Today, more on CEQA insertion technique on the ASGE SuTab tip of the week. Last week we discussed insertion in very difficult colons and we're going to extend that discussion this week, but I think it's always important to discuss safety issues related to insertion. So our rules for safety, first of all, don't push against fixed resistance to avoid rupturing the colon. And secondly, to switch to water in every tight, angulated sigmoid to avoid barotrauma. Fixed resistance is something that you feel with your hand when you're pushing. The colon should give way and move with you. If it stops moving, it feels that it's providing a fixed resistance, then you have to stop pushing. And this is an incredibly successful and reliable rule for preventing perforation in normal colons. I'm sure it always works in a sick colon where a perforation could potentially occur before there's actually fixed resistance felt, but in a normal colon, it's incredibly reliable for preventing perforation from the side of the scope, so-called diagnostic or rupture pushing perforations. Another reliable safety rule is that to avoid barotrauma, which is that every time you enter an angulated difficult sigmoid colon, you switch from gas to water to fill the colon and to guide you in finding the lumen. And that's because although barotrauma is rare, when it does occur, the patient always has a difficult sigmoid colon where apparently they can trap gas between the sigmoid and a competent ileocecal valve. And you have to recognize the risk early because these perforations have typically occurred before the scope reaches the proximal colon. So recognition of the risk and prevention by installation of water rather than gas is the essential step. We don't have a clear rule for prevention of splenic injury. My own recommendation is that anytime you have the scope tip proximal to the splenocolic ligament, you have to be careful about torque or pulling on the insertion tube that could stress the splenocolic ligament, bend the spleen, cause a crack in the capsule, initiate bleeding either into the peritoneal cavity or into the parenchyma of the spleen, which can cause a large hematoma, eventually disrupt the capsule. The main risk factor for splenic injury is female gender, and I think especially in thin females one should be cautious, but just in general as a rule, this crude drawing reminds us that the spleen and the colon are connected by ligaments and we want to be careful about forces that cause twisting or pulling on those ligaments. So with those safety comments in mind and returning to the issue of best methods and techniques for secal insertion, what are you going to rely on primarily? Well, everybody's going to rely on loop reduction because getting the loops out and keeping the instrument as straight as possible is the fundamental maneuver of good, safe, comfortable and fast insertion to the cecum. So speed to the cecum is not about any sort of rushing. It's about getting the loops out so that the forces you apply to the insertion tube are transmitted to the tip and keep it moving forward. But after that you can rely on abdominal pressure and position change, and which of those is more important? Well, I think there are some cultural influences on that. The studies with the magnetic imager, the UPD or scope guide device showed long ago that in general position change is probably more effective on average than abdominal pressure. But in the U.S. we are relying on it less because we're using deep sedation and we're concerned in deep sedation about rotating patients onto their back, particularly the right lateral cubitus position, that there's an increased risk of aspiration. And secondly, because many of our patients are very heavy and especially in the redundant colon population, on average, the BMI is very high. Not all of these patients have a very high BMI, but quite a few of them do, and that makes it also hard to rotate them. So we tend to rely, I think, more on abdominal pressure in cultures and countries like the U.K. where they're using moderate sedation more or in countries where unsedated colonoscopy is the norm. Then position change is easier to do, the patient helps with it. I think it's a very elegant way to perform colonoscopy, but this deep sedation thing that is going on in some countries, including the U.S., has driven us to use abdominal pressure more. So here are my own poor depictions of different types of loops that occur during colonoscope insertion. The end loop, alpha loop, reverse alpha loop. You can get very complex loops, multiple loops in patients. You can read about these in colonoscopy textbooks. You can see them in real time if you're using the UPD or ScopeGuide device. I've got tremendous respect for the people that developed these concepts about colonoscope insertion. Having said that, and agreeing that it's useful to learn about different types of loops that develop during colonoscopy, I will say that during insertion I am not thinking about the shapes of different loops. While I am extremely interested in whether loops are present and getting them out as quickly as possible, but not thinking so much about their shapes because I don't use MEI the UPD device or fluoroscopy with any regularity. So I can't actually see the shapes of the loops. We recognize loops by loss of one-to-one transmission of force on the insertion tube to the scope tip and looking down and seeing how much scope is in the patient. If you're in the transverse colon, you've got 100, 120 centimeters of scope in the patient. Then by definition, you've got a loop in there and you want to get it out as quickly as you can. You feel as you're pulling back on the scope, the direction to unwind, whether it should be a clockwise torque or counterclockwise torque by whether or not when you try one or other directions that the scope feels like it's going into the loop more or it's starting to come out. If it feels like it's going in more, you go the other way. I think there are times when you have to push through a loop during colonoscopy or you have to push into a loop and go around another term before you can really effectively unwind the loop. So that happens at times, no matter what one will tell you. Just like at times you have to slide by turns. That's part of colonoscopy also, and it's safe as long as you follow the rules of not pushing against fixed resistance. But the general message is that even if you can't see the shape of the scope, you need to recognize when loops are present and get them out of the scope as quickly as you can. So abdominal pressure is an art form. As I said, I tend to use it more than position change because of deep sedation and because of seeing many very large patients in our U.S. population. And I think it's important in the redundant colon, the incomplete colon, where sometimes we have to have several people pushing at once. It's often also important after getting through a narrow angulated sigmoid because you're using a very thin scope and it's very floppy and you need some pressure to make the scope go forward. The person who's giving the pressure should be able to see a monitor. They learn better that way what's effective. The best use of pressure is to prevent a loop from forming. So if you start to form a loop, take it out and then apply pressure before you reinsert to try to prevent that loop from reforming. Also very important to remember that after you've passed a turn through creation of a loop and then you've pulled it out, you want to take the pressure off because pressure can block the forward movement of the scope and you want to be aware of the risks of the technician of prolonged pressure. There's often a discussion about whether they should apply pressure with their open hand or the closed fist. And I think mixing it up, making sure it doesn't hurt, but trying to not have them pushing for long periods of time is important. Remember that there should often be a combination of both posterior and a direction to it. I'll come back to that in a minute. Each position and direction for pressure should be only tried once and then you should try something different. If during a case you feel a loop in the scope in a particular place on the abdomen through the abdominal wall, remove the loop and then put the pressure there to try to prevent reformation of that loop. Putting some direction to the abdominal pressure other than just straight posterior is often useful. So to counter sigmoid pressure coming from the right and pushing down and toward the left to move across the transverse colon pressure in the left upper quadrant that is directed somewhat to the right to counter transverse looping, pushing from the lower abdomen up and to move the scope down the right colon, pushing from the right side toward the midline. In general, with regard to abdominal pressure, the floppier, the thinner the scope, the more likely you'll need it at some point during the procedure and the very redundant colon, especially these very high BMI patients, we sometimes have four or six hands on the abdomen pushing and I may have the pushers try massaging, perhaps a better word is kneading the abdomen, trying to catch the side of the scope or the side of the bending section and push the tip forward. Position change can be very effective in advancing the scope during insertion, but the extent to which you rely on it as opposed to abdominal pressure again can depend on the type of sedation you're using and the BMI of the patient. In general, colonoscopy is started in the left lateral decubitus position, but it's useful to know that there are literatures on doing the entire procedure in the supine and in the prone position. When starting in the left lateral decubitus position, position changes that are particularly useful included going to the supine position to cross the rectosigmoid junction or the transverse colon and then it can be very useful in the lightly or moderately sedated patient to rotate from supine to right lateral decubitus to move the scope from the mid ascending or just above the ileocecal valve down into the cecum. Today we reviewed principles of cecal insertion that are important in all colonoscopy, even routine colonoscopy, getting the loops out, appropriate use of abdominal pressure and position change. Last week we reviewed techniques and tools for achieving cecal insertion in anatomically difficult colons. Over the next couple of weeks we'll observe both the basic principles and the techniques that are important to difficult colonoscopy in actual performance of colonoscopy, first in extremely angulated colons and then in a subsequent tip in the very redundant colon. Thanks and see you next week on the ASGE SuTAP tip of the week.

colonoscopies

insertion technique

safety issues

barotrauma

splenic injury