introduce Dr. Leslie Rickey. She's an associate professor in the Department of Urology and Obstetrics and Gynecology and Reproductive Sciences at Yale University School of Medicine. Dr. Rickey was on the urology faculty at the University of Maryland School of Medicine from 2007 to 2013 before accepting her current position at Yale, where she is also the IRPS Fellowship Director and Vice Chair of Faculty Affairs in Urology. She is the Yale PI in the NIH NIDDK, Prevention of Lower Urinary Tract Symptoms Consortium. Welcome, Dr. Rickey. Thank you. All right, thank you for that. And I just wanna say I'm really excited to be here. This is my first Augs APP course that I've been to, so I'm really looking forward to giving this talk to you all and also learning from everybody. So financial disclosures, I'm an author for UpToDate, and I also have to say I am deeply grateful to Dr. Gray, our previous speaker. He taught this course last year, and he shared his slides with me to use as a foundation for mine, so you'll see some little gray-isms scattered throughout. All right, so the main objectives of this talk is to talk about the interpretation of the components of urodynamics, being the filling or storage part, which we call the systemetrogram, and also the voiding elements, which would be the non-instrumented uroflow as well as the pressure flow study. This is not gonna get into the nuts and bolts of how to do the urodynamics. There's actually a workshop on Saturday that's a little more hands-on for that, but this is like you're in the room. What are some things we need to think about? So first, I wanna say, you know, what are the aims? The primary aim is to reproduce the patient's symptoms so that you can try to come up with a reason for the cause for their symptoms. You know, this is like not a great test, right? It's invasive. Someone's sitting in a chair. They have a catheter in their bladder in either their vagina or rectum. They're having to leak in front of people, pee in front of people. It can be uncomfortable for many, many women, so I think it's really incumbent on whomever is ordering the urodynamics and whoever's doing it to really have a good indication for doing it and then understand if you are carrying out somebody else's study or order. I think it's really important, yes, to look at the note ahead of time from the previous one and then also try to touch base with that provider if you're in the clinic or not just to really understand, especially if somebody's a little more complicated because you wanna make this a meaningful test. One of the worst things is, you know, I might be planning a surgery on somebody and I don't do urodynamics in every single one of my patients. I use them quite selectively, but say I really need a diagnosis before they leave so I know what I'm doing. If the person doing it, if we haven't touched base ahead of time, which is not their fault, not my fault, it's just we should have all thought about that, and they come to me and say, hey, the patient's in the room. I say, hey, what did the test show? Well, we didn't show any leakage. I mean, at that point, what am I gonna do, right? So I'll say, I'll try to say before the study starts, look, this is what I'm looking for. If you don't see this, please come get me before you get the patient off the chair and dressed and all of that because that's just a missed opportunity and you've also put them through this test and you don't have the information that you want. The other thing that I think is important, which is why I think this talk is really important, is it's one thing just to technically carry out the test, but ideally, the more someone does of these, and yes, you get used to troubleshooting, but you know what you're looking for during the test and you're starting to make some decisions during the test of what you might need to change to get the information that you want. So ideally, that interpretation and diagnosis happens during the study. So then when either if you're making your decisions, you're making them in partnership with somebody else, you can have a good discussion about that. So again, there's like the technical aspects and then the next level, which is really the interpretation and critically thinking about what you're seeing while you're seeing it. All right, so the lower urinary tract like really is a fairly simple system at its base when you think about it. The bladder should store urine, bladder and urethra, and then evacuate urine. What does it mean to store urine in a healthy state, no leakage and comfortably hold it for a reasonable amount of time between voids? So this is looking at it from more of a health perspective than a disease perspective. What does it mean to optimally be able to evacuate urine? Volitional voiding, meaning it's when you want to, where you want to, where it's in your control, and then adequate emptying where you're not struggling to empty the bladder. As we know, this goes sideways a lot of the time, however, which is why we're all here and part of the reasons why we're in business. So principles of interpretation. My research is in prevention of LUTs, just so we know, so I'd be happy to be out of business, but I think we're a little bit away from that. So you want to produce tracings that are valid and reliable. This takes a little bit of troubleshooting and knowing your equipment. Ensure that the testing procedures adhere to International Continent Society, Society for Urodynamics, Female Urology, and also, sorry, American Urogyne Society standards, and document the key events that are essential to the accurate interpretation. Somebody's gonna go be, like I look back at other people's urodynamics all the time because sometimes if a patient's coming to me for a second opinion, I don't want to have to repeat that test if I don't want to. It's not just like a, hey, you're here, we're gonna do it. A tracing without documentation of events, you don't really know what you're looking at. You don't really know, like, they coughed, like, did they leak or not? Because you don't really see that on any of the urodynamic channels. What happened with that pressure flow study? Did they, it looked like there was a PVR of 500. Was that just the end of it? Or did that patient then go into the bathroom and urinate to completion on the commode when she wasn't sitting in front of three people with three catheters in? So some of that you can document on the tracing. Some of that you can document in the report. There's definitely a move to, like, having these really standardized reports, and I think that's helpful. But I think adding what I call, like, field notes, adding your own notes on there. I tell, like, the fellows all the time in the APRNs, just write what you see. Like, it doesn't have to have super technical jargon. Just write what happened. If there's just a leakage event and there was no increased abdominal pressure and no detrusor contraction, just say it. Like, just write it like that. And then we can have a conversation about it and see what we think is going on. So here's Gray's five questions that you're looking for during urodynamics. I figured, why change a good thing? I made a slight revision to it that I'll show you the next one, but I think these are all super relevant. So what is the capacity, the systematic capacity? We'll talk about different types of capacity measures in a minute. What is the sensation of the bladder like? What is the compliance of the bladder wall? Is the urethral sphincter mechanism competent? And what is the detrusor response to filling and storage? My only change was that I like to think of urodynamics in terms of storage and evacuation. So I just made a little change here. What is the detrusor response to bladder filling? And then what is the detrusor activity during bladder emptying? So I didn't exactly know what level everybody was in the room. So I just wanted to just show you a normal urodynamics and point out the channels you might see. One thing I'm sure you all know, these channels can be in all different orders. Where I work, we have like PVES, PAB, PDET at the top. But in general, you're gonna have, here's the flow channel and the voided volume. So these you're not gonna see anything on until the end. They're just gonna be flat during filling. PVES is the total pressure in the bladder that is measured by the catheter in the bladder. PAB is the abdominal pressure, again, directly measured by a catheter either in the vagina or in the rectum. And then PDET, which is what is referred to as the true detrusor pressure, this is calculated. It's PVES minus PAB, which makes it subject to sometimes artifact and you have to, you can't just look at PDET when there's changes in it. You have to look at PVES and PAB and see what's going on. EMG, we're not gonna be going over EMG today. This is a add-on component according to the ICS. And then volume here is volume instilled. So you can see here, like this person at this point has had 257 mLs and then you can see various pressure readings. But I just wanted to do a quick review of that to orient everybody. So the first thing we're gonna talk about is what is the systematic capacity? Now, you'll hear the term, and this is an ICS term as well, functional capacity. So this is what I think of as a more physiologic capacity perhaps. This is what you might see on a diary or if you ask somebody to come in with a comfortably full bladder. I don't know about in your practice, that happens about 30% of the time in mine. But if they have come in with a comfortably full bladder and they're doing their uroflow, which is a more physiologic void without the catheters in place, those are functional volumes. In general, on a recent systematic review of healthy slash asymptomatic women, the reason I put this here is if you look at a lot of studies of urodynamic parameters in healthy women, a lot of times were people in a urogyne practice that had LUTs of some sort. They weren't necessarily like community-dwelling women with no LUTs. So healthy slash asymptomatic, and the average maximum voided volume was 425 on Voiding Diary and 324 on Uroflow. Just to give you some sense, there is a wide range there. There's a wide range, so take that with a grain of salt. Also, when you look at different lower urinary tract symptom conditions, as you might expect, women with urgency urinary incontinence have about a 30% lower maximum systematic capacity compared to their asymptomatic controls. This was in one very recently published study. So 279 mLs compared to 413. So I was taught as a fellow, and even now, we generally try to get people to around 300. Everybody has these techniques to talk them through. Some people just aren't gonna make it, and you guys know this, but forget about your bladder pain syndrome patients, but in your overactive bladder patients, they might not make it that far. They might have a leakage episode, or they just might be uncomfortable at that point. Women with SUI have a mean voided volume, or MCC, of 392, so a little bit closer to the asymptomatic controls in the other study. So the other thing to remember, I don't know how many of y'all have been in this situation where you filled them to 300, they urinated out 450. What should be recorded as the MCC? It should really be 450. Like don't be a slave, this is where I said you can take some field notes. Don't be a slave to the urodynamic report, or those channels I showed you. You know, and say that it was added together. Yeah, she urinated out this more. And of course, you know, this is most likely due to additional urine production during the urodynamics. It's gonna happen more in some than others. Maybe they took their diuretic that morning, maybe younger versus old. But one study that actually looked at this, it's an older study, but I really couldn't find any data that represented this well, that the total volume was, the voided volume was 14% higher than what had been infused. So there could be pump error also. I don't know how many people have been like, oh my gosh, you like, your voiding diary says you pee every hour, but we're at 500, and like what's going on? And you hear the little pump going, and you look over there, and there's like no fluid has gone through. So you do that like once, and then you know, you say something to the patient like, ooh, you know, you won't do it again. But it's gotta, I swear it probably happens to everybody at least once. So it could also be a pump error estimating the infused volume. So just keep an eye on that as well. So what is the compliance of the bladder wall? What is compliance? The compliance is essentially the bladder's ability to accommodate changes in volume without a large change in pressure. And we probably all use the balloon example, you know, when we're describing it to patients. And there's actually a physic law called Laplace's law, which basically says in a spherical object, as the radius increases, the tension increases. Think of the flat balloon versus the full balloon. Tension isn't bad, like it's just gonna increase in tension that allows the bladder pressure to stay low. So that's what you want. You want a low bladder, you want very minimal change with high volume, and we'll go over that formula in just a second. What allows the bladder to do this? Well, the smooth muscle tone, as well as the viscoelastic properties of the bladder wall. The reason we have to care about this is because, so low compliance, I'm sorry I said that wrong, you want high compliance. Low compliance is associated with damage to the upper tract or the kidneys. The reason being is that, remember, we have a closed system, right? Kidneys, ureters, bladder, urethra, that's it. It's all together. So if you have pressure building and building in that bladder for whatever reason, maybe it's lost its viscoelastic properties because of having neurologic issues or diabetes, things that have made that bladder wall more stiff. If they're not leaking, that pressure's gonna pop off somewhere and it can pop off to the upper urinary tracts. And so, we'll show you a picture of that in a minute. When you're calculating, so this is a great picture. Probably most of us are treating non-neurogenic patients in a urogyne practice, but there are patients that have neurologic diagnoses that you're gonna see. Women with MS, women with maybe some mild spinal cord abnormalities that are ambulatory and they might not have a lot of musculoskeletal decompensation yet, but you just gotta think about this so that when you see it, you know it. So in general, if you look at PDET here, when somebody's filling, like I said, this could be like 400 mLs, no change in PDET, not at all. So this is a normally compliant bladder. If you look here, you see this PDET going up, So this is indicative usually of a neurologic issue with the bladder. If you hear the term neurogenic bladder, I don't love it because neurogenic bladder can represent like 10 different things. However, that's what we call lower urinary tract dysfunction in the setting of a neurologic disease. So you can see PVES going up, PAB is flat. This is not someone just straining, straining, straining, so PDET is going up. And you can see here, I don't know, I don't think it has the infused volume here, but it's not, you might see this at 200, you might see this at 300. It's getting up to a dangerous pressure because right here it's 42. There was a study done a long time ago that showed that 40, PDET of 40, not when you're urinating, not like intermittent, but like sustained when you're filling, that pressure's holding, right? Like it's just sitting there at that high pressure that that can cause damage to the upper urinary tracts. And you can actually get a situation like this. So you can see here, here's the bladder, here's the ureters, and here are the calyces at the top. So this is a dilated, blown out system. This is not like a KUB after a CT scan. This contrast is all going up from the bladder. So this just, and this can happen in somebody that has a poorly compliant bladder, and it might actually be silent. So I'll sometimes check just renal function, ultrasound, even if I'm not highly suspicious of someone that has a neurologic diagnosis, just to make sure I'm not missing something so it doesn't sit there for years and years. All right, the next thing we're gonna talk about is the urethral sphincter mechanism. And this is probably a focus of a lot of the studies that we do if we're trying to diagnose stress incontinence, urgency incontinence, or mixed. So what are measures of urethral sphincter function? The two main ones that we use are the leak point pressure and the urethral pressure. We'll talk about this in a second. The leak point pressure is what it sounds like. What is the pressure when you leak? Somebody doesn't leak, they're not gonna have a leak point pressure. That's like a favorite PIM question of every new fellow or resident. What's your leak point pressure? And if they'll kind of go, oh, I don't know, maybe it's like 200 or something, and then we'll follow up with, do you leak, which might not be a nice question to ask somebody. But most of them are young and they don't leak, and so they don't have a leak point pressure. Sometimes these measures can be used to direct the surgical plan for stress incontinence. I'm not gonna get into that data. There's actually not a lot of great data that urodynamic parameters help you counsel the patient in front of you about how well their sling might work. There's a little bit. But in general, the lower these values are, the more incompetent the sphincter. Every sphincter where someone has stress incontinence is incompetent to some degree, but the worse it is, like the less successful your treatments might be. So first we're gonna talk about abdominal leak point pressure. So this is something that we usually do at around 200 mLs. You don't need to keep doing it. If someone's in a study, there might be some protocol where you have to do it every 100 or something. But in general, 150 or 200 mLs. If you have one of those patients that's having repeated DO contractions, this is where you have to think about what you're seeing a little bit, you might need to start over, fill really slowly, and try to sort of like catch them before they get in a DO episode. Because unfortunately, but that, you know, unfortunately once these patients get into those DO episodes it's hard to get them into a non-urgent state where you can cleanly separate your urethral measures from your bladder measures, but you just do your best. You're gonna ask the patient to cough or perform a Valsalva maneuver. You know, ideally you want the P-Vest to go up some. You know, we probably all have those like patients where you ask them to cough. I've seen this in young and old people and they go like, eh. And you're like, no, cough really hard. They go, eh. And it's like, it's like 30, you know. So this is great, like this is high. You do your best. You know, strain, that sort of thing. So try to get it as high as you can, especially if you're not demonstrating their symptom. And then the leak point pressure is the pressure where the leakage is observed. Now, most people are not fast enough to get their finger on the clicker, especially during a cough, right at the moment of leakage. Therefore, if you have a platform where it automatically measures, it's gonna just measure the highest point. You know, sometimes with Valsalva leakage, if you ask them to go slow, you can click it and you might get it more on the rise than the peak. Or you can also ask them, if you really wanna get a more precise measurement, just have them go down, like cough a little less or bear down a little less, and you might get a more precise measure if you need that. Yeah, so this is just, this is the same tracing I showed before. This is just like a normal urodynamic study. As you can see, this person did like, okay. You can see the measures up here. You know, no leak, no leak, no leak, because usually with a stress incontinent episode, the leakage volume isn't enough to register on the flow. Like a big detrusor contraction, you might see actually, if they have a DOI episode, you might actually see a little like blip or flow here. With stress incontinence, you're not usually, so you're really reliant on that measurement effect up there. Just like we also talked, you can see here, you know, this is PVES. Remember that you're gonna, it's gonna register, increases in abdominal pressure are gonna register both in PVES and PAB. PDET's just gonna be flat. There's no detrusor overactivity here. Every now and then, like if these aren't exactly, you know, aligned, which happens, you might see little blips here and there. But in general, you're gonna see rises in both. So calculating the abdominal leak point pressure. So I use, and most people I think use the change in PVES from baseline to the point of leakage. There are some people that will use just the raw number, like the number that they see. So when you're also looking at studies, you wanna see what they used as leak point pressure in their methods. Did they use just the actual PVES at the time of leakage, or did they use the change from baseline? It doesn't probably really matter. You just need to know what you're dealing with if you're using these numbers to direct you towards one type of incontinence procedure or another. And really, you're just gonna subtract PVES at leak from PVES at baseline. So just in this example, PVES at leakage is, you know, about 172, just kinda trust me on that. PVES at baseline is about 45. So 172 minus 45 gives you a leak point pressure of 127. One thing I wanna say is that, it's sort of confusing terminology, and I look back at the ICS terminology just to make sure. Sometimes you'll see VLPP. That doesn't mean like vesicle leak point pressure. It means valsalva leak point pressure. Now you can use PVES or PAB to measure LPP, and the ICS does say this. However, it's usually measured using PVES and not PAB, even though it's called abdominal leak point pressure. So just know, VLPP is gonna mean valsalva leak point pressure. CLPP is gonna mean cough leak point pressure. And even though it's called abdominal leak point pressure, you're using the PVES channel most of the time. So a lot of times, PVES and PAB will be pretty similar anyway. But just know this, I swear this confused me until like five years ago. I was like, what's the V mean? Have I been doing this wrong my whole life? Is it vesicle, is it supposed to be PAB? So in general, just know what you're doing in your practice, know what you're reading in studies and stick with it, but this is what the V is gonna mean, valsalva and not vesicle most of the time. All right, so now we're gonna move on to urethral pressure profiles. How many people do UPPs in their practice? Yeah, so a pretty good, it looks like about half. You know, even, we do them where I am. So one thing to remember is this is not done during a leakage event. This is a static measure with somebody at rest. This is not used to diagnose stress incontinence. Leak point pressure, like a cough stress test, remember the definition is transurethral loss of urine in the presence of increased abdominal pressure. So LPP, you leak, you got your diagnosis of stress incontinence, urodynamic stress incontinence. These numbers only really matter in somebody that has stress incontinence. So if somebody's there for voiding dysfunction, like you can look at your UPPs, but you're not really diagnosing anything because they don't already have stress incontinence. Some people will use the UPP numbers to let them decide whether they're gonna do like a trans-obturator midurethral sling versus a retropubic midurethral sling. There's not a ton of studies on it. There is one like good RCT that showed in women with really poor sphincteric measures that they did not do well with a trans-obturator sling. They had a higher repeat. Now, what am I saying from like really poor, I always call it like a crap sphincter in our pre-op conference, and one of my partners is like, what's a crap sphincter? So the measures for intrinsic sphincter deficiency, another problematic term, because like I said, everybody with stress incontinence has intrinsic sphincter deficiency, but these are some of the terms we have. The traditional measure is an MUCP less than 20, which those of all that you that do this, like that's really uncommon. Like how often do you see, I mean, it happens, but not that often. It's a really low number. And then for the leak point pressure, it's less than 60. So that just means that they're like leaking at low pressures. So the maximum, so there's a whole like urethral pressure profile that you do with a pressure sensor that's being pulled slowly through the urethra, and I'll show you a picture of that in a minute, but the maximum urethral closure pressure is measured just like the leak point pressure, and it's the difference between the highest urethral pressure and the baseline. And remember, this is done at rest. So in terms of the technique, I tried to draw like a catheter in here to show you. So the airfield catheters, like if this part's in the bladder, it's a dual channel. So there's a little balloon at the tip that's essentially staying in the bladder, and there's another one several centimeters behind that's gonna help you measure these urethral pressures as it's slowly withdrawn. So a three channel urethral pressure profile when you have that dual lumen catheter allows a very precise measurement of MUCP. So remember, P-ura is measured, P-ves is measured, P-closure is calculated, just like when we're talking about like P-det or the LPPs. So the urethral closure just, you know, it's the highest point versus your baseline. You can do a cough test at the beginning just to make sure the channels are picking up correctly. There is a catheter puller that slowly withdraws at one to two millimeters per second. Anybody that's used that knows that sometimes it breaks, it doesn't work. It doesn't mean you have to abandon the test, however, because you can also just slowly withdraw it yourself. And essentially, you can also use a single channel because that, let me go back, that, sorry. If you don't have this balloon, you can just use this balloon. And it's basically, you're not gonna get all the measures at once, but you're gonna know what your baseline P-ves is. And then as this balloon goes through the urethra, you're gonna get these same spikes. You're gonna get the same spikes. So you can use a single one. Don't worry if it's broken. You can still get your information. Again, note it in your notes. You pull it out slowly. It doesn't matter if you're not quite as steady as the puller, but those pullers sometimes can get a little wonky. So same thing. You just pull it out and it's in the bladder. It's coming through the urethra. And then here, it's out of the body. And then you can estimate your MUCP that way. We're gonna move on to sensations during bladder filling. There is, unfortunately, not a whole lot to say about this. There have been multiple, I had a co-fellow who developed an urge-o-meter during fellowship, Lior Lowenstein, and there's been all these different things to try to capture urge. I don't know how many of you are of an age where you might have a little bit of OAP, but you might have an urge and be like, oh my gosh, and then it goes away. And maybe you gotta run to the bathroom. Maybe you have 15 more minutes. So that urge sensation can sort of come and go. We have these pictures that we ask people, but it might get, when Lior was developing the urge-o-meter, we would have people that were like, it's here, say, and then a couple minutes later, they were back here. They kind of got over that urge and went on. It's just a subjective measure. It's neither here nor there. It's okay. I think it's a really interesting area of research because urge is interpreted by the brain. So there's all sorts of ascending and descending pathways that determine that, as well as your external environment, key and door syndrome, right? Nothing magic about the bladder volume then, but there's some external stimuli that's gotten hardwired into the McJurisian reflex. So as Dr. Gray noted, this was one of his pictures and slides, there's multiple techniques. They all have serious limitations. In the urodynamic platforms, most of them have first sensation, first desire, and strong desire. And so we have this in our, I don't know how many of you all have this, we have this literally on a big board, like in our urodynamic room. And it's just good to remind the patient, remind the provider. I'll be honest, I don't love first sensation because sometimes just getting the catheter in causes a first sensation. Dr. Gray's up there. I don't even know what it means. I don't use it. I don't know. First desire and strong desire. Also, you sort of know what you're gonna get with some patients. I think it's actually, I think if you're planning on doing a surgery on somebody with mixed symptoms, it can be a little helpful just to know what you're dealing with at baseline for if things change after. Or in somebody with voiding dysfunction, maybe they have voiding dysfunction because they have a completely A contractile bladder with very diminished sensation, and they never, you've probably seen that, they never get to their first desire, and you're at 700 mLs and you just stop the study. Okay, what is the detrusor response to bladder filling? All right, so ideally, the detrusor should remain the bladder muscle in a relaxed state until an individual has a conscious desire to void. This is that volitional voiding I was talking about. Involuntary detrusor contractions, meaning you get them when you don't want them, might just produce urgency and or leakage. This is called detrusor overactivity. Right now, according to ICS guidelines, if you just see the contraction, if it is associated with a leakage event during the contraction, then we're gonna call that detrusor overactivity incontinence, okay? Like I said before, neurogenic detrusor activity occurs in the context of a neurologic lesion or disease. Idiopathic detrusor overactivity, which is the vast majority of the patients that we see, have no defined medical cause. So this is a nice tracing of what that detrusor overactivity is gonna look like. I will also say that I have had patients who are having very clear detrusor overactivity episodes with no urge. They may or may not be leaking. It's gotta be something in their afferent pathways or maybe the motor is there, so it's producing this contraction, but not the urge. Not exactly sure. You don't see it very often, but you will see it sometimes. So you can see here, again, just to remind you of our channels, this is PVES, total pressure in the bladder being measured. This is PAB, the abdominal component, and then this is PDET, which is going to be PVES minus PAB. So you can see a rise here. PAB is pretty flat, so you see a rise here. One thing, like I said, that you have to be a little careful of, this is not all of a sudden some bottoming out of the detrusor. There's been no bladder perforation. There's nothing nefarious is going on here. There was simply something going on here in PAB. We don't see it in PVES, so it was probably not like a cough or a strain. If this is in the rectum, it may be like a rectal contraction event. This is when you're gonna see a dip down here. But as you go on, you see another little detrusor contraction here. Now, at this point, and you all have probably also been in here, you know that patient's getting ready to leak slash pee. It's not maybe completely volitional, but they're at their end, so you're like, quick, permission to void. Go ahead, you can do it. Because otherwise, if they have some huge, big leakage episode here, you could, in a pinch, call, you know, you know they're emptying. You know they had a large volume leakage episode. You know they're not retaining. You can use that sort of as the pressure flow. But ideally, you label it so that your software is picking up all the important parameters. Yes, and then I just wanted to note down there that the pee debt is calculated. And then you can see up here one other thing. So right here, when they have this little detrusor contraction, there is a little bit of leakage picked up here. So that would be DOI. Here you don't see anything yet. Here is actually during their urination. You might note also that this is, we'll get into detrusor activity during voiding. This is a pretty big detrusor contraction. It's like 60 with pretty minimal flow. Looks like I would say like 10 or below. This is looking a little potentially obstructed for some reason, but we'll go, we'll talk about that in a minute. Like now. So, what is the bladder activity during voiding? So there's a couple different measures of urine flow. These are affected by the bladder contractility, the urethral resistance, and also abdominal straining. So this is what I tell my patients. Like if someone's having trouble urinating, there's limited, there's only a few things it can be. It's either the bladder muscle isn't contracting or there's a blockage somewhere out. It could be the urethra. It could be the pelvic floor muscles. It could be iatrogenic from a sling we put in. It could be kinking off from, anyway, it's either the bladder outlet or it's the bladder muscle. It's really just gotta be one of those two things, and then that's what we're looking for. So urine flowmetry is done before the systematogram. So this is what I like, so it's called non-intubated, non-invasive. They come in with the full bladder and they urinate. This is simply a measure of urine volume voided over time, like a velocity. When you get to the end, you do the pressure flow study. The difference in this is you're adding pressure measurements on. Sometimes, I've seen the pressure flow study at the end sometimes get referred to as uroflow. You just wanna be careful and precise in how you're describing it. I find that sometimes, actually, in the software, the terminology gets a little goofy. So just make sure that it's still a voiding study, but you have the pressure measurements because those catheters are in from your bladder filling, and so this can give you an idea of the actual pressures of what the detrusor and the urethra are doing at this time. So when you're interpreting uroflow, and I feel that this is sort of complicated. It trips a lot of people up. Admittedly, in women, I find that pressure flow studies, a lot of them might not add a lot or you might have a hard time interpreting them. Women tend to urinate at low pressure. Some people have suggested that some women urinate almost more by relaxing their pelvic floor and their urethra. You might see a really low pressure and a great flow. That's not, you don't call that detrusor underactivity. As Dr. Gray spoke about and we'll talk about before, you have to look at what's going on with the detrusor pressure and the flow together to make some of these calls. But ideally, the first thing that happens in the micturition reflex, and if you, we don't do this. It's a little uncomfortable for patients, but you could just to see. If you have the urethral catheter right at the, balloon right at the urethra and the pee vest like inside on that dual lumen, ideally, you can see sometimes the urethral pressure drop out first. Because when you're urinating, you don't want a squeezing bladder against a squeezing pelvic floor or sphincter. This is why I tell people not to do their pelvic floor muscle contractions while they're peeing, which people love to do. They just love it. And then they tell you it doesn't work. You know, I'm like, don't do that. Or if you wanna just try it to test it fine, do not use that time to do your like, one set of 10 contractions you're gonna do. Anyway, so the urethral pressure drops out first and you'll see this on the urodynamic study. It's really elegant when it happens. This comes out and then right after, you'll see the detrusor muscle contract. So those are the different things that are supposed to happen. A lot of women use straining as well. So you wanna make just a mention, is the detrusor contraction strength adequate? Is it normal, is it underactive, or is there just nothing going on? It's a contractile. And then what is the level of urethral resistance to urinary flow? This could either look normal or obstructive. Remember, we are not directly measuring the urethral sphincter. There is that Pura balloon. Some people like EMG patches. Are they measuring the sphincter? Are they measuring just pelvic floor activity? Little hard to know. And in neurologically intact women, might not be as important as it is in women that you're really worried about, they do not relax. You know, like they have a neurologic problem and they're in a situation where their bladder's generating dangerously high pressures because of the urethral sphincter not relaxing. So non-intubated, this ICS term, you might also hear non-invasive uroflammatory. So this is just gonna give you, this is the urine flow rate, milliliters per second, and then this is the second. So this is just urinating over time. The more urine that's in the bladder, generally the higher the flow, you might see some other parameters change, like the time to void, right? Like, yeah, there's more in there. There's 800. It might take a while to get out. So it will affect your flow curve. Also, does somebody need to urinate? Like some women just kinda don't pee until there's 400 in there. They come in with 250. They can't urinate, you cath them. That doesn't mean they're in retention. They just might need a little bit more to urinate. So I'm gonna show you a picture. You guys know artifacts occur here, right? That container gets jostled. All you have is a bunch of this. You don't actually have any curve of any sort. The urine misses the funnel. It only collects 20. The rest of it's on the floor. Like all sorts of things can happen here. So you just do your best. We've all seen this. The main flow categories you're gonna see, so I will say that in terms of ICS definitions, and I did like a review on this recently, if you look throughout the literature in systematic reviews, the terminology's like all over the place, but in general, the guidance that ICS gives right now is is it continuous or is it intermittent? And then you can make some other kind of field notes or judgments there, but continuous is like this. Like it's fairly, you know, it's fairly continuous. You could have a few little spikes here and there. In some people, you won't see this at all. You won't see any spikes. In general, and this is not ICS guided. They don't give actual numbers for women, but I looked at an older study, a little bit newer one, and as Dr. Gray said before, Q max of like greater than 15 mLs per second just in general I think is what we could call like non-obstructed, non-detruse, or like normal-ish if you wanna call it, not a concern. There's also a pattern that we see a lot, especially in older women, where they're continuous or prolonged, but prolonged. They're fine, it just takes them a little bit longer. Their Q max might be less than 15 mLs, but they're voiding to completion. And then this is the last one. This is the intermittent interrupted. The main thing in this, these spikes can go as high or as low as you want, but the flow reaches zero. Remember, this is during uroflow, so we don't know what's happening with the bladder here. This bladder could honestly like potentially be obstructed if the PDEC Q max is very, very high. It's not likely, but possible. This could be also, this could be detrusor underactivity, or this could be obstruction. We have no pressure here. Studies have shown in general if on the uroflow they have a pretty normal flow, they're not likely to be obstructed. Like when they've compared the pressure flow study to the uroflow. Not 100% of the time, but pretty high. I wanna say like 75% or 80. So that's when you're gonna use like your clinical judgment. You know, you're not gonna just automatically call them obstructed or non-obstructed, but depending on the symptoms, what they're presenting, did they have a sling or not, you're gonna just decide whether or not you need to do a pressure flow in them. So these again are uroflows. Remember, if all you're seeing is flow and volume, that's a uroflow. That's not a pressure flow study. This again is showing the maximum flow of 40, average flow of 19, pretty short voiding time. That's the entire voiding time of about 15, and they voided 295. So this is what you would call normal or continuous. This one, again, is a uroflow, sometimes generating some higher pressures here, but you can see that the flow goes all the way to zero. So this is going to be an interrupted flow. You can see the maximum flow here is 22. Does that mean a whole lot to me in this situation? Not really, because like it's clearly not a normal, continuous pattern, and it's going down to zero in between. You can also see their voiding time. Remember that last one was like 17 seconds. This one was a minute 24. There's also a higher voided volume, so they actually did eek a good amount of urine out. It was probably though with either the bladder working overtime or them straining during it. And then this is just like a super low flow. So maximum flow here is seven, voiding time two minutes, void and volume 200. So the same voided volume as the first one, but it took two minutes. You know, you see very low flow in between, and of course the flow going down to zero. So these are all different kinds of curves that we could see. This is sort of what it's going to look like during a pressure flow study. I just took the pressure flow out so we could see up here. So this is where it gets a little funny. See how it says euroflow start here? This is like the software. Don't call this a euroflow though. This is the pressure flow study. We know that because it has all these different channels here, it's not a euroflow. So anyway, you see the flow here, a nice bell-shaped curve. You can see the accumulated amount. This person urinated out 420. We can see, you know, PVES here. This is where you're like, I don't know. Is there a detrusor contraction? I can't really tell. Doesn't look like straining, but then you can see here, there's nothing going on in the PAB during that flow. And now you can more clearly see a detrusor contraction here. And I just went in and did a little bit closer look. This is 25 mLs per second for continuous flow, PDET of 20. So this is a person voiding normally. These are some other ones that are a little more abnormal. So in general, there's nomograms for what's the combination of PDET and flow that means obstruction. They used to be based on men. Now there's ones that have looked a little more closely on what does it mean in a female that may void at lower pressures. In general, there's a couple different nomograms. If your flow is, let's say, over 20 to 25 and your flow is under 10 to 12, using a couple different nomograms, that's when you start thinking about obstruction. So a high pressure, low flow state. So in this example here, you see kind of that low flow like we saw before, and it's intermittent. They eventually do get like a decent amount out, but it's over this long amount of time with low flow. So this is intermittent flow. The Qmax is less than 15 mLs per second. The PDET is under 20 centimeters. So in our PDET channel right here, we see this low flow, but you see nothing really, not much going on in the bladder channel. You see a little bit of pressure coming out. So we would call that underactive bladder. If you compare that to this, where again, look at the flow up here where you really don't see much of anything, you see this enormous bladder contraction. That's like more than 20. It's like more than 100. So you see this enormous, or maybe more than 50. You see this enormous one. If you just had this flow or this flow on your uroflow, you don't know if it's underactive or bladder outlet obstruction. But the combination of a low flow, or no flow, Qmax less than 15, and a PDET greater than 20 makes you worry about bladder outlet obstruction. And then lastly, there's this one, which you wouldn't necessarily look at this and go, oh, that's an obstructed bladder. But when you look at the numbers and the parameters, it actually does fit into a potential obstructed situation. So you can see the flow up here is about 10 mLs per second. It's kind of that prolonged but continuous. You see PDET here is 45. Now, one thing you've got to be a little careful of is PAB drops out a little bit here. This is just one of those interpretation things I've been talking about. So is the PDET really 45, or is it more like 25 or 35? It's a little hard to know. You could try to use PVES here instead. But nonetheless, it's over 25. So in the setting of having PDET greater than 20, Qmax less than 15, this is going to be an obstructed picture. I spent a little more time on the voiding parts because I find those can sometimes, again, there's more artifact in the pressure flow studies, especially with women, and can be hard to study. The other thing to keep in mind is as age goes up, your PDET goes down. PDET goes down. And your Qmax goes down. So we talk about normal, but there's different, probably, normals given somebody's age and gender. So keep that in mind as well. People have tried to, how many people have this on their urodynamic report? These always confuse me. I don't know. So this does have the nomogram. And so in that study I was talking about, they took 20 controls, no voiding symptoms, 169 women with anatomic bladder outlet obstruction. Now remember, a lot of women that can't urinate are going to have detrusor underactivity. In men, bladder outlet obstruction is very, very common. They got the prostate. They might have urethral strictures. They have a longer urethra. In women, anatomic outlet obstruction isn't as common. Strictures aren't as common. Yes, they might have prolapse causing it. They might have a sling that we put in that caused it. But there's not as many intrinsic urethral anatomic issues that are going to cause bladder outlet obstruction. So these were women without any symptoms compared to 169 with anatomic. So when they looked at the combination of the highest sensitivity, meaning if they have the test, they have the disease, like you're going to pick it up, you're not going to miss it, with an acceptable specificity was that cut off. This is why I said 12 and 25. Q max of less than or equal to 12. And P debt more than equal to 25. Remember, these numbers are, this is in symptomatic women. So like if you have a woman sitting in front of you who is unable to urinate for whatever reason, maybe she generates a detrusor, maybe she can't, but she has zero, her PVRs have been low. She's asymptomatic in her daily life. Don't write in your report she has voiding obstruction. Describe what you see. Oh, she couldn't urinate. She went to the bathroom and she urinated out 500 mLs. She said to me she did not strain during that void. She says she never has hesitancy. She has a normal flow at home. Her PVRs, her physiologic PVRs in your clinic have been low. Again, don't be a slave to the nomogram or to the numbers that you're seeing. You really have to take into account, whereas a lot of men are getting urodynamics because they have bladder outlet obstruction, more of our patients are probably getting it more for storage issues, like leakage or overactive bladder. There are some times you're gonna be looking specifically for bladder outlet obstruction, and then you need to pay super careful attention to this. But remember, these numbers are in symptomatic women with voiding symptoms. The last thing I just wanted to say when you're assessing voiding function, this is actually not a bladder. This is like a blood pressure thing, but I've seen ones like this before, where this is what your uroflow looks like because the container's all over the place, and the machine spits out their Qmax is 50. Like, don't put that for their uroflow. Just say there was too much artifact to make an interpretation. Similarly, this is what I was talking about. You can't see it very well up here, but here's permission to void. Here's unable to void. We don't see anything going on in PDET. We don't see any flow. Again, don't just call this a day and call it voiding dysfunction. It might be, but describe it. But if that woman doesn't have any voiding symptoms, don't call that voiding dysfunction. So just to go back to what we said at the beginning, the aim is to reproduce the patient's symptoms. You must know the question you wanna answer before you start. Don't go into the urodynamics blind, because then you won't know how to troubleshoot what questions to ask, whether or not to say, hey, is this what you normally experience? Would you normally leak with this kind of cough? Would you normally not be able to urinate in this situation? You wanna identify the underlying cause for the symptoms, and again, get more comfortable with your ability to interpret and make decisions on the fly during the study. That's it. Thank you for listening. If anyone has questions, you can come up to the mic. If anyone has questions, you can come up to the mic. I was gonna say, if anybody had questions for Dr. Gray's previous lecture, I don't know if there are any from that. Oh, I see somebody coming up. And then I actually have a question for Dr. Gray. Yeah. Hi, thank you for the talk. If you have a patient you're doing UDS on who has OAB symptoms refractory to medication, do you typically want them to stop their medication before having the test, or do you wanna see how their bladder's functioning with the medications on it? And if you wanted them to stop, how long beforehand? Yeah, so if you ask 10 different people, you'll probably get 50-50 split. For me, if they are symptomatic on their medication, it's not working, I don't have them stop it. I used to. It's hard enough for me to get them to come in with a full bladder, and then stop it and start it. But in reality, what they have is what they have. And if somebody has refractory OAB, remember, you might not pick up detrusor overactivity like 30% of the time. Doesn't mean they're lying. I've done urodynamics a week apart on somebody that I was trying to decide, and they did not have any DOI one day, and the week later they had like three episodes. Like, you're just getting a snapshot during the urodynamics. So for me, I don't torture them and make them stop. If it's not working, it's not working, and so we're gonna see what we see. But Dr. Gray might feel differently. People might do it differently. I don't think there's a right or wrong way for that. Thank you. I try not to torture people more than we're already torturing them with these tests. Yeah. Hi, I actually have a question for Dr. Gray, and a comment. I believe you had said you weren't sure if APPs were doing Botox injections. I can tell you in our clinic, we are. And we always start off with 100 units first. My question for you is, has there been much data in how many injections you're doing? Because you had mentioned doing 20 injections when you're using 200 units. We usually do 10 injections for 100, but some of our providers will do five injections instead. Have you seen any data or any evidence if there's a difference of the efficacy of that? So I'll start out with the first question and comment. Didn't state it clearly. There is no research documenting the proportion of APPs that are doing Botox. I have anecdotal evidence of other practices such as yours. Keep doing it, by the way. Don't back off. The second question is, I don't know of any systematic research that's looked head-to-head with dosage per injection. The obvious idea is that you've got to get around globally to the bladder, because it's going to be dispersed locally, we think. We know there's some systemic dispersion as well. So I think a lot of folks are going at various places locally to try to perhaps maximize local dispersion of that medication. But remember that it is a little uncertain at best. Thank you. My question for Dr. Gray was, for PTNS, like you had mentioned, like the ankle size and everything, I struggle with the patients that have a lot of lower extremity edema. And I've looked through the studies to see like whether that affects the efficacy of PTNS. Not the implantables, but like doing it in the office. Do you have any thoughts on that? I will tell you that if your patient has lower extremity edema and they're in there because of nocturia, when they get their legs up at night, when they go to sleep, then you're going to have polyureic nocturia, obviously. And that's going to have an impact that's hard to overcome. I am generally able to get in and get a good PT, generally get a good PTNS, get a good session on them. And I've found them because they tend to be severe to have really great responses. But we both know that's regression to the mean. That's probably just because they were so severe. I can think of a couple, I literally wound up treating them both. It was very lovely. I got to sit them on a couch and both partners had their PTNS together and they really enjoyed themselves. They said they'd never had such experience talking to one another because there was nothing else to do. You should market that. But they both improved dramatically because they were both so extreme. The thing that I find is the most troublesome in my practice is a lot of my patients have chronic venous disease. And I have no, I have done it in fairly severe chronic venous disease, but I have no idea about am I increasing the risk for venous ulceration. That's a separate consideration, but in general I would say that I've had good results with PTNS in patients with very large edema, but I'm getting that needle in 85, 90, 95%. Thank you.

urodynamics

Dr. Leslie Rickey

Yale University

bladder function

cystometry

stress urinary incontinence

detrusor overactivity

clinical decisions

international standards