Today, Injection Fluids and Dynamic Injection on the ASGE SUTAB tip of the week. First what to inject. This is not a comprehensive list, but it does represent most of my experience and I think probably for most practitioners they've used the agents that are listed here. Saline and head of starch are still popular. They have to have contrast methylene blue or indigo carmine added to them. And even some experts prefer it because it's soft during snaring, but I think the general trend in EMR is to move to solutions that are more viscous and last longer. So head of starch, we don't have really good clinical data about it, but in non-clinical studies that perform very similar to succinylated gelatin, which was better than saline and which is not available to us. So that started the head of starch movement. You can get head of starch as generic head of starch or voluvin, Hespan, 500, 250 milliliter bags. Our pharmacists allow us to put it in a separate room, put the methylene blue or indigo carmine in it, and then to draw aliquots out to use during the day. So if we're doing multiple EMRs or a very large lesion, this has some cost advantages. Now the commercial products, Elevue is the one that has the most data, SICK 8000, and that was because these are approved by the FDA as devices and only the first one has to have good clinical data, then the subsequent ones can get approval using Elevue as the predicate device and using non-clinical studies to show safety, et cetera. So in the initial randomized controlled trial, it was better than saline, meaning less of it was needed to complete the EMR and the EMR could be removed. The EMR could be done in fewer pieces, fewer snared pieces than saline. And then we did a randomized trial single center study comparing it to head of starch and it was better than head of starch, but I still use head of starch some as I implied because of these cost issues, multiple or large, very large EMRs. The other commercial products, O-Rise and Everlift, we don't have as much clinical data about them in terms of what people anecdotally say because we do not have randomized controlled trials comparing any of these commercially available products. In Elevue, you hear people saying that there are bubbles during ESD, which can be a problem. I think it's a little bit too light in color, has methylene blue in it, maybe not quite enough. I think in terms of color, O-Rise and Everlift did a better job. All of them, I think, produce a very good lift. You should know that we're seeing reports that O-Rise is visible or some derivative of it is visible histologically. That's important for the pathologist to know so that they don't mistake it for mucin or amyloid or some other substance. While O-Rise can be visible histologically, I'm not aware of any adverse clinical consequences from that. Again, this list of injection solutions is not comprehensive. Another question they ask is whether to add epinephrine. I think this is a matter of personal preference. I think when you use epinephrine, the field tends to stay drier and it looks cleaner, but it's not essential in the colon. For ESD, I've heard ESD experts say that they don't like it. They think it increases the risk of delayed bleeding because they think that vessels should be treated during the procedure. If they're not, if they're shrunk from epinephrine and not treated, that could increase the risk of delayed bleeding. I don't know that there's really evidence of that for EMR. You do have to ask whether it's compatible with the injection fluid. I've added it to all the solutions that I showed you, but the manufacturer will tell you for ORISE that they're not certain whether the gel keeps its same properties if epinephrine has been added to it. When you use it in the colon, you want to dilute it. It comes as 1 to 10,000, what we use, and so we'll take one half an ml of 1 to 10,000 and add it to 10 ml of injection solution, and we do that syringe by syringe, so we're ending up with 1 to 200,000 for most cases. I've heard people using dilutions anywhere from 1 in 100,000 to 1 in 500,000. If it's a very, very large lesion or I'm doing multiple EMRs, and for example, a patient with seriated polyposis, I'll dilute it further down to 1 to 400,000, so that's a quarter of an ml of 1 to 10,000 in 10 ml of injection solution. The only downside that I've seen in the colon is that some patients, not all of them, will have a bellyache afterwards, and it will last usually for 30 to 90 minutes, as long as you feel confident that the defect looks fine, you haven't injured the muscle, just wait and it will subside. This is a granular lateral spreading tumor in the right colon, and we're going to perform inject and resect EMR. The goals of injection are, first of all, to make it easier. That is the strategy. We don't want to inject it and make it harder, and next week, we're going to talk about how you select the strategy, which is basically how do you select the location for the initial and the subsequent injections. Right now, we're just going to talk about the injection process itself. Now, you'll notice that injections are commonly going right through the middle of the lesion. That's fine to do, as long as there's no suggestion of cancer. There's no morphologic changes, such as depression that suggests cancer. There's no changes in the vascular pattern, NICE 3 or KUDO 5 features. We'll talk about those in a later tip. This one has none of those changes in it, and it's a good lesion to demonstrate injection technique because it's granular. Granular lesions tend to have very little submucosal fibrosis, and you can see that it is lifting very well. When we start the process, typically, we want to put the needle out before we enter the tissue and just lay the tip up against the lesion and then start the injection. We'll say to the tech, inject, and then we want some verbal response immediately as the injection starts so that both you and the tech know that fluid is coming out of the end of the needle because as the injection starts, you're going to push the needle in and you're hoping that the fluid coming out the tip of the needle will find the submucosal space for you. So communication is important so that both of you know that fluid is coming out. You should be seeing the submucosal space start to expand. If you don't, something is wrong, and there are basically four places that fluid can go. One of them is into the lumen, in which case you need to push harder. One of them that occurs sometimes is into the mucosa, and this will appear as a very distinct, usually fairly narrow, but reaching a significant height very quickly, what we call an intramucosal bleb. Oftentimes, there's some blood in it. If you see that, you want to push through it to get into the submucosa. If it gets very big, you can just cut it with the needle and let it drain. The third place that the fluid can end up is the submucosa, and here we're seeing good submucosal injections. And the fourth one is if you push the needle through the wall and it goes into the peritoneal cavity or through the muscularis propria outside of the colon. In that case, you want to pull back until you start to see the submucosal space expand. So those are the four places basically where fluid can end up. The initial injection is the one that usually is sometimes, or it can be a little bit difficult to get. Once you've got the initial injection in, all the subsequent ones are going to be easy because you're always going to make those, at least whenever possible, into the mound that you've already created, the mound of submucosal fluid. So that mound has, it expands the submucosal space, and it's typically quite easy to make all the injections after the first one. The second thing that you'll notice as the resection was occurring is that as we got into the submucosal space and we saw it expanding, we were starting to lift the fluid, lift the needle toward the lumen. And that is what we call dynamic injection. The main component, the fundamental component of dynamic injection is to move that needle toward the lumen. So let's demonstrate dynamic injection again, this time with a granular lateral spreading tumor and adenoma in the rectum. So we have the needle out. We say inject. The injection starts. We're pushing in, hoping to see that submucosal space expand. There's a little bit of contraction of the lumen, maybe a little bit of spasm, but we're not getting fluid. And right there, right there, you can see that submucosal space start to expand as we withdrew the needle. So the idea is that the colonoscopist and the tech are communicating. As the injection starts, the tech is reporting, injecting, injecting, injecting, especially if they're watching the screen themselves, they're going to primarily say they're pushing on the fluid and you're both watching to try to find that submucosal space. Others like for the tech to say 1ml, 2ml, 3ml. And you know that by the first ml or two, you should start to see the submucosa expand or you're not in the right place. If you are not seeing anything, then you're too deep. You need to withdraw the needle as we did in that case. If you get an intramucosal bleb or hematoma, you need to push through that to get in the submucosa. The dynamic part of this is that once we get that submucosal bleb developing, we're going to lift the lesion toward the center of the lumen. We're lifting up with the submucosal space, trying to expand it. Here again, middle of the resection, we have the needle and we're lifting toward the center of the lumen. We're trying to turn this into a sort of a polyp within a polyp, something that's going to make snaring easier. It's going to facilitate snaring. Didn't do a great job in that case. The injection was fine, but it just sort of flattened out. That happens sometimes. The more fibrosis there is, non-granular lesions, they tend to not lift as well as these granular lesions do. We're injecting another part of the lesion again. We're lifting that submucosal space toward the center of the lumen, trying to push the fluid into the upper parts of the submucosal space. This one is working out pretty well. It's kind of making one of these polyps within a polyp, a little bit more of a dome-like area that's going to be easier for us to snare. We just repeat this process over and over again. The contrast, of course, in the submucosa helps us to identify any muscle injury. We're checking that each time. Now we're over on a part of the polyp that's over on the right side. We're lifting toward the left to get it up into the center of the lumen, and again, turn it into that kind of polyp within a polyp that will facilitate snaring. Notice on the left, you can see the mucosa. Outside the defect is blanched. That's because we're using epinephrine. Just in general here, we have a very dry defect. It's not bleeding. Oftentimes, when you see videos of these very large, blue, beautiful, smooth defects, a lot of that has to do with the inclusion of epinephrine. When you don't have the epinephrine, things are just a little bit rougher, and they're a little bit more bleeding. This is a typical appearance of an EMR done with epinephrine. The major goal here, though, is to show these principles of injection. Find that submucosal space. Most difficult, usually, in the very first injection. Use this dynamic process of lifting that space toward the center of the lumen. Next week, injection strategies on the ASGE SuTab tip of the week.

injection fluids

endoscopic mucosal resection

saline

communication

dynamic injection