It was very interesting to see this morning. At our committee, Advanced Endoscopy Committee, we had this discussion about the course, who to be the course directors, and for the fellows that are here, there is a background to it. This course used to be in Cleveland for many years and it was extremely successful. So it was a logical choice to have two course directors from Cleveland to transition into this, and what happened is actually they brought Cleveland with them here today. That is fantastic because if you have a winner, stick with it. So sorry for disrupting the disorder. So I practiced at the University of Florida, and my case is single case, and I have two teaching points for two things that are relatively uncommon but extremely important to recognize. So I'll go as basic as it gets. I actually prepared two cases. I'm skipping the first one. This is my second case, 66-year-old man with WIPO for pancreatic cancer a year ago, and now has elevated bilirubin. MRCP suggests stricture at the colloidal jejunostomy, and the surgeons wanted us to do ERCP, but the patient's serum sodium was 114 millimoles per liter. Of course, that gives us on the GI side, and of course on the anesthesia side, a pause. The question is, why is this patient hyponatremic, and what one test do you want to do at this point? Let's give everybody a time to think it over. I see one hand went up, and you may have seen a case like this, but this is bread and butter internal medicine boards, right? Hyponatremia. You can definitely count on getting one question. Okay, nobody. Let's go with you. So there are three causes, hyperbilirubinemia, hypertriglyceridemia, and paraproteinemia. Usually, bilis are more than 20. That's when they cause hyponatremia. Hypertriglyceridemia, more than 1,000 can cause that. Paraproteinemia can result in it as well. So bilis could be one of the potential causes. We don't have TG levels and albumin over here. Sure. Why this patient could not have SIADH? That's another possibility. That's a common cause of hyponatremia. I didn't say they may have diarrhea and be volume depleted. I didn't give that information. So yeah, another hand went up. Yeah. I was thinking about doing it according to the volume status, hypovolemic, hypervolemic, or euvolemic, and then approach it from there. Generally, people who are like hypovolemic, you can just easily hydrate them with fluid, and it's just going to slowly correct the sodium. Hypervolemic, you can sometimes just water restrict them and start them doing diuresis. It's going to bring it down, and it's kind of a challenging if they are euvolemic, like SIADH and other like content. Absolutely. So that is indeed a major branching point in the algorithm, whether the patient is edematous or hypovolemic or euvolemic. But before that, there is one more test. Not one more, but one test that you do before you come to that branching point. I'm not going to tease you too much. It's serum osmolality. Just a blast from the past. So you check. I thought the answer was order a renal consult. That's what's happening. There we go. There we go. So you check osmolality, and actually the majority of hyponatremia will be the hypotonic. So the osmolality is low, and then you go to the volume status. But indeed, as this part of the algorithm is frequently forgotten because it's not a common one, it's isotonic hyponatremia, and as eloquently pointed out, it could be high protein or high triglycerides in the serum. The reason is that the way we measure serum sodium, and by the way, that isotonic hypovolemia is also referred as pseudo-hyponatremia. So the most commonly used technique is indirect technique where you dilute the patient sample, and just as a quick visual, if this is normal, approximately seven percent of the serum is lipids or protein, but if those are increased, and now you dilute this 10 to 1, and you dilute 10 to 1, you end up with a disproportionate representation of the plasma in your sample. So you'll be measuring lower sodium when actually sodium is normal. Just to briefly recap, it's either elevated serum protein or elevated lipids, and here are some examples. I did not list immediately one example, which is lipoprotein X accumulation, such as in biliary obstruction. So if you have obstructive jaundice, lipoprotein X can accumulate. It's not commonly seen to a point to cause overt hyponatremia like that, but keep that in mind. So if you have a patient like that in your unit, low sodium obstructive jaundice, check serum osmolality. That is your most important test. If that is normal, that is pseudo-hyponatremia, you should continue with your case. This is just a reminder of the algorithm. So we actually proceeded with ERCP with general anesthesia. It was a pinpoint stricture at the colloidal jejunostomy, and we spent quite a bit of time trying to cannulate that. It was difficult cannulation. We were using a pediatric colonoscope for the procedure with CAP, and angle was not favorable. Eventually, we got in. The stricture was dilated and stented, but the patient remained hemodynamically stable during the procedure, ventilating well. We finished the procedure, and when we transferred them back to the gurney, and from prone to supine, the patient developed an abrupt oxygen desaturation, ocular deviation, and actually had forehead skin discoloration, and this is actual picture of the patient. Any ideas what could be going on now? Raju, that's not to you. I just want to remind everyone, we are still in the advanced endoscopy conference, in case you are wondering, and we are not mindless scope jockeys as presented by this case. So, a rare complication I want to add that this was a case of mine that I did about 15 years ago, and that is important, and the reason it's important is that after this case, this patient died, unfortunately. At that time, we converted our endoscopy unit to CO2 insufflation. So, the answer is this patient had air embolism. Unfortunate complication is a rare complication, but it is usually lethal, and the reason I'm presenting this case is there is this things that you can do to hopefully help this patient. The patient had a bunch of stuff done. This is a CT angiography because there was a concern about PE, and actually it was negative, had a head CT which show air in the brain, and show trans-thoracic echograms revealed left-sided intracardiac air, and patent for ramen ovale, and that's why the patient had a stroke because of the patent for ramen ovale allowed the air to go from the biliary system into the portal system, into the inferior vena cava, from there into the right heart, left heart, and into the brain. So, what are the risk factors for embolism at TRCP, and here is the advanced therapeutic endoscopy comes into play. So, prior biliary sphincterotomy or biliary surgery, because now you have an open conduit in a closed loop, particularly in WIPO, you have a dead-end loop, you're pumping their air or CO2, and you have an anastomosis that is open to allow air to go in. Patients that had PTCO tips, liver biopsy done at same session. So, in our unit, we reverse the order of liver biopsies in ERCP. Now, we first do the ERCP in transplant patients, then we do the liver biopsy if needed. Cholangioscopy is identified to risk factor. If you're doing a direct cholangioscopy, meaning not using spyglass where we usually instill water, but use a small diameter like transnasal type of scope to do your cholangioscopy, please, you must use CO2 in that case. Never, ever use air and prolonged procedure. So, the key is to recognize early the symptom onset during the position change is one of the hallmarks of this because usually, when you flip the patient on their back, then the air moves up, and that means it ends up in the heart. So, bedside echo is the usual test, and CT angio, of course, can help head CT, but those are not as important as you just have a high index of suspicion if this happens, and you even have the slightest suspicion that this may be aeroembolism. Immediately, place the patient in Trendelenburg position, meaning feet up, head down. Initiate high flow of oxygen, aggressive intravenous fluid resuscitation, and those are the first three things that you can do. After that, you can do air aspiration through venous central catheter and hyperbaric oxygenation, but the first three are the key, because that can save the patient from dying or even having significant neurologic sequelae even if they survive. Of course, I hope most all units are now equipped with CO2 for all procedures, but there are cases in the literature of air embolism, although obviously a misnomer, but with CO2, it can still happen. So, don't count it out just because you're using CO2. So, to basically summarize, air embolism is rare, but usually fatal. There is recognized risk factors, particularly with ERCP. It can happen with other procedures, but prolonged procedure, probability of surgery, PTCO tips, or liver biopsy. Symptoms start or get worse with position change from prone to supine. High index of suspicion is the key, and involve your anesthesiologist, because their mind usually goes elsewhere. They don't think of that. So, you may be the one that prompts this patient, rather than be getting head CTs to basically start the high flow of oxygen and intravenous fluids. The actual diagnostic procedure is bedside echo rather than CAT scan, because that will kill another 45 minutes of the patient going down for PE protocol CAT scan. Finally, with pseudo-hyponatremia, obstructive jaundice is one of the predisposing factors. Keep in mind, you'll see plenty of patients with obstructive jaundice since you do ERCP. Check serum osmolality as your initial test. If normal, most likely you're doing with pseudo-hyponatremia. Thank you. Yeah, that was a fantastic case. Remember, it's not all about what you're doing with the scope. Oh, yeah. This is endoscopy conference. I forgot about that. I think, Peter, you brought up a good point. Even though most of us, we all use CO2 for all the cases, that does not exclude the possibility of air embolism, quote-unquote, with that. That's always should be in the consent when you talk to the patient, especially procedures like direct endoscopic necrosectomy, or you're planning on doing cholangioscopy, large biliary splinter procedures, et cetera. So always, that's one of the consent items. Yeah, absolutely. Thanks for bringing direct endoscopic necrosectomy. That's another procedure where we sit there for prolonged period of time pumping CO2 into enclosed cavity. So definitely a major risk factor. That brings up another point, how you should be very careful when you have so much stuff carried over even though we recommend CO2 for all. You'd be surprised how many times you are on regular air instead of CO2. So always turn around and make sure. As you can feel it with the pressure on your finger on the air channel, but always turn around and make sure you are on CO2. Right. Because when they switch to cleaning the scope, they have to switch to air. Right. So depends on the system that you're using, you may be fully set up for CO2, but on the current 190 series Olympus processors, you have to press a button to switch from air to CO2. So you may be fully hooked to CO2. If you don't press that button or somebody incidentally depressed it, you'll be still pumping air. So I hope they address this on the new X1 platform, but I don't know that for sure. Thanks. We'll move from the lumen now to pancreas.

advanced endoscopy procedures

hyponatremia

air embolism

ERCP

CO2 use