Podcast – June 2024 Monthly Round Up – Nebulised Ketamine, Risky Intubations, Better Presentations, DSED, Preoxygenation and more

Welcome to the St Emlyn’s podcast, I’m Ian Beardsell.  And I’m Simon Cully. And this is our podcast discussing all of the blog content from St Emlyn’s for June 2024.   

It’s summer in the UK today, which means the sun is shining. It meant that yesterday there was seemingly some form of hail storm, but that’s summer in the UK. Sam and Anaya here, ready to chat through a load of content that I must admit both ready for a holiday. And Simon, you’re about to go on your travels. 

Yes, I’m off to the Balkans, it should be really good fun travelling through that part of the world, but now before and really looking forward to it. 

We don’t have quite a holiday planned here yet. In fact, our household is entirely committed to thinking about both A level and GCSE results. So if the internet ether could think of my boys on the 15th and 22nd of August, I’d appreciate it massively, but it’s that time of year for us. But once that’s done, that will be holiday time for us.   

Simon, just a couple of other things we should mention before we start, we’re so grateful to a couple of conferences for the support they’ve given us in going to join them. Tactical trauma is taking place in October in Sweden. It’s centred on pre-hospital emergency medicine and other aspects of pre-hospital care. Check out their website, lots of really exciting speakers, really exciting content. And dare I say flights to Sweden are not that expensive. It’s taking place north of Stockholm, so the chance to take in some of the delights of their capital city as well. We’re also really grateful to the team at Incrementum, a conference that’s taking place in Mertia in Spain in March next year. As you may have seen, emergency medicine has just become a recognized specialty in Spain. So it’s an exciting time. And they’ve got a roster of speakers that is frankly unbelievable. Many names you’ll recognize from the FOMED world, MRAP and others. Scott Weingart, Ken Mill, Hany Malamet, Celine Rosai, the list goes on. Oh, and of course, one, Simon Carly will also be there. And we’ll be there taking some interviews from speakers and getting some more content for you on the podcast. So lots to look forward to, lots of exciting times. And if you’re interested in contributing to St Emlyn’s, please do get in touch. We’re always looking for new authors, people to bring different voices to what we’re doing. So just email via the website, and we can get back in touch. It’s also good for those things you might need for appraisal or an ARCP if you’re a trainee in the UK.   

  Simon, let’s crack on with the blog content and start with a paper that you reviewed from the annals of emergency medicine. And this is a really rather tempting option about whether we can use nebulized ketamine as an analgesic in the emergency department.   

  We’re a big fan of ketamine here, aren’t we? And at St Emlyn’s, we love it. It’s a great drug, particularly for those patients whom you’re struggling to use opioids, or those opioids aren’t working. And we have used it by the various different routes. I’ve used it IM, I’ve used it IV, I’ve used it intranasally quite a lot. The prospect of using it from a nebulized approach is an interesting one. But we are using more inhaled drugs, aren’t we? With things like Penthrox and stuff like that and becoming increasingly popular in the UK. So this is an interesting trial. It took patients, adult patients, which in the US is aged 18 and older, not like here in the UK, where it’s 16. And they had a pain score of more than five and they randomized them to either getting an IV ketamine, 0.3 milligrams per kilogram, or they had nebulized ketamine. But not in the sort of nebulized that you and I would recognize. It’s a breath-actuated nebulized. So you put it in your mouth, you suck it. Nebulized is as you do that. It doesn’t mean that you’re spraying ketamine all over the department and making everybody feel slightly happier in recess. It’s not like that. It is bespoke to the patients. And they took those patients and they measured their pain scores. There’s 150 patients that they did. It was a randomized control trial. It was quite, it was really quite well done actually. They followed those patients up and looked at their pain score. Before they had the drugs, they had an average pain score about 8.2. And that went down to 3.6 and 3.8 at 30 minutes. So within that 30 minute time period, which is where you want that sort of acute pain to disappear, there was really no statistical or clinical difference between the two really. So this study basically says that if you want to go down this route, then you can. You think it’s an interesting one. We don’t have the breath actuated nebulized, so it’s not option for us at the moment. And I’m not going to start putting it into a normal nebulized room spraying it around the back of an ambulance. I don’t know. Do you think there might be some patients in whom this might be a useful choice?   

I definitely think anything that reduces the time to analgesia is a useful thing. And we should look outside our routine practice to see if there are other things to do. As you say, from my reading, this is really well done. So if you’ve got the IV ketamine, you did also get given a placebo nebulizer. And if you’ve got the ketamine in the nebulizer, you’ve got a placebo intravenous injection. So it was the truly double-blinded type of trial. And as you say, the analgesic effects were pretty much the same. It seemed to me, Simon reading it that more of the group in the nebulizer did need rescue analgesia. But even then, there were still no main differences between the group. So I think this is a thing to watch, relatively small numbers, 150, I think of all the patients we have with pain in our department. We probably have 150 a week who could do with something like this. But an interesting thing to think of, I do wonder whether or not the lack of perhaps any commercial benefit for this may mean it’s less easy to take up. Obviously, other companies who’ve made inhalational pain relief, they’ve very much got skin in the game, haven’t they? And like lots of things, ketamine, when we can get hold of it, is not a massively expensive drug. And this may be something that holds it back.   

I think that’s true. And as I say, there are potential alternatives, which are potentially cheaper, even with use of ketamine. So I’m quite a big fan as a set of intranasal. Give you a classic example, I’ll try to use it a lot in, is sickle cell patients, which you see quite a lot of in Manchester. It’s a great drug for them because they’ve often got difficult venous access because they’ve had so many transfusions and things before. And you can get really high-quality analgesia. That’s mostly with using fentanyl, but ketamine is still not shown for that group of patients as well. Great. So our first paper from the annals of emergency medicine, published relatively recently, check out the blog post, all of the references and more are on the blog post, due to reading more detail. And as we always say, don’t just take mine and Simon’s word for it, go and have a look at the literature yourself. And as ever, if you don’t agree or you have a different perspective, just write in the comment section under the blog post. We’d love to hear from you because it’s in those discussions, I think, that we all learn more.   

The next paper, again, reviewed by you, Simon, about risky interventions in the emergency department. I have a feeling that most people would describe any intervention in the emergency department as having some element of risk, but these were the particularly risky ones, weren’t they?   

I think we’ve briefly mentioned this earlier in the year when we were looking at top 10 papers because this one that makes you stop and think. So there’s an interesting trial for several reasons. The topic is interesting, the intervention is interesting, and also the design of the trial is kind of interesting. So this is in patients in the US who are suffering from significant haemorrhage, and that’s defined as patients who need to go essentially straight to the operating room within 60 minutes of arrival at a level one or level two trauma centre. It’s the bleeding patients, the one we were most worried about, the shock patients that are coming through the door and they were going to move through us very quickly, go for definitive control. That’s fine. And what they looked at, it’s observational, it’s going back and looking at the trauma registries, the National Trauma Data Bank between 2017 and 2019, but it’s big numbers because you can do that when you do observational trials like this. So they’ve got over 9,000, over 9,500 patients in this across 253 trauma centres, a lot of trauma centres over there. They look to see whether if you get intubated in the ED versus if you get intubated in the OR, the theatres made a difference to your outcome. And so they had a look at that data, and they found that if you get intubated in the emergency room, then your chances of basically all sorts of badness go

 up. So you are more likely to die, you’re more likely to need more blood products, you’re more likely to have complications, all general badness. And so you think, “Oh, well, okay, so we should never intubate somebody in the emergency department.” Well, it’s a little bit more complicated than that. They’ve tried to adjust for this because obviously there are some patients who you think, “Well, they’re just so sick when they arrive that they’ve got to be intubated in the emergency department.” It was never really an option, it just had to be done. And they get that. They’ve tried to adjust for that, and you can do this statistically by looking at risk scores, and injury severity scores and things along those lines. And even when they’ve done that, they find that there’s still a difference between the two. Having said that, when you look back into a database like this, you’re never quite sure that the groups are equal. It’s not a randomized control trial, it’s not an option that people were done. This is a group of patients in whom we just saw what happened. And there is a real risk in these sort of studies that actually the patients were, in fact, different at baseline. There are some nice lessons that were published following this that show that in the group who got intubated in the emergency department, there were much higher instances of things like chest injuries. So they’re probably not quite the same. That’s a big risk with these observational-type studies. The last thing in this study, which I thought was very interesting, is that when they did try and adjust for what the patients were like, what they found is essentially there were some trauma centres where the majority of people seemed to be getting intubated in the emergency department, but the same sort of patients in another trauma centre would go to the operating room to have it done. And what that speaks to is that there’s a culture in some areas that this is where we do it here, and in other areas, this is where we do it there. I see that in practice. I see that people are very keen to do a procedure. If that’s what they want to do, if they’re very keen, they’re very skilled at it, they want to do it because it’s a great thing to do. As a great John Hines said, there are two indications, pretty much for any procedure, this is my paraphrasing of it. One is that you want to do it, and the second is the patient needs it. And it’s just a question here in that some places, are they doing it because they want to do it, or is it because it’s the best place for the patient? And that’s really to get people thinking.   

It does play into that ongoing debate about whether patients should be intubated in the emergency department, and then heaven alone knows who should be the person doing it. This is a registry study, so it is retrospective, and there are limitations to that, and Simon does explain really nicely in the blog post about why that is less robust, perhaps than the other trial we’ve talked about so far, which is a double-blind randomized perspective trial. This is looking back, looking at data, and it is large numbers, very different to our population as well, in that this is over 70% have penetrating injuries, and we’re requiring blood products. It’s certainly not my experience in the UK at the moment. I keep my fingers crossed that it won’t be my experience over the next five or 10 years, because obviously that tells us something about the types of patients who are being admitted, and why they are getting their trauma. But it’s an interesting thought, and one we should be looking at, shouldn’t it? We shouldn’t be doing things just because we can, we should do them because we need to do them, and double-checking that everything we’re doing is things that the patients need, it is a really worthwhile thing to look at, and look at in a properly robust data-driven way.   

I think that’s right. I mean, I don’t know what your practice is at the moment, but you have to twist my arm quite hard to intubate in the emergency department a hypotensive, most likely penetrating, the injured patient who’s going to the operating room within the next few minutes. I think you’re going to have to really try and persuade me if that’s the right thing to do, because those patients have a real risk of crashing and arresting post-intervention.   

And this has to be one of those things where this is not about ego, this is not about whether you can do it, it’s about whether you should do it, and at the centre of that, there has to be that patient and considering what’s there, and I think hopefully we’ve all started to leave our egos at the door, and whatever background you come from, whatever specialty you’re doing, it’s all patient-centred, and we try and do the best for them. Would be my hope anyway.   

Now, one of the other things that St Emlyn’s, well, Simon and I, we’ve worked on really hard over the last decade, is getting better at our presenting skills, and actually the whole team, if we were to compare how we were presenting a decade ago to what we do in a presentation now, it has changed hugely, and that is in no small part to the influence of Ross Fisher, and others like Vic Brazil, and then Natalie May, and yourself Simon, just giving positive feedback to try and get ourselves better, there is no doubt that if a presentation is given, and it’s done in a way that the audience receive it, the chance of learning is undoubtedly higher, and this is opposed from Natalie, but with contributions from that group, actually, Ross, San Vic, and yourself Simon, talking about some of the top tips for making presentations better. Have you got any particular things from this broad post, Simon, that you’d like to reinforce for the podcast audience?   

  The number one thing, and the theme that runs all the way through this, and I think where medical education is now, is it’s not about the teaching, it’s about the learning, and if you had to summarize everything that we’re trying to do, so it’s not about whether or not you can get on a stage and you have a great time, and you do a great thing, it’s whether or not the people at the other end are actually getting something out of it. What we’re trying to do with these top 10 tips is to do that. Plan your talk for your audience, get the context of setting, understand what’s going on, and then start with your presentation preparation with the story, with what it’s going to mean to the people in the room. Classic mistake I see people doing is, I’m going to do a presentation, I’ll sit down, I’ll start writing my slides. And so many people do that, and it’s just the wrong message. You need to start with a story, you need to tell them what it is that you therefore get the message first, and then you can put all the other bits later. Third one in this one is about activity. A lot of teaching and education is a very passive experience for the audience, so it is, they’re expected to sit there and listen to you. Well, you might be the world’s greatest speaker in the world, but you’re probably not. So what is it that you can engage the audience with so that they’re doing? Even if that’s just actively thinking, give them ideas about what to do, and you can do that in a group of five people, you can do it with 5,000, and you and I both done it, we’ve done activities with a whole auditorium for the people, you can still get people to have an active learning experience, and that means they’re going to learn more. Slides, they are there to support your presentation, they are not the presentation, and it just annoys me so much when people say, “I’m going to give a talk, oh, I can’t come, can you send me my slides?” And I go, “Well, there’s not a lot of point, they’re not going to mean anything.” You’re not there to look at my slides, you’re there to listen to me, and experience and learn with us and together. The slides are there, purely to complement your message. If you want to give somebody a handout, give them a handout, but don’t give them your slides. Lastly, and this happened to me famously some years ago, is anticipate that your whole presentation, the audiovisual thing could go down completely. So if it completely failed, could you still give your presentation? If all of your slides disappeared, could you still give it? And I would argue that if you can’t, if you just need, if you’re so wedded to having your slides in your media that you couldn’t actually give us a talk without them, you probably haven’t practiced enough and you haven’t got your message there enough. This happened to me many, many years ago. I was on stage for the Royal College. I was giving the Valedictory Address, or so they’re called for the delegates and my slides failed on the stage was the President, the Treasurer, the Dean at the time, and Princess Anne, and everything failed, and I had to do it with nothing. I wasn’t prepared back then as well as I would be now, but believe me, when the day comes and you really have to do it, oh, you need to prepare. There’s lots of messages in here, and the biggest one for me has to be to take on feedback. We also, oh, I love feedback. I’m a big fan of feedback. The truth is most of us really like positive feedback cause we like people’s tellers were really good. But actually in this case, having a critical friend who can watch you and explain what they’ve got from your message and to practice over and over has been the best for me. Just recently I’ve started to deliver a new

 course about critical decision-making, and my partner is a teacher. She works in her primary school, and she’s on school holidays, and she offers to come and watch me do what I do. And actually having somebody from a teaching background, who dare I say is actually been taught to teach, was so unbelievably useful. It did help that she could tell me things that maybe from someone else I might find hard to hear, but I delivered this same course over three days, and day three was undoubtedly better than day one, because she’d really given me things that I could do to engage the audience. This was small group teaching, and getting that feedback was valuable. Anytime you or I Simon, and we’ve done a talk at one of the bigger conferences, we’ve usually done it for each other a couple of times beforehand, haven’t we? And I think the other thing that really about this for me is to do this takes a lot of work. I find it exhausting preparing a talk. The people who are in the audience, they see the final product, but people don’t often know quite how well the stress of it, and the anxiety, and the amount of time you spend. And yeah, the idea that you can borrow somebody’s slides and still do the same is just, it’s not really there, is it? But the other thing I’d like to say really is, is that it doesn’t matter on your audience about how much effort you put in. Every audience deserves your best, and this is particularly me coming from the idea of teaching undergraduates and medical students, all too often I hear people say, well, it’s only the medical students. If anything, that audience needs your even better effort, they need to be inspired, they need to have role models, you can’t just pitch up to an undergraduate session, and hoping you’re going to get away with it just because the learners are seen to be less senior. And actually, as people come through school these days and through university, they’re incredibly educated about learning, and they’re incredibly educated about what good learning looks like. And so our audience is more critical perhaps than they were for our generation when we were turning up a conference and happy just to sit there, whatever was put in front of us. So lots to learn, and the main thing is take advice, get feedback, and we can all do better, even those of us who’ve done it lots, I still get anxious about presenting, I still got anxious about this new course I’ve just done, and to get somebody to watch you and to help you get this is a big thing.   

  The next post is taken from the Premier Conference in Wessex, and this was just a summary of some of the talks that I attended on day one. And actually, there is some content there that you can read and look at, but I’m delighted to say the conference organises, Clarissa Chase and others have let us take all of the audio recordings from the Premier Conference to release to you as podcasts. And as a listener to the podcast, you will have heard already talks about hybrid, closed loop, insulin pumps, you’ll have heard about sudden cardiac death, all sorts of things we’ve already released, top quality education from really experienced people, and I’ve learnt a lot putting these talks together. So keep an eye out on your podcast feed. If you’re a non-paediatric emergency person, please don’t be put off. Everything so far that we’ve released on the podcast really does have relevance to you in the adult world. Hybrid, closed loop, insulin pumps is a particular one. I had no idea that NICE had recommended that every patient who needs insulin with type one diabetes should have one of these pumps in the next five years. This is certainly something that never existed when I was at medical school and learning how to manage the technology and how patients may well present to us in the emergency pump is key. So do go and have a look and listen to those podcasts. And for each of the podcasts, there is a substantial blog post that you can use to reinforce your learning.   

  So Simon, we can talk about two posts together now. They’re both taken from analysis of the same trial, the dose of the F trial, but looking at slightly different things. You’ve critically praised both of them, and we can talk about them both now. Give us a little bit of a background first about the dose of the F trial, which I think we’ve covered in the past, and then how these other studies relate to it.   

  Oh, we have. I mean, the dose of the F trial, I think is one of the most significant trials, which has come out with regard to cardiac arrest management in the decade, really. Even though it’s not been widely adopted yet. But basically what they did is they took patients who were in refractory VF and they defined that as somebody who’s still in VF after three shocks and they did one of three things. They carried on with the pad positions in the normal place. They went to a peep, which is an option, from anterolateral to anteroposterior, or they did DSED, which is to put a second defibrillator on, and then to do two shocks, one, and then another a second later. Essentially, that was the plan. And they showed in that study that you had many more survivors if you went for dual sequence, emergency defibrillation. Quite substantial. I can’t remember the numbers off the top of my head, but I think it was on live 15% versus 30%. It was really big. We’ve covered it a lot. We think it’s something that should be considered, and certainly I’ve done it in practice. What these two studies have done, these are secondary analysis, and they’re both quite interesting, because they both refine it a bit more. Because for many years, and I think we’ve mentioned it on the blog before, when people are still in VF, such as the word, still in VF after a few shocks, there’s two options here that either, that they’ve gone into VF, the shock has worked, and then they’ve gone back into it, VF. So that is recurrent VF. The other chance is that they’re actually in refractory VF, so they never got out of the VF at all. So the shock just did not work. And you see, there are two groups of patients who are really quite different. And in my head, I’ve always felt that the patients in whom you have recurrent VF, they’re the ones who need to give them some sort of anti-dysrhythmic drugs to stop them from going back in, whereas the ones who’ve never ever come out of VF, those are the ones who used to have to think about different shock strategies, but we’ve never had the technology to really look at which one is which, and we still don’t do a large extent. But when you do studies like this, and you go right back into the baseline data that’s recorded by the D-Fibs, you can differentiate between who’s a refractory VF, and who’s a recurrent VF. So refractory, they never came out of it, recurrently going back into it. So in the secondary analysis of the dose of the F-trial, they looked at the 345 patients in whom they could differentiate between another of the refractory, which was 60 of them, and the recurrent, which was 285. And it’s pretty clear that when you looked at this, if you were in refractory VF, DSED had the chance of getting you back out of it, 28% so at the time, whereas if you didn’t use dual sequence, you had a 0% recovery rate. So essentially, if you’ve got refractory VF, carrying on as normal just does not work. Whether it’s refractory or recurrent, if you go for DSED, you get a better outcome. You’re more likely to get a risk, but in terms of survival hospital discharge, it was only really a benefit if you were in refractory VF. So I spoke to Chesney about this when we were out in Austria, and what he’s saying is that, you know, when you shock somebody, you’re trying to get the whole heart to be defibrillated. But if you just use one single AP or an AL, there’s often a small part of the heart that doesn’t get defibrillated. Most of it does, but that sort of small recurrent area can then restart the VF in that heart, and those are the tricky ones to sort of deal with. Bottom line is, it seems that DSED is better for any patient, whether it’s recurrent or refractory, but in terms of hospital survival, it’s really the most important for those ones who are refractory. They never came out of VF in the first place.   

So Simon, if you could summarize all of this for people who are managing cardiac arrest in the shop floor or pre-hospital environment now, how would you say this fits into the current management? Obviously, guidelines take a little while to catch up. We’re all wedded to ALS, and I think ALS is a good starting point for the management of cardiac arrest, but where does this fit in? And what does it mean to you when you have a patient in front of you who’s had ventricular fibrillation, either started with that, still got it, or never got out of it?   

Don’t get sacked is the first thing to say. Don’t get sacked by doing something which you’re not permissive to do in your service. There are restrictions in a lot of places that say that we’re not happy for you to do dual sequence defibrillation, but the evidence would suggest, and from both dose of the F and from a number of other trials which existed before this, that at the moment, if you had to say on balance, what’s the best evidence? The best evidence is if you’re in your refractory VF, you should go for a dual sequence approach. And the evidence is also there, although not as strong and not as good for hospital discharge, that if you had three shocks, a anterolateral, then you should probably change your paddle position to AP. And that is in the guidelines, and that is in the JRCALT guidelines, which is the UK guidelines, and therefore permitted for ambulance service personnel and also in hospitals. I think but check with your local people, blah, blah, blah, don’t get sacked.   

So currently obviously your safest way is to follow the ALS guidelines, but it may well be that evidence is getting ahead of that, and hopefully will be in the next update. And these are options when the patient you have in front of you needs other things. And so the dual sequence defibrillation is an option. We have also mentioned the past with this paper, the idea that just check your manufacturer’s guidelines, because not only losing your job is also not ideal, but blowing up your defibrillator in your recess room is also a bad thought. Please, as we’ve always said, don’t just do something because you heard it on a podcast, but it maybe starts a conversation with your resuscitation services, with your leads for resuscitation with some of your cardiology colleagues about whether this is an option you want to explore, and whether this is something you might think of, particularly in those patients. And sometimes here we’re talking about younger patients with primary arrhythmias, and these are the ones we can really help if we’re there quickly. They are the patients who we may be able to help with this new technique.   

So the next study, again, sub analysis dose VF, is to look at that timing for the patients who had the dual sequence, to have a look at the timing between the two shocks, because what they wanted to do was to have the two shocks one second apart. And that’s largely about keeping the manufacturers happy, because they weren’t happy to defib both at the same time. So they said, we’ll have a one-second pause between them, and that’s less likely to damage your machine. All the damage your machine actually, if you look at the days, it seems to be pretty unlikely. Anyway, that’s what they decided to do. But in reality, what happened is it was two people pressing a button, bang, bang, one second apart. And obviously there was some variation in how quickly they did it. So what they’ve done, again, is go back and have a look at the patients who had the dual sequence and said, well, actually, does the timing between those two shocks make a difference? And interestingly, it does. And this may have a change going into the future. So they divided them up into different time periods, so less than 75 milliseconds, which is under a second, 75 to 150, and a couple of others about what the timing was between the two shocks. And what they found is that if you had a shorter time between the two shocks, so you did them as quickly as possible close together, you had a better outcome. So essentially, if you had it less than 75 milliseconds, your chances of coming out of VF for 48%. If it was more than 75 milliseconds, the chances were around about 25%. And so most of the advantage of the DSED seemed to be in those patients who have a shock very, very close together. Now that’s interesting, isn’t it? Because that puts it as all the cat-mongers of pigeons again about having the two shocks together, how closely is it going to change the machines? Can we make sure that they’re OK together? All of that kind of stuff. But the principle here is that what we’re trying to do is get massive defibrillation of the whole heart at the same time, so everything is reset at the same time, and then you’ve got more chance of getting a risk. These are the people, as I’ve said, truly believe we can make a difference with cardiac arrest is a diverse set of symptoms and presentations that the patient comes to us having had lots of other things happen. But the ones where we can make the difference is there’s primary arrhythmias where the patient has ventricular tachycardia or ventricular fibrillation that’s caused them to lose their cardiac output, such that they’ve ended up on the floor in cardiac arrest. This is a treatment that works, and in those patients, we can really help. And if sometimes we can nuance that treatment, then so much the better, because this is where for me, you get, dare I say, more bang for your buck.   

Our final paper for June Simon talks about something that really took the social media world by storm. This was about non-invasive ventilation for preoxygenation during emergency intubation, the PEROXI trial. And this is one of those trials that was published at critical care reviews, Rob MacSweeney’s superb conference that takes place in Northern Ireland every year, where he gets the actual authors to come and present, often with simultaneous publication in high impact journals. It’s really one heck of an achievement by him. And I’m sure he’s got a team behind him, but it’s his passion that’s led at all. And this was one of the papers that was presented. And this is the pragmatic trial examining oxygenation prior to intubation or the PREOXI trial. People really do work hard at their acronyms, don’t they? And this was published in the New England Journal of Medicine just earlier this year. So this is about, can we make intubation in the emergency department safer by using non-invasive ventilation prior to giving the patient the drugs and then intubating them? This was talked about someone’s being as a practice-changing paper.   

Good paper. Published in the NEJM, as you say, which has some moniker of quality about it. So it’s critically ill patients undergoing tracheal intubation. We know that hypoxia is a bad thing for this group of patients. So they did a multi-centre RCT, 24 emergency departments and some intensive care units. And they randomly assigned patients to either go of a preoxygenation with a non-invasive system or just with a simple oxygen mask. Well, it wasn’t a simple oxygen mask. I liked to call it a mask with a reservoir bag, but many people would call it a non-rebreed mask. So they were randomly assigned to either tracheal intubation with a period of preoxygenation with a non-invasive circuit or with an oxygen mask with a reservoir bag or a Hudson mask, as some people call it, or, as some people say, a non-rebreed. What they were looking essentially for is whether they had hypoxia during intubation or in the peri-intubation period. And that was defined as less than 85%. And what they found is 1,301 patients are pretty decent size, actually. And they found that they had hypoxia in 9% of the patients with a non-invasive preoxigenation. And in 18% of the patients who just had the mask. So that’s quite a significant difference, both clinically and from a statistical point of view. Other factors didn’t really change that much. So they’ve said that the way forward to avoid hypoxemia in this group of patients is to use a non-invasive circuit. Now, the non-invasive circuit was preoxygenation for three minutes, fraction of the oxygenation of 100%. They had 5 centimetres of peep. They had 10 centimetres of inspiratory pressure support. And they had a respiratory rate of at least 10 per minute. Put the mask on, preoxygenate patient with this non-invasive circuit and then progress to intubation. You get less hypoxia if you do that, which kind of makes sense, doesn’t it? But there’s a couple of questions to be asked.   

You say questions. I felt from the social media outpouring that this was game-changing. And we should be doing it tomorrow. And in fact, within 24 hours, I’d been into my emergency department recess room and asked one of our expert nurses about our equipment and whether or not our ventilators could do this. You sound less convinced.   

I’m convinced that you need to preoxygenate people properly. But I’m not sure that the comparator group in here is what we do in practice. In our practice, we don’t preoxygenate people on an oxygen mask. We in the UK tend to use a MAPUS and C-circuit adults, of which you can apply a bit of peep. So then you have a spontaneously breathing patient who’s then got a peep valve that they’re breathing against. Or you can put a peep valve on a BVM. And that’s a different preoxygenation technique to just using a simple mask. It’s sort of halfway between a simple mask and using the non-invasive circuit because you don’t have the pressure support using a water circuit unless you choose to apply it yourself, which you can do if you’re skilled enough to do it. I think it’s not a fair comparator to what we do in the UK. And I think probably using a mask somewhere a bit of peep on will give you a better preoxygenation process than this. And at the moment, is this a problem that needs fixing? Well, there are undoubtedly some patients who we could do better with our preoxygenation before we intubate them, I’m sure. I don’t want to delay that decision. So for us, this process is often done by people who are visiting the emergency department, rather than people who work within it. Again, let’s not get into a debate about who should be doing interventions in the emergency department resource room. But in my hospital, it’s often a team approach with our either intensive care colleagues or an anaesthetic colleagues and will be helping alongside that too. But sometimes the equipment is not necessarily the stuff they’re familiar with. And the environment certainly isn’t and the people may be new to them. So adding in this extra step of trying to get a non-invasive ventilation machine set up, asking for it, it may not be familiar to the nursing staff, change takes time, all of

 those things do present some boundaries. And as you say, the comparator group here isn’t necessarily what everybody would be doing. I am quite taken with it as an idea ’cause for me, physiologically, it does make sense. And so I’m quite keen. I’m not perhaps in the group of let’s do it tomorrow, but I am in the group of, I’d like to investigate how we can do this and what it might take to introduce into our emergency department.   

Yeah, and I think there’s certainly some patients in whom this is absolutely what you should be doing. So the patients who are difficult to pre-oxygenate beforehand, who are tired, who are struggling to breathe, especially giving them some non-invasive support before you perceive the NRSI, absolutely, 100% that whether you need to do it for absolutely everybody, I’m not yet convinced. I think probably a wall circuit or a BVM with a peat valve on will probably get you most of the way there, but actually I don’t have the evidence for that. The evidence is in the paper and that wasn’t there as a comparison. So that’s my supposition and I’d be interested to see what other people say.   

And if you’re interested in this paper, there’s been lots in the foamed world, not least with Scott Weingart on M. Quitt with one of his free podcasts, where he actually talks to the trial authors at great length about how this trial was done and then goes into it in huge detail. So this is something you are really interested in and you’d like to investigate further. Maybe you want to go to your hospital and suggest that this is something you do. Then don’t just, I say take our word for it, read the paper from the New England Journal of Medicine and listen to what Scott and others have got to say. They are all very bright people and it’s worth hearing their opinions.   

Simon, that is June 2024, lots of content, lots to think about. As ever, thank you so much for listening to the St Emlyn’s podcast. Please do tell your friends if you think it might be something that might be interested in. We are trying to widen our listenership and we do think it’s probably appropriate for all sorts of people working in emergency medicine, pre-hospital care, not just doctors, but any form of clinician. So if you’ve got a friend who’s a paramedic and maybe nurses working in the emergency department, please do point them in our direction and not least because the more feedback we get that what we’re doing is useful, it makes us do more and that can only be a good thing going forward as we increase all of the output and bringing it to you as long as possible free to you so you can listen to it as and when you’d like to have it.   

Simon, thanks again for your time. Please do go enjoy your holiday exploring the Balkans. But for now, let’s say goodbye and we’ll talk again to you very soon.