S2:E3 "POGUS or BOGUS? Gastric Ultrasound for Hungry Doctors!"

We're about to step outside the box. Come join us to find out if you've got the stomach for this episode. I'm Amit Pawa. Starving for digestible information on pocus? Grab a taco or two and stay tuned. 

I'm Jeff Gadsden, and this is Block it like it's hot. Hey, Amit. How is it going, bro? Jeff, it's going great. Well, actually, that's not quite true. 

I've been sulking a little bit. Oh, no. Ugh. What what drama do we face this week at Casa Power? Well, it's it's not that bad. 

I I guess I've just been sulking a bit after Timberlake singing got slated a little bit after our upper limb episode. But, you know, that that kind of upset me a bit. But you know what? In some positive news, did you see that post from Arun Nagdev on x about the, another ED use of genicular blocks for acute on chronic knee pain. That was cool. 

Right? I did see that. It's neat to see how these techniques are being applied in emergency medicine and and other settings. It's amazing. And listen, man. 

Regarding the the singing gags, don't worry about it, Ahmed. I think we sounded great. Thank you so much. Speaking of which, yeah, I I mean I mean, I thought you sounded great. We should probably take a look at recording our long awaited block it like a tot rap. 

Right? You know what, Jeff? I am so ready for that. Well, apart from that, you know, my week's kinda been pretty quiet. I've been slowly saying yes to a few more speaking commitments, and my to do list is getting a little bit longer. 

Plus, I've still got to write my keynote speech for REUK, and I'm getting nervous now. I'm definitely gonna need some tips from you. Isn't that like isn't it like next week? Yeah. Well, it's pretty it's it's pretty soon. 

And in addition to that, you know what? I've got an RFI. Okay. Let's let's start with the obvious. What is it RFI? 

Radio frequency no. Yeah. It kinda sounds like that. But do you remember my PPI from one of our earlier episodes, my Peter Point injury? How could we all forget? 

Yeah. Yeah. So this isn't a PPI. This is an RFI. I've got a ring finger injury. 

So I was I was rapidly drawing up some medications prior to doing a block last week, and I managed to impale my ring finger with a clean drawing up needle. It went straight through my proximal interphalangeal joint and almost out the other side. Oh god. Yeah. And I've got some really weird nerve symptoms. 

In fact, I'm rubbing it right now. I'm getting this weird paresthesia. So I must have got a or some kind of thing. I don't know. Oh, jeez. 

Do want do you want me to block that? No. No. No. You're okay. 

Oh, hopefully, gets better soon. You know, I had a when I was when I was a first year attending, I was holding up a vial of, I don't know, ANSAF or something for the resident to draw up, you know, like, stick the needle in the through the rubber stopper into the glass vial. I don't know why I was holding it up and she was doing the poking. Okay. Seems seems like seems like a bad SAP. 

But Yeah. She, yeah, she she missed the vial entirely and stuck. And and we were using sharp needles at that point. There were the whole blunt needle thing was just sort of coming into but anyway, so, yeah, it went right through my finger. She felt she felt really bad. 

I was trying to reassure her, like, it's okay. This this is occupational hazard. Anyway, in regard man, the Bruce Scott lecture, you're gonna crush that. You you know I'm here for you, and I'll be happy to heckle from the virtual sidelines. Well, thank you very much, and I I will look forward to that. 

But, yeah, I'm getting myself all head up. It's gonna be fine, but I'm just a bit nervous because I kinda It's gonna be amazing. Thank you, man. I wanna do it justice. Well, listen. 

Enough about me. How have you been? I've been good. Yeah. Thanks, man. 

Not a whole lot. I saw Dune two. Have you have you seen this movie? Do you know what? I've missed the whole Dune thing, so tell me about it. 

I I I wish I wish I could. I was I was awake for approximately 30% of it. So Oh, no. Yeah. No. 

It's it it was a combination of it being a late night the night before. So I was Right. Tired to begin with. And then I went and had a meal with my friend Henry and Henry from the podcast? Henry from the podcast. 

Yes. Exactly right. We, you know, had a couple beers and then went to the theater. And this this theater has, like, the cushiest seats. We drove out of our way to get to this one theater because it it had reclining Right. 

Cushy and heated seats. So and it was dark, you know, I was done. That sounds like a recipe for snoozing. Right? There's no way you're gonna stay away through that. 

There's no. And and Corey Corey said that ahead of time. She goes, there's a 0% chance you're gonna stay away for this movie. So what the parts I thought I saw were good, I mean, it was, yeah, pretty impressive sci fi movie. I don't know anything about what happened, like, plot wise because I just I wake wake up intermittently, and there'd be, a sandworm. 

And then I I saw a couple of memes for Dune, that featured Joey from Friends, and there was, like, a picture of him with his face. It was like, how you doing? But doon Dune say, did you did you see this? No. I didn't. 

That's good. Alright. Cool. Well, that's something for me to to think about. So listen, Jeff, what are we gonna talk about this week? 

So here's the thing. We we've talked about some pretty big regional anesthesia topics so far, and there's lots more to chat about, moving forward. But I think it's time to spread our wings a little bit and, you know, kinda think outside the box. Hey. Hold on a minute. 

I'm scared, Jeff. I didn't realize we were in a box. What what are you gonna make us talk about? You you look like you're in a box right now. Listeners, if you You you bet you better clarify this. 

Amit has has shifted his recording studio to an empty room, and there's a bit of reverb in the background. So what we decided to do for this this particular recording session is just drape his entire setup, including him with a with a big duvet. So this is a this is an amazing image. I wish you could all see this. I hope you haven't taken a screenshot of this. 

I have taken a screenshot. But but, yes, going back to being outside the box that I'm in right now. Yeah. So having just released a video on this topic, I thought we could talk about gastric point of care ultrasound Wow. And get into some of the pros and cons of that. 

What do you think? Okay. Listen. I sent some controversy about this, and I'm definitely gonna need you to walk me through this kind of, like, some real time c CME, but but I'm I'm keen to get into this. But before we do, I just wanted to ask you something. 

So I've heard people call this so we're, of course, we're talking about point of care old ultrasound, which many people will refer to as POKUS. I've heard people refer to this as POGUS, point of care gastric ultrasound. Have you heard of that, that that use of that term? I I haven't actually, but I I kinda like it. POGUS. 

Yeah. It's like pogus Pogus. Yeah. Okay. So so let's stick with pogus. 

Pogus sounds like a character on another sci fi film or something like, you have to go and find pogus in his cave. Yeah. Exact and, again, the cave thing very much fits the imagery of the of the scene I've got in in this inside this cave. Intentional. Okay. 

So let's let's get into it, man. So so where where do we start? Because there's been a lot of interest in the jobbing anesthesiologist learning pocus. So the the people are really excited about this because it it seems like we're good at using ultrasound to do nerve blocks. So this feels like it's a natural extension of our skills. 

You agree. Right? Absolutely. Yeah. And so, you know, we've seen people who are doing central lines and nerve blocks every day just naturally transition over to scanning the heart and the lungs and the IVC and the stomach and the bladder and all that kind of stuff. 

So but I think what has made the gastric stuff even more relevant and urgent right now for us is the rise of some of these medications that delay gastric emptying. Which medications? The GLP-one agonists specifically. So there's been a lot consternation and hand wringing and chatter about, like, what do we do with these meds? Because we have seen and and the you know, different societies have come out with guidelines about what to do with fasting and how to change the fasting intervals. 

But despite that, like our protocol at one point was, okay, we'll just stop the medication a week beforehand, you know, and it's a weekly injection, the most common ones like Ozempic and Wegovy. But even despite that, we have begun scanning every patient for gastric contents and a substantial number of those are still full. Wow. Even though they've stopped their medications and are fasted for, you know, sometimes up to twenty four hours. So this is a problem. 

Like, I've canceled elective cases because they come in and they're like, can't safely put you to sleep or or give you a sedate deep sedation knowing you have a full stomach. So that that I think there's a lot of work still to be done as to what is the right way to handle those particular patients. But in the meantime, we can use this super quick, super easy, simple technology to just quickly, you know, say, oh, yep. You're full or, yep. You're safe. 

I mean, the other thing we've noticed is varying, between institutions. People have got different starvation guidelines, and we don't really know what the right answer is. Should you be starved for six hours? Does it matter? Some people allow you to drink water right the way up until you have the surgery. 

So I guess having a tool like this could potentially give us the answers. So I guess the questions we're asking is, are you starved or not? Right? Yeah. The history of this of this starvation or fasting guidelines is really interesting if you get into it. 

So they are largely based on observational studies of people back in the eighteen hundreds and early twentieth century. So if you eat a quail's egg, how long does it take for that to get through your stomach? And and it was really fascinating study that was done by and I forget who it was. I'll try to find it and put the link in the in the description. But there was a patient that had a gastro cutaneous fistula. 

And so the clinician could, like, actually watch what was happening in his stomach. So this patient would eat something, and then he'd make these little handwritten notes. Patient ate porridge today, and it took six hours to get through. Or That's that sort of thing. So that's where this knowledge comes from. 

Is that right? Yeah. Yeah. I mean, that's one of one of the sources. But for the for nearly a hundred years, our fasting guidelines were based on that kind of observational data and didn't really change. 

And and so there's not a lot of hardcore good science. And and what we also see is a ton of variability. So, you know, what what fascinates me sometimes is like the patient will come in and for an urgent case or maybe maybe a semi elective case is a better example. And that surgeon will say, well, they ate at 8AM. When can we go? 

Uh-huh. Expecting there to be an answer like, well, eight plus six equals 2PM. So but that's not reality. Right? Like, very few human beings actually stomachs adhere to those six hour numbers. 

Again, it reinforces the need for an objective Yeah. Quantifiable image guided test that you can just quickly put on, and in thirty seconds, get an answer. Okay. Well, listen. I'm gonna just stop you there. 

Right? So what difference does it make? Because if they've got a stomach which you consider not to be empty, why can't you just, you know, thiosucks tube them? What's the big deal? If it's you know, if it's emergency surgery and you gotta crack on, you'll do that anyway. 

Right? Well, it's true. And and so there there are cases where you think to yourself, well, either way, this patient has to go. Yeah. And so for those cases, it doesn't oftentimes truly influence our management because either way, I'm treating that patient like it's a full stomach. 

You said Pentothal. Is that right? Yeah. Thiopentone. Yeah. 

Yeah. That that used to be the thing. Thiosuctube. We we still got thiopentone. We don't in this country. 

And I think it has to do with the supplier manufacturer in Europe not wanting to make it available to Americans because prisons were using it for capital punishment. Oh, gosh. Yeah. Yeah. Yeah. 

I remember hearing about that. And so there was, like, the last manufacturer in Italy or something, know, took a stand and said, we're not gonna support that. But so yeah. Pro but probe sucks tube. Okay. 

Probe sucks tube. Yeah. Right. So there there are cases where it is doesn't matter. The case has to go, we're gonna do something and assume they're gonna have a full stomach. 

Yeah. At the same time, you you can characterize it. Is there something in there? What is in there? Is it solids or is it liquids? 

And how much is in there? So do I need to pass an OG tube down and suck out as much as I can while the patient's already asleep? Right. But interestingly, there was a study out of Switzerland that was published in anesthesia. The lead author was doctor Beitig. 

And they scanned both emergent and elective patients that were coming through for surgery. And what was interesting to me was that in the emergent patients, the airway plan got liberalized in eighteen percent of cases. So they these are patients that would have gotten a rapid sequence induction with an endotracheal tube, but they said, oh, actually, even though you haven't been fasted for six hours, your stomach is empty, we can do something else, deep sedation with no airway device or LMA or something like that. Right. And, you know, potentially avoid the morbidity associated with an RSI or a endotracheal tube. 

I mean, that's interesting. But what I'm kind of interested though is when did gastric ultrasound for this side sort of indication really become a thing? Because I remember I I know Anahi Perlas had done some work on this. I'm sure there was another another name, Van de Puter or something. But but, you know, have you done some research into this? 

When when did it all start? Yeah. I remember I can remember this coming about I was a co resident of Anahi Perlas's, or I was a year behind her at University of Toronto. So it's really interesting to me when she made this Uh-huh. A real focus of her her research, and she became the authority very early on. 

I think it was 2009 is Right. Is the first day I can remember when she published. Is this feasible? Can you do a point of care assessment? People had scanned the stomach for different reasons and different studies, you know, back to the eighties, but this that was the first time someone said, I wanna influence clinical decision making at the time of surgery, and she showed that it was it was feasible. 

And then, yes, Peter van de Put and Anna Hee were the early pioneers and wrote a lot and did a lot of the early research. Okay. So so we've we've got this idea. We've got this concept, and so you got your probe out. What are the type of decisions you can make? 

When you got that probe, what are the what are the the answers you can get? So when you stick a probe on, what are you likely to see? So the first the there's two bits of information you can get from from this. One is qualitative, which is what is in the stomach, and then the other is quantitative, how much is in the stomach. But just to back up a second, you're gonna put a probe in a sagittal position in the midline just below the xiphoid process, and the part of the stomach you're going be imaging is the antrum. 

And that's the part that is sort of the last bit of the stomach before it becomes a pylorus. It's a reliable cross section of the stomach to say whether it's, you know, whether there's stuff in it or not. What's easy about that is it kind of lines up with the aorta and the spine. So if you put the probe on and you kind of slide back and forth a bit until you see that pulsating aorta or in a slim patient you can see the spine a lot of times, you know, okay, for sure that's the antrum, now look inside it and see what's there. And you can make a very quick decision, is it empty or has it got something? 

And then if it's something, you can look at the characteristics of it and say, that that looks like clear fluids because it's dark and it's sort of swirly or they're sort of two characteristic patterns for solids. The early solids have a lot of air in it, there's a frosted glass type appearance, which if you see that, you're done. You're like, okay, stomach is full. End of story. Mhmm. 

And then as the air begins to settle and and the stomach churns up all that solid material, it becomes more like a soup. And so you see this kind of mid grade homogenous material Right. As as a solid part in the stomach. That's the qualitative part. You can say empty, clear fluids or solids. 

And what's important to mention here is that you should be doing this exam in two positions. So you start with the patient supine because most patients come to you supine and it's easy. So you put the probe on and if you see solids or liquids, you're done. Full stomach. Then you're done, right? 

Yep, exactly. But if you see an empty stomach in the supine position, then you turn them on their side, so right lateral decubitus, Put the probe on again and see if anything has changed from the empty supine position. Because what sometimes happens is if there's a smaller moderate amount of fluid that's sort of trapped in the or settled out in the fundus or the body of the stomach. Right. When you turn them to the right side, it'll spill into the antrum, and then you're like, uh-huh. 

There. Now I see some some clear fluids in the antrum. I saw a cool little thing in your video that you made on point of care gastro ultrasound where you showed, like, a can and changing the position of the can and just showing how the fluid can settle from exactly as you described from from the fundus towards the antrums. That's a cool way to think about it. Yeah. 

Thanks. I'm a I'm a simpleton, so these little simple analogies help me personally. But, we do and we see that sometimes. We we put the probe on, and and so I remember, a fellow was like, oh, look. It's empty. 

And we thought, okay. Hold on a second. Let's just turn them on their side and see. And sure enough, there was there was some clear fluid that settled out in the antrum. And then what you can do with that information is, again, if they're supine and you see stuff in the stomach, then the implication is there's enough in there that you should consider that a full stomach. 

Right. If you see empty and you turn them and it's empty, that's that's called a grade zero stomach and that's you're empty. Proceed as you normally would. If you see empty on supine and some clear fluids that settle out in the antrum in the right lateral, that's a grade one stomach. And the implication there is it's probably less than 1.5 mils per kilo or about a 100 mils. 

And that's associated with, you know, a very small amount of either routine background gastric secretions or a small amount of clear fluid. So that's probably okay to go ahead. Well, listen. I I I think it'll be useful in the later part of the podcast to go through the sequential process by which you do this, but I wanna ask some questions that I think are important to ask, certainly for skeptics or newbies to this technique. What is the evidence that gastric ultrasound scanning makes a difference? 

Is there any evidence, and should we be using this to inform decisions? There are some data. And so Jamie Cieslak and and I did a study back in 2020 that we published where we looked at elective patients under the the schedule for GA, and they were all, you know, quote unquote fasted Uh-huh. The right amount of time. And we asked the anesthesiologists who would be looking after that patient that day, hey, what's your anesthesia plan for this patient? 

Got it. Great. And then we scanned the stomach, and fourteen percent had solids. Fourteen percent. Wow. 

And this is pre GLP one agonist time. Seven percent had clear liquids and so there's about twenty percent of patients had a non empty full stomach. Then we went back to them with that data to the anesthesiologist who were looking after them and said, hey, this is what we saw. What are you going to do with that information? About ten percent changed the airway plan. 

So if that's the case in convenient sample of a 100 patients that were going through for regular elective surgery in 2020, ten percent of the airway plans changed, I think that's important. Well, you know, I think this is I wanna share a story here. So, Ara UK, in conjunction with the Association of Anesthetics, did a a a a pocus course, and and, you know, we had some really big poker stars there. So we had Kareem Elbock Dudley, Rosie Hogg, Johnny Wilkinson, Justin Kirk Bailey Seggs, who's Iceman x on on x. They were all there teaching us how to to do the whole gamut of point of care ultrasound, actually. 

So we did the cardiac, lung, and gastric. Yeah. And after doing that that course, I kinda had a little bit of confidence with gastric, ultrasound, and I had to anesthetize a patient who was having, elective shoulder surgery at a hospital that, you know, was relatively new to working at. When I went to go and do my pre op assessment, I asked about starvation, and he sort of said, oh, yeah. Yeah. 

I had, like, I had a coffee. I thought, well, how long ago? And he said, oh, about about two hours ago. And I said, was it black coffee? And he said, yeah. 

With a splash of milk. I said, really? How much milk? He said, oh, just a splash. Okay. 

And I actually had my own I had my own ultrasound with me at the time. I had a a a handheld ultrasound. I said, do you mind if I just have a quick scan of your stomach? And he sort of said, no. No. 

That's fine. I said, it's just to see how empty your stomach is. So I I I did what we're about to describe in the second part of the podcast. It's you know, went through the sequence. I put the probe on his stomach, and he had full solid material in there. 

It's kind of like churning around. And I said, I said, was it just, was it just a little bit of milk? He said, actually, it was a latte. And so Actually, it was mostly milk. Yeah. 

It was basically mostly milk. And I take it at face value. I might, you know, I might have got caught with my proverbial trousers down. Hopefully, not literal trousers down, but yes. No. 

Not not yeah. Yes. Yeah. Sorry. It's just that being under this duvet, I'm suddenly starting not to be able to think properly. 

But yeah. So so it Are you sweating? It was definitely I'm I'm sweating just a bit. So it's definitely a role. I I I think that helped me in that indication. 

Yeah. So I I don't I I don't know. You know, we should I have just cracked on with a tube anyway? In that particular case, we deferred the surgery. But I just wonder whether there's there's if there's any downsides to learning it. 

And at the moment, I can't really I can't really see that there is. Do you have any other anecdotes apart from the ones you shared already? Well, we've we've it's gone both ways for us too. So we have scanned people. Another common well, relatively common scenario that comes up is surgeon comes up and say, I had this case. 

I I just saw in the emergency room. I'd love for it to go today, but they ate three hours ago. What do we do? Uh-huh. An easy answer based on our American fasting guidelines would be, well, we're gonna wait six hours. 

But now we just say, hey. Bring him bring him or her up. I'm gonna scan the stomach. Yeah. And sometimes it's still full, but then sometimes it's empty. 

And we can say, hey. Dude, let's do it right now because we can safely do it. I think the clinical decision making can get nuanced and complicated depending on the urgency of the case and the the consequences of waiting versus, know, cracking on ahead. There's too many combinations to try to go through today, but but just at least knowing what you're dealing with objectively and empirically can, can help. Right? 

Okay. No. I I I I can definitely see that, and I'm kind of you're slowly starting to convince me that maybe there's a role. But I I wanna go through a sequence of how we do that. But before we do that, I think it's time to take a very quick joke break. 

And Love a joke break. And it won't surprise you to know that I have some episode themed gags for you. So we'll start off with the first one. What do you give a deer with an upset stomach? What? 

An Alka set seltzer. Alka Elka set seltzer. Get get it, though. Yeah. No. 

I maybe I ruined the delivery. Okay. Okay. Well, is that No. No. 

No. I it's it was good. It was good. Okay. I've got one more. 

A local glassblower inhaled whilst at work. He ended up with a pain in his stomach. Okay. I like that one. That's good. 

Okay. I sort of have I've got one more. Why did the customer feel sick after he ate a salad? Don't know. He had gastroenteritis. 

Oh. Yeah. Okay. That was bad. Listen. 

I think, again, you're gonna have to raise the level of the jokes here. You got something I like the glassblower one. One out of three, that's not bad. That's not bad. What's pretty impressive is they were all they were all thematic as well. 

Completely. Oh, yeah. Well done. Thank you. Mine is not thematic, but I I it is it made me chuckle. 

So where do bad rainbows go? I don't know. Tell me where do bad rainbows go? They go to Prism. It's a light sentence. 

Oh, that was the second part to that. I like it. Yeah. Listen. Just moving away from jokes for a second. 

I got a couple of questions emailed through to us, by a doctor Tim Moll, who's a friend of mine. He works in Sheffield. And he wanted to ask about differential blocks for hand and wrist surgery. And his question was, they currently do short acting auxiliary brachial plexus blocks, and they do long acting distal nerve blocks. But he wondered after listening to our last couple of episodes whether there is a reason that they should consider a move to infraclavicular brachial plexus blocks and use the same strategy there. 

So moving from auxiliary, short acting blocks to infraclavicular short acting blocks with long acting distals. What do you think about that? I think I think either are fine. I mean, I wanna I think about my decision making as it relates to what brachial plexus block I want to do. I typically default, if it's just me, to infraclavicular, as I think you probably do too. 

Yeah. Our reasons to do axillary are sometimes anatomical, like, just cannot see because the patient's so big. Yeah. Or it's for teaching benefit because the trainees want to see some because you don't do so many these days. Uh-huh. 

Although I love it. I I love it. I love a nice axillary. And, you know, it's it's the plan a upper limb block according to that paper. So, so I think, Tim yeah. 

Either either way, I I think, that's what I would do too. That that's my sort of split differential recipe as I'll do a a short acting in for clavicular with lidocaine or mepivacaine and then pick off the little ones distally with bupivacaine. So it's interesting is when I, when I initially responded to him, essentially, I said to him, if it ain't broke, don't try to fix it. If you've got a system you know, they've got a whole system where they've got their practitioners trained up doing auxiliary brachial plexus block. I said, you know If if it's working for you, don't change the proximal technique just because you feel that, you know, we're saying it's better. 

If you're comfortable and confident and you've got a program activity where everyone's happy doing it Yeah. Then, you know, then then there's no need to change. Agree. We happen to think, you know, through through our practice that the infracurricular is better. But, you know, in another people's hands, they may be faster and slicker and more efficacious performing auxiliaries. 

And, of course, if you take on a new technique, there's always gonna be a learning curve associated with that, and there's a potential that things may go downhill a little bit. So Agree. And before we get back into it, I do have, our friends at Salisbury's. We bumped into them recently, and Charlotte Salisbury had, she knows I like, Star Wars. So she came up with one joke for me. 

Okay. Okay. Good. Good. Charlotte. 

Okay. Here we go. Alright. So Charlotte said, how does Darth Vader like his toast? Join the join the dark side, the life force. 

I don't know. You almost got it there on the dark side. Oh, I I I completely missed that as I was thinking about that too. With Charlotte, well done. Again, Charlotte's on fire with these jokes. 

She's she's coming out with a great, great content. Okay, man. Let's let's get back into it. So I want you to imagine that I'm your resident, and and I know be because of that vast age difference between us, it's not that much of a, of a stretch of imagination. So let's talk about how we're gonna perform gastric point of care ultrasound. 

So, you know, we've got a patient who wanna do this in. I've got an ultrasound machine in front of me. What probe am I gonna use? Right. So, ideally, a curved probe. 

That's what you're gonna need for the majority of patients, and that allows you to see not only the depth, but the side to side stuff. So you can see the liver as a landmark, as a sort of landmark, and then some of the other, you know, vessels in the spine and all that kind So, of now in a slim adult or a child, a linear probe is fine. So we do want a mixture of depth and the width of the footprint. Right? So you're kind of saying in the average patient, might need you know, the curved array will be ideal just because it allows you to penetrate a little bit deeper. 

Yeah. And and get you to more of that side to side view. Yep. But you could potentially use a linear probe with you know, some of these machines have a virtual convex component to it as well. Right? 

Or that the trapezoid function or whatever. Yeah. For sure. Yeah. So you're gonna put the probe on in a sagittal orientation right underneath the xiphoid process. 

So pretty easy to start. Right? There's not a lot of calculating Euclidean geometry or anything like that. Just slap it slap it on the midline. Straight in the midline. 

And then 90% of the time, that's exactly where you need to be. Sometimes you need to to shift left or right a bit in order to get the right cut of the stomach. And as you said, the right cut is the antrum. Now, the antrum is easily Okay. Identified with a couple of clues. 

Number one clue, aorta lies beneath it. And that's a typically easy thing to see in a lot of patients, right? Because you I will be scanning it in long axis, so it'll look like a long tube. Long axis, right. So it'll look like a long tube, it's pulsatile. 

Now sometimes you scan it a little bit further and see the IVC and like, that's IVC and that means that's aorta and that sort of thing. That takes little bit of practice, you can identify that. And then in a lot of slim patients or, let's call them medium sized patients, you can see the bony spine as well beneath the aorta. So that that tells you, yes. I'm in the midline. 

I'm lined up with what should be the antrum. Now we often hear people talking about a couple of other structures there. Right? One of them is a superior mesenteric artery and the other is a pancreas. How important is it for us to be because I can imagine I can see liver. 

I can imagine I can see the aorta and the spine. How important is it to see the SMA in the pancreas? To me, it's a good question. And I when I was first learning this, I got really discouraged because I was I was trying to see these structures, the superior mesenteric artery and the pancreas in every single scan and I was finding I couldn't and I thought I'm just a bad scanner. And it turns it's not that important. 

So it it's cool if you see it. It's it makes for neat teaching and you can say, oh, there's there's SMA coming up. But the SMA is often curvy when you get these, you know, one in fifty scans where you can see aorta and a beautiful vessel coming off and arching over inferiorly and you say, oh, that's the SMA. It's wonderful, but not important, I find. Because all you're all you're really trying to do is make sure you can see the stomach. 

Okay. So that you'll see the the liver on the superior superior side and it kind of the the inferior edge of the liver kind of hugs or arches over the antrum. So the antrum is just below that and then below the antrum you'll see the aorta and the spine. Now the antrum has a very characteristic appearance and like anything else with ultrasound guided skills, as you do these, you begin to develop a little library in your head of what the antrum looks like. If you scan with someone who's used to scanning this and you can they can confirm for you, yep, you're right. 

That is the antrum. Then you'll begin to build that library for yourself. When it's empty, it often looks like a bull's eye or a target. Yeah. So I've heard that before. 

Yeah. And that's because there are there are five different layers in the wall of the antrum of the stomach and it echogenicity of the different layers like the serosa is a bit bright and then you have this thick dark muscle layer, the muscularis layer, which looks dark and then you go back to the bright layers of the submucosa and the lumen mucosa interface. And so you have the bright, dark, bright and then sometimes a little bit of dark in the middle of that which is, sometimes a bit of trace fluid. So that gives you that sort of ringed structure of a target like an archery target. Right? 

Now it doesn't always look like that. It's nice when it does and it's this sort of circular target sign right underneath the lip of the liver. You know, like, oh, there's Antrim. Sometimes it just looks like a deflated soccer ball. I tend to think of it as, yeah. 

Right. Okay. But the key is seeing it in the right cut. So aorta and spine, just below the lip of the liver, and whatever that hollow viscus is right there is gonna be the antrum. Now, and you said when we start off, because patients often come to us in the supine position, we start scanning them in the supine position because there are certain parts of the algorithm. 

If you see stuff in that position, then they kind of you're done. You don't need to move them. Right? So Exactly. Starting off supine. 

And does it matter where you have the probe marker oriented? So, you know, does it need to the probe marker go towards the head? Yes. So traditionally, the probe marker goes to the head so that every scan should look similar. And so you have the you'll have the head side on the left with the the liver kinda in that sort of northwest quadrant. 

Okay. So let's imagine we we start the probe on exactly as you described it with the patient in the supine position. I remember in your video again, you talked about there are four types of qualitative assessment that you can make. So I'm guessing the first one is empty. You've got a starved patient and you've a bull's eye allowing for the fact that, yes, it's empty in the supine position. 

So that's one view. Yeah. What else might you see? Exactly. So empty is the first one. 

And then the next pattern you can see is clear fluids. And clear fluids are are easy to recognize as well. Imagine that that antrum which has if it's empty, it's kind of like it looks like a a sphincter. Right? Like it's all compressed and so you get that that almost like corrugated look of the muscle because it's all shrunken in. 

But then when you have clear fluids, imagine that's expanded so the antrum becomes a bit thinner Yes. And it's filled with something and that something looks like dark fluid like we're used to seeing when we inject local anesthesia. Now a lot of times if someone has recently consumed some some clear fluids or if the clear fluids have carbonation bubbles in it, you'll see this these little starry night type appearance with the swirly little dots in the dark fluid. But that represents clear fluid. Okay. 

So that's number two. And then there then there are two types of solid pictures. The first is the as I said before, the early solids, which because we often swallow a lot of air when we're eating and swallowing, that air creates this frosted glass Uh-huh. Interface at the superficial part of the antrum, and then it's all artifact below that. So you can't see anything, and all you see is this frosted glass, and you're like, great. 

That's full. That's all we can say. And that will look grossly abnormal as opposed to that bull's eye sign or that something height slightly distended antrum, which looks starting out. This will just look all messed up and and, like, shreddy, kind of look really weird? Yeah. 

You'll see your is your liver and your your rectus muscle, and then you'll see underneath that inferior lip of the liver, you'll just see this this rim of frosted glass and then nothing below that because you because you can't penetrate beyond the air. So you're like, great. I'm it's full. Now I now I know. Okay. 

That's number three. And then so what's number four then? So then as the air gets dispersed with the churning movement of the stomach and the food the solid chunks of the food begin to be digested, it becomes this it becomes chyme. Right? Like the soupy material, like a smoothie. 

Chyme. I haven't heard that for a long time. I know. I I've pulled it out of, like, you know, these little medical school facts that live in the back of my mind. Impressive. 

So it looks so you'll you'll begin to see things again because you don't have that air interface and what it'll look like, it'll it'll again, the enterobe will be expanded but you'll see a non black Okay. Type of fluid. It'll look lightish. Right? Like a like, imagine what a smoothie would look like in your stomach. 

Okay. So I got that. So we got four four appearances. Now in the supine position, which of those outcomes would make you think, okay. Well, the stomach is full. 

I don't need to proceed to move them into the right lateral position. In the supine position, if I see empty, then I'm okay with that for now. And that probably means my stomach is empty truly. If I see anything but empty, if I see clear fluids or if I see solids Okay. That's a full stomach. 

Okay. So let's assume we see empty, in the supine position, then you're saying the next thing we should do is to move them into the right lateral decubitus and then repeat the scan. Right? Correct. If you see empty in the supine, you're not done yet because you have to turn them on their side scan again to see if you've tilted any of that stomach content into the antrum with your position shift. 

Do you have to wait a period of time before you then start scanning? No. It's it's it's pretty instant. Yeah. And actually, I'm just gonna pause here and say, a really fun thing to do is to well, it depends on definition of fun. 

You can tell what a tell what a like Well, we know what your definition of fun is. Right? Ultrasound nerd I am. So is to fast and then come into come into work with a bit early with a coffee and then like a smoothie or something. You know, get get the probe on your on your stomach in the right lateral position. 

That makes it easier. And then Uh-huh. In real time, watch what happens when you go from empty to clear fluids, and you'll see the antrum expands. It's really cool. And then take the smoothie and watch that clear fluid that's in your antrum suddenly get infiltrated by this thick fluid. 

It's really it's really instructive. And will we get will we get frosted glass, or will we go straight to your smoothie like stuff if you if you're having a smoothie? What I found is it depends on how you swallow. If you if you yeah. If you're careful about it and try just to, you know, glug glug the smoothie with a you know, without sucking a lot of air down there, you can get just that homogeneous full appearance without the frosted glass. 

Deal. Right. Listen. I often fast when I go to work anyway. So I am gonna do this, and I'll see if I can post a picture, on X or Twitter or Instagram. 

That that's this sounds like a challenge. You know, just just getting back to the fasting guidelines for a second and how inaccurate they can be. When I was making that video, I had my two older kids with me at a workshop. I'm like, hey, guys. You know what we're gonna do? 

We're gonna get you in early the next morning because they were ultrasound models. Duke and Reef, we said, alright. Don't eat or drink anything when you get up in the morning. They must have loved you for that. I know. 

Reef still talks about it. He's like, you force fed me water to get that image. Anyway, so I scanned them when they were quote, unquote fasted. Now, I will say that we had gone out for a decent Mexican meal the night before that finished up probably around 8PM. Right. 

But then I scanned them at 7AM, and so that's eleven hours. Right. They should be fasted. Should be fasted. Both of them are full. 

What? Yeah. Yeah. Yeah. So, when I see that in real time, I'm like, man, how many patients am I potentially putting at risk for gastric aspiration just because they follow the ASA guidelines? 

Especially if they went out for a a curry and some beer the night before. It does make you think. Right? It does make you think. Yep. 

Okay. So I'm so I'm gonna sort of take us on a little bit further with this process. So we we've got this information. So if they're empty in the supine and the lateral position, you call that a grade zero stomach, which is low risk. Right? 

That's right. Yep. Absolutely low risk. And you and you said there's evidence for this. So if people start quoting this stuff, there is evidence to back this up. 

Yeah. This grading system of grade zero, grade one, grade two, which we'll go through in a second, it has been well validated in slim adults, in obese adults, in kids, and in pregnant patients. So it's very reproducible and an objective. Okay. Well, that's good to know. 

Okay. So now let's say we we're in the supine position, we're empty, but in the lateral position, we get some fluid. So that you classify as a grade one stomach. Right? That's a grade one stomach. 

And so the assumption there is you've got less than one and a half mils per kilo or roughly a 100 mils in your stomach, which is associated with baseline gastric secretions. So the assumption is that is also low risk for gastric aspiration. Okay. And then I guess the follow on from that is if you've got fluid in the supine and the lateral position, that would become a grade two stomach, which would imply, if I follow your argument through, that you've got more than 1.5 mils per k per kilo, and that would then be high risk. Right? 

Exactly. Yep. So if we see clear fluids in the the supine position, we'll often not even bother to scan them laterally because that automatically is a grade two stomach, which makes them high risk. Wow. This is really interesting. 

So that's all the the, the qualitative stuff. But in your video, you made reference to this quantitative exam that you can do, which involves looking at the cross sectional area of the of the, antrum. So once you've got the information and you work out what the cross sectional area is, what can you do with that? Right. So it's important to understand the grading system, the qualitative grading system is really, really it's well validated and reproducible and is enough to help make your decision most of the time. 

So you don't have to bother to quantify much of the time. Now, where the quantification helps and it only helps in clear fluids. So for solids, you're done. Right. Empty, you're done. 

You're done. But if you have clear fluids, for example, that grade one stomach, nothing supine, but I have some clear fluids when I'm lateral, then you can further refine your assessment and say, much clear fluid? What you do is you pause the image, freeze it, and then you can use a couple of different tools. You can use the ellipse or the tracing tool or or or, you know, calipers to calculate the cross sectional area of the antrum and it's important to make sure you're including the muscle layers and the serosa. So the entire organ, not just the fluid within it. 

And then once you have that number, then there's a, again, a well validated nomogram that Doctor. Perillas has published in some of her papers that she developed where you say, okay. I've got a patient of this age and this cross sectional area, and you follow it along and say, okay. That means they have 243 mils in their stomach, and that gives you a much more refined, precise value. Listen. 

This I mean, I'm sorry to interrupt. This all sounds really interesting. And, you know, I'm kind of you had me up to the qualitative stuff. I get that. But once you know you've got over a certain volume, what difference does that make clinically? 

You know, how are we gonna use that data? If you know that somebody's got more than 1.5 mils per kilo of fluid, that should be enough. Right? So do we need to know that extra information? And what can we do with that quantitative data? 

It it's a good question. I mean, I I think that if what we're looking at is reducing the risk of pulmonary aspiration of gastric contents, then just saying yes, no as a binary question is often enough. Now sometimes we'll have someone who's, you know, chugged a carbohydrate drink Right. Before their surgery because they were told to. That's part of this enhanced, you know, recovery pathway. 

Yeah. And that's a whole different topic that we can get into. But and we'll scan them and say, okay. Well, you have two hundred mils. Let's wait forty five minutes. 

I'll scan you again. Because the emptying time for the stomach with clear fluids is twelve minutes. The halftime is twelve minutes. So if you wait, you know, twenty minutes or thirty minutes and scan them again, you may find, oh, indeed, your quantitative volume has dipped now below down to a safe level, 100 mils or less. Well, listen. 

I wouldn't be complete to talk about this without talking about some skeptics. Now one of our, online colleagues, Hans Hugnik from X, says he says, you know, patients with empty stomachs can still aspirate bile, and we shouldn't be postponing urgent surgery. And he was quite forceful with his thoughts against gastric ultrasound. Said that there's no point we shouldn't be making airway decisions based upon based upon pocus. And is there any evidence? 

So how would you respond to that? Because I don't feel qualified enough to make an answer, but I think it's a valid point. Well, yeah. And I I I appreciate Hans's stance on that. And and I think that when we're thinking of adopting an intervention or a a diagnostic test like this, one of the questions is what is the risk? 

What is it what is it or what is the hassle factor? The hassle factor is very low. The this is really easy to learn. Hassle factor to do the investigation, you mean? To do the yeah. 

Like, I'm sending them down for a a CT angiogram, that's a whole different hassle factor. Right? And and comes with some risk. This is a non ionizing radiation. It's it takes all of thirty seconds to do this. 

And the learning curve is is quick. So it doesn't take you don't have to go to a a week long course to learn this. You can get a very good precise answer quickly to get that data. But then to his point, what do you do with that? I I would argue that it does change my management sometimes and it in both ways. 

So there I have canceled cases. I have delayed cases Right. In cases where I I found unexpected contents in the stomach or change my area management plan from LMA or spinal with deep sedation, which is I don't think a safe thing to do with someone with a full stomach Right. To, you know, controlling their airway with a rapid sequence induction. And the other way too, so I've I've used that data to say, oh, you know what? 

I would have done a an RSI with a tube in you, but I can avoid some of the potential morbidity of that Right. Because your stomach truly is empty, and I'll just do an LMA or sedation. So you definitely have changed your practice based upon this, which is really interesting. Yeah. So, you know, the other thing I'd be curious to know because that and actually, Hans makes this point as well. 

We're starting to allow patients to drink clear water. In fact, we've got something at our place at Guy's in Saint Thomas' called Sip till Sends. They're allowed to sip water right the way up till surgery. I'd be really interested to know what point of care gastric ultrasound is showing in those patients and whether it's associated with still having an empty stomach if the, you know, if the empty time is twelve minutes. That's something we should really look at because we're doing sit till send on the basis thinking about it. 

It's better for patients', satisfaction. They're more comfortable. But but are we exposing them to more risk, or is the stomach truly empty? I don't know. It's a really good question. 

And I I wanna say I totally agree with liberalizing fasting guidelines because I think there's a lot lot of good data about patient satisfaction and dehydration and Yeah. PONV and just feeling better. So I'm I'm all I'm on board with that. But we have found that with the carbohydrate drinks and, you know, we let them go till about two hour two hours ahead of time as is the guideline. So but a lot of them are are literally chugging stuff at at the two hour points and say, alright. 

Now I'm now I'm compliant. It'd be yeah. I think it'd be fascinating to actually take a cohort of patients in whom you are doing this siptal send, and just prior to injection of anesthesia, make an assessment of gastric contents. Okay. Well, that's something for somebody to do. 

Maybe one of our listeners might wanna do that and and present as a poster or a paper somewhere. That sounds like a cool thing to do. Yeah. And and then and I just wanna talk about one thing. So Nav Sidhu, who's one of our our ex followers from from New Zealand, he made the point there was a recent video, that came out talking about point of care gastric ultrasound. 

And within that video, part of the demonstration showed what possibly, according to our qualification here or our quantification would have been a a grade one stomach, with a very small amount of fluid. There's a trace fluid, but they did a cross sectional area in that particular video and and and consider there to be in fact, looked at the cross sectional area up to 10 centimeters squared. But what Nav pointed out was actually looking at trace fluid in that, that was probably the incorrect use of this technology. Do have you seen that? Do you know what I'm talking about? 

I I did see that post. Yeah. I I think that one of the highlights is the need for repetitions and education and and doing doing a lot of scanning, but doing it with someone that's competent and has seen a lot to say, yes, you're right. That is Antrim and it's empty or that's not Antrim. Just shift over a little bit here until we until we're confident with that. 

So Right. It's not it's not terribly difficult, but like it like anything else with ultrasound guided skills, it's a lot of pattern recognition. So making sure you get the correct pattern is is important. And also, I think it's stressed the importance about using the correct online resources. So I'm gonna take this as a second to promote your latest point of care gastro ultrasound video, which I have to be honest, I love the style. 

I love the I love the way you use that educational material, but do it in a fun way. You know, man. It always very clear. So we would definitely signpost that video. And in the tweets that will follow, release this podcast, we'll make sure we we send the link for that there. 

Now tell me tell me, does billing have feature when it comes to, point of care ultrasound gastric ultrasound in The US? Does it have a billing implication? Yes. You can. So, I mean, I'll give you my personal answer, which is I don't care. 

I mean, I'm I'm doing this to to get an answer that might save a patient's life or or change my change how I do an anesthetic. But, you know, we work hard for all this, and and we're expending resources and thoughts and energy on dealing with that data. So in The US, you can bill for focused gastric exam. That billing code is 76705 for what it for what that's worth. And it does require that you put an order in the medical record. 

So, you know, you've ordered that imaging study. You properly document those sonographic findings. That can be electronic in most cases, but you could potentially print out a picture just like we do for the nerve blocks. But archive those images in a in a relevant and durable way. Right. 

And you have to document your findings. So, you know, little notes saying, I imaged the stomach. I found this. That that's sufficient. So you're saying you, you know, you do it because you believe it has value or adds value to the care of your patient. 

But for our US listeners, there is a potential billing component that can form part of that as long as you fulfill the criteria that you described there. Yeah. Exactly. Yep. Okay, man. 

Listen. I'm feeling hungry now after talking about all of this. So if we were to if we were to sum this up, what do you think the take home point is? I'll tell you what my take home point is. My take home point is that I need to make sure I start scanning more stomachs so I can learn the technique. 

But, you know, there definitely may be a role for this. But what do you think your take home point of this episode is? I think it definitely is a role for this. And having implemented this in our practice fairly regularly now with the rise in full stomachs that we're starting to see, I do think that this is gonna be something we're doing for many, many patients as a routine. So patient comes in, they get their IV cannula, they get changed into their gown, they get their pre op stuff marked, and then before we move back to the OR, we scan their stomach and, you know, yes, no, full, empty, clear liquids and make that's part of our preoperative assessment the day of surgery. 

I think it's great. Listen. You've you've you've sold me. I'm sold. I'm a pogus believer. 

So guys Pogus. I like I like pogus. We're gonna use pogus. Right? That I think that's the thing. 

Yeah. Even if it wasn't a thing, we made it a thing, but I'm pretty sure it was a thing. So, guys, you know the deal. Please do like, subscribe, and rate our podcast from your usual podcast provider, and and then you need to know where you can follow us. So what do we have, Jeff? 

Ma'am, we're all over Twitter at block it underscore hot underscore pod. Check out our YouTube channel. It's at block it like it's hot. Yes. And we also have Insta, block it like it's hot with underscores in between each of those words. 

And don't forget our abbreviated hashtag, hashtag b I l I h, or you can use the long version if you like. Yeah. I guess that's it, man. Till the next episode. We hope you all block it like it's hot.