The Deal with Seals

Greg Brown returns to look at an important thing relevant to first responders (and lots of other people really) – the sucking chest wound. 

We’ve all been there – sitting through some kind of “first aid” training and having some kind of “first aid trainer” speaking authoritatively on some kind of “first aid style” topic. If you are like me you’ve used your time productively over the years and perfected what my wife refers to as “screen-saver mode” – it’s that look on your face that tells the instructor that you are listening intently, often supplemented by the insertion of “knowing nods” or head-tilts, but in actual fact you are asking yourself “if I was able to collect all of my belly button lint over a 12 month period and spin it into yarn, I wonder if I could make enough to abseil off London Bridge?”

Don’t get me wrong – I reckon effective and accurate first aid training should be a mandatory part of having a car / bike / truck / bus licence. More appropriately trained people should mean faster recovery rates for most injured people (and less work for overstretched first responders).

It’s just that sometimes first aid trainers teach stuff based on ‘we reckon’ or ‘that’s how we’ve always done it’ rather than evidence or knowing it works in the real world. This post is about one of those things.

“What is a sucking chest wound?”

In the Army questions come in a few different shapes and sizes. A popular one is “there is only one obscure answer you should have guessed I wanted”. Trust me, the muzzle velocity of your primary weapon is 970 metres per second.

Another popular one is “the question that should be about one thing, but is actually to demonstrate a quite tangential point”.  Like,

“What is a sucking chest wound?”

For an army instructor the answer is not what you are thinking right now. It is “Nature’s way of telling you that your field craft sucks and everyone can see you and now you got shot”.

Let’s Go With the Medical One

We’re going to go with the alternative, more medical one. A sucking chest wound is defined as air entering the thorax via a communicating wound that entrains air into the space between the lungs and ribs more readily than the lungs can expand via inspiration through the trachea.

This is about pressure differentials – in order to inhale, the lungs must generate a relative negative pressure such that air can be sucked into them via the trachea. But if you make a big communicating hole in the trachea, that might become a pretty big highway for air to enter the space with the negative pressure.

The communicating hole does need to be pretty big. Depending upon which textbook you read, this hole needs to be a minimum of a half to three quarters the diameter of the trachea. Also, the patient needs to be undergoing relative negative pressure ventilation (or, in simple terms, breathing spontaneously). If they are being artificially ventilated (which requires positive pressure) then the pressure inside the lungs will be higher than the pressure on the outside of the body; the result is that air will be forced out of the intra-pleural space (or thorax) by the expanding lung (as opposed to being entrained into the thorax via the hole in the chest).

Are sucking chest wounds really that bad?

Well, yes. They suck in fact.

A sucking chest wound creates what is known as an open pneumothorax. Let’s consider the option where that hole does not seal on expiration. We’ll get onto the also very annoying sealing with a flap version in a bit.

In this slightly not so annoying case, the patient will have a ‘tidalling’ of air in and out of this communicating hole. The effect? Respiratory compromise, increased cardiovascular effort and reduced oxygen saturations. Patient satisfaction? No, not really. Death? Maybe – depends on what other injuries exist and the ability of the individual to compensate. See Arnaud et al (2016) for more details.

But if this communicating hole were to seal itself on expiration then you now have an open tension pneumothorax. Sounds bad; IS bad.

In such a case, each time the patient breathes in they will entrain air through the communicating hole in the chest wall (that whole “negative pressure” thing in action). But when they breathe out, instead of having that additional intra-pleural air tidal outwards, the flap will seal it in place; each time they breathe in, the volume of trapped air will increase and you’ll end up with the tension bit.

How much air is required? Well a randomised, prospective, unblinded laboratory animal (porcine) trial conducted by Kotora et al (2013) found that as little as 17.5mL/kg of air injected into the intra pleural space resulted in a life-threatening tension effect.

Actually, that’s a fair bit of air…for those of you who are lazy and don’t want to do the math, that’s 1400mL for an 80kg person. But remember, any tension pneumothorax (open or closed) is progressive – each time you breathe, more air is trapped; therefore, it doesn’t take long to reach crisis levels.

“But are they common enough for us to be worried about?”, I hear you asking. The short answer is yes – in fact, the long answer is also yes.

Kotora et al (2013) reviewed the statistics from the Joint Theater Trauma Registry regarding contemporary combat casualties with tension pneumothorax and found that they accounted for 3 – 4% of all casualties, but 5 – 7% as the cause of lethal injury.

“Yes, but I don’t live in a combat zone…”, I hear you say. I have two responses:

  1. Good for you; but also,
  2. According to Littlejohn (2017), thoracic injury accounts for 25% of all trauma mortality. And sure that stat is for all forms of thoracic injury and a sucking chest wound is but one of those but there’s a neat article by Shahani which sums up the incidence nicely and it turns out you should give this some thought.
The Table
We even saved you some time by grabbing the relevant image.

So, your field craft sucks – now what?

Now that we know that sucking chest wounds are both possible and bad, we should probably discuss treatment.

Some History

Back in the mid 1990’s, Army instructors were very big on rigging up a three-sided dressing. Unwrap a shell dressing, turn the rubbery-plastic wrapper into a sheet and tape three sides down with the open bit facing the feet to allow blood drainage.

And, in an astonishing turn of events, everyone I’ve met who tried this confirmed it didn’t really work that well.

In that Littlejohn paper they make reference to the fact that by the 2004 ATLS guidelines (which are not usually that quick moving), it was being written unblock and white that there was no evidence for or against the three-sided dressing option. It was done because it sounded good in theory, but the evidence wasn’t there.

Now to the New

Actually, not that new. Chest seals already existed.

These chest seals (at that time the Bolin produced by H & H Medical, and the Asherman produced by Teleflex medical) included one-way valves to allow for the forced escape of trapped intrathoracic air and blood. basically they took the impromptu three-sided dressing and made it a ready-made device in the form of an occlusive dressing with an integral vent.

But did they work?

Yes and no.

On a perfectly healthy (albeit with a surgically created open pneumothorax) porcine model with cleaned, shaved, dry skin they sealed well and vented air adequately.

However, once the skin was contaminated (dry blood, dirt, hair etc) the Bolin sealed much better than the Asherman. And if there was active blood drainage too (such as in an open haemo-pneumothorax) then all bets were off. Both vents clogged with blood and ceased to work. Sure, you could manually peel the seal back and physically burp the chest but if you did so the Bolin became an un-vented seal and the Asherman was as good as finished (i.e. it wouldn’t reseal). But hey, at least you had sealed the communicating hole and in doing so stopped entraining air.

“Is this the best you can do?” you may be asking. Well to be honest, since the vents didn’t work for more than a breath or two most people decided that the vents were pointless. The outcome was that we all decided to forget about the vents and just seal the wound. That way, assuming that there was no perforation to the lung, this open tension pneumothorax (aka sucking chest wound) became a routine, run of the mill, plain old pneumothorax. And if there were signs of tensioning (e.g. increasing respiratory distress, hypotension, tachycardia….) one just needed to peel back the seal and manually burp the communicating hole thus relieving the pressure. Use a defib pad – those bad boys stick to anything! Problem solved….

Or how about a newer idea + research?

In 2012 the Committee on Tactical Combat Casualty Care (CoTCCC) started questioning the efficacy of contemporary practices regarding the placement of chest seals on sucking chest wounds. It had already been accepted that the current vented chest seals had ineffective vents, so practice had changed from using a chest seal with an ineffective vent to simple, “soldier proof” unvented seals and burping them as required. Surely there had to be a better way…?

Kotora et al (2013) decided to test three of the most readily available vented chest seals in their aforementioned randomised, prospective, un-blinded laboratory animal (porcine) trial: enter the Hyfin, Sentinal and SAM vented chest seals.

What they found was that all three were effective in sealing around the surgically inflicted wounds and in evacuating both air and blood. Thus, in 2013, CoTCCC changed their recommendations back to the use of vented chest seals.

But there were still some questions:

  1. Once life gets in its messy way, do they seal (or at least stick to skin)?
  2. Are all vent designs equal?

To answer question 1, Arnaud et al (2016) decided to evaluate the adhesiveness of the 5 most common chest seals used in the US military using porcine models. What they found was that the Russell, Fast Breathe, Hyfin and SAM all had similar adherence scores for peeling (> 90%) and detachment (< 25%) when tested at ambient temperatures and after storage in high temperature areas when compared to the Bolin. The researchers admitted, though, that further testing was required to assess the efficiency of the seals in the presence of an open tension haemo-pneumothorax.

In response to question 2, Kheirabadi et al (2017) tested the effectiveness of 5 common chest seals in the presence of an open tension haemo-pneumothorax (again, on porcine models). Essentially, there are two types of vent: (i) ones with one-way valves (like in the Bolin and Sam Chest Seals), and (ii) ones with laminar valves (like in the Russell and Hyfin Chest Seals). Their question was: do they both work the same?

What they found was that when the wound is oozing blood and air then seal design mattered. They found that the seals with one-way valves (specifically the SAM and Bolin) had unacceptably low success rates (25% and 0% respectively) because the build-up of blood either clogged the valve or detached the seal. By contrast, seals with laminar venting channels had much higher success rates – 100% for the Sentinel and Russell, and 67% for the Hyfin.

The Summary


  1. Sucking chest wounds are bad for your health.
  2. Sealing the wound is good.
  3. If the seal consistently allows for the outflow of accumulated air and blood, then that’s even better.

Therefore, now that we know all of this, one’s choice of chest seal is important. At CareFlight we use the Russell Chest Seal by Prometheus Medical (and no, we’re not paid to mention them we’re just sharing what we do). Why? Because it works – consistently. Both for us and in all the aforementioned trials.


The premise of this addition to the Collective is that you’re a first responder. That being the case, use an appropriate vented chest seal on a sucking chest wound.

However, you still need to recognise that the placement of the seal does not automatically qualify you for flowers and chocolates at each anniversary of the patient’s survival – you still need to monitor for and treat deterioration. Such deterioration is likely to include a tension pneumothorax for which the treatment is outside of the scope of most first responders (other than burping the wound).

If you are a more advanced provider then your treatments might include the performance of a needle thoracocentesis, or perhaps intubation with positive pressure ventilation and a thoracostomy (finger or tube).

In essence, know the signs and symptoms then master the treatments that are inside your scope of practice. (Or you could enrol in a course…such as CareFlight’s Pre-Hospital Trauma Course or even THREAT… OK that was pretty shameless.)

Meanwhile we’d love to hear:

  1. What chest seal do you use?
  2. Why?
  3. How does it go?

Or you could just tell us what other things you think suck.

Could be the leafy green thing. Could be a person maybe.


We’re not kidding about hearing back from you. Chip in. It only helps to hear other takes.

You could also consider sharing this around. Or even following along. The signup email thing is around here somewhere.

That image disparaging all things Kale (or kale) is off the Creative Commons-type site and comes via Charles Deluvio without any alterations.

Now, here are the articles for your own leisurely interrogation.

If you’re time poor and will only read one, make it this one by Littlejohn, L (2017). It’s “Treatment of Thoracic Trauma: Lessons from the Battlefield Adapted to all Austere Environments”. 

Another great one (albeit somewhat longer) is by Kheirabadi, B; Terrazas, I; Miranda, N; Voelker, A; Arnaud, F; Klemcke, H; Butler, F; and Dubick, A (2017). It’s “Do vented chest seals differ in efficacy? An experimental evaluation using a swine hemopneumothorax model”.

An oldie but a goodie is this one by Kotora, J; Henao, J; Littlejohn, L; and Kircher, S (2013). It’s “Vented chest seals for prevention of tension pneumothorax in a communicating pneumothorax”.

To round it out, take a squiz at Arnaud, F; Maudlin-Jeronimo, E; Higgins, A; Kheirabadi, B; McCarron, R; Kennedy, D; and Housler, G (2016) titled “Adherence evaluation of vented chest seals in a swine skin model”.

Cobras and the First Look

Dr Alan Garner has been here before, asking whether we’re asking the wrong questions when we try to measure quality advanced airway care. Here’s a fresh bit of research that adds to the discussion.

Unintended consequences would hardly be a new thing in medicine or in any other endeavour.  Here is one of my favourite examples taken from Wikipedia (look we all go there from time to time):

“The British government, concerned about the number of venomous cobra snakes in Delhi, offered a bounty for every dead cobra. This was a successful strategy as large numbers of snakes were killed for the reward, but eventually enterprising people began to breed cobras for the income. When the government became aware of this, they scrapped the reward program, causing the cobra breeders to set the now-worthless snakes free. As a result, the wild cobra population further increased. The apparent solution for the problem made the situation even worse, becoming known as the Cobra effect.”

Check this link for some more cracking examples.

Avid or maybe even occasional readers who chanced to come back at exactly the right moment might recognise that I have previously expressed my doubts about reporting the first look intubation rate as a quality measure for intubation.  Have a look here for the previous post.

Now where might you go to find a basket of cobras these days? Well I have just spotted a new paper published in Prehospital Emergency Care which fits the bill.  You can find the full text here. I guess we’d better start picking up the snakes.

It’s probably a friendly one, right?

Let’s Start with the Headlines

This paper is a look at a ground paramedic system in a small US city (Spokane in Washington State) where the paramedics have used muscle relaxants for more than 20 years i.e. you would have to consider this a mature system.  It appears to be a well supervised system and paramedics have a minimum number of intubations they must successfully perform each three-year certification cycle in addition to a well-structured training regime.

Superficially the system appears to be working well.  They had a 95% success rate and 82% first look success.  Although 95% overall success rate is below par compared with other systems world-wide, all patients not successfully intubated were successfully managed with a supra-glottic device.  That should be OK, right? That probably means the primary focus is on managing the airway to achieve the goal that really counts – oxygenation. And that first look rate of 82% seems quite respectable compared with reports from other systems.  So not a star system but safe enough if these were the only quality measures you were looking at.

Let’s Get Our Hands Right Amongst the Snakes

The thing is the paper also reports physiological data captured by the patient monitor during the peri-intubation period and this tells a very different story.  Much of the data is not that surprising.  Desaturations were more common when patients were being intubated for respiratory pathology and were also related to the highest SpO2 achieved at the end of pre-oxygenation.

How about we look at some oximetry data highlights?

  • Oximetry data was available in 110 cases. Peri-intubation desaturation occurred in 47 cases (43%) and in 32 (68% of the desaturations) it was severe (<80%).
  • The median nadir was 71% and median duration was 2 minutes. Among cases with any desaturation, the time in the unhappy valley was at least 2 minutes in 46% of cases with first-attempt success and in 100% of cases requiring multiple attempts.
  • Although the frequency of desaturation was significantly higher in cases requiring multiple laryngoscopic attempts versus a single attempt (70% vs. 37%; p = 0.01), 70% of all desaturations occurred on first attempt intubation success. Only 11% of desaturations were reflected in the EMS patient care report.

Heart rate changes

  • 13% became bradycardic, 7% profoundly. The median SpO2 nadir during bradycardic episodes was 30% with median duration of nearly 5.5 mins.
  • Sixty percent of bradycardia events occurred on first-attempt intubation success.

Yes in the multiple attempt cases the desaturations were worse than cases requiring a single attempt.  But given the very high rate of desaturation events in this study is reporting the first pass success rate providing any meaningful quality data?  Is there subtle pressure placed on the paramedics in this system to achieve first pass intubation at the potential expense of desaturation events, by the very fact that first pass rate is being reported?

We can’t be sure and I’ll put my hand up and say “yes, I’m inferring a little bit from what we can see in the paper”.  But clearly the overall success and first pass success rates provide no real indication of process safety in this particular EMS system.  It is only in reporting of clinically meaningful quality data like desaturation that we see the real safety performance.

Who Else Thinks This?

To quote the paper itself “What may be obscured by this focus on the risks associated with multiple intubation attempts is the large absolute number of physiologic derangements occurring on first-attempt success. In our study, 70% of all desaturations, 60% of bradycardia episodes, 63% of hypotension episodes, and one of the two cardiac arrests occurred on first-attempt success.”  That’s really the nub of it and it’s excellent work by the authors to make sure that’s right up there in the discussion.

The authors conclude that first attempt success “is not a reliable indicator of patient safety.”  The authors specifically note that prolonged duration of first pass attempts is a contributor to the desaturation rate and that prolonged attempts might be “a consequence of lack of awareness of the passage of time during an intubation attempt, or lack of awareness of the occurrence of desaturation”.

But is the very fact of reporting first pass success rate a subtle psychological contributor too?  The authors clearly agree with me here when they comment “prolonged desaturations on first attempt success could be an unintended consequence of the focus on first-attempt success itself and the common use of first-attempt success as a primary measure of intubation quality.”

Maybe it’s an example of the Cobra effect.

The Take Home Bit

Prospectively it is right to set yourself up to get the ETT in the right place on the first attempt and with minimal complications.  However once the intubation attempt commences the emphasis needs to shift to prevention of complications by reacting to physiological changes as they occur.

We want to encourage this.  I want my teams obsessed with preventing complications, not first pass success.  Why are we reporting a process measure as a quality indicator when it might well be having the perverse effect of encouraging those very complications we were trying to remove?  The system I work in here in NSW requires us to report first pass success.  I remain hesitant to do this as I don’t want to signal to my teams that this is actually something that matters.  I would much rather them be proud of the 0% desaturation rate that we have for intubation over the last 9 months – that is really impressive.



That paper is this one:

Walker RG, White LJ, Whitmore GN, et al. Evaluation of Physiologic Alterations during Prehospital Paramedic-Performed Rapid Sequence Intubation. Prehosp Emerg Care. 2018;

And the link to that first post covering similar ground is right about here.

The image of the cobra came via Creative Commons off flickr and is unchanged from the post by Luca Boldrini.





The Social Resuscitation

There are parts of the resuscitation with no algorithm. No protocol. How do we improve that part? What are the social resuscitation skills we need to work on? We’re very pleased to have Dr Ruth Parsell chip in with some thoughts. Ruth is a current ACEM Registrar working on the CareFlight Rapid Response Helicopter in Sydney. She joined the NSW Ambulance Service in 1998 and has worked in prehospital and hospital settings in varying roles since that time. 

The “social” resuscitation is a term I’ve been using for quite some time now. I apply it in dire situations. In both adults and children. But this is about the paediatric resuscitation and, specifically, cases where the prognosis is highly likely to be tragic. It is in these cases that I utilize this term because we are clearly treating more than just the patient when we resuscitate. I use the term because when I treat the child I am treating their family and all of the social connections that are linked to such a brief, precious life.

Experience We Don’t Always Want to Gain

The sad reality is that every paediatric resuscitation we do offers an opportunity to improve more than just our clinical skills. We all wish we didn’t see these cases but if they continue to occur then we will continue to do our best to serve the needs of both the patients and their families. What if we were able to improve the way we serve them? Which part of the resuscitation we call “futile” is the opposite of futile?

The best way to do both would be to have the “miracle” recovery. The “against all odds”, the “everything was against them”… the full recovery of a child who has had a terrible insult. The drowning, the fall, the pedestrian, the horse riding accident… all the terrible insults we see and all those mechanisms of injury that can potentially cause an early cardiac arrest or a moribund child.

Instantly we think of our algorithms, our protocols, our list of reversible causes and the sequence of steps we might take when we arrive at the scene. We hear the age, we think about weights, sizes, drug calculations. None of this should ever change and I’m not suggesting it should.

But what about when we hit that turning point?

It may have been an inkling early on. The thought that the mechanism is just too great, the injury just too severe, a poor response to even the most efficiently and expertly performed algorithm. It’s a moment where, sometimes even without verbalizing, the whole team is aware of the magnitude of the odds against this little one.

The Pause

What if in these cases we took a moment? Just a brief moment. When it comes to adult resuscitations I find we seem to automatically provide explanations to the family even while we are working. To explain that his heart is not beating and that we are working very hard to restart it; with a breathing tube, trying to stop the bleeding and with powerful medicines.

Perhaps it feels automatic because we just see more of those cases. We get to drill those algorithms more so there is a window that gives us space to look around.

So how do we provide this window in those paediatric prehospital jobs?

What if it was just a kiss before the transport? What if the family could have a little more from us? What if we suggested getting their daughter’s favourite teddy or blanket from the house? Just to fill their arms for the trip to hospital, to stop Mum’s hands from relentlessly wringing or something to give her tears a soft landing when they fall.

What do the books say?

The evidence for family presence during resuscitation has evolved over many years. Factors examined include the resuscitation team performance, stress levels amongst staff, clinical outcomes and psychological outcomes for family members. The evidence in paediatrics, including in some randomized control trials, demonstrates that there are improved measures of coping and positive emotional outcomes among families (1). These outcomes are achieved without impeding team performance.

There are many barriers to family presence in the pre-hospital arena. These scenes can be highly distressing, emotions are raw and the procedures required are time critical. Transport logistics can be a huge barrier too. It is rarely practical for a family member to travel with a child to hospital when they are critically unwell or in cardiac arrest. The confined environment of the back of an ambulance is usually congested and the potential unpredictability of a relative may compromise staff safety. The evidence regarding family presence is also more difficult to obtain.

However, there is some evidence regarding family presence during pre-hospital CPR in the adult literature and this also confirms positive results on psychological variables in family members without interfering with medical efforts, either clinically or with regards to health carer stress.(2)

When I have used the term “social” resuscitation in the past, I used it primarily in the dire situations I mentioned previously. Traumatic cardiac arrest in children fits this description, with a less than 5% neurologically intact survival rate (3).

I use this term in cases where I feel the resuscitation efforts are more a resuscitation for a family than the  patient. I use it in the context of transporting to an appropriate place, where I feel that the optimal ongoing social supports for family members can be best met. Somewhere where others can assist with tissues, quiet rooms and hushed explanations. Somewhere where others can understand the welled up look that we give them when we enter the bay.

Now I think that the social resuscitation needs to start earlier. A more conscious and deliberate effort. Maybe not every time. Not when you can feel yourself buckling under the cognitive load. Not when your emotions are so close to the surface you can’t get the words out. Not when the scene is like a powder keg and you might just be putting people at risk.


But in those paediatrics cases we need to make a conscious effort to find a window, even where the algorithm is crowding us a little more. That might be the part of the resuscitation that isn’t futile for those left behind.

Try the explanation. Try the kiss. Wait for that teddy. Just try it and let’s see if it improves our social resuscitations. It might even just improve things for all of us.



Notes and References:

  1. ANZCOR Guideline 10.6 Family Presence During Resuscitation, August 2016. 
  2. Jabre et al. Family Presence During Cardiopulmonary Resuscitation. NEJM. 2013;368:1008-18.
  3. Fallat et al. American Academy of Pediatrics. Policy Statement: Withholding or Termination of Resuscitation in Pediatric Out-of-Hospital Traumatic Cardiopulmonary Arrest. Pediatrics. 2014;133.  

That image is shared unchanged from the post by Gabrielle Diwald at under Creative Commons.


A Quick Look Back at 2017

Well everyone else is doing the “look back, look forward” thing, so why not us as well?

It’s that time of year. You know, the one where we just want a few more days to kick back and relax or enjoy a southern hemisphere summer. What better way to look busy than a review of the posts that got the hits in 2017? Ssshhh. There may well be better ways but this is what we’re going with.

First up, music for the ears

Podcasts. People do them and people listen to them. Clever people do them regularly. We are not that clever it seems. We did finally get around to putting up a couple this year though and the most recent one was very comfortably the most popular podcast we’ve done. OK, it’s a field of four but it’s not nothing.

The podcast features Dr Blair Munford. Blair has been in the retrieval and prehospital field since the mid ’80s. He has stories. Lots of stories. This story is his though and in it you get to hear a little about what it’s like on the day you’re getting picked up by the helicopter. So maybe have a listen. Lots of people obviously thought it was worth it.

The Not Very Final Countdown

We’re not packing up or anything so it’s nothing like a final countdown, but is there a theme amongst the posts that people seem to click on the most? Well let’s see. Here are the 10 top written posts through 2017:

10. This is how he does it

Coming in at number 10 is a post from a new contributor, Dr Shane Trevithick. This one is a great example of someone describing where experience has led them when they’re looking after a patient for retrieval.

9. Tactics for hostile places – Tactical Medicine still going strong

The series on tactical medicine dates from 2016 but still gets plenty of interest. The third instalment just keeps clocking up the hits (and provides an easy link to chapters 1 and 2). People just want to know about phases of care I guess. If you like that you might also find this conference update worth your time too.

8. An old classic – little kid RSI

A couple in the year’s top 10 were all about kids which is a pretty pleasing thing. The care of kids isn’t just about shrinking stuff from adults and there’s plenty to gain from being kid friendly. This post went over the reasons that the approach to RSI in kids has changed and what we should be trying to focus on.


7. Necessity and the mother of invention

As much as we like kits sometimes you have to be flexible. This post on how to use what you have when you just have no choice is designed for when you’re stuck in one of those moments that will make you thank your gods for your real equipment when you’re back on a real job. Tourniquets? Check. Pelvic binding? Check.

6. Holding the line

Could there be a practical theme emerging here? This post covers a simple thing that you can really use – a way to keep that IV line in no matter what the world tries to pull it out.

5. Sucking and blowing and the pleural space

Did you feel like this list didn’t have enough physiology in it? Alan Garner’s post covering pressures and the pleural space is a really interesting revisit of something we all ‘know’ from way back when.

4. Kids and drips

This practical post on putting cannulas in little people certainly grabbed some interest. Maybe it will help out next time you’re facing a procedure that can cause pain at both ends of the needle.

3. More physiology when you pick a person up

This post comes from 2016 as well but it just keeps people coming up. A topic not covered that much elsewhere, but the physiology of a patient being winched is certainly relevant to lots of people in the  rescue space.

We’ll level with you the rescuee here is apparently a mannequin so the physiology would be pretty forgiving but you get the idea.

2. In a bind

What is it about pelvic binders that gets people coming back for more. Our long running series on pelvic binders got a boost with number 5 which covered a case where the binder really probably didn’t help. You could drop by and end up down the rabbit hole of the other 4 posts with those links at the start of it.

1. Back to basics

And the top spot for 2017 goes to one of those great posts that covers things we often think of as basic but which might just make the biggest difference to patients – “basic” airways and adjuncts. Maybe you’d like to drop by this edition of those things we wish we’d known way back when we started.


So that’s the list. And the theme is pretty clear. People like practical things. And physiology. And things about kids. And things that touch on the literature. And … actually people probably just like all things prehospital and retrieval. Better get back to it.



The image from was posted just like this by Neil Thomas.

Maths and Choppers from Norway to New South Wales

There are a bunch of ways to figure out where to put your resources. Dr Alan Garner found a guy who can crunch the big numbers to look at it a little differently. 

What’s the answer for optimal locations? First ask what is the question.

We have just had a new study published in BMC Emergency Medicine on modelling techniques to determine optimal base locations for helicopter emergency medical services (HEMS).  There is always more to say than can be covered in a publication so I thought I might have a look at some of those issues here.

First up is a big thank you to my co-author Pieter van den Berg from the Rotterdam School of Management in the Netherlands.  Pieter is the real brain behind the study and the mathematician behind the advanced modelling techniques we utilised.  Pieter has looked at HEMS base location optimisation previously in Norway and has done some modelling for Russel McDonald’s service Ornge in Ontario, Canada as well.  Without him the study would not have been possible.

So what did we do and why?

As already noted Pieter had recently done a similar exercise in Norway where the government has a requirement that 90% of the population should be accessible by physician staffed ambulances within 45mins.  Pieter and his co-authors were able to demonstrate that the network of 12 HEMS bases easily accomplishes this – indeed it could be done with just four optimally positioned bases.  They also modelled adding and moving bases to determine if the coverage percentage could be optimised with some small adjustments.

As it happens New South Wales (NSW) and Norway have very similar population densities and both are developed, first world jurisdictions.  Hence this previous study seemed a good place to start for a similar exercise in NSW.  Both jurisdictions also have geographical challenges; Norway is long and thin with population concentrated at the southern end whereas NSW has almost all the population of the state along the eastern coastal fringe with high concentration along the Newcastle – Sydney – Wollongong axis.

We were interested in population coverage but we also wanted to look at response times as this also is a key performance indicator for EMS systems.  It is certainly reported as a key indicator by NSW Ambulance.  Response times were not modelled in the Norwegian system so we were interested in seeing how the optimum base locations varied depending on the question that was asked, particularly in a jurisdiction such as NSW where the population is so concentrated to a non-central part of the state.

If you look at the study you will note from Figure 1 the existing arrangements in NSW. You’ll be shocked to know these arrangements weren’t planned in advance with the aid of a Dutch maths guru. These things happen organically. Nevertheless it provides a reasonable balance of response times and coverage although the gap on the north coast is immediately evident.

Figure 1If you start with a clean slate and optimally position bases for either population coverage or average response time, both models place bases to cover that part of the coast (see Figure 2).  Hardly surprising.  When we modelled to optimise the existing base structure by adding or moving one or two bases, the mid north coast was either first or second location chosen by either model too.

Figure 2

This seems an obvious outcome from even a glance at the population distribution and current coverage in Figure 1.  What is surprising is that the 2012 review of the HEMS system in NSW (not publically released) which utilised the same census data in demand modelling did not come to the same conclusion when two previous reviews in the 1990s and 2000s had recommended just such a change.  Certainly the Reform plan for helicopter services which was released the following year did not make any changes or additions to base locations leaving this significant gap still uncovered.

Wagga Wagga was the other location identified for a HEMS base in the 2004 review.  Interestingly it is favoured as the first relocated base when the existing structure is optimised for average response time by moving Canberra to this location.  But a Wagga Wagga base also was not mentioned in the reform plan.

What about the green fields?

When the green field modelling was done it is clear that the current NSW system mostly closely resembles the model optimised for average response time, rather than coverage.  The Wollongong base really justifies its location on this basis as it contributes to a better overall average response time.  Its population coverage falls entirely within the overlapping circles of the Sydney and Canberra bases so it makes no contribution here, at least if a 45min response time is used as the standard.

There was another aspect that interested us compared with Norway.  In Norway all aircraft have the same capability and this is also true for the recently tendered services in NSW.  The unusual feature in NSW though (unique to Australia although common in Europe in particular) is a dedicated urban prehospital service operating from a base near to the demographic centre of the largest population density – Sydney.  The performance characteristics of this service have been well described (by us, because I’m talking about the CareFlight service which I think does serve a useful function) previously and when it was operating with its own dispatch system was the fastest service of its kind in the world to our knowledge.

Like the Wollongong service it operates entirely within the population coverage circles of other bases, but it makes an enormous contribution to average response time.  When this rapid response urban service is added to the network of large multirole helicopters in NSW the average response time across the entire state falls by more than 3.5mins because that service is able to access more than 70% of the state population within its catchment zone, and significantly faster than the multirole machines.

This modelling only takes into account the response time benefit of the specialisation afforded by such as service.  We have previously been able to demonstrate that the service is also much faster in almost every other aspect of care delivering patients to the major trauma services in Sydney only a few minutes slower than the road paramedic system but with much higher rates of intervention and ultimately passage through the ED to CT scan faster than either the road paramedic or multirole retrieval systems in NSW.  At least this was the case when it had its own specialised dispatch system but that is a story we have discussed previously too.

There are recurrent themes here.  The Rapid Response Helicopter service adds significantly to the response capability in NSW whether you model it using advanced mathematical techniques or whether look at the actual response data compared with the alternative models of care.  Indeed the real data is much stronger than the modelling.  It seems that at least in large population centres in Australia there is a role for European style HEMS in parallel with the more traditional multirole Australian HEMS models that service the great distances of rural and remote Australia.  Different options can work alongside one another to strengthen the whole system and better deliver stuff that is good for patients – timely responses when they really need them. The capability differences however need to be reflected in dispatch systems that maximise the benefits which come with specialisation rather than a one size fits all tasking model that takes no account of those significant differences.

Every version of the numbers I look at tell the same story.


Notes and References:

While this post covers a few ways of looking at a tricky sort of problem, there are lots of clever people out there with insights into how these things work. If you have ideas or examples from your own area, drop into the comments and help people learn.

Now, the paper that’s just been published is this one:

Garner AA, van den Berg PL. Locating helicopter emergency medical service bases to optimise population coverage versus average response times. BMC Emerg Med. 2017;17:31. 

The paper on optimal base locations in Norway is this one:

Røislien J, van den Berg PL, Lindner T, et al. Exploring optimal air ambulance base locations in Norway using advanced mathematical modelling. Injury Prevention. 2017;23:10-15.

And if you like any of the posts on here, then maybe share them around. Or sign up for an update when new posts hit with the email sign on thing.


Tactical Update – A Report from TacT17

OK it’s a few weeks back, but here’s Greg Brown with the lowdown on a conference about tactical matters. 

Conferences: a formal meeting of people with a shared interest, typically one that takes place over several days; the means by which professionals from around the globe congregate with a view to learning from each other. Sometimes also referred to as junkets, jollies, paid holidays and tax write-offs.

But in all honesty, oftentimes the only way one can be afforded the chance to be surrounded by like-minded professionals with a view to learning from the experience of others, benchmarking your intellectual property against that of other organisations operating in the same “space” and refining your knowledge thanks to the latest in international research is to travel to the other side of the world and attend a conference. So, as one of the few non-government providers of tactical medicine training in Australia, that’s precisely what we did.

In mid-October 2017 two of CareFlight Education’s staff travelled to sunny (well, we assume there was sun above the pouring rain) Sundsvall, Sweden, to attend the inaugural Tactical Trauma conference.  If you are on Twitter, you can search for it using #TacT17. If you are not on Twitter, then join Twitter and search for it using #TacT17….

This post provides a summary of what we found, what we liked, what we didn’t like and some takeaway points.

The words are cool probably, but maybe put a shirt on when you hold Death back buddy.

The Peeps

This was truly an international event. Presenters came from across Europe (with a strong Scandinavian presence, as expected), North America, the Middle East and even Australia. Participants included both hospital and pre-hospital doctors, nurses, paramedics, police medics, retrieval (road and air) clinicians and military folk.

The Stuff to Chew On

As the name “Tactical Trauma” suggests, the conference was focussed on the medical management of trauma with a tactical twist. It should be noted that discussions regarding any tactical imperatives were limited by the realities of operational security. For obvious reasons, nobody wished to describe their unit’s tactics in great detail.  They were enough to paint the scene though.

Therefore, if you were looking to learn how to become the next big thing in SWAT team medicine then this conference probably wasn’t for you – and there certainly were no skill sessions on how to kick in doors, breach a terrorist stronghold or fast rope from a helicopter (although these might be popular sessions next time).

Rather, focus was placed on the provision of “good medicine in bad places”. There were sessions by military doctors discussing what worked (and what didn’t) on recent deployments (including topics such as blast injuries, penetrating chest injuries and rates of injuries in dynamic events), the usefulness (or otherwise) of helicopter emergency medical services in hostile mass casualty events, comparisons of contemporary haemostatic agents versus conventional bandages in wound packing, the perils of acute traumatic coagulopathy, discussions on vascular access options, and the progress over the years in the application of clinical management strategies. It is also worth noting that since this is in fact 2017 no medical conference would be complete without at least one presentation on POCUS (that’s Point Of Care UltraSound – and yes, it is very useful) and one on REBOA (or Resuscitative Endovascular Balloon Occlusion of the Aorta – and no, there is not enough evidence to definitively support it); these were dutifully attended to.

Case studies are always useful; in this instance we were treated to reviews by the Finnish and Norwegians of their tactical emergency medical support systems, the Israelis and their medical response to contemporary domestic contingencies and both the French and Swedish on their responses to recent mass casualty events. There were also a few “closed door” sessions for police medics regarding recent mass casualty events in the USA.

But finally, as most of us already appreciate, being outstanding at your trade is only part of the job; the ability to communicate effectively with your team members whilst managing your own stress levels are also vital in providing optimal patient care. As such, sessions on crew resource management skills, the cognitive revolution, tips for centring one’s self prior to and during a job, and how to get the rollout of good ideas actually rolling were welcome additions to the program.

Things We Liked

  • Firstly, whilst it is obvious that military experiences inform civilian practices, we appreciated the fact that this conference was focussed on civilian (not military) practice. Other conferences of the type claim to do this yet the majority of the auditorium is filled with uniforms of various militaries.
  • Secondly, sessions were kept at a length that were short enough to retain audience attention but long enough to cover the required level of detail for the given topic. If a topic was not floating your boat, a new topic would commence in 20 minutes.
  • Thirdly, at no point did we hear “you must do it this way – if not, you are wrong”. The overall feel of the conference was that no single entity had all the answers but that through collaboration we can all improve. Participants were encouraged to seek out presenters (who were all easy to find) and undertake collaboration.
  • Finally, the focus was on “good medicine in bad places” and not cool Velcro patches, the latest fashion in tactical gear (which would obviously only come in black and be stamped with a label consisting only of numbers) and the liberal application of mutual back-slapping.

Things That Were Not the Business For Us

  • Despite the fact that the conference was aimed at civilian practice, the majority of presenters referred to TCCC (Tactical Combat Casualty Care) and not TECC (Tactical Emergency Casualty Care). It is possible that the presenters were using the term TCCC out of habit, but when one considers that the latest review of TCCC by the Committee has lead to their terms coming closer into line with that of TECC (and not vice versa), it is time that the world started embracing the correct terminology.
  • Having a single track makes it hard to keep everybody interested, and at times we felt sorry for certain members in the room. These folks included frontline police officers who have a secondary role of medical response – whilst the clinicians were riveted by the maps of clotting cascades and stories of roadside REBOA, the Police Medics just wanted to know (a) how best to plug the hole, and (b) how fast to drive.

[Note: we got the impression that the conference convenors were victims of their own success – we are not sure they realised just how popular it might be when they originally floated the idea on social media. We are confident that this issue will be alleviated next time.]

The Takeaways

If you had to sum up the content of a jam-packed two-day conference in just a handful of points then these would be them [note: these are more paraphrases than quotes]:

  • “Learn from the experiences of others. Recognise that no single agency has all the answers, so work with and not against each other.” Matt Libby, flight paramedic with Boston Med Flight, USA
  • “In resuscitation, the most effective therapies are those that can be applied quickly. Time is blood.” Dr Richard Dutton, trauma anaesthetist, USA
  • “You can possess all the best haemorrhage control devices in the world, but if you are not using them properly then they are worthless. Training is key.” Dr Mark Forrest, medical director of ATACC, UK
  • “Battlefield medicine is like plumbing: if it’s blocked, clear it; if it’s leaking, plug it.” Gary Grossman, CSAR paramedic, Israel
  • “In a high risk or major incident, it makes sense to have all rescue agencies working together under a common SOP that has been tested prior.” Dr Stephen Sollid, medical director and retrievalist, Norway
  • “REBOA has a place in pre-hospital care; we are just not quite sure what that place is. Blood will still be lost from backflow.” Dr Tal Hörer, vascular surgeon, Sweden
  • “Medics in the hot zone should focus on not getting themselves killed and not endangering the mission. Cross training is vital.” Dr (LTCOL) Ishay Ostfeld, IDF and cardiothoracic surgeon, Israel
  • “In a critical patient, performance of life saving interventions should take precedence over applying rigid protocols around immobilisation.” Dr Thomas Dolven, intensivist and retrievalist, Norway
  • “People only improve if they actually want to. You cannot force improvement.” Michael Lauria, former USAF PJ and current medical student, USA
  • “When it comes to vascular access, there should not be different hospital standards and prehospital standards. There should just be standards.” Dr Knut Taxbro, anaesthetist and retrievalist, Sweden.

The Recommendation

So I guess the big question that remains for everyone is “was 50+ hours of travel from Australia to central Sweden for a 17 hour conference really worth it?” Given that we were able to assess the content of our training against that which other like-minded organisations from around the world provide in an open and non-threatening forum, tweak our content in line with the latest evidence, build contacts with groups and individuals that have the same struggles as we do in Australia, and provide some guidance to participants who were looking to develop their own tactical medicine training – the answer is obvious.

Look it’s hard to respect an animal mascot that doesn’t spend most of its time sleeping like a koala but good effort I guess.

Wait, I almost forgot the really vital lessons

These things:

  • The Swedish love speed cameras. I mean, seriously, they are everywhere!
  • Reindeer is actually quite tasty.
  • Moose is a bit, well, meh….
  • When it comes to rivalries, Norway is to Sweden what New Zealand is to Australia.
  • The Australian TV shows “Prisoner” and “Flying Doctors” are compulsory viewing for Swedes.
  • And 50+ hours of travel by air is in fact a very long way – but it beats driving.



Hey, are you interested in this stuff?

Well you could choose to read our previous posts about TECC here, here, or here. If you do you’ll find heaps of references and further reading on all things tactical.

CareFlight does have courses on that sort of stuff (it’s one of the bits you can find here) so you might find a bit of interest in that or, [looks shy, kicks dirt] y’know, do whatever. If you were interested (but no pressure) it runs pretty regularly (like in 2018 it’s happening on 12 February, 26 May, 20 August and 24 November).

Meanwhile if you like the stuff on the site you could always share it around. Or even sign up to get the emails whenever things hit.



Podcast #4 – Another Side

Straight back with another podcast and with the same guest, Dr Blair Munford. 

This time Blair has a very different type of story to share.

Please have a listen and consider sharing. Or if you like the site consider signing up to get emails when posts hit.

Anyway, here’s the various ways to get the podcast.

Right click and choose save as to download the podcast. (That’s control-click if you’re on a trusty Mac.)

Of course you could just find the podcast over at iTunes here.

Or the rss feed is here.


There’s a chance that something about Blair’s story might make you want to help someone, somehow. If that’s the case either drop a message in the comments or email at and we’ll follow up.

In this episode all the music is by Broke for Free and available via Creative Commons at the Free Music Archive.

The image is by Justin Luebke and was uncovered at


Podcast #3 – Introducing Blair

Finally, we decided to record someone. Dr Andrew Weatherall with a new contributor, Dr Blair Munford. 

So we always meant to include the occasional podcast. Finally it might happen. This episode features Dr Blair Munford, whose career in prehospital and retrieval medicine started back in the mid-80s when flight suits probably required shoulder pads and big hair. Blair should be dropping by pretty regularly but this is an introduction with a reflection on a bit of history and a few tales of a life in retrieval (all de-identified and with clearance previously provided).

Anyway, it’s a long history (if you want to get some sense of it if you drop by CareFlight’s publications page you can see him way back at the start, around the time he was kicking off with descriptions of the CareFlight stretcher bridge in 1990).

Les Chatfield
Actual line up of potential multi-patient retrieval transport vehicles when Blair started.

Anyway, here’s the various ways to get the podcast.

Right click and choose save as to download the podcast. (That’s control-click if you’re on a trusty Mac.)

Of course you could just find the podcast over at iTunes here.

Or the rss feed is here.


Intro and outro music is here under Creative Commons via the Free Music Archive. The intro is from ‘Only Instrumental’ by Broke for Free. The outro is ‘Lewd’ by Just Plain Ant.

The image was via flickr Creative Commons and posted by Les Chatfield (and is unaltered here).

Simple Systems for Getting Things Done in Retrieval

Well this time around we welcome a new contributor. Dr Shane Trevithick is a retrieval doctor with many years experience covering prehospital, interhospital and coordination work when he’s not being an emergency doctor. He’s got a bit on simple systematic approaches that get the job done. 

One of the exciting things that practicing medicine out of a helicopter does is make you a “Rock Star” of the medical world.  Your colleagues and the general public are amazed by your method of arrival on scene, the ensuing dramatic interventions, the sexy uniform, your appearance on the evening news and your general confidence back in the hospital when you can manage dramatic medical problems which seem much easier when they are not trapped upside down in wreckage.

The problem with being a Rock Star performing in a band is that to continue being the Rolling Stones of Medicine [Ed: we would not suggest this reference is in any way a sign of author age] you feel compelled to keep releasing new albums regularly.  This can be a problem, especially with social media, as developments in medicine do not keep pace with the need to tweet and podcast and you are at risk of grabbing the latest study or technique involving patient plumbing and announcing this to the world as the next big thing in the world of Helicopter Rock Band Medicine.

This does tend to mean that you can gloss over some of the basic things which really make a difference to your medicine and your patients. Just like a Rock Star will be completely familiar with the basic things that makes playing their instrument possible, it helps if you can really nail the basics.

So here are a few tips that work for me to do a better job as a retrievalist in whichever team I’m working in.
Have a Plan

A good plan when you approach a patient makes a big difference, especially for an interhospital retrieval. This makes a huge difference to the smoothness of how your retrieval will flow and reduces your risk of making an error by omitting something.  This is a bit like having a checklist but I don’t quite use it like that because really a checklist involves a bit of call and response.  It’s not quite a strict list, more like having a systematic approach to reduce the risk of error.  If you have the same pattern to how you do things you get much quicker and slicker and you are much less likely to miss something.

It took me a lot of years to work out I didn’t have a consistent system.  And when I analysed some the mistakes and complications I had I realised they came about because, like a good anaesthetic registrar would, I modified what I did to fit the Paramedic I was working with, rather than communicating a system that would ensure I didn’t miss things.  If I had actually had any system to do the job myself then I would have avoided a lot of problems.

So here’s the system I created for myself. It might work for you, or might just prompt you to think through what system would work best for your brain.


A: Airway

  • Check ETT Size and measurement at a fixed point (e.g. teeth).
  • Check ETT Security – that means connections and how well it is tied/taped. I almost always find myself fixing something about security.
  • Check ETT Site – on an X-ray.

duncan c

B: Breathing

  • How well is the patient breathing? It’s a seemingly simple step but yes, I still remind myself.
  • What are the ventilator settings? Got it, now match them (with the transport ventilator). I tend to work with paramedics who make logistics and practicalities in a brilliant fashion. It always seems that just as I get this step done they are ready with a patient slide to transfer the patient onto the stretcher.

duncan c2

C: Circulation

  • What’s the IV access? Secure that well too.
  • What about the arterial line? Critically ill patients being moved should have this so now is the moment to make sure it’s connected, working and zeroed. This usually matches up with when my friendly paramedic is miraculously also up to the exact bit where I should be helping with the monitoring.


D: Drugs

  • Think “I need enough sedation for 3 times the anticipated length of transfer” and make sure you’re ready (plus see the bit below).
  • Also have a think about what things you have handy as downers (mostly sedation and analgesia) and uppers (like metaraminol) which might just come in handy if you get the downers bit not quite right (or for other reasons of course).

Bart Everson

E: Everything Else

  • Do you have all the equipment you brought with you?
  • Do you have the notes?
  • Do you have any scans?
  • Do you have ALL the equipment you brought with you?
  • Do you have any patient belongings, either the material ones or the relatives that also belong to them that you might be bringing?
  • No, really, do you have ALL the equipment?


Now, about that sedation

Yes, I gave this its own bit because it is really important. Let’s assume you’re highly skilled at drug-assisted intubation. After that there is the post intubation phase, whether you have intubated the patient yourself or whether the patient comes already intubated.

I think it is really important to make a couple of distinctions in retrieval.  One is you are giving “a Retrieval” and NOT “an Anaesthetic” or “a Sedation”.  An Anaesthetic is an art form so important there is an entire medical specialty devoted to it.  But it is basically focussed on having someone pain free, unconscious of what item number is being performed on them, and then woken to a state of bliss in a a calm quiet environment surrounded by nurses fussing over you.  Usually woken relatively quickly after the item number as well.

This does not apply to retrieval.  In a retrieval you do not want your patient to wake up.  Especially over that last speed hump on the roads leading to the hospital.  With apologies to ICU that your retrieval patient will take a day longer to wake up than someone they lightly sedated you have to remember it is not a “sedation” it is a “retrieval”.

There is very little fussing (doctor dependant) and a lot of shaking up/moving/noise/vibration/stimulation.  When I was a retrieval registrar no one discussed this with me and since I was very comfortable to treat people with morphine and midazolam either together or separately, with propofol, (ketamine hadn’t come into use again when I was a registrar) and with fentanyl I just kept running whatever the hospital had chosen assuming that since they were a hospital they had correctly chosen the right sedation for the right patient.  It was also quicker and easier to just keep running whatever they started as we didn’t have to go through the entire fuss of drawing up new drugs.

I am now, with experience, absolutely sure that this is not best practice.  Now I don’t use propofol at all for a retrieval – it is an ideal anaesthetic drug which makes it very poor for A Retrieval. Of course that is only my opinion born of experience with no published data I am aware of (there is a study for someone) however I can promise you that performing a “retrieval” after intubation requires only two drugs for maximum benefit:  Separate infusions of fentanyl and midazolam.  If you are running two inotropes and only have one pump left I will allow you to mix them together but the ideal concentrations are 1000mcg fentanyl in 50mL and 50mg of midazolam in 50mL.  Run them at 10x higher doses than you would use in ICU so you need to think about starting at 200-400mcg/hr fentanyl and heading north and 5-10mg/hr of midazolam.

And if you arrive and your patient is light and coughing on the tube, if their haemodynamics will tolerate it just give them substantial loading doses of these drugs, say 0.1mg/kg midaz and 2mcg/kg fentanyl and then start your high dose infusion.  I can promise you this will be the best tolerated, most cardiostable way of performing “A Retrieval”.

Just remember the gotcha – as your helicopter starts to land at the hospital it will shake violently for 30 seconds or so.  This will cause your patient to wake up and extubate themselves at the one time you can’t go out of  your seatbelt to fix the problem.  Remember to bolus before landing.


So there you go.  Some of the basics that can help you be the Rock Star you want to be.



All the images here are via Creative Commons on flickr and are unchanged here and put up by Izzy by the Sea, Duncan C, ThoreauDown and Bart Everson.

If you have suggestions for future posts hit us up. And if you like the stuff around these parts, you could always consider sharing or signing up to receive emails.




Just a Prick – Things that Might Just Work with Kids IVs

Putting a cannula in kids can be… well, an experience. Dr Andrew Weatherall has a collection of tips and tricks that might just be useful. 


Cannulas. Little people. Not always a match made in heaven. At the joint I work doing kids’ anaesthesia, we often note that they are the great leveller because it doesn’t matter how special you’re feeling, you’re just one lousy cannulation day away from feeling very, very mortal.

They are sort of essential for prehospital and retrieval work though. The thing is that we know that if you’re not working in a designated paediatrics job, the chances are that the little sprocket end of the market is by far the group you see the least. Which is not ideal for gaining and retaining skills.

So short of approaching random families in the street to see if the kids have always felt like their life was missing a cannula and would they like you to help with that (and that is a terrible start-up idea, don’t do that),  you have to make your best of the opportunities you have and draw on thoughts from other people.

So collected here are a bunch of things that help me get those little cannulas in. It’s not an exhaustive list of everything everyone has ever come up with of course. It’s just stuff that works in my hands that I’m sharing, partly in the hope that other clever people will chip in with suggestions in response. There must be some experts out there that we just need to poke enough to make them vomit up their wisdom.

I’m even going to leave out the “give them an anaesthetic and get them to sleep” one because it feels a little like cheating for this scenario.  And for the purposes of this post I’m not going into ultrasound stuff because that’s a whole extra thing. Let’s just put on record that if you’re cannulating for retrieval give it a strong thought.

So in a “not necessarily the most sensible order” kind of way, here’s how I’d think through that whole cannulation palaver:

1. What’s my aim here?

Knowing why you’re bothering with that cannula might seem like a dopey place to start but it sort of determines a bunch of decisions that follow. If you’re in a prehospital setting and you’re thinking of the cannula to get analgesia happening, do you have options you can start with first (intranasal or methoxyflurane etc) that will treat the clinical problem in the short-term and buy you time (plus help the kid, family and you) before getting to the cannula you might need long-term?

Are you adding one as a precaution for transfer? Is that the best choice for the patient and you? If it’s not time-critical do you have time for local anaesthetic options to do their thing?

Do you need the sort of urgent access that might befit an intraosseous option, then quick resuscitation and then an attempt at an IV once there are actually veins that have actual circulating volume in them to work with?

In this setting, it might well be that the IV is exactly what you need of course. But making that an explicit step in your thinking is a good thing. It makes you really prioritise the vital steps for management of the patient.

2. What’s my limit?

This flows from point 1. How many attempts would you consider before you try something new (like a different form of access, or asking someone else to have a go)? If it’s a cannula that must be done, your limits are going to be different than if you have nothing to start with. If you’re in a retrieval, rather than prehospital setting through there might be lots of clever people who can help (or who could do it while you do things that only you can do).

Setting some sort of soft limit where you will stop and reassess does stop you getting into the hole that comes with “I have to get this in” to the point where you forget the primary needs of the patient and it becomes mostly about pride. I’ve been there. A pride hole helps no one.

I don’t think you run the risk of mentally setting up with an assumption that your attempt will go wrong by having that limit either. It’s just about keeping whatever the primary goal of care (which is almost never the cannula itself, but what you can provide with the cannula) foremost in your mind.

Limit Vandys
Thinking and prep time might just save you a bit of time later

3. Super prep

Preparation is pretty much everything here.

The Patient

And whoever is helping them obviously but mainly the patient. If you’re with an awake patient, then telling them what you’re going to do and why is a pretty important place to start. The style that people employ for this can vary but one thing I’d be pretty firm on is that you can’t win by being dishonest. If it’s likely to hurt, don’t promise it won’t. If they’ll still feel pushing (like when you’ve used local anaesthetic cream), probably warn them. Let them know if you’re going to get someone to do the work of keeping a limb still. Explain steps as you go.


If you can, choose to work in a position you find comfortable. Removing any degree of strain from your own posture just makes it easier to keep your later movements refined and precise. Not always possible, but working at the right height or even sitting down can make all the difference.

Look Everywhere

Way too often over my career I’ve gone to put a cannula in a spot because it seems convenient and later realised there was a much more accommodating vein somewhere else. There is something even more convenient than a vein that is close to where you’re standing. The vein that will actually help you out that’s all the way over there. Over that other side.

Check all 4 limbs, every time you can.

The Kit

Stuff for cleaning, stuff for doing, stuff for securing. Have it all ready to go (and that includes a back-up cannula ready in case you need to move on to another attempt). Once it’s in you want to be able to have it secured as quickly as possible. And once you’re under way you don’t want to be distracted by needing to reach for anything else.

A really good clean with an alcohol swab has an additional purpose. Sometimes it highlights a change in contour of the skin as the light picks it up and this reveals a vein. Sneaky and appropriate infection control.

4. The Actual Doing

Right. The pointy end. So to speak. Not so certain about this bit? Well these are all things I  do or have seen others do. Comprehensive? Probably not. For everyone? Maybe not but worth a think I reckon.

Choose your cannula

First up, examine that vein and decide which cannula you think will actually go in it. We all love a cannula big enough to rehydrate a woolly mammoth (and think how dried out those codgers would be now), but the truth of paediatric patients is that you don’t need a massive cannula to achieve good fluid loading. And you can definitely resuscitate more effectively with a smaller cannula in the vein than a bigger one in the subcutaneous tissues.

I’d even cope with a not-super-huge cannula in the cubital fossa if that’s what you need to get things rolling. At the hospital we regularly resuscitate kids without a huge cannula. It just needs a syringe and a 3 way tap (and you can actually do with most lines without a 3-way tap). Mostly it’s actually about paying attention and doing it, rather than letting it run.

Line it up

Absolutely the commonest thing I see trainees do when they are struggling is not actually lining up the cannula with the vein it is supposed to slide into. The entry point is somewhere near, but if you look at the barrel of the cannula, it doesn’t line up with the direction of the vein. Good luck with that.

Don’t focus so much on the entry point you forget the rest of the thing.

Make a hole

OK this one is probably more for the retrieval setting (and particularly for tiny ones) though I guess in principle as long as you have good sharps management you could maybe consider it for prehospital work (I’ve never done it there though). Not sure I’d try it in an awake child without some local numbing happen either.

After you choose your cannula, get a needle bigger than the gauge of the cannula. Make a hole in the skin at your entry point. Now when your smaller cannula passes through the hole you shouldn’t have the skin dragged in with it at all. You should lose all resistance at that level actually. Do it right and pretty often you’ll feel the end of the cannula pop into the vein before any visual clue like a flashback tells you that you’ve made it.

Note that having gauze handy for any small amount of blood ooze that would obscure the entry point is helpful here.

Petras Gagilas
Look, not so big you can see light through it, but something.

The saline trick

I think this only works with non-safety cannulae. Basically you fill the hub with saline and when you hit a small vein you’ll see a super quick flashback (even just starting with a quick change in the light in the saline). This one’s particularly useful for getting early warning in tiny veins to avoid going straight through.

Short and sharp

You probably understand that you need to come really flat to the vein with your angle of approach (by all means be at a more acute angle to get through the skin, but approaching the vein should be pretty flat).

The other key bit though is short, sharp movements forward followed by a pause. I tend to find slow advancing just doesn’t do the job in little people’s veins. It’s like the slow distortion of the tissues encourages them to roll out of the way (you can even see it on ultrasound). A sharp move forward, then a pause, then repeat just seems to work better.

The Roll

You get the flashback. Victory! Except you still need to advance and you’re worried it’s a bit small that there vein. So do a really small advance. Then rotate the whole cannula (as in the needle bit as well) 180 degrees. The leading edge of the needle is now closest to the skin, and the pointy bit isn’t going to go ahead and spear the back wall. Advance a little more. Now feed off the cannula.

The Twist

This trick is more well known. Once you think you’re in that vein, twist the cannula off into the vein. In bigger kids it’s probably no help but in smaller veins it does seem to sometimes help get it not to catch up on the wall of the vessel.

Wired for Not Sound

This one is not really a prehospital thing but if in a retrieval-type situation you could consider this one. Have a think about getting familiar with wires for Seldinger options. There are manufacturers out there making short wires that will feed down a 24 gauge cannula. Arrow make one that is 0.018 inches (diameter) and Cook make one even smaller (at 0.015″). When you have one of those cannulae you really want but after you feed it off it’s all gloom, a wire can rescue you.

The technique (with appropriate cleanliness and wire precautions to ensure you don’t lose it in the vein all in place) is to gently start pulling back just the cannula until you have blood freely flowing back. If you gently advance the wire up the cannula at this point it will sometimes find its way perfectly up the vein. If so, you now have an introducer to place a cannula (maybe even one larger than the one used for access).

Not a technique to try in anger for the first time without someone who has done it nearby I’d say.

It’s also worth noting that not all wire/cannula relationships are without challenges. For whatever reason a Surflo 24 gauge cannula will absolutely not allow a 0.018 inch wire through. A 24 gauge Insyte? Well they were made for each other. Go figure.

4. The Strapping

Well that’s a completely different post. I only wish someone had good tips for things like that (like say, here).

For kids cannulas there are a lot of techniques out there and lots of strong opinions about tape. My main thoughts would be:

  • The tape has to be in contact with the actual thing it is supposed to hold. Sometimes I see people holding tapes tight as they put it across the cannula, thereby guaranteeing the tape only contacts the top surface and is then stretched onto the skin. Form the tape closely to the cannula itself. Squeeze it right on there to get maximum tape-to-cannula contact. Then lay it across the skin (no stretching) and put some pressure on it to get adherence happening.
  • Really think hard about things like boards. If they are not adding security for that cannula, you can almost guarantee they are adding annoyance for the patient.


So there’s a start. I bet people have more I’ve forgotten or don’t even know about.

You might just find some of these tips help though. And if that’s the case you will hopefully end up not being the big prick finding it a bit of a prick to get a little prick done for a little kid.

Little kid. What did you think I was going to say?


I am not kidding about hoping people will have better tips. That’s what the comments bit is for. Go nuts. Or share the post and see if someone else has one.

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The images here were from vandys (the speed limit one) and Petras Gagilas (the tunnel thing) and used unchanged from their spot on flickr under Creative Commons.