Thank you to Tom and Catherine as the course directors for allowing us to share the passion that we have when it comes to electrosurgery units from West Virginia University. You know, it's my pleasure to speak to you on this topic. When it comes to electrosurgery, it's essentially one of the greatest tools we have in endoscopy. It allows us to perform palpectomy, endoscopic mucosal resection, endoscopic submucosal dissection, luminoposy metal stent placement, argon plasma coagulation. Many of you saw, all of you saw this probably now in the hands-on this morning of how we can apply this. We're going to go over really the principles here today. And you know, one important point to keep in mind is that, you know, it's also one of the potentially most dangerous tools we have in endoscopy. And so it's really important to understand these principles, understand how they work so that we don't cause an injury or put our patient at risk. So here are just my disclosures. So when it comes to electrosurgery generators, they produce a high-frequency alternating current. So as you go back and remember your electrosurgery kind of principles, there's DC, direct current, and alternating current. We don't use any direct current in endoscopy, okay? That results in the formation of acid and bases, and that's not something that we use in any way, shape, or form through our electrosurgery generators. In essence, we use alternating current, which means that, you know, the current can travel. It has periods where it travels in different directions. But in essence, this allows us to perform what we want to do, which is our coagulation effect or our cutting-type effect, okay? And so, you know, why is a patient not electrocuted during electrosurgery? I think this is a good point to kind of go over. So if you recall, the hertz is the frequency by which how much current is delivered over time. So in essence, in a second, 60 hertz means that there's been 60 propagations of current over that time. Household currents typically function at about a 60 hertz. If we stick our finger into a socket, we'll certainly get a shock that way, right? And so many of you may have done this as a kid. As we get up in frequency, however, you know, I hope none of you are still doing that now, by the way. But as we get up in frequency, once we get to about 100,000 hertz, that's when neuromuscular stimulation kind of goes away. And the frequency of these waves is too frequent for the brain to perceive. And as such, we can now start potentially getting the benefit of being able to provide that current without shocking the patient. And so electrical surgical units work at about 300 to 350 kilohertz, which is 300 to 350,000 hertz or 3 to 3.5 megahertz. And at this level, again, we get that benefit of being able to deliver the energy, perform the intervention without getting that negative of shock because the frequency is too fast for the neurotransmitters to perceive. Now how is heat produced? Essentially, it's a high-frequency alternating current, and it flows along a circuit which involves a device. So it starts with the electrical surgical unit, goes through the device into the tissue, and the tissue offers some form of impedance or resistance. And that creates heat as the current is passing through there, and then it ultimately returns back to the electrosurgical generator. But in essence, it's this production of heat at the cellular level that allows us to perform our interventions. And this heat can allow us to perform coagulation or cutting, depending on the impact or the outcome we want to achieve. And so the basic principles here are that when we want to produce a cutting effect, we increase the force of that current that goes to that tissue. And in this way, that's how voltage is measured. It's essentially the force of the current going forward. And so in this way, when we apply a higher voltage, what we're essentially doing is boiling the cellular water and bursting it, and that allows us to transect and cut away that tissue. On the flip side, when we have a coagulation-type effect, what we're really doing is using a lower voltage, so it's not as much force through the current. So the coagulation portion, the cells heat more slowly, and we're applying that voltage force at a low—excuse me, we're applying that current force at a lower voltage. And so there's a slower heating, and this allows the cells to desiccate and to shrink up, essentially. And this is how we perform clotting of blood vessels or a coagulation-type effect or ablation that you guys saw during the hands-on portion this morning as well. All right, so how do we achieve different temperatures and thermal effects by changing our waveform? This is essentially what we're able to do with our electrical-surgical units, okay? We can modulate these waveforms to create the impact that we want to create. So in essence, you can see in the image on the left, the coagulation is 6% on, 94% off. That 6% on basically means that our duty cycle is active for about 6% of the time. The rest of the time, it's not, okay? When we do a duty cycle anywhere from 6% to 12%, that generally is the amount of time that can give us a good coagulation-type effect. And what that means is that we're heating the cells very rapidly, and then we're allowing the cells to cool off. And this allows us to create a desiccation, cell shrinkage, and ultimately create that coagulation-type effect, okay? On the right-hand image, we have a pure cut current. So in this case, what's happening is that we're applying that voltage at a continuous 100% duty cycle, 100% on, and it allows us to cut through the tissue more efficiently, and we don't get then that cooling and charring, and as a result, there's not as significant of a desiccation. A blended current, okay, is essentially not a combination of these, but is essentially a cutting current with some pause to allow some form of coagulation to occur during that time period. We call it a blended current, but it's really a blended cutting current is what we're really putting forward. And here you can see the different impacts on the tissue, okay? So at a 6% duty cycle, you can see here that the depth of injury is very small. However, the desiccation is larger and wider, and you can see that that's the type of charring or coagulation-type effect that you can have. In a blended-type current, you can see here that the depth of injury is more significant with that cut, and the desiccation is still mild to moderate, but not as significant as you saw in the coagulation-type effect. And then when you get into more of a pure cutting current, okay, what you can see here is the depth of injury is quite deeper, and that desiccation is minimized. And when we reduce the voltage and apply that continuous current force, but at a reduced voltage, then you primarily get a desiccation-type effect in that regard as well. And so here you can see kind of our electrical surgery unit and how we have some of our settings. I'm going to focus on the bottom numbers there, which is the cut duration and the cut interval, okay? The cut duration really references how much time is spent during the cutting portion, and the cut interval is in between that. So this is, again, a blended current where you're taking one second to cut and three seconds to pause to allow some coagulation effect to occur. And so, you know, individuals have looked at what's best when it comes to resection. You know, this was a nice study, randomized controlled trial of 928 patients with lesions that were greater than 20-millimeter non-pedunculated colorectal polyps. And they were comparing a coagulation current versus an endocut current, and so essentially a blended current. What they were able to demonstrate was there was no difference in severe adverse events or polyp recurrence despite the type of current you used. And that basically bottomed down to it really becomes more of an endoscopic preference, what type of resection you want to have. Do you want to have a cleaner cutting current when you do the resection, or do you want to have more of a coagulation application where you're desiccating the area there as much as possible, okay? I prefer more of a cleaner type cut, and if there's anything bleeding, I like to treat it right there and then and see it, you know what I mean? Because that, to me, makes me feel like I can identify things that are potentially there, and it's a smoother type cut in my mind. But this goes back and forth, and it really is more endoscopist-dependent. We talked a little bit about resistance earlier, and I'm going to speak to it a little bit more again. So as we talked about, the energy travels from the electrical surgical unit through the device into the tissue, and the tissue offers some form of resistance, okay? And that's what ultimately results in the creation of heat at the site. And GI mucosa, blood, very vascular-type areas, this is a conductor. In other words, it conducts the energy very easily, okay? And it allows for the flow of current very easily, okay? And so there's a very low resistance going through that. Now when we talk about, you know, drier-type substances like bone or plastic, these are substances that are more insulative in their properties, and it requires much more heat to generate any type of injury to that area, okay? So the obstacle of the flow of current, the greater the resistance, the less the current flow through there as well, okay? So when we're thinking about this, it's important to realize that as you're treating an area, say you're treating a bleeder, and, you know, you've applied current energy, as you continue to build up eschar there, and it gets drier and drier, and you're still trying to treat because you still see some areas bleeding, but in essence is becoming more and more scarred, it becomes more current energy that you have to apply to overcome some of that charred area, okay? And so what are the thermal effects that occur on cells when this occurs? So, you know, we know that, you know, at 104 degrees, there's reversible cellular trauma, and at 120 degrees, you get irreversible cellular trauma. Coagulation really occurs when that heat, when that temperature with that resistance really reaches a temperature of about 158 degrees, okay? And cutting essentially occurs when we reach a temperature of about 212 degrees Fahrenheit, all right? One other principle to keep in mind is current density, okay? Current density is the amount of focus of the current that we have at a particular point, how we're focusing the current at the site, okay? So it's like a magnifying glass. If you use a magnifying glass to really focus the heat of the sun, you're really going to burn an area very focally, right? But if you have it more dispersed, then that current density over that area is less. And whenever we're doing resection or we're doing coagulation type effect, the amount of density or pressure you apply to that site, the more the current that's going to go there, of course. And so this comes into play when we're talking about tightening a snare around a polyp, right? The more focused the energy is, then that results in the area where we're essentially going to apply that current. And some of the things to keep in mind here are there's really two variables at play here, okay? There's the heat at which we're applying when we cut through this, and then there's the shearing force that occurs when we're cutting it with the snare, okay? That shearing force, we want to approximate that polyp stock into the snare so that when we apply that energy, we swiftly cut through it. What we want to try and avoid is trying to strangulate or take in a lot of tissue at a time that can potentially become excessive. And there's some cases where we want to do that and tighten a little bit more. But for the most part, you want to have a nice swift cut through there, okay? The problem with creating a lot of tissue in different ways is that it can increase your resistance, and then you're increasing your heat. And when you start to do that, it can also create your risk for a transmural injury, okay? So really, the idea that you want to get used to right now is when you get around a polyp, you get your snare around there. You have it nicely approximated but not necessarily overly strangulated and fighting the tissue to close the snare. You are, in essence, able to then, with the approximation type method, able to swiftly cut through and apply that energy without a potential transmural injury or a post-polypectomy type syndrome we can call sometimes occurs. And so here's just an example of how we close that snare. 10 to 15 millimeters, independent movement, short traction time that you want to have when you're closing through it. And with those two forces of the heat and that shearing force, we resect the polyp, okay? All right. So now let's talk about our circuits. So the electrical surgical generator, okay? Some of you, most of you probably learned this by now through the morning. But if you haven't or it wasn't clearly talked about, you know, it produces our energy. That energy goes through our device. That device then interacts with the tissue. The tissue offers some form of resistance, that heat is created, and then that current has to come back to the electrical-surgical generator. This closes the circuit. There are two ways in which we do this in endoscopy. The first is our bipolar mode. The bipolar mode has the actual electrodes in the device. That means it has the delivery electrodes, the active electrodes, as well as the return electrodes, the neutral electrodes. It's all in the device. As such, when we apply this to the site of where we want to perform our intervention, all of you this morning used the bipolar gold probe. This was to create coagulation to treat a bleeding blood vessel as an example. When we do that, the focal area between that active electrode and the neutral electrodes is where that energy is being dissipated and recollected and returned back to the electrical-surgical unit. As such, we don't need a grounding pad in these cases whenever we are applying bipolar. We also want to stick to a little bit of a lower maximal power output, primarily because when we have a higher maximal power output, what can happen is that the tissue can stick. We use things like that water flush to help us at the end of our coagulation effect to release us and not necessarily pull off the clot at the same time. In essence, we want to use also lower powers because the higher powers we use will create more of that sticking effect as well. There's no current in this case that runs through the body. That is very different than monopolar. This morning you also saw us use argon plasma coagulation. We're going to get into that a little bit later, but we used a different receptor on that generator that we were connecting to, which was the monopolar receptor. We also had a grounding pad to those stomachs that we were applying to. In monopolar, very different from bipolar, the current is actually conducted by the body. It comes in from the electrosurgery unit, through the device, through the tissue, through the body, back to the grounding pad, back to the electrical-surgery unit. This way, we're completing our circuit. We use monopolar for various interventions. We use it for polypectomy, endoscopic mucosal resection, ESD, lumen-opposing metal stamp placements, sphincterotomy, needle knife. We use monopolar a lot. Understanding how the grounding pad is placed and how we use it is really important because there can be bad outcomes associated with that as well. There are four rules of grounding pad safety. First is that area should be clean and dry. There should be good musculature and vascularity at the sites of where you're applying that. You want to avoid bony prominences, prosthetics, scars, and you want to have it close to the electrical-surgical site. The closer you have it to the electrical-surgical site, the better potential activity of that device is. You can get better arcs with argon plasma or you can get better application through your snares and things like that when it doesn't have to travel as far. What about hair? Hair can increase resistance and it is flammable. It can build the current density at a spot and this can actually lead to a burn on the patient. When you apply the grounding pad, you want to be careful that the grounding pad is not in a very spot where there's a lot of hair. We typically choose the flank area. That's an ideal site for placement of the grounding pad with the long side pointing towards the spine or the thigh where the long side is pointing towards the head. We want it to be a well-vascularized area. You're trying to create the shortest circuit possible, again, to optimize the performance of that device. You want to have a short distance from the electrosurgical site to that grounding pad. There's not a lot of body, a lot of resistance that that current has to flow through. Then you want to place it in these places to ultimately optimize that. Avoid tenting. When we tent that grounding pad, what can happen is that it can increase the current density at that site. When it increases the current density at that site, it increases our risk for burn at that site. So we don't want that to happen, obviously, to our patients. Another thing here is the cord that leaves the grounding pad. We want it oriented such that it's towards the electrosurgical unit. If it's away from the electrosurgical unit, then any tension on that cord can potentially lead to peeling of that grounding pad. These are really basic things. You're listening to me talk, and you're like, man, this sounds really basic. It is. But the bottom line is, you can see that while these things are basic, I guarantee you in the next three months, whenever you're in the endoscopy unit, there's going to be problems with your electrocautery. There are going to be simple problems that are troubleshooted because the grounding pad isn't on properly, or things aren't connected properly, or someone forgot to connect the snare to the cord. Things like this. Very, very simple things. And the bottom line is that if you recognize these, and you implement them, and you catch them, you can avoid really significant problems or catastrophic injuries that can occur. What about pacemakers and ICDs? So pacemakers, modern-day pacemakers are much more sophisticated and essentially can tolerate most types of monopolar activity that occurs, or really any type of monopolar activity that occurs. Some things to keep in mind is that if you're anticipating prolonged monopolar activity, or something like gait, or you're doing a deep endoscopy with multiple injectations, you're expecting to burn a lot of different things along the way, it's a good idea to get your cardiologist involved and consider deactivating that pacer. You also want to place the pad on the leg a little bit away from the body, and you want to keep more than 15 centimeters between the active electrodes and any EKG electrode as well. ICDs, it gets a little bit more complex with these. The ICD can interpret the current from the electrosurgery unit or the device as an R-wave and essentially interpret that as a potential arrhythmia and lead to an ICD firing to shock the patient. But we don't necessarily want that to happen because the patient's not in an arrhythmia, right? So, and vice versa, it could actually interpret it as a normal rhythm and not shock the patient when it has to. And so the bottom line is that we need to consult our EP specialists before those procedures, have them come down, turn off the defibrillator using the magnet. And so what's the information they take into consideration? The make, the model, the year, the type it is, where the magnet's placed. Because depending upon the device specifications, there's different orientations to how you place the magnet that can allow for that deactivation. And then post-procedure, they reactivate. You don't do these cases in an ambulatory surgery center. These patients with defibrillators, pacers, they're done in a hospital setting, okay? And understanding that this is the situation, you make sure your EP colleagues are available because they probably work 9 to 5 or something like that, or 9 to 3. So you want to schedule these times, otherwise you're going to be waiting hours to get them down there and things like that. Now, certainly, you know, what can happen is you want to have the external defibrillator and transcutaneous pacing available should you need it during the procedure, right? Because now you've turned the defibrillator off, you're doing an intervention. What if the patient develops VTAC or anything like that? You know, you need these devices available for you. And this is why we undergo ACLS training, right? So we understand how to apply these devices. This is why we have anesthesia specialists involved in these cases, so they know how to quickly and safely resuscitate the patient appropriately from a cardiopulmonary standpoint and avoid any major catastrophic pathology. Bottom line is that this is how we manage these patients, and this is in their best interest to ultimately achieve the desired outcomes. Real quick about argon plasma coagulation. You know, you guys all got to use it this morning as well, saw how different it was. I could see all the smiles on your faces when you were spraying the plasma across the stomach wall. You know, argon gas is essentially a gas that becomes ionized through the monopolar current to apply to the tissue. And as you saw this morning, it's a very superficial application. By definition, plasma is an ionized gas, and that's essentially what we've created here, okay? It's transferred through a catheter, very similar to the polypectomy-type snare catheter, very thin catheter. And we can do it through an angulated approach through the circumferential probe or through a direct approach through the straight-fire APC. It's a non-contact, so you're spraying essentially to the area, and the current can travel up to 10 millimeters. The sweet spot is about 3 to 5 millimeters or closer to 3 millimeters from the tissue in order to treat it. It really, though, also depends upon the settings that we have it set at. You know, we can set it anywhere from a wattage from 20 to 90 watts and a flow rate anywhere from 0.8 to 2 liters, depending upon where we are and what we're trying to do. You know, if we're in the small intestines, we'll probably want a lower wattage versus in the stomach or rectum. If we're trying to burn a stent as compared to a superficial angioectasia, we're going to want a very higher wattage for that stent and a very low wattage for that superficial angioectasia. And so these are the things we take into consideration along with our flow rates in order to determine how much we want to apply. One thing to keep in mind also, as you guys all probably saw this morning, when you're applying it, that stomach blew up pretty nicely, right? Because argon gas expands very rapidly, so we want to constantly be decompressing to minimize that expansion and putting that patient at risk for discomfort or worse of viscous perforation, okay? And so here you can see the applications of those energies, the straight fire in the image on the left, the circumferential fire more so on the image on the right. And there you can see just kind of how we apply. It's an even, uniform coagulation. The current seeks the best area of conductivity. So as you can see, it would hop around a little bit the closer you are, and the more conducive that area is with the mucosal surface, the more likely you're going to apply there, okay? But if it becomes more charred, it's less likely to go to that spot. And again, it's a non-contact, shallow depth of coagulation. We're only talking about three millimeters of depth of coagulation. And here you can just see some more images and video of argon plasma coagulation. Many of you did this, all of you did this this morning, I'm pretty sure. And this is actually video from you guys this morning, right? So yeah. But in no time, you'll be doing it like this and really be able to control those areas and enjoy the satisfaction of controlling those bleeds in no time. So what are the other applications? Well, certainly vascular ectasias, gastroenteral venous ectasias, radiation proctitis, isolated AVMs that we can treat with this. Other things that we can treat with this, tissue ablation. So sometimes we do these large endoscopic mucosal resections after performed. We like to ablate the edges of that resection to minimize any risk of tumor recurrence, polyp recurrence. And then finally, to augment us in endosurgery. So in essence, if there's a fistula that we are trying to close with endoscopic suturing, we can treat the edges of it to raw up that tissue a little bit, then we suture and it helps increase the apposition. In bariatric endoscopy, the bariatric endoscopists really like to do this by lining the stomach wall with argon before they do suturing to create that sleeve gastrectomy because what that does is, again, increases that apposition of mucosa to mucosa and can help potentially reduce the total volume of the stomach as well. And so in summary, you need to know your current generator and electrocautery devices. As a physician, this is your primary responsibility. You know, I told a lot of you this morning that, you know, a monkey can do this stuff. A monkey can spray the argon, right? But what separates us from the monkeys is our ability to understand the technology, our ability to understand the devices, and our ability to apply it safely without an injury to the patient, okay? And you know, last but not least, you're only as good in the suite as the smartest person in the room. So if you don't know this stuff and somebody else does, well, that's great that there's somebody in the room that knows it, but guess what? Now you're not the smartest person in the room, and you're not able to help the patient the best, more so than anyone else in the room. And you know, what if that other person doesn't know it? Then all of a sudden, your patient's at risk, right? So the more you understand about this technology, the more you understand about the equipment, the more you understand about the devices, the better off you'll be. You know, I think it's really important that whenever the physician, you know, takes a scope from you, don't just stand there. Go over to the tech and start learning them, or start assisting as the tech, start assisting as the nurse. It'll help you develop understandings and comfort with these devices and the equipment that'll be tremendously beneficial as you go forward. And so with that, I'm happy to take any questions. And of course, this is what we're trying to avoid. Thank you for your time. Thank you.

electrosurgery

endoscopy

principles

safety considerations

risks

argon plasma coagulation

patient safety