Tag Archives: intubation

The Dangerous Little Details

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.” 

 

Should we stop looking at first look intubation rates?

A brief note: I get to do the editing duty this week (Dr Andrew Weatherall that is) and I could not let it pass without a word of tribute to Dr John Hinds. I had only had the chance to learn from the good Dr Hinds via his online presence. It was a big presence. 

As one who did not know him personally, I can only reflect that he demonstrated many of the best qualities of a passionate doctor and that his passing, far too soon, has revealed many of the best qualities of his colleagues. 

Just in case you needed another reminder, you could watch him in action here, or read good words by @Eleytherius here, or sign a really worthwhile petition to deliver a vision for a better prehospital service for patients in NI here. 

As to this week’s post, Dr Alan Garner has a post on looking for the right outcomes so we’re doing the right thing for our patients. 

Can’t see the wood for the damn trees

As part of their intubation quality program many services now report their first look intubation rate. We have been doing so for a couple of years now. This looks like a really good thing to do. We know that more than one attempt at intubation is associated with greater incidence of serious adverse events in critically ill patients, and the more attempts the more likely those adverse events become (reference 1).

Therefore a strategy of aiming for first look success is probably a good idea, a strategy that my own service employs. So this should be a good thing to report as a quality measure too. Indeed why would you not? After all, the more attempts, the worse things get right?

Well wait a minute …

First let’s have a think about why we would report it. Is it telling us something that actually matters?

The outcomes that really matter are did they die or end up with hypoxic brain injury. The process issues that really matter are did they get hypoxic or have a cardiac arrest during the intubation process. There are other hard complications/process issues you can measure too like aspiration with unnecessary additional ventilator days, or even did you break their teeth.

First look intubation tells us none of these things. It does not tell us if the patient became hypoxic, aspirated or even arrested. Yes it is associated with lower incidence of these complications but it does not tell you if the complication actually occurred.

And what if emphasising first look intubation rate as a quality measure shifts the focus in the wrong direction? Could you risk making the risk of hypoxia higher?

Am I losing the plot here? Let’s go back to first principles.

The outcomes that really matter are death and hypoxic injury. I don’t think anyone is going to argue these should be avoided. Fortunately the incidence of these is pretty low so we tend to use surrogates for these things instead, things like the incidence of hypoxia or hypotension/bradycardia during intubation. These are pretty direct measures reflecting outcomes that matter.

First look intubation isn’t an outcome. It’s not even a surrogate for an outcome – it’s a surrogate for a surrogate of an outcome. My concern is that surrogates for an outcome, rather than the actual outcome can lead you way up the garden path. The MAST suit again comes to mind. The patient’s BP went up so it had to be a good thing surely. Of course when someone finally did a decent study on the outcome that really mattered, mortality, it was trending to worse not better.

Although there are no randomised controlled trials showing hypoxia to be bad for you, the circumstantial evidence is pretty overwhelming so I agree this is not quite like the MAST suit situation. However in using first look intubation as a quality measure we are now reporting a surrogate for a surrogate of the outcome that actually matters. I.e. we are reporting first look as it is associated with lower rates of hypoxia because lower rates of hypoxia are associated with lower rates of death and brain injury.

This is a risky game and recent audits of my own service show why. For the past year we have had a monitor that records the vital signs every 10 seconds and we download the data at mission end and attach it to the record. I have been going through these records to see what our rates of peri-intubation hypoxia actually are.

First thing I need to say is that our first look intubation rate so far this year is 100%. However we did have a couple of episodes of significant hypoxia.

My concern is that by reporting the first look rate, we draw attention to it and we send the message to our teams that this is the thing that we think matters. So better to press on a little bit longer even though the sats are falling to make sure I nail that tube first time!

What was the big picture again? [via Jarod Carruthers on flickr under CC 2.0 and unaltered]
What was the big picture again? [via Jarod Carruthers on flickr under CC 2.0 and unaltered]
Why are we reporting a surrogate for a surrogate? I have really accurate data from the monitor on the peri-intubation hypoxia rate, hypotension, bradycardia and arrest. Why report a surrogate for these things that might actually encourage our staff to focus on the surrogate and cause an episode of hypoxia, bradycardia, hypotension etc.

It remains important to emphasise optimising conditions for the first intubation attempt as that appears to have lower complication rates. However it is a means to an end. We should emphasise the outcomes (or at least the surrogates with only one degree of separation from that outcome) that matter. Why report a surrogate for a variable when you have the data to report the actual variable?

Some services like our own are now reporting 100% first look intubation rates, but no one is yet reporting 0% peri-intubation hypoxia rates. Aim for first look intubation as that appears to be a smart strategy, but tell your people it is the hypoxia that matters by making that the centre of attention in your reporting.

What do we mean by hypoxic?

Another thing I have been forced to look at is the definition of peri-intubation hypoxia. I had intended to use the definition of hypoxia used in many of the studies on this subject:

“Desaturation was defined as either a decrease in SpO2 to below 90% during the procedure or within the first 3 minutes after the procedure, or as a decrease of more than 10% if the original SpO2 was less than 90%.” (reference 2, see also 3-5)

I excitedly opened the data file of our first patient that we had intubated when we got our shiny new monitor a year ago to see what had happened. It was easy to identify the timing of intubation from the capnography data as we routinely pre-oxygenate our patients with a BVM device with the capnography attached. The sats pre-induction were a steady 90%, for 2 readings they were 89% (20 seconds) and then climbed to 98% when ventilation was commenced. So according to this definition we had a desaturation!

I don’t think anyone would claim a fall in SpO2 of 1% is clinically significant. It is also less than the error of the measurement quoted by the manufacturer of the oximetry system. This set of circumstances is not going to occur that often but it does not make sense to classify this case as a desaturation. We have therefore modified our definition to:

“Desaturation is defined as either a decrease in SpO2 to below 90% (minimum change at least 3%) during the procedure or within the first 3 minutes after the procedure, or as a decrease of more than 10% from the pre-intubation baseline if the original SpO2 was less than 90%.”

So what should we be reporting?

Thomas reported that each subsequent attempt at intubation was associated with an increased risk of hypoxia, aspiration, bradycardia, cardiac arrest etc. If we have the data on these variables then why not report them directly instead of reporting the surrogate for them. For hypoxia I would suggest our slightly modified definition above.

As for other variables why not use the definitions from Thomas’ paper?

Bradycardia HR <40 if >20% decrease from baseline
Tachycardia HR >100 if >20% increase from baseline
Hypotension SBP <90 mm Hg (MAP <60 mm Hg) if >20% decrease from baseline
Hypertension SBP >160 if >20% increase from baseline
Regurgitation Gastric contents which required suction removal during laryngoscopy in a previously clear airway
Aspiration Visualization of newly regurgitated gastric contents below glottis or suction removal of contents via the ETT
Cardiac arrest Asystole, bradycardia, or dysrhythmia w/non-measurable MAP & CPR during or after w/in intubation (5 min)

 

For the physiological definitions Thomas includes percentage change from baseline like we do with the hypoxia definition. This acknowledges that these are critically ill patients and often have deranged physiology before we start. These definitions can therefore be used in the real world in which we operate. If we all adopted these definitions we could meaningfully compare ourselves with Thomas’ original paper and with each other.

And as for us…

We are seriously thinking about ditching the reporting of first look intubation rate. It is not telling us what really matters – and we can’t get better than our current 100% rate anyway. Despite this we are having occasional episodes of hypoxia and other complications, and it is possible that the rate of these complications are being exacerbated by emphasising first look.

We are therefore looking at moving to the much more comprehensive set of indicators used by Thomas (along with our modified hypoxia definition). This will demonstrate to our team members the factors that we think really matter, because we measure them and report them externally.

You could argue that the only way to achieve 0% hypoxia is to accept that we are not going to have a 100% first look intubation rate. I for one would gladly give up our 100% first look rate if in doing so we achieved 0% hypoxia. I don’t yet know if this is achievable but I have some ideas. Those who walk the quality & patient safety road with me know that we might never arrive, but that should not deter us from the journey.

Anyone coming?

 

Reference:

1 . Thomas CM.   Emergency Tracheal Intubation: Complications Associated with Repeated Laryngoscopic Attempts. Anesth Analg 2004;99:607–13. [Full text.]

  1. Anders Rostrup Nakstad MD, Hans-Julius Heimdal MD, Terje Strand MD, Mårten Sandberg MD, PhD.   Incidence of desaturation during prehospital rapid sequence intubation in a physician-based helicopter emergency service. American Journal of Emergency Medicine (2011) 29, 639–644

 

  1. Reid C, Chan L, Tweeddale M. The who, where, and what of rapid sequence intubation: prospective observational study of emergency RSI outside the operating theatre. Emerg Med J 2004;21:296-301.

 

  1. Omert L, Yeaney W, Mizikowski S, et al. Role of the emergency medicine physician in airway management of the trauma patient. J Trauma 2001;51:1065-8.

 

  1. Dunford JV, Davis DP, Ochs M, et al. Incidence of transient hypoxia and pulse rate reactivity during paramedic rapid sequence intubation. Ann Emerg Med 2003;42:721-8.