All right, switching to the colon. So we're going to hear a talk about therapeutic colonoscopy from Dr. Sawanee Nam from Johns Hopkins. And she's an expert in the colon, in resecting very large, very large lesions. And when I say very large, I mean very large. Thank you for the introduction, and thank you for having me as part of the faculty in this course. Good evening, everyone. This is a very long session. This talk is 40, 45 minutes. But I'm not the only one talking. We have several video clips within this presentation from ASGE faculties. And we will not talk about anything big in this talk. So my disclosure, I'm a consultant for Olympus Boston Scientific, Puget Film, and Neptune Medical. So we'll start with overview, lower GI bleeding, colonoscopy polypectomy, chronic decompletion, and complication from colonoscopy intervention. First, lower GI bleeding. So for acute lower GI bleeding means bleeding that occurred within the past three days. Traditionally, it means the bleeding source is after, I mean, distal to ligament of thrice. But because small bowel bleeding is now a new category, so acute lower GI bleeding now defined as the bleeding in the colon rectum, or so distal to IC valve. These are the common etiologies of lower GI bleeding. So diverticular bleeding is the most common cause of GI bleeds, about 50% of all cases. Other causes include ischemic colitis, angioepthesia, hemorrhoid, colorectal, neoplasia, post-polypectomy bleeding, inflammatory bowel disease, infectious infection, encephalopathy, radiation pathopathy. Neurocoral ulcer is like ulcer in the colon or rectum from constipation and fecal impaction. Rectal varices, dura foliations. So the first case, 75-year-old female presented to emergency room with five hours painless bright red blood per rectum. In the toilet, she's reported blood every one hour. No prior history of GI bleeding, no NSAID use or aspirin use. Vital sign was okay, no autostatic changes. Hemoglobin was normal at 13, normal platelet and INR. So what is the best next step? Angiography, consult surgery, upper endoscopy, red blood cell scan, or bowel prep, then colonoscopy. So please vote. Okay. Okay, 17 people vote. 18. Okay. Okay, 22. So the answer is, okay, let's see your response. Okay, majority of you recommend, some of you will change your mind, recommend colonoscopy, which is the correct answer, bowel prep, then colonoscopy. So lower GI bleeding, the patient can present it in many different way, can just present with anemia and actually has low occult bleeding, or myelina, if the bleeding is low and in the right colon, it can present as myelina, or scan intermittent hematochesia, for example, hemorrhoid, or severe hematochesia, large volume bleeding. So first thing you do, similar to upper GI bleeding, is assess the patient, resuscitate. Consider upper GI source as a reason for hematochesia, particularly patient that have risk factors, for example, history of peptic ulcer disease, portal hypertension, the patient's history of NSAID use, or you put NG tube in and lavage positive for blood. So those cases, you need to perform upper endoscopy. Majority of patients, after resuscitation, the bleeding slow down or temporarily stop, then the first thing, first test is actually colonoscopy. There has been a debate, the timing of colonoscopy, should we do urgent colonoscopy within 24 hours, or we can do in a non-urgent manner? So the result of meta-analysis show that there's no benefit of doing urgent colonoscopy over non-emergent colonoscopy in terms of lead bleeding and mortality. So the update guidelines now recommend non-urgent colonoscopy. So resuscitate the patient, give biopreparation. Once the patient stabilize, do procedure at the next available opportunity. So you also don't want to delay and prolong hospital stay. So this is why colonoscopy is the test of choice for acute lower GI bleeding. Because you can first precisely identify source of where the bleeding is. Once you find it, you can provide treatment, intervention at that session. If it's a tumor, neoplasm, you can obtain biopsy at the same time. Complication from colonoscopy is also very low. The downside is you have to give bioprep. So if the cleaning biopreparation is not adequate, you can miss a lesion, you can miss a source of bleeding. You have to give sedation. So in the patient that you have not really resuscitated well, the patient can become hypotensive when they get sedation. So that overall answer colonoscopy. So the second case is a 55-year-old male, history of atrial fibrillation on Warfarin Underwent colonoscopy five days ago. Removal of secal polyp. Now presented with painless brilliant blood colorectal, but vital signs was okay. Hemoglobin was slightly low at 11 and INR was 2. Underwent repeat colonoscopy and found a 15-millimeter ulcer at the polypectomy site with non-bleeding visible vessel. So what is the next step in management? Inject epinephrine alone, do nothing, non-contact thermal therapy like air-gun plasma coagulation or mechanical clip across the vessels. Okay. 25, 26. Okay. 28 of you answer. No one change your mind? Less one. Okay. Let's see. Okay. Most of you answer clips. So similar to upper GI bleeding lecture, you see non-bleeding visible vessel, epinephrine alone is just temporarily measure, it should not be the monotherapy. And visible vessel increase risk of the recurrent bleeding, so you need to do something. You cannot do nothing because that patient will come back with the bleeding. So air-gun plasma coagulation usually is only superficial treatment. There's very limited data on using air-gun plasma coagulation for visible vessel, and generally we prefer to use mechanical treatment or the firm pressure on the blood vessels. So you can notice that most of the time you use APC for superficial small blood vessels. For larger blood vessels, there's a concern that it may not be adequate. So that's why the answer here is D. But these are options, like injection, thermal therapy, bipolar is contact, air-gun plasma is non-contact. Mechanical can be clips, but there are many other over the scope, clips, suturing, hemostatic powder, gel, so on and so on. But this is the initial therapy you usually think about. The preferred treatment option for colonoscopy, so if it's post-polypectomy bleeding, typically is clips. But other things, you can use thermal therapy or over the scope clips. For diverticular bleeding, so most of the time when you do colonoscopy for diverticular bleeding, you can't find a bleeding source because it's stopped. But if you see the bleeding spot, these are the three modalities that has most data, endoscopic band ligation, clips, or coagulation, like thermal therapy. But among all these three, you can see that initial hemostasis are very high, 99 to 100% of all these three treatment. But the early delay, sorry, early bleeding is lowest, seem to be lowest with the band ligation. So if you can do band ligation, it might be the preferred option for diverticular bleeding. You can do clips and coagulation. So coagulation, you try not to do if the bleeding is at the dome of the diverticulum because it's very thin. But you can do it if it's at the neck of the diverticulum. So other management of acute low OTI bleeds include tag-bladed basal scan. But this scan, although it can detect bleeding that's like bleeding slow, like 0.1 to 0.5 cc per minute, but you cannot really localize where exactly it is. Like you can see bleeding somewhere in right upper quadrant or something like that. Where is it? It's hard to tell. And take hours to complete. So it's not very, usually not the first modality you do for acute low OTI bleeds. Multi-detector CT angiography, this become more commonly used for low OTI bleeding. It's quite sensitive for bleeding and it's fast, take minutes to finish. And it can help localize if it's positive for extravasation on the CT scan. You can find, like, is it from what side of the colon where it is. And that will guide a subsequent therapy, like either followed by colonoscopy or angiography. CT can help guide that. So angiography now generally is for the patient who cannot or too unstable to undergo colonoscopy. Usually positive CT angiography to help guide where it is. And the radiologist will follow with IR, angiography, and embolization. The complications also higher than colonoscopy. So up to 5 to 17% developed ischemia, ulceration. And that can lead to secondary GI bleed. Surgery is rarely required these days. You only do that for patients that endoscopic or radiologic intervention have failed. Again, diverticular bleeding, this is most common source of cause of GI bleeding. Generally acute painless bleeding also oftentimes stop spontaneously in 80% of patients. But about one third of the patient will have bleeding in three, four years. It can be, most of the time it's bright red blood. But if it's in the right colon and slow bleeding, you can see melanoma as well. So treatment, we already mentioned, talked about the treatment in the previous slides. But if you're going to put clips, for example, you don't want to pull scope out, go back in to put a band, you're afraid you're going to lose it. You want to just put clip right there. So it's better to put clip directly at the blood vessels rather than put clips at the opening of the diverticular lobe to seal it. Because the bleeding is higher if you close it at the diverticular opening. So try to put clips directly at the blood vessel is the best method. So the next video will demonstrate how the… Medical data suggests that endoscopic intervention for diverticular hemorrhage is safe and efficacious in certain cases. Injection therapy shown here to treat bleeding at the neck of a diverticulum has been reported with limited success. Due to the lack of muscularis propria at the dome of the diverticulum, therapy at this site using injection or thermal coagulation must be carefully considered. When surveying the colon for the source of the diverticular bleed, it is often difficult to relocate the bleeding site following initial identification. We recommend using an endoscopic clip for marking in order to ensure future endoscopic identification as well as localization for future radiologic or surgical interventions if necessary. Direct clip application should be applied if a clear bleeding site is visualized. In this case, an actively bleeding large vessel is clearly identified at the neck of the diverticulum. After initially marking the location, direct clip therapy is applied. The clip is carefully positioned near the base of the artery in order to entrap the immediately surrounding tissue. The usefulness of the water jet is emphasized for precise clip application. Slight downward pressure is applied, the lumen is collapsed with minimal suction, and the clip is deployed. Although a single clip may be sufficient, we typically place two additional clips in order to ligate the feeding vessel proximally and distally to the bleeding point. This case demonstrates direct clip application to the dome of the diverticulum. An adherent clot is directly visualized in the diverticular dome. Bringing the clip close to the endoscope provides the most controlled technique. The clip is carefully positioned close to the vessel in order to entrap the immediately surrounding tissue, being cognizant of the thin diverticular wall. A second clip is placed at the opposite side of the defect in order to ensure hemostasis. Okay. So, in summary, if you can see, if it's at the dome, try to clip inside the dome at the blood vessel. At the neck, also, if you can, just go ahead and clip directly at the blood vessels. The application doesn't work quite well if it's at the dome of the diverticulum. Next, angioectasia. So, this is also a very common etiology of lower GI bleeding you will see more frequently in elderly patients with renal failure or aortic stenosis. And generally, you see in the right colon, very rarely in the left colon. The primary treatment is usually contact or non-contact thermotherapy by APC. So, in the next video, we'll show you. This case of AVM bleeding shows initially that argon plasma therapy was used. Bleeding nonetheless continued, and endoscopic clipping was necessary. Multiple clips were required to achieve primary hemostasis. On follow-up, the patient had no report of re-bleeding. So, if it's in the right colon and AVM is large, and you have the concern of the argon gas that can cause complication, so use aggressive APC. You can cause perforation in the small bar in the colon. You can perform submucosal injection using just saline, inject underneath the AVM, and followed by APC. That way, you kind of protect, have the cushion below the mucosa and protect the muscle. So that's one option. Next we move on to colonic polypectomy. So to perform polypectomy, there are several treatment options. Depends on various factors, mainly the polyps, the size, the morphology, the shape. So this is an example of the classification that we normally use to describe lesion morphology in a GI tract, Paris classification. You hear this throughout your fellowship, or even after you graduate, because it's very important. So we first categorize it into protrude, like it's sticking out, is 1, and is 1P, is peduncleate. 1S is cesarean, 1SP is subpeduncleate. So okay, this is one category. Flat elevated lesion is we call 2A. So it's basically slightly raised from the wall, not more than 2.5 millimeter. And flat, like flat lesion, that is 2B, which is at the level of the wall. And 2C, which is depressed, like pressed into the wall. So if you see the lesion that has depression, like 2C, either 2C alone, or depression in combination with other features, that is usually increased risk of cancer. So if you see this lesion like that, you want to try to remove it completely, on block, for example. So that would be one type of treatment. If the lesion is like peduncleate, for example, a hot snare polypectomy is usually adequate. But if we see a deep ulcerated lesion, that is usually an invasive cancer. You will not try to remove it. If you try to remove it, you're going to encounter a lot of problems, bleeding, perforation, and it's not appropriate. So try to classify the type of lesion can help guide therapy. For choices of polypectomy, OK, we talk about morphology. Now come back to overall the treatment that you would normally be doing. First, cold forceps, using just standard bio-C forceps. This is an alternative for polyps smaller than 3 millimeter. Because you can use the forceps, remove the polyp in one bite. You don't want to do a cold forceps polypectomy for 5 millimeter polyps. And you're going to have to bite three times. You're going to have residual polyps. So cold bio-C forceps, only for the lesion that you are sure you can remove in one bite with the bio-C forceps. Cold snare polypectomy is now the mainstay modality for removal of polyps smaller than 10 millimeter. Almost all polyps, 80% of polyps we see during colonoscopy are smaller than 10, or smaller than 2 centimeter, and majority of them are less than 10. So this is the technique that you're going to be mainly use to remove polyps. If you can use hot accotary, for example, for peduncleated polyps, because of feeding vat vessel, you need to, you want to use electro accotary. Hot bio-C forceps is now not recommended to remove polyps. The only time we use it nowadays is as an adjuvant therapy for scar lesion, for local recurrent lesion that cannot be easily removed with a snare, and because of scar tissue, that's the only time we use hot faucet. Using hot faucet can do, because you apply the cautery, that's increased risk of thermal injury and complications, and the specimen will be distaught from the cautery. EMR, so endoscopic mucosal resection, is a technique that you perform submucosal injection using either saline or other lifting solution to separate the lesion from the muscle layer, and then remove the lesion with snare. So we have example of that. First, cold faucet polypectomy. In addition, this technique can be performed in patients who are therapeutically anti-coagulated, and the risk of bleeding is extremely minimal to none. Okay, what you see is all these polyps are like 2-3 millimeter, and align the faucet the way that you have nothing left, you pull out, everything come out completely. So the other thing is, you need to, you have the polyps really close, so don't have the polyps somewhere here, and then you don't even know that you get it, the faucet, completely engulf the polyps. So for snare, yesterday you saw several side type snare, like we have like from 10 to 35 millimeter snares, different shape, thickness, some of them are rotatable, spiral, depends on the type of lesions and your preference. So my preference would be a stiff snare, because stiff snare you can grab the tissue easier, not like bending easily. So we'll show you the main thing in co-snare polypectomy or EMR is lesion positioning. So if the lesion is here, somewhere here, 11 o'clock or 9 o'clock, you will not be able to get a snare over there, because a snare usually come at 5 or 6 o'clock of the scope. You have to rotate it down to the lower part of the screen. So even if the polyp is somewhere at 3 o'clock, you can kind of put the snare over, but not the optimal position, you will see part of the lesion. So try very hard to get the lesion at 5 to 6 o'clock every time to when you try to put a snare. And this is the same thing for co-snare, hot snare, or EMR. This is a key to remove the polyps, positioning the lesion. If there's a stalk, the peduncleated polyp, you want to position the snare at the lower, as low as possible, lower third of the stalk. That way you have a large normal margin from the head of the polyp and the resection site. In case if there's a cancer, you have the negative margin. So have the snare, you don't want to push the snare far outside the tip of the scope. That way you see exactly what you get, the tissue, how much you get, and you have the better control of the scope, of the snare. This is co-snare polypectomy. I usually try to remove a thin strip of normal mucosa around the polyp, a technique that is not recommended with electrocautery use. Cold snaring is devoid of bleeding complications in patients with normal clotting. Immediate bleeding is typical with cold snaring, but is of no clinical significance. The technique is to grasp the tissue around the polyp, including a bit of normal tissue, and then mechanically transect it. Tenting is not necessary with cold snaring, since there is no risk of injury to the deep layers of the colon wall. I currently use this technique for about 80% of the polyps that I remove during colonoscopy. Here you see the removal of a sessile polyp. We can grasp some normal tissue at the base and cut it off. It will stay in place as long as we don't tent. And after removal, we move the biopsy channel up to the site and suck the polyp back into a trap. OK. Key point, couple millimeter normal tissue should be removed along with the lesion. You see all this cut, the tip of this snare has to be firmly placed to the wall. That way, it's anchor the teeth. And when you cut, you get the tissue resect. No tenting for cold snare, unlike a hot snare. OK. These are the key main thing. This next is the hot snare polypectomy. Here we see a pedunculated polyp that we're going to grasp by the stalk of the polyp and then lift or tent into the lumen. Please notice that we see a white cautery burn on the polyp before we begin the actual mechanical transection. We instruct the assistant to hold off on transecting the polyp until we see that white coagulum. Now we've got a sessile polyp about a centimeter in size. Notice that we're grasping right at the edges of the polyp, which is different from what we discussed with cold snaring. Again, before we begin the mechanical transection, we want to see a little bit of coagulum near the snare. That's the whitish color. And then we'll begin the mechanical transection. And then we're going to inspect the polypectomy site. Some people prefer to photograph the polypectomy site, but I don't think the standard of care requires that. OK. So you don't need too many large amount of normal tissue with hot snare because that will increase risk of complication. You need to tent the tissue, the polyps, away from the wall to avoid thermal injury. But when you tent, you don't want to overdo it. And when you cut the snare, jump to the other side of the wall and burn the other side of the wall. So to cut, like Dr. Rex mentioned, you see the white. So when you do this, he used either endocut or false coagulation. If you use hot snare and you cut too fast, it's going to bleed because you don't allow time for coagulation to work. So he mentioned here that you see the white coagulum, and then you tell the assistant to slowly close. So you will notice when you start doing it, if there's a lot of bleeding, that means you cut too fast. You have to slow down, let the coagulation to work, and slowly close the snare. OK. After resect the polyps, then examine the site using white light NBI to make sure that there's no residue. You can see the difference in surface pattern. If you see the residual polyps, you can do additional resection. For large polyps, actually the concept is very similar to when you remove smaller polyps. You don't want to have any loop in the colon because then you will not be able to rotate the lesion in the position you want. If you have the polyp at 6 o'clock, slightly suction air in the lumen, because if you insufflate this tender colon, you have a hard time grabbing the tissue because it's too tense. So slightly deflated the lumen. I normally use a plastic distal attachment cap to keep the distance between the target and the scope lens, and it also helps stabilize the scope tip. So I use it routinely for when I perform colonoscopy with plan to remove polyps. Non-lifting sign. This means when you perform submucosal injection to separate the lesion from the muscle, the surrounding area around the polyps lift up, but the polyp still doesn't lift. This is the sign of having submucosal fibrosis from the polyps and the muscle wall. And that submucosal fibrosis can be benign, might be because someone attempt polypectomy, partially remove the lesion, or multiple aggressive biopsy, tattoo at the polyp, create scar, so now the polyp doesn't lift because of the scar tissue. But it can also be malignant fibro scar from deep invasive cancer. So you need to examine the surface pattern to see whether there's any sign of deep invasion. If there's no sign of deep invasion, it's not a contraindication to remove these polyps. After removing large polyps, it's recommended to perform prophylactic thermal ablation of the margins, not at the residual visible polyps, but at the normal appearing mucosa. This is to treat microscopic residual polyps to decrease risk of local recurrence. And for polyps larger than two centimeters in the right colon, it has a high risk of delayed bleeding, so it's recommended to perform defect closure with clips. So injection, as shown earlier, you can use saline or one that mix with blue dye, either indigo carmine or methylene blue. Recommend to use dynamic injection, mean you move the tip of the needle to kind of guide the fluid to the area you want. If you don't adjust the needle, it will just stay in one place. So dynamic injection, so for peduncleated polyps, you may consider using epinephrine injection. That will decrease, can decrease size of the polyp and decrease immediate bleeding. So to inject, you're going to decide how you're going to inject in order to help you perform snare resection. Like this one, so inject here. You see the needle is slowly pull back because of, you see, pull back, and you can move to get the needle more this side to get the fluid more to this side. So you may have to puncture more than one time. So like this one, I'm going to move it faster. Okay, so now we see the base of the lesion is here. The top has enough fluid, but okay, the snare can go over easily. So now I want inject somewhere more here, and I may have to add more here. It's just how I decide that if I put a snare, it's going to cut easily. So you have to decide that. But you also don't want to over-inject. You can, if you keep injecting, it doesn't work, you keep injecting, it's going to cause surrounding mucosal edema. So later on, you can't see anything. So don't over-inject. Retrieval. Moving on to polyps that are too large to suction through the scope, if a large polyp is removed in one piece, we pick up the resected polyp with the snare and drag it behind us. If we have one large piece and multiple small pieces, we suck the small pieces through the channel and then pick up the large one with the snare and drag it a few centimeters behind so we can continue examining. Okay. You can suction, use snare or retrieval net for retrieval. So if you encounter the polyps that you're not sure that you can remove, try not to cause fibrosis by multiple biopsy. You can tell this is polyps, right? You don't need biopsy to tell you that. Unless you have the concern that this is invasive cancer, okay, do biopsy. You should tattoo. If the lesion is not in the cecum or in the distal rectum, you should tattoo for localization for future intervention and document where you tattoo. So avoid multiple biopsy just to confirm this is a polyp, adenomatous polyps. If you think that this is going to need endoscopic resection, don't do partial resection or that doesn't help the patient. It just make the subsequent procedure difficult, high risk for the patient, and sometimes even not possible. So tattoo, this is again for localization. Typically in the colon, you put two to three tattoos, distal to the lesion, okay, three to five centimeter distal to the lesion. You don't want to put tattoo too close because once you inject, the fluid is going to spread around and you don't want the tattoo to get into the lesion. It will interfere with subsequent endoscopic resection. Document where you tattoo, take pictures, like I said, clearly you tattoo a couple of like two, three, five centimeter from the lesion. Notice that we strive to get the needle tangential to the mucosa. Then we need to get the needle tip through the mucosa into the submucosa, and a good way to check that is to see that we have just a couple of millimeters of needle in the tissue. Then if we lift the needle toward the lumen, you actually see the impression of the needle in the submucosa right there, and that's a good indication that we're in the submucosa and we can start the injection. We must immediately see fluid starting to collect in the submucosa or we stop. We're going to inject one to several cc's into each site. If we have a mound of saline already in the submucosa, then it's easy for us to reinsert the needle into that same mound and inject ink. Here you see in this next injection that we'll poke right into the submucosal cushion and inject again. Injection to put some more is a very easy way if we have some fluid there either from the previous submucosal injection for the polypectomy, a very easy way to find the submucosal space. The other way you can do is when you're going to tattoo, inject saline. So when the saline bleb you see is in the submucosa, while needle is still inside the bleb, switch to tattoo. That way you be sure that you inject to the submucosa. Injecting through the muscle or polytonium, you can cause polytonitis, and it doesn't help the surgeon. They can't see where the tattoo is. So next we'll go over very briefly about post-polypectomy complications, bleeding, immediate or delayed bleeding. Bleeding depends on lesion type and size, but in general it's about 1% to 5%. Perforation rate is also low, usually less than 2% to 3%. If it's in the side of the colon in the retropolytonium, it can lead to abscesses. You can sometimes feel subcutaneous emphysema. So the therapy we mentioned earlier, post-polypectomy bleeding, you can use all kinds of treatment, usually mechanical clip closure or thermal therapy. This bleeding can occur immediate. Next complication is barotrauma. So that the lumen can be clearly identified, but additional air encephalation will lengthen the colon and make insertion more difficult, as well as increasing some risk and discomfort for the patient. Be particularly careful about air encephalation after passing a tight stricture or angulation in a patient with severe diverticular disease. In such a patient, air may not be able to escape around the colonoscope in order to exit through the anus. If the ileocecal valve is competent to air, a closed system can develop. So closed system means air doesn't go into the small bowel. It's just going to keep distending the colon and cause perforation. So there are two mechanisms of colonoscope perforation. So one is this one. There are two basic mechanisms of perforation during insertion. The first of these is mechanical rupture by the colonoscope, which usually occurs when the side of the colonoscope ruptures the colon in the vicinity of the rectosigmoid junction. The most important step in avoiding this type of perforation is to not continue to push the instrument when fixed resistance is palpated by the hand on the insertion tube. Fixed resistance is the sensation that the colon will not stretch further as pressure is applied. No matter whether the lumen is in view or not, you must stop when you feel fixed resistance. That's really clear. There are two basic mechanisms. The second mechanism. Mechanical perforations may also occur when the colonoscope tip is forcefully pushed against a diverticulum. Remember that not all diverticula are small and occasionally diverticula will mimic the lumen even for an experienced examiner. Mechanical perforations occur more rarely when the colonoscope tip is pushed against a stricture that is too tight to allow passage of the scope. Continued pushing can cause the tip to forcefully slip off the side of the stricture and dissect the normal colonic wall. This type of perforation can be avoided by either first balloon dilating the stricture or by passing a guide wire through the stricture before attempting passage as shown in the animation. The guide wire will prevent the scope tip from slipping off the side of the stricture. Now that we have a newer colonoscope, you can use slim colonoscope. Smaller diameter like EGD diameter, that's another option as well. So lastly, colonic decompletion. This is indicated for distant colon, particularly when the cecum is larger than 11, 12 centimeter. This can lead to wall tension, bacterial translocation, and perforation. We see this condition in the colonic bowel lust, colon tumor obstruction. However, we rarely perform colonic decompletion tube for colon cancer because colonic stain is more effective and less complication. Another commonly used indication for colonic decompletion is pseudo-obstruction, basically dilated colon without mechanical obstruction. The primary treatment for this condition is neostigmine. But for patient that fail neostigmine or has contraindication for neostigmine, so colonic decompletion is a secondary therapy. So sometimes you have to perform this procedure in the unprepped colon because patient has very dilated colon, cannot take the bowel prep. If possible, use CO2 and minimal insufflation. Because if you keep putting more insufflation, you can cause perforation during the procedure. Once getting inside the colon, suction as much as possible air fluid to decompress and leave the decompression tube. This can be done over the guidelines. So basically, get to the colon as far as possible, advance the guideline through the scope, remove the scope, and then pass the tube over the wire. If you have fluoroscopy, it will be even better because you can see where the guideline end and where the tube will be. But it's not mandatory. So in summary, we talk about lower GI bleeding. Choronoscopy is the primary test of choice. We talk about polypectomy. Depends on size and morphology and risk of cancer. That will determine how you perform resection. And we also went over complications of colonoscopy. Okay. So I think I'm a little bit over time. Okay. Please wait. Okay. Any questions? Open for questions. No questions. Okay.

therapeutic colonoscopy

lower GI bleeding

polypectomy

colonic decompression

post-polypectomy bleeding

barotrauma

perforation risk

submucosal lifting