This post is based on a talk prepared by Dr Andrew Weatherall for the South African Society of Anesthesiologists Congress for 2017 held in Johannesburg. As invited faculty
I think when they first offered this the plan was to do sedation in the dental chair. Which I’ve never done. And this is for a refresher course.
So we changed the topic to sedating kids in strange places. Which I have done.
But they’re strange places so by definition they should seem weird to you which means you probably haven’t done it before in which case it’s not a refresher course topic at all. Just like it’s hard to have a refresher course on swimming with sharks in bathtubs, it’s hard to have a refresher course on undertaking sedation in places people don’t do sedation.
So I guess I’ve screwed this up every which way.
Nothing for it but to sedate someone though. So let’s start with a 18 month old who has a hand injury. We’re going to sedate him to get things fixed up rather than waiting for a free operating theatre.
At the start of any sedation we need to ask some questions of ourselves. And I like to start with the Cluedo questions. The ones about “Who?” or “Where?” or “How” that help us make the choices to get this sedation done.
What are we talking about?
It’s pretty vital up front to understand what we’re describing. We need to understand what we mean when we talk about sedation.
Well as good a place as any to start is with the ANZCA documents on this (this is my low rent version of international colour for this one). ANZCA include a couple of key points:
- There is an implication that you’ll be using pharmacological support to improve tolerance of uncomfortable or painful procedures.
- They try and separate out some levels of sedation.
That latter one can be a little problematic but they do talk about conscious sedation, where the individual will produce a purposeful response with minimal stimulation, and deep sedation where there will only be that purposeful response with painful stimulation.
To be just this side of general anaesthesia however you do need to have some sort of response. Plus you need to consider if what you’re really talking about is analgo-sedation because you’re expecting some pain to be dished about.
The “Who?” is important in planning for a bunch of reasons. Is it you or someone else actually delivering the sedation? What’s their level of experience or expertise? What’s their clinical background? The background of the practitioner is highly likely to influence the choices they make, particularly when it comes to pharmacology.
The “Who?” also covers the patient at question because the needs of an 18 month old are not the same as those of a 12 year old, and aren’t the same as the needs of a 40 year old.
Lastly, the “Who?” question applies to the proceduralist. If you’re giving sedation to get a job done, then the needs of the proceduralist to get things done have to be taken into account.
Well, we’re talking about strange places, right? So that definitely matters for this scenario, but it matters for every sedation scenario. It will influence what you feel comfortable offering, and what help is available. It will also heavily influence where they get looked after when it’s done and might influence how quickly you want them back to their entirely normal state.
Wait, this is the strange places post so I should probably mention something….
Today’s patient is in a bathtub. He’s had his hand stuck down the drain for 2 hours with people trying to get it out. It’s 22:00. It’s about 6 degrees Celsius outside. Your proceduralist is the rescue volunteer with the jackhammer who is going to have to work through concrete to reach the bath and dismantle it.
Well I think in this case we already know that. For other sedations though it’s worth making an assessment of when it has to be done? Does it really have to be now or can it wait a little if you have concerns with sedation. Will the timing matter for available care afterwards?
What about that fasting question? All if it helps at all there is very limited evidence that fasting intervals influence things like aspiration rate. The Pediatric Sedation Research Consortium looked at 139142 patient records in 2016. They found a total of 10 aspirations and 75 major complications. 8 of the aspirations were in kids fully fasted (though that was from 82546 records whereas the non-fasted made up 25401 cases with details). Both rates were < 1 in 10000.
Another look at 12 years of nitrous oxide procedural sedation in kids not necessarily fasted revealed 1058 cases with 0 major complications (and I think quite astonishingly only 11 cases of nausea and vomiting).
So I probably would still make an effort to fast most times, I’d also be pretty relaxed if clinical need indicated we were in a “right now thanks” scenario.
This isn’t a moment for an existential pause. It’s the key question about our goals of this sedation. Personally I find it useful to think about the ins and outs of it.
What are the sensory inputs we’re going to inflict on the patient and what is the level of cerebral output we’re aiming to see?
In radiology you might just need a little stillness. The inputs might be almost nothing, or just a little noise. That’s clearly different to a burns dressing, or a quick pull on a fracture.
Remember our little punter? This kid is stressed after 2 hours of messing about and there are 10 weird people in bright orange in the bathroom with him. They’re using noisy tools. His hand is sore. He is way past his bed time. The extrication is thought to be a 2 hour job.
Our goals are to achieve a comfortable light snooze that might have to deal with variable pain input.
Finally we get to it. And you might figure we’ll dive straight into drugs. Nope. This is a super short chat so I’m more interested in an approach that will work, while assuming that clever people checking this out have an armamentarium of things they are good with.
So I think when we get to the “how?” it’s easiest to remember we need to offer some REST.
Let’s work through them.
In most sedations establishing a good rapport with the patient is vital. Sedation isn’t like general anaesthesia and there is the potential for recall and moments of discomfort. Establishing trust is therefore a big help, because if there is one of those moments it’s a lot more ideal if the relationship you’ve established means they’ll trust you when you try to provide reassurance. The same goes for if you’ve got a carer around.
So there are plenty of ways to work on that beyond this scope, but slowing down to take this step pays off.
As much as possible setting up an environment to support the sedation is ideal. Simple things like choosing a specific spot where you can, reducing noise in the area (bugger, jackhammer), ensuring easy access to the patient and controlling the numbers of people in the space can make it a much calmer experience all round. If the environment is good, really you should need less pharmacology. The environment is also a key element of …
Sedation is actually pretty safe overall. Biber et al have published stats showing a 4.8% adverse event rate in 12030 patients. For the really concerning ones they only observed airway obstruction in 1% of those sedations and laryngospasm in 0.6%. 1.2% of patients needed some bag-mask ventilation. Unsurprisingly issues were highest in the 0-5 age range.
Obviously we need to be actively focussed on safety though. And I’d start with your eyes, ears and hands. Personally I think delivering good sedation can be much more taxing than giving a general anaesthetic. To keep them consistently at a state of sedation, which can be a lot more dynamic than anaesthesia, requires a continuing close quarters assessment of where they are right now and what the inputs are about to be.
So being able to reach out and touch or gently stimulate the patient matters. Close observation of respiratory patterns matter. This doesn’t suggest we should abandon monitoring. We should have at a minimum pulse oximetry, a means of measuring pulse rate and BP and I’d argue that in hospital or static settings capnography is a must.
Every sedation also requires a plan for how to manage airway complications, support breathing well and manage any circulatory issues, rare as they all might be.
Safety requires a team too. The ANZCA documents suggest that beyond yourself you need at least one person available to assist you at the drop of a hat. Or a clatter of the safety helmet I guess.
Which brings me to the last point, don’t forget PPE. That’s not just for you either. Your patient might need it.
We finally got there. This really comes down to two big groups:
- Non-pharmacological, which should absolutely not be considered as a lesser item. If you have some good distraction and redirection techniques they can get you a long way there.
When it comes to agents this isn’t really the space to argue for one over the other. I would say that if you’re sedating in a new spot or new situation, I wouldn’t try out that cool drug someone told you about for the first time.
Each agent has its pros and cons. Propofol is great for sedation when used right but can sting a little and respiratory depression can be an issue. Ketamine has a lot to recommend it but I have seen nasty dysphoria and that shouldn’t be dismissed. Dexmedetomidine has some strengths but there’s no doubt patients are sleepy for longer afterwards. Nitrous oxide clearly works but you do need a way of delivering it and you might not want it for too long in a tight space. Opioids obviously are superb for analgesia but require caution, particularly if used as an additive to another agent.
Again the key thing is to choose agents whose characteristics feel familiar to you and use them to manage the goals you came up with in the “why?” bit.
Is it just sedation you need. If it’s painful, how painful? Is that pain likely to be consistent or variable in nature? Does the time to wake matter? Would regional options help with those inputs?
Now choose the agent that lets you get things there.
Because a strange spot for sedation is really just a different office to do your work.
Here’s your patient. You can only just see some of the elements here, but the patient is covered up in blankets. They have earmuffs on. They have oxygen going and a cannula in place. After some midazolam, fentanyl and ketamine in we managed to sneak in digital nerve blocks. From that point on we really didn’t much of the ongoing infusion to have the patient snoozing but rousable to touch. The one obvious flaw here? We didn’t control the environment quite well enough to know the family had sent in a news reporter to get a shot.
And one hour in, with the patient relaxed we figured we might as well try a gentle pull on that hand. And it slid right out. Pity about the bath.
And all it needed was a bit of REST. Maybe that’s not so strange after all.
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Yep I’ve had previous clearance to use this case in public.
The image of the job is as it appeared in the local paper, The Illawarra Mercury.
The other images are both from flickr in the Creative Commons area and are unchanged. The clown was posted by lorenzoclick and the sign came from Roadside Pictures.
Now, reading things:
Here are those ANZCA Guidelines.
Here are those fasting type things:
Here’s that adverse events one I looked at (though in GI endoscopy work):
Biber JL, et al. Prevalence and Predictors of Adverse Events during Procedural Sedation Anesthesia – Outside the Operating Room for Esophagogastroduodenoscopy and Colonoscopy in Children. Pediatr Crit Care Med. 2015;16:e251-e259.
Now here’s some more general reading of things that might have some interest:
And here’s a couple of things I’ve had a chance to contribute to:
Now have you scrolled all the way down here? Then I have a bit of a treat. In the presentation version I had a multi-exposure shot of Danny McCaskill in action in his film Cascadia. You could watch it by clicking here and reflect on safety. Or maybe just watch it because it’s amazing.