We'll move on to our last video on argon plasma coagulation. What we're going to do now is look at a technique called argon plasma coagulation or APC. What this is, is this is basically using argon gas and putting an electrical charge to it to get coagulation or fullergation. We use this when we're either after taking off a large polyp doing EMR technique so that we can do the edges with coagulation or in certain conditions we apply this to get hemostasis or control of bleeding or potential bleeding. These are in cases of radiation proctitis or in a condition known as GAVE or gastric anterovascular ectasia. With this, it's a charge so we have to have our grounding pad hooked up to the patient. This is a monopolar system and what we'll do is we place this down and we control both the flow of the gas as well as the charge or the wattage that comes out. There's different settings for these. Some of them fire in a radial or a round fashion. Some of them fire forward. What I'm going to do is demonstrate APC right now outside of the body on the model so you can see the burst. We'll have here a focus on the stomach and I'm going to depress and you can see the argon gas and the flames firing. That's going to coagulate the tissue. It doesn't get deep, typically one to three millimeters, so we don't do this for vessels per se when we have active gastrointestinal bleeding where we would use other mechanisms such as either mechanical hemostasis with clips or injection or bipolar which we'll demonstrate in another series. For now, let's see what this looks like inside the stomach phantom. I'm going to grab my endoscope using standard technique, holding it properly, and we'll place the catheter for our APC down the channel. We'll watch it come out outside the body first. And I'm loading these instruments outside the body mainly so that you can see what it looks like. In a standard case, we would go down, get our visualization first, decide what instrument and tool we would use, and then place the catheter down. What you can see is the catheter coming out of the tip and you can see on the endoscope footage there, let's try to clean this lens as best as I can, some black lines which indicate how far out our probe is. Again, we want to try to work not within the channel because you don't want to burn up your tip of your endoscope, but you want to work outside so that you gain good control of your device or your pieces of equipment, but not so far away that you have no control of the tip. So let's take this out. We'll lubricate our endoscope and then we'll go down and we'll apply some APC. I'll have my assistant here. We'll get it lubed up, we'll go down, and we'll get ready for our application of APC. I'm going to insufflate the stomach. We're going to find an area to apply our APC to. I'm going to place our catheter down and we're going to do application of APC. Now with this, because there's gas coming in at a certain rate, we have to remember to suction it back out or it will insufflate as well. So what I'm going to do is come close to the tissue, so this is non-contact, meaning I don't have to be on the tissue, and I should not be on the tissue to apply APC, but I should be a little bit above it and the current or the charge will go to the tissue that I want to coagulate. So let's do this now. We'll suction that smoke out and as you can see, it fuller gated that mucosa there. I worked about a centimeter away and was able to apply that. Again, to do application, you don't touch the tissue, you are above the area that you want, so this is non-contact. We can take out the catheter, remember, sucking out the smoke as well as sucking out the argon gas. And that's our application of APC. Okay, well, argon plasma coagulation is really one of the neatest tools that we have in terms of controlling bleeding by coagulating small vessels. We can also use it to destroy tissue, any residual precancerous tissue that we're concerned about. As Dr. Opstein mentioned, it's really important not to be touching the gastrointestinal wall because the gas that's flowing out the catheter can dissect into and underneath the wall of the digestive tract, creating a perforation or the risk of a perforation, which is one of the dreaded complications we have doing gastrointestinal endoscopy. We can adjust the flow of the gas and we can adjust the current or the charge that's being applied to deliver more or less energy to the digestive tract wall.

Argon plasma coagulation

APC

bleeding control

gastric anterovascular ectasia

tissue coagulation