John was with us in the past at Hopkins, now he's at Stanford, hands down the best gastroenterologist I know, and I'm not exaggerating, really appreciate you being with us, and you will be showing us videos and tracings of pH and manometry. Go ahead, John. Thank you. Thanks. I really appreciate the kind words. So I'm going to go online here, and what I'm going to do here is go through a couple live cases and show you exactly what I'm doing when I'm looking at these studies. And so instead of a slideshow in the spirit of doing endoscopy live, I'm going to walk you through five manometries, two pH impedance, and if we have time, a flip, and I'm going to do so in 20 minutes. So starting with the first case, this is a 58-year-old woman who was sent to CS based on Globus, and she's getting manometry and pH impedance. And so this is a study that I have not marked yet on purpose to walk through in real time when we're looking at these studies, what exactly we're doing. So what you're seeing here is you're seeing essentially the manometry, where you've got color corresponding with pressure, you've got time with the x-axis, you have the esophagus with the y-axis. So the mouth is at the top of the screen, the stomach is at the bottom. Purple corresponds with impedance, which is flow. And what I'm going to do as I open this is I'm going towards the end of the study, I'm going to quickly calibrate just because you get sensor drift from the temperature. And so it's important to reset that when you start to look at it. Then I'm going to go and first look at the landmarks here. And so we have at this stage a nice 30-second rest phase, and I'm just going to set where everything is. And so I've got the upper sphincter in this area, I've got the lower sphincter here. I'm going to take a look at the diaphragm and see where exactly this inversion pressure point is. And it appears to be right about here. It's where one of the lines is going up, showing you're in the thorax, the other is lower, showing you're in the abdomen. And then I'm going to just set the borders with the lower sphincter, which is approximately here, then set the gastric baseline. And then once I've got that locked in place, then I'm going to go through 10 swallows within the supine position. And I'm just going to move this so I get velocity of the contraction coming down. And I'm looking at essentially three things with this, four. The first one is that I'm looking at relaxation in terms of the lower sophagus sphincter. And this is characterized with what's referred to as the IRP, or essentially the integrated relaxation pressure, which is the lowest non-contiguous four seconds of pressure within the sphincter within a 10-second period. And this should be approximately 15 or less. Now, you're not looking at every individual swallow, you're instead looking at the mean on throughout the pan. That's the first thing. Second thing that I look for is the amplitude of the contraction. Hey, John, can you just repeat a little bit about the IRP, which as you mentioned, this is the most or one of the most critical things to look for when as fellows and as people who are doing this in practice are looking at. So can you walk us a little bit slowly through exactly that IRP thing? Sure. So this gives you a window when the sphincter is relaxing. And in the past, they looked at different metrics such as your single lowest pressure point. But what they found is that what you really need is you need a lower pressure, plus you need that to be open for an adequate length of time to let this pass. And so what the IRP is essentially is it's the relaxation pressure of the gastroesophageal junction, but to try and capture both the pressure plus the time that's involved with that going through, they've made this formula where it's essentially your lowest four seconds within a 10 second period to try and account for the fact that sometimes with diaphragmatic contractions, you'll have a little bit of a higher pressure at certain periods that may not necessarily reflect obstruction. Now, when looking at the IRP, there's three main motility companies which make equipment. They all make great equipment, they're all excellent, but because the catheters differ a little bit with each of these, what's considered the upper range of normal will vary based upon the equipment that you have. Now for this particular system, 15 is what's referred to as the upper limit. You can see here, this particular swallow is 20. So you would say that this is a little bit high, but it's not uncommon to have variation across swallows and what you're looking for is not the absolute highest, but more the mean that's present throughout the study. Now this becomes an important metric when you're looking to look at outflow obstruction or achalasia or else what's normal, what the IRP is, is going to help you separate that. And so what you're looking to see for a study that's normal is to have an IRP that's less than the upper limit, which in this case is 15, as a mean throughout the study. If you're above 15 and you've got symptoms that are consistent with a possible obstructive process and you have segmental pressure that's elevated, then you're looking at outflow obstruction or variants of achalasia based on what's happening within the body of the esophagus. Now, one of the challenges with phenometry from a technical standpoint is that this all gets referenced to one gastric pressure. So based on where you set that gastric pressure, you can see that I can make this, you know, five, I can go up and make it 13, I can go down and make it 20. And this is one of the limitations in the art that goes into doing studies. Now I'll kind of just go through this study a little bit more quickly, but you can see as we go through, what you're seeing is peristalsis that comes down that looks pretty appropriate. You've got pressures that look in a range that's average, and what you're looking at that is this formula, which is the distal contractile in to roles, essentially a composite of the amplitude, the duration of the contraction, as well as the length of the contraction. And this should be anywhere from 500 to approximately 8,000. If it's below 500, then that's considered to be a weak, weak swallow. If it's above 8,000, that's considered to be a hyper contractile swallow. And so as I go through this one, you can see that what we're seeing is peristalsis that looks okay. We've got pressure that looks okay. It looks like the IRP is a little bit elevated. And so I'm going to keep on going through. Now with the fourth swallow, the IRP is now in a range that's normal, it's 14.8. And as I'm going through, you can see that these are now in a range that's less than 15. So as I go through these 10 swallows, what I'm left with at the end of the day is that we've got swallows that look pretty normal. We have an IRP that looks appropriate. We have amplitude that looks pretty good, and this looks normal. Now we do have some provocative maneuvers, which we can do as well in the manometry. And this is what's referred to as multiple rapid swallows. And the idea with this is that it's almost like an esophageal stress test, where if you can ask them to do multiple rapid swallows at small volume, what should happen is that you should inhibit the lower esophageal sphincter so that you'll get this nice relaxation period. And then because you've inhibited peristalsis throughout this, you'll get this deglutitive augmented contraction afterwards. And so here you can see that this looks like a robust swallow, and maybe a little more vigorous than some of the other ones that I've shown prior. And there's now some nice literature from the group at Wash U that if you were to look at patients with GERD and you were to consider doing any mechanical procedure to try and boost the sphincter pressure, that if you look at the rates of postoperative dysphagia, that if patients have a normal response to this maneuver, that they are less likely to get symptoms afterwards in terms of swallowing materials. So this is now something that we are doing with every manometry. It's a nice maneuver in that it only takes water. It takes about 30 seconds extra. So it's very simple to incorporate, and it may give some information diagnostically in terms of what to do with these patients. Now after we've done the 10 supine swallows and we've done this maneuver, we then sit them upright and do five swallows within the upright position. And here you're essentially just looking to see if there's any different motility patterns that you see in the upright versus the supine. So as we look again here, once again we've got this IRP that looks a little bit higher, but we see normal peristalsis, normal pressures in this area. And as I go through, you can see that once again the IRP normalizes as we do additional swallows. Now after I've gone through these five swallows within the upright, when I'm doing the interpretation, I then go back and click on the impedance. And what this is, is this is essentially a way of looking at flow that's present throughout the esophagus. And on this particular software, this comes through as purple. And I'm going to adjust this so that you can see well the flow of fluid going through. Now where this is helpful, this study from the manometry, it looks pretty normal. So I'm not expecting to see anything that jumps out from the impedance. But if this patient had ineffective motility where you have a lot of weak contractions or spasm, then impedance can be very helpful because it can show whether the esophagus is actually pushing things down. And very similar to that multiple rapid swallowing that I showed prior, if you do have good impedance passage and you're seeing fluid going through well, then you're a little more comfortable that if you were to do any mechanical procedure, whether that be a diff or a supplication, that you may be less likely to have issues afterwards. And so that's essentially the way that we would read a baseline manometry. Now- John, thank you. John, if we have 10 more minutes, if you can highlight the high-end stuff in the other manometries. But that was excellent. Sounds good. Sounds good. So let me go through and do this one's pH impedance super fast, and then I will go back. And so with the pH impedance, you've heard a wonderful talk about a wireless capsule, but the pH impedance has its pros and cons. And the way this works is you place this catheter again from the mouth down, we've got the top of the esophagus at the top, the stomach at the bottom, and impedance translates in this software to color. So that white corresponds with fluid, black corresponds with air, blue is the esophagus at rest. And you can go through and scroll through a 24-hour period looking at movement. And what we do is we mark this. And so here you've got some swallows coming down, you can see the white at the top of the screen coming down. And then as we go through, we've got some more swallows, and then we've got some reflux episodes, which I'll point out quickly just to show that that's different. Now this is laborious to read. And so this takes me probably 20, I'd say about 20 minutes per study, and I've done several thousand. And so when I was first starting, this was a good 45 minutes at least. It's almost like reading a capsule endoscopy, where it's a nice study, it adds something, it's amazingly dull. And so this study with the pH impedance, what we get at the end of the day is that the acid throughout the study looks normal, the reflux numbers with impedance look normal, and this is essentially a study that's normal. So let me switch and go through some interesting manometries in the next nine minutes. And this is one that was sent to me because of reflux, he's 40. And I'm going to just point out the high yield facts, I've marked these studies so that we don't have to go through everything. But the key thing that I want to show you here is that if you look at his lower esophageal sphincter, you can see peristalsis coming down here and ending right at this point. So this is essentially the lower esophageal sphincter. But if you look at the diaphragmatic contractions, the change in pressure in the diaphragm is right down here. So he's got a hiatal hernia that's about four centimeters. Essentially, you've got a separation of the lower esophageal sphincter and the diaphragm here. And he's got peristalsis that looks normal. If we look throughout all 15 swallows, these look pretty similar. He's got bolus clearance with impedance that looks fine. But take a look at what happens with this. He clears his swallows, but then this fluid sits in the hernia sac and it just comes back up after. And so as we look at this patient from the standpoint of reflux, he's got neuromotility, he's got a hernia that's about four centimeters, he's got GERD coming back up after. And then if we go and we take a look at his pH impedance study, which I've got up here, his acid exposure on meds is pretty normal. But what I want to show you, too, is just the extent of reflux that he has after meals. And if you were to go through, contrast it with that last patient where you had just small white swallows going down. And here you can see these massive events of reflux coming up from the stomach and going up. And once again, white is fluid, blue is the esophagus. And as we scroll through this, this is all just reflux and reflux and reflux. So as we went through, when I counted his reflux events within the study, he had about 300 events. And so this is a patient, based on this information, that we can go back and say, you've got a hernia of four centimeters. You've got GERD that is profound. It's mostly after meals. And this is someone that I would expect to do very well with going in and fix it. Now, in the last six minutes, let me go through three interesting manometries and just point out the salient features. And so this is a patient who has GERD and dysphagia after a length. And so what you're seeing here is you're seeing peristalsis that looks appropriate. You've got some vascular patterns here. And so this isn't anything that's clinically significant. But again, you've got a bit of a hernia where you've got the lower esophageal sphincter coming down here. Then you've got this intermittent high pressure band below about four centimeters. And what this is actually is this is the links that's slipped down a little bit. And so you've got this hernia. And then you've got outflow obstruction from the links itself. Now, we're still in the process of working up what to do with this patient. Our first step will probably be to stretch the links and see if that'll make a difference. Because at present, the GERD is probably less significant than the dysphagia. Going towards the next one of interest. So this is actually a case that I saw in clinic about a month and a half ago. And he's 35, has a long history of dysphagia. But he had a prior manometry that was read as showing spasm. And a barium study that was read as showing spasm but was felt not to be consistent with achalasia. And so this is his manometry. Now, technically, he had some tortuosity in the esophagus. And he did have tightness at the junction that made it difficult to get a true gastric baseline beyond that. So this study is a little bit limited. But that's not uncommon for what we see in real life with these patients. But as you're going through, despite the weak gastric baseline, what you see here is that his lower esophagus sphincter is not relaxing appropriately. You've got this band that's persistent throughout. He has an IRP of 28. And you don't see any peristalsis above this. And then as we're going through and we're doing additional swallows, you never see this sphincter open. And you see this isobaric pressurization throughout. And that becomes more significant as we change towards upright swallows, which are seen here. And so this is a patient that we can look at and say, he has achalasia type 2. This is classic. And he's someone that is actually going towards home. And we expect to do very well. And then finally, in the last manometry, this is a patient who was sent to me based on chest. And what you're seeing here is as we look at these swallows, and I'll turn off impedance to make this a little bit easier to see, your first glance is that you do have an IRP that's elevated. That's elevated. And regardless of which of the three systems you have, 26 is higher than the cutoff. So this does appear to be high. There is elevated segmental pressure and interbolus pressure that appears to be maintained here. And then if you look at the pressure of this contraction, this range with the distal contractile in integral should be between 500 and 8,000. And here, you can see we've got 13,000. So it looks like what we've got here. But if you look here, peristalsis looks pretty normal. So if you were looking at what this is, you would say, if this was every swallow, this would be outflow obstruction plus also a hypercontractile esophagus or jackhammer. Now, as we go through and we look at the other studies, now, it's not a type 3 achalasia because you have peristalsis. But in terms of your actual management, if this was outflow obstruction plus hypercontractile esophagus, you may treat this exactly the same way as type 3 achalasia. So that difference may, to some extent, be semantic. Now, as we go through, what I want to show you is that the distal contractile really stays high. And you're persistently above 8,000. But as you go through this a little bit, in supine swallows, you do have an IRP that's persistently elevated. But as you get to the upright swallows, your IRP actually drops down. And so here, it's 11.8. Here, it's 9. So this is someone that has an elevated IRP in supine swallows but not an upright. And in Chicago classification version 3, which came out in 2016, this would have been outflow obstruction. But in Chicago 4, you have to have an IRP that's elevated in both positions. And so the fact that this is normal in the upright position would say that what we're looking at is jackhammer, but we're not looking at outflow obstruction. So now, that may not change management. If the chest pain is severe, you may still be thinking of home or possibly other measures to drop pressure. But it does change diagnosis. So I'm at 20 minutes now. So I'm going to stop here.

manometry

pH impedance studies

interpretation

outflow obstruction

achalasia

motility disorders