relative team sizes for the two operations. There may well be advantages in highly familiar teams. There is certainly some evidence for this in other areas of medicine.

What do we make of this?

Overall however I think specialisation is the key. If we again compare the HIRT rapid response model to the Dutch physician staffed HEMS system the similarities are striking. Like the HIRT system, the Dutch only perform prehospital cases, they only operate within a limited radius of their operating base (including urban areas) and they do not have hoists. Like most European HEMS they have small team sizes. And their times are remarkably similar to that achieved by the HIRT HEMS system in our study. It is all about how the services are structured and their role definition which makes them good at what they do.

There are clear implications for the task allocation system in Sydney from this data.

The current pattern of tasking appears to allocate physician teams primarily on who is closest. This allocation only makes sense if the two teams are interchangeable in capability. This is very clearly not the case. The two systems are quite different. The relative strengths of each service should be taken into account in the dispatch policy so that patients will get the most rapid and most appropriate response possible given their location and clinical condition.

The patient doesn’t care who started out closer. They want the service they need for their situation. The different strengths of the two services should form a complimentary system that ensures the fastest and highest quality care to patients, whether they are on the roadside, already in a smaller hospital, at the base of a cliff or on a ship off the coast.

What about dispatch?

The evidence from this study combined with the previous study on the Sydney paediatric trauma system also indicates that the HIRT case identification system significantly outperformed the RLTC in both speed and accuracy.

The trial case identification system operated for nearly 6 years without a single report of any type of safety incident, even of a minor nature. Once the RLTC came into being in 2007 the RLTC and HIRT systems operated collaboratively to identify severely injured children and ensure a speedy response. When HIRT identified a paediatric case, they checked with RLTC who retained tasking control to ensure that there was no additional information or competing tasks that might affect the dispatch decision. In this way Ambulance retained central control and oversight of the system and a double up of tasking to paediatric patients was averted. This would seem to be the ideal system with patients benefiting from the increased speed and accuracy of the parallel case identification process when the HIRT and RLTC systems were operating together, but Ambulance retaining central control so that competing tasks could be balanced. The HIRT dispatch system was however discontinued in 2011 when the last patient was recruited into the trial.

The practical difficulties of applying this level of sophistication to resource allocation, given the sheer volume and variety of demands on the centralised despatch system, need to be acknowledged. Nevertheless it might be time for a rethink.

Here’s those references again:

HIRT.

The comparison of dispatch systems in paeds patients.

The times paper.

The Dutch study.