At this time, we're going to go ahead and introduce Dr. Wernz. He's a graduate of the Kirksville College of Osteopathic Medicine with subsequent training in internal and occupational medicine. He's both MD and DO boarded in occupational medicine, has a private practice in occupational medicine based in Morgantown, West Virginia, including occupational and environmental medical legal consulting, reviewing cold minor x-rays and spirometry for NIOSH, federal black lung evaluations and aviation medical evaluation. He's the course director for the AOCOPM, commercial driver medical examiner class. At this time, let us welcome him to this presentation. So here's my difficulty, and is you guys come in two flavors. Some people work in occupational medicine, there's two flavors. Some people work in clinics where you do your own spirometry. And so I want to catch you guys up to what's, there's been a bunch of changes in the last couple of years. And the second group of people is people that don't have their own spirometry, but may occasionally be reviewing spirometry results from afar. And you guys, and I'm trying to include this for everybody where we're at. Is this the, oh, and that makes it go. Oh, that is so cool. Okay. So what I'm trying to do here is to include everybody. You could do this talk and have, and say in 2005, they changed this in 2007, they changed that. I've done that in the past. We're going to go, we're going to jump to 2024. And this is everything that has changed up to today. And it's the current correct recommended way to do it, except for the one thing that I'm going to tell you, I think is stupid, but we'll get to that later. That is the current recommendation. I still think it's a stupid recommendation. We'll talk about that in a little more detail. These are the learning objectives, but instead of just reviewing them, let's do them. Okay. So let's keep, we're going to just go. So this is your, we're going to start with a case. So this is a 74-year-old male, he's 64 and a half inches tall, and this are his, these are his results. Anybody want to make a hazard at what pattern this is of spirometry? So basic spirometry, obstructive, restrictive, normal, or uninterpretable, or mixed are the five choices. So COPD is not a, not a pattern. We'll come back to that later. So whoops. So we're going to go over here. So his FEC is less than the lower limit of normal, right? These are the key things, lower limit of normal and compared to their actual value, the lower limit of normal. Is the ratio, FEV1 or FEC, is greater than the lower limit of normal, right? What pattern is that? So restrictive is, I heard that in the field. So and you also have, so the basic answer is it would be a restrictive pattern, right? The second question is, is it restrictive lung disease? And we answer that by looking at the TLC. His TLC is greater than the lower limit of normal. So and he has elevated residual volume, so which we'll come, we'll talk about that more in a minute. So he has a restrictive pattern. He does have moderate air trapping suggested by the elevated residual volume. So I would call the, it's not true restrictive disease. I call this pseudo-restrictive disease. And the current way that we're being taught to think about, use lung, the new recommendations don't diagnose restrictive disease on the basis of FEC. It uses lung volumes. And we'll come back to that in just a minute. This is a big change. So a bit about, this is spirometry basics, just so we've, you have to kind of include this so that we're all starting with the same vocabulary. Spirometry testing, the recommendation now is that it'd be done seated. I realize ACOM still wants you to do it standing, but Mary Townsend's the only person on the planet that still recommends that, and that's because she's not a clinician and doesn't have people fall over when they're trying to do spirometry. Everybody else wants this done seated. All of ATS's recommendations since 2005 have been for seated spirometry. Your lung volume goes down about 50 to 90 milliliters when you do it seated versus standing. So it's a change. So if you're doing serial spirometry, it could be important. If you're not, don't do it because people will fall over. We use nose clips. It is okay to yell at the people. You need to have a, the technician needs a monitor screen that's big enough to see. Those monitors where the screen is the size of a large postage stamp are not adequate to see what's actually going on in the maneuver, and that doesn't work. Thankfully, you can buy big screens now for like $50 at Best Buy. So this is not a huge ask. This is the way they worded it. A couple of things I picked out. They're to start breathing normally, have them inspire as deeply as they possibly can. The patient should look moderately uncomfortable. If they just look like they're just having a grand old time, they're not doing it right. They need to breathe in more deeply for that before they blow. I want to have them blow out as fast and as hard as they can, and then I leave them on the machine and have them inspire. Now not all spirometers can do that, but most of the ones sold in about the last 15 years can also track the inspiratory, the inspiratory breath. So that's actually, it's kind of a quality control thing that we'll come back to a little bit. Not required at this point in time, maybe in the future. And we still have them do three maneuvers, usually never more than eight. And we do look at repeatability and keep repeating the maneuver if we get weird stuff. Seated versus standing. As I mentioned before, everybody else since 2005 has recommended that you do this seated. ACOM still, in 2020, still recommended standing. GLI doesn't care, which is the new kind of, the new predictive equations everybody's using. They include both. They just don't care. And other than serial spirometry, it's probably not important. So when you do spirometry, you're going to get some outputs. I, with my gray, a little bit of gray hair, just a little bit, I'm old enough that when I was, I was originally trained on doing spirometry on a dry rolling serial spirometer, and all you got was the volume time curve. And we spent time in the class on how to make sure that the paper was feeding through the machine at the right speed, and how to operate the thing that made the pen go up and down on and off the paper. That was a key part of the class. And so I'm more comfortable with this. Flow volume loops require a computer to be involved, and that came later. And you can have either the ones like on the top, which is just shows the expiratory loop only, or you can have one that shows the expiratory and inspiratory loop. And that's something on a lot of modern machines, you can turn on or off the inspiratory loop, but most of them can do it. If it can do the expiratory, it can do the inspiratory too, except for one technology that only one machine used, because it didn't work going the other way. First question is, is the maneuver acceptable? Did they meet what's now called end of test criteria? I get a plateau that's over a second, or the whole thing just goes over 12 seconds, even if it keeps going out, and we'll talk about that in just a second. Do they have any disqualifying changes? Are there additional breaths? Did they cough? Is there glottic closure? So we'll kind of look at each of these. So this is kind of a normal volume time curve. There's lots of extra lines on here. But basically, we're looking at this little triangle right there. If they took forever and a day to get from not blowing to blowing hard enough to make the thing go up to show flow, if that triangle gets to be too big, that makes the whole, at least the first second of it, not usable, because they want to draw that line down and have it go directly down to the—they want to draw this line down and have it go down to the—or whatever the horizontal zero line is. If that space is too big, you've lost too much volume before they really started blowing hard. It's now point—it used to be—it's now 0.1 liters or 5% of the FEC. It used to be 0.15 or 5%. So they've made that a little tighter. They want the technicians to work a little bit harder. This is glottic closure. Way too many people, especially newer spirometry technicians that were trained—especially newer respiratory therapists that were trained using the flow volume loop, missed this because you can't see this on the flow volume loop. See where it goes? There's an abrupt turn to flat, especially like that one's super obvious. This one's pretty obvious. It didn't—they didn't plateau. They went—they were going up and then sideways. That's glottic closure. I mentioned earlier that the new standard recommends we do the insertory loop too. Their goal is that that little delta right there would be less than 0.2 liters. It's not required. It's optional. And the reason is because we have no idea how many people can actually do this. They've never done it in a population study. So my guess is the next time they come around, they're going to say, yeah, you have to do it or, well, maybe 0.2 liters isn't real—actually, it disqualifies too many maneuvers. So we just don't know that. That's why they did not make it mandatory. How do you get your numbers off the person blows in the machine? I need to know their force vital capacity is just the total of how much they blow out. Where did it plateau? Draw the line across. It's that many liters. FEV1. I go out one second after they started their blow, draw that back over to find out what the volume was. And that's pretty straightforward. And then comes the ratio. So the FEV1 to FVC ratio is done with the largest valid FVC and the largest valid FEV1. So I don't care if—they can be from different maneuvers, and we'll talk in just a second. You might even be from—you might be using the FEV1 from one where the FVC is not valid, or you might be using—or the other way around. So they've given us a lot more options here to try and get valid testing out of—valid results out of mediocre testing. So current recommendation is to present this as a decimal. So just to make it look different from all the other numbers. And so it's like 0.78 would be what we used to call 78%. Either way, I mean, we're just presenting the same number in different ways. The one thing I encourage people about is don't calculate or even think about the percent predicted of the ratio. Just don't go there. You're just taking a percentage of a percentage, and it doesn't help you any. Many of the mid-levels I work with fall into this trap of, well, look, is percent predicted for the ratio is—I don't know. I don't care. It's not a number you can do anything with. Just don't even calculate it. They've recommended since 2005 and then again in 2017 that you don't calculate it and put it on the report. To date, 100% of all the machines that I have any contact with still put it on every report. So the manufacturers are not keeping up with ATS. So there's now the concept of the end of forced expiration. And this can be a bunch of different things. You can have expiry plateau, so less than 0.025 liters in the last one second. You can have next return time exceeding 15 seconds, in which case they're just going to blow out forever, and that's an adequate test. Or—and this is the one that's the hardest to explain to people, and I have trouble with this too—the FVC is within the repeatability tolerance of or is greater than the largest prior observed FVC. So this is not for diagnostic testing, but let's just say—and one of the things we know is that the sicker people are, the harder it is for them to do adequate spirometry. So this is intended for the person who is struggling to do spirometry at all. And you kind of get one or two good maneuvers, after which you have to let the patient—give them like 20 minutes to rest just so they can walk back out of the office, because they're just like—medically, they're just a basket case. This is an option for those people. I don't recommend it for most normal people. You should not need to do this. But that's what that's for, is they're trying to make that number of people that we can't ever get a valid test on smaller by giving us this extra trick. So most reports, if you look at the detailed report, tells you in this particular case that's back-extrapolated volume absolute. So this is for each maneuver, and you can see in the number, those are all less than 0.04. 0.04, just a math review, is less than 0.1 liters. So those are valid from that perspective. But you've got this thing here that says endo, which—I'll help you—means end of maneuver was not met. I recommend that you, for whatever machine they have in the lab that you're getting stuff from, is know what these codes are or how that works. A lot of them have a series of 1s and 0s to tell you what flaw they think the spirometry had. And that can be very insightful when you're trying to decide if I can rely upon this result. Now this person specifically had all these end of things, so theoretically those are not valid, except the machine's only half smart. This is the pictures that go with that thing, with that last thing. He's out to 15%, but he never really plateaus because this guy has horrible air trapping or COPD or whatever word you want to use for it, but he's got the pattern of lots and lots of air trapping. So that's why the machine knew he didn't have a plateau, which is true, but didn't then think about it more and look at the picture and go, but this is the pattern of air trapping, and just allow him to be that way. So you have to be smarter than the machine, and it's taken me a while to figure out how to do all this stuff, to know when I can trust the machine and when I can't. This is one where you can't. There's a new concept that came out in 2019 of the idea, or slash 2022, of acceptable versus usable values. And the idea is maybe in a maneuver that doesn't look okay, you can still use some of the data. It might be usable. So for example, well, let me back up. These are the things, if you've got any of these, the whole thing is trash. So if you've got leak at the mouthpiece, obstruction, obstruction of the exit, or a zero flow error, any of those happen, you're done, none of it's usable. But without that, if you don't have any of those things, the question I can look at, now this does not change what the technicians does, it changes what I can do as the physician or the interpreter. I can look at it and go, well, if I want to use the FEV1, they've got good effort, back extrapolated volume's okay. I don't worry about the end of test criteria because I'm only using FEV1. And I might be able to use the FEV1 off this maneuver because they did something, they coughed five seconds in, or they took another breath. Well, the first second was fine. So I might be able to use the FEV1 from that maneuver. Likewise, I can go for FEC, make sure I've got good effort, termination of effort is okay. Maybe they did something weird in the first second, like the back extrapolated volume is too high, or they kind of hesitated a little bit. I can't use the FEV1 now, but I might be able to use the FEC. And these could, so you might have a maneuver where I can use the FEC, but I can't use the FEV1. You may have to fight with the machine because the machines aren't this smart yet. You may have to actually calculate out your own ratio by using the best FEV1 that's okay, and the best FEC that's okay, even though the machine's telling you it can't use them because it's not this smart yet. Any questions about this so far? I can probably do that. Okay, so way back when, when I learned how to do spirometry, we were told that normal was anything from 80 to 120 percent predicted. In 2005, they said, use the lower limit of normal, which we'll talk about in a second. And starting 2019, they want us to use the Z-score. Fortunately, the Z-score and the lower limit of normal are identical. It's just math and making it more confusing for clinicians to understand what we're doing. So this is the whole idea of lower limit of normal. We assume, having tested people with no pulmonary disease, that 5 percent of those people are abnormal. This is kind of like the p-value of 0.05 being the gold standard. For some reason, the bottom 5 percent of people are a little abnormal. Now, the key thing for this to keep in mind, so that's the lower limit of normal, which when they call it LLN, that's the value. If they don't call it LLN, it's a Z-score of minus 1.645. That's exactly the same number. They're both the fifth percentile of values in an air quotes normal population. Correct. No, my point is that we've decided that 5% chance that we're wrong is okay. This is the same thing here. The thing I want to point out to you is that 5% is of normal people. So the system that I am involved with at NIOSH, we have this as a hard, hard, hard cutoff, the 5%. And we look at the table, and if you were 0.01 below that, it's abnormal, right? And we will tell you that, we will call the pattern. Clinically, don't do that. Clinically, this is kind of a concept. It's kind of the same idea that if we say that when you were doing hospital stuff and the range for the AST was 20 to 40, and the guy's AST is 41, and all of us will all go, you're fine, don't worry about it. Same thing here, okay? If this is, you know, because remember that z-score, if they're anywhere right around here someplace, it's normal. Don't get lost in that detail. But if it's way below, then that's a problem. Just as an example, so this is using the lower limit of normal, which is put on there in orange, and the 80% cutoff, which is in bright green. And what you'll notice is they're kind of in the same neighborhood. When we're younger, we expect people to have a little bit better lungs. There's a tighter, tighter squeeze. So sometimes you can see, like, the low limit of normal for, like, a 25-year-old or 22-year-old might be, like, 83 or 84% predicted. And when they get to be old, we let them be a little bit more variant, just because of the way older people's lungs work. So it might be, you know, 74% predicted as the FEV1 that would still be normal. So first step is always compare the value of whatever their test is to the lower limit of normal, or see if they're doing z-scores, is it less than minus 1.645. And then I want to look at either the value on the test. That's the first thing I have to do, is compare, get the, you know, what did they get? What's the lower limit of normal? Are there more or less? And if they're equal to the lower limit of normal, that's a normal, because it's a lower limit of normal, right? Compare the FEC and the FEV1 or FEC ratio. I don't care about the—the FEV1 is unimportant. Don't even waste your time on it. Not part of pattern recognition. Then you go into one of these things. This is written up, like, three different ways. You can—they're all the same. It just depends on what order you want to go through the things. This one starts with both the FE—that you can be normal, you can be—just to point on this, let's see if I can do this right. You can be normal, you can be obstructive, you could have a mixed pattern, you could have restrictive. All these things are possible, and if we go back the old-fashioned way—still probably okay, still what I do clinically—the whole thing, based on the FEV1 percent predicted, is either mild, moderate, moderately severe, severe, and very severe. They're the five choices based upon the FEV1 score. So—and all the—no matter what the pattern is, you always use the FEV1 percent predicted to say how severe the whole thing is. And this is doing it all together, which is my preferred way, but not the currently recommended way. We'll cover that in just a second. This is a fancier version of kind of the same logic. This is right out of Pellegrino 2005. Notice that in order to get all the way to a diagnosis, or at least a family of things to worry about, I need to know both the lung capacities and the DLCL. And this gets you to all the different diseases, and you think about, you know, is this a chest wall thing, pulmonary vasculature, neuromuscular, and it kind of works them across there. Now, this is an idealized patient. Not every patient's going to play along this well, but this is at least the flow chain for all those diseases, 2005 style. Here's the current recommendations for pulmonary interpretation, and this is the part that's a little bit weird, okay? You may have noticed, if you look really carefully, obstruction is still found using FEV1 over FVC ratio being less than the lower limit of normal. That's not a change. However, restricted disease may have noticed that the words FVC is not on there anywhere. They're diagnosing restrictive disease on the basis of total lung capacity, okay, using lung volumes. They don't even—the only thing that they mention FVC is down here that you might—reduced FVC does not prove restrictive impairment, but may be suggestive of restriction when the ratio is normal or increased. So, it's a backup plan that you might be able to use, but only in this one circumstance to use the FVC for restrictive disease. This is a big change, okay? I don't know how widely this has been implemented, but this is a big change in how you interpret results. Still mixed would be both the FEV1—the ratio and the TLC being low, below the low limit of normal. That sort of makes sense. That's a big change, though. Yeah? Go back now to the example. Yep. Well, what I'm going to do is I'm going to do another—there's another example in about eight more slides where we do the same thing with more results. So, this is a question that I think is important because this predicates some of what comes after this. The big question when you are thinking about spirometry is what are you trying to do? What is the reason for doing spirometry, okay? First thing is, if you're trying to diagnose lung disease, like, I think this person has a lung disease. I don't know which one. I need to get testing to diagnose the correct pattern, get spirometry, get lung volumes, and probably get DLCO to go with it. And what I didn't mention here is you probably need some sort of imaging, at least a chest X-ray, maybe a CAT scan of the chest because I need that to figure out, like, what's really wrong with their lungs, okay? Pre-employment, the recommendation from ACOM—and we don't have a recommendation, but probably us too—is you normally don't need to do pre-employment spirometry. Now, Carl's personal—and if you're going to do it, if you're going to do spirometry pre-employment, you want really wide, acceptable numbers. Like, anything down to, like, 60 percent predicted is probably fine, okay? Don't be super—you don't want to be restrict—keeping people away from the workplace based on a spirometry number. Now, my personal spin on this is if they're in an IDLH environment, immediately dangerous to life and health, one breath of the environment outside the respirator can kill them, we'll talk about spirometry, okay? But I have a much—but for anything less than that, I probably don't want to just pre-employment spirometry. Now, if I'm using it to decide—I may be getting one on their way in the door that's just a baseline, that's fine if it's because you're going to compare it over time, but not where you're using it as part of the decision-making whether they're fit for work. So, if you're going to monitor people in the workplace, simple spirometry, FEC FEV1 is fine, right? I just want to—I'm following them over time. If I'm thinking spirome—reactive airway disease, what—the way I like to do it, and you have to have a pulmonary function lab that'll play along, but the way I order it is I ask them to do spirometry, and if it's abnormal, administer albuterol and retest, and if it's normal, I ask them to do methadone-choline challenge testing. That saves everybody a step to the—trip to the PFT lab. They can't do—you have to pick—because there's a dichotomy. They, you know, pick, and then they do one test or the other. So, how do lung volumes help me? Well, without lung volumes, I can get you a pattern of spirometry, but I can't get you an actual diagnosis. So, I can look for air trapping, which is my big thing, or diagnose true restrictive disease. Air trapping can give me either pseudo-restriction or pseudo-obstruction. You can see both, and I do see them on a fairly regular basis, and there's—I guess there's pseudo-mixed also, but usually one of the two goes away once you realize you've got air trapping, because you—I've never—pseudo-mixed wouldn't make sense because some—one of them's got to be not real for it to be—for it to be pseudo. Does that make sense? We'll look at one in just a second. So, I get lung volumes. It's a separate test. Most—if you send them to a PFT lab, they can do lung volumes. If you're doing it yourself, they have to have either a body box or a machine that does nitrogen washout or helium washout. I mean, there's a couple different technologies you can use, but it's a separate test, and one that I hope will become more available, because trying to make diagnoses without it is hard, at least for me. So, this is my second example, so follow through on this one. So, this guy, when you look carefully—let's see. I'm going to just do this with the boxes. So, his actual FVC is 2.74 liters. The low limit of normal is 2.87 liters, so he's less than the lower limit of normal, right? So, he's—so that means—and then when I look at the ratio, the ratio is also less than the lower limit of normal, right? So, this would be what pattern? This is mixed. Very good. Okay. So, this would be a mixed obstructive and restrictive pattern, and just for the record, the order that these go—restrictive and restrictive—doesn't matter. You could call it restrictive. It doesn't—you just got to communicate that it's a mixed pattern. I always—I add those words, because if you just say it's a mixed pattern, they don't—if a non-hormonologist reader may not know what you've mixed. So, this is—these are the curves, because you just always have to show people the curves, and you'll notice that the flow volume loops are a little scooped out, which suggests some obstruction or maybe a little air trapping. If you look over here, these kind of go up and go up and go up on the—I'm on the—looking at the—on the right-hand side, the volume time curves. So, that does suggest maybe a little bit of air trapping, but they're not super long. They're not the ones that are out to, like, 15 seconds. So, maybe, but it's hard to know. So, then I went and got long volumes on this guy, and so I'll be real honest. There's a lot of volumes on there. There's only two you care about to make this simple. You need to know their total lung capacity, or TLC, and you need to know the residual volume. All the rest of this is less useful for our purposes. So, his total lung capacity is greater than the lower limit of normal, right? So, this is not true restrictive disease, and his residual volume is 183 percent predicted. Now, over time, the recommendations use the upper limit of normal, right? Kind of the same thing that we showed back to 5 percent, but it's the other end for residual volumes, but the computers don't do that yet. They're working on it. It's a computer thing. When they get that far, but until then, we use 120 percent predicted as the kind of the cutoff, and when they're over 130, I'm confident in it. That's what we do today because they said they don't have the upper limit of normal programmed into most systems yet. This particular change of using the upper limit of normal for residual volume is a new 2022 change, and you may remember since 2022 until about now, people have been staying home and not working, so they haven't quite gotten that into the software yet, but that'll come someday. So, he's got air trapping because this is 183 percent predicted. It's way more than 120 percent, so he's got definite air trapping. So, what I would call this, remember restrictive went away, but I would call this pseudo-obstructive because he's got a lot of air trapping. It's still obstructive lung disease, but the cause is air trapping. You could also call it obstructive lung disease with air trapping. That would also be a clinically appropriate diagnosis or interpretation. So, in COPD, that's correct. In asthma, it's not. The question is whether, and so, if you kind of think about it, COPD is I've got blebs and the air can't get out, right? Asthma is I've just made the air passages way too tight and the air just can't get out because it's too tight. So, obstructive disease without increased TLC is asthma. I'm sorry, without increased residual volume is asthma. When I increase the residual volume a lot, and you might see it like 118 percent, that's still okay, but when it's a lot increased like this guy is, he's got air trapping, he's got blebs. Okay, going around the corner here, we're talking a little bit about predicted values and ethnicities. This is one of the areas that's gotten super weird in the last year. So, we're talking about predicted values. They got a bunch of humans, we didn't have any known lung disease, and tested them in spirometry in different settings. Some of them they tell us who they tested, some they don't. Some they just wandered around some hospital in New York and just tested a bunch of people. We don't know who they are, and they come up with equations. The inputs to the equation are always the age, height, and sex. And my talk about weird things, it's their sex at puberty is what we care about. Most address ethnicity somehow or another, although some of them just kind of ignored it. There's a lot of equations that are still in use in West Virginia for workers comp, we use Query from 1961, which has absolutely no idea who they tested. 300 people they found in a hospital. I don't know if they're white, black, they're all male, that's all I know. Come down through these other tests, these are all, all the ones above PREPO are all convenience samples. He had a bunch of data from somewhere and mathed on them and got predicted equations. NHANES did a population-based study, got much broader age ranges, and a pretty big group, there's like 7,000-something samples that they used to generate the equations. Since then, we've had the GLI, the Global Lung Initiative, we'll talk about in a second, which came with ethnicities, and then in 2019 they added GLI Global as a new concept that we'll pick on it for just a second. This is just using the FEV1 for all, a bunch of those different equations, not all of them, but a bunch. And you'll see that they're all a bit different, they have different groups they looked at. Some of them only looked at people in certain age ranges, and then they just kind of extended the line. Morris and Crapo did that, and the early Knudsen did that. The thing I want you to notice, the two that are, I would call, in play right now, and just even if you do the cotton dust standard, they've progressed on to NHANES. They don't use Knudsen anymore. That's done. So the purple one is NHANES, right? The gold one is GLI. I would like you to notice that they're essentially identical. Little difference here and there, but they're essentially identical. GLI is the Global Lung Initiative. The biggest difference you'll see is up here, and we'll zoom in on that later on. It's the same data. All the NHANES data is included in GLI, OK? The NHANES for Caucasians, there's the US data, plus there's from Europe and Australia and some other primarily Caucasian places. For African-Americans in GLI, it is only the US data. There's no, there is, there's zero data from Africa included in the one for black, just as an aside. Sure. What difference does it make as one race? Stand by. I mean, just for a second, stand by, because that's where I'm going. So these are who they included, OK? So Knudsen in 76, they just tested Caucasians and then said African-Americans are 85% of Caucasian. That was the recommendation. There was just, that's all yet, for all values. NHANES, they tested Caucasian, African-American, Mexican-American, and then said, we didn't have enough Asians, but use 88% of Caucasian for Asia. That's what we got for NHANES in 99, for just 7,400 and change people that were tested. The Global Lung Initiative has 74,000 people in their database, but includes all the NHANES data, OK? And they ended up with programs for Caucasian, which they said included Hispanics, because the difference between Mexican-American and Caucasian is not very big unless you're very young. Because it's an age of maturity thing. They also have African-American, Northeast Asian, Southeast Asian, which has to do with the northern half of China and the southern half of China, which are apparently ethnically different. And then they also initially came out with GLI Other. They literally took all this data and made up one called Other, or Mixed. It was called Other in most places. The idea being, if you're more than one of these groups, just use the other one, the one for Other, OK? And that was 2012 when that all came out. And that was OK. We were talking about the transition to GLI and using the ethnically-based GLI, which I think would be fine. Carl's personal opinion. There's so little difference between that and NHANES. I don't think we're losing any science. OK, and those are the ones that I mentioned. Those that are in GLI. So racial differences. We'll spend a couple of slides on this. The first spirometry that I can find was done right after the Civil War, when they had all these people in the army they didn't know what to do with, because they hadn't figured out you can tell the army people to go home. But they were in the army. They signed up for three years, and the war was over. And then what do you do with them? So they did all this descriptive science, like how hairy people were, and comparing different races and how many people were hirsute, and how many they rate on a 1 to 10 scale. And one of the things they did was they found some machine that was designed to measure coal gas that they sold to people in their houses, and had people blow into it. And it could somehow measure how much they did it. But it was in, I don't know, cubic feet per furlong or some damn thing. It was an odd unit of measure, but they at least could get. I asked math people if we can convert these units into units we understand. And they spent about a couple of days on it and came back and said, no, because the units of measure were just so far off that we couldn't figure out what they're really talking about. So things we know, and since the Civil War, we've been trying to figure out how to deal with race in spirometry. We know that African-Americans have smaller total lung capacity. The osteology people will tell us that African-American people have flatter ribs and just simply less space inside the chest than European-origin people who have rounder ribs. Now, that's not 100%, because ethnicity is not 100%. And so we don't know what to do with that. They've tried using sitting height, BMI, wingspan, other things to try and compensate for this, and none of it works very well. They even tried calipers to caliper your chest. And the problem is people who are a little more adipose are still thicker than people who are not as adipose. So that didn't work either. If you correct using the total lung capacity, it all gets better. Then you can ignore ethnicity. It doesn't make any difference. But that requires that we do TLC testing on everybody, which is right now not a easy-to-feel test. So these are the predicted equations for different. This is in GLI. I didn't leave GLI. So GLI global is the gold. The GLI Caucasian is the red. African-American is the blue. And purple is GLI other. So this is for somebody who's the same age, same height, and same gender for FEV1. You'll notice that there's quite a difference. If I use the African-American one, a normal for a 20-year-old might be 3.75 liters. But if they're Caucasian, it's almost 4.4 liters. That's quite a difference for my normal predicted equation. So racial correction. The problem we had was, what do you do for multi-ethnic people? So I'll use President Obama. What table do you use? His mom was from Ireland. His dad was from Africa. What's the right chart? So originally, we were told you would use GLI other, which is not a bad choice. I don't have a problem with that. For workplace programs, the recommendation was give people a list and say, these are our three choices. Pick one. And then whatever one they picked, you write it down so you know what one they said. And you use that same measurement for them forever. Because if you change it, if they're Caucasian now and Mexican-American the next time and African-American the time after that, you just end up with uninterpretable serial data because you're using different equations. That was the recommendation for NHANES. But which one do you use? There is some cultural stuff. The question is, is the reason that African-Americans' lungs are smaller physiologic or sociocultural? One of the problems is that in a lot of that early literature from the 1890s, it would say something like, and please excuse the language, but it's what it said, that the lungs of the Negroes was inferior to that of the Caucasians or of the whites. And what they're talking about was numbers. In the same way that three is inferior to four, they were using that vocabulary not to talk about the quality of the people, but literally talk about the size of their lungs. But that wording has permeated into, is this a cultural thing? Is this a racial thing? Some of that was used way back when to talk about racial separation and things like that. So there's that history. And so that was true. It's an unfortunate part of the history. There are equations for some folks. But again, how would you address multi-ethnic people? This is a conundrum. The current best way I can call it, well, I think it's on it. No, one more. So in the 1990s, we finally got enough data on African-Americans and Mexican-Americans to be able to draw curves for people with those backgrounds. And that was in the NHANES data. GLI did two things. One, they did the more smooth curves. Because the key question is always when you get around the knee, what happens? Where you go from getting bigger to getting smaller, how do you draw that curve? And everything before GLI was an equation. And you just plug in a number, and math happened. Plug in their age, date, and gender, and math happened. The GLI did something called multiple splines, which I don't know what that means. But apparently, you get a curvy curve instead of a rigid corner. Well, OK, we'll come back. Anyway, but that's why you just get it. It's a nice curvy thing at young ages. In late 2022, we had the article that said basically, we think a committee has surmised that differences between the races in spirometry is a sociocultural thing, not anatomic, not physiologic. And the theory being that by having different equations for African-Americans, we would be under-diagnosing their disease, because we've got lower levels to start with. And then they would get less health care. In 2023, ATS had an official statement that came out at the beginning of the year that we should use GLI global for everyone. This is the part that I'm not sure I understand this. I don't think this is science. This is, of all the things I'm going to talk about today, this is the one that I don't know whether it's going to go over time. I will be shocked if this stands and it gets widely adopted. Most pulmonary labs have not switched to this approach, at least none that I've. Has anybody seen one where there comes in everything everybody's GLI global yet? This is very controversial, because what you're going to end up with is, I guess you could sit there and go, OK, so if you're Caucasian, your normal range is 100% to 130% predicted. And if you're African-American, your normal range is 75% to 105% predicted. I mean, you could play different. It's all math, but it's just not making our diagnostic abilities better. Yes, sir. I submit that if I took somebody, regardless of what the shape of their skin is, and their mind size, that their anatomic aspects are going to be about the same as mine, whether they're physiologically the same or different than me, maybe a function of their training, and by that I mean physical training, and being able to perform, et cetera, et cetera. But somebody smaller than me is going to have a different size lung, and somebody bigger than me is going to have a larger size lung. In all, that's more reason by that, and not based upon the color of our skin, or our religious heritage, or anything else. Absolutely. The point was made that size is probably most important, and that's true. So none of these equations are leaving height out. Every single one of them uses height. So we still have a height, and a sex, and an age. Those things don't change. The question is just, do I have one curve for everybody on the planet that's the normal for their height, sex, and age? Or do I have one for less melanin, one for more melanin, one for different eye configurations? Those are deep questions. I'm not claiming I know the answer. I'm not comfortable with the current thing if we're trying to do diagnoses. Now, if we're doing other things, might be fine. And if we're following people over time, that's all we're doing. It doesn't matter. If you're 85%, you're 85%, you're 85% over the years, I don't care what the normals are, we're fine. I only worry when you change. But if you're trying to do diagnoses, I think that this is going to miss the point. But that's Carl's opinion. This will change. I made it to AECOM last year, and I sat through two lectures on this topic with no good answer. I don't know where we're going moving forward. One person was passionate one way, the other person was trying to explain the change, and then said, I don't know. It depends on what you're trying to do. This will change. I don't know how, but this will be different, I think, or more settled in a year or two, or three, or four, or five. So I'm going to leave that, because they said that's a conundrum. I'm not sure where to go. You're going to hear, this is Carl's thing. I do this on, I can't tell you the number of people that I have to explain this to. People have probably heard of gold criteria, right? Please, a few people. Somebody say yes. Somebody, anybody? Yes. OK, good, good. We've got gold criteria. So this has to do, it's about diagnosing COPD. And so what they said was that if their ratio, if you want a refugee ratio is less than 0.7, they have an air flow limitation. And then you need to diagnose the cause of that limitation. And I will say, in full fairness, that gold is, I have no problem with anything gold does as far as their recommendations for treatment beyond the first drug you try. When you've got complex patients, this is actually a very, they've got a very good hierarchy of when you add llamas and lavas and all that stuff to get the people the ideal treatment. No problem with any of that. The key thing you have to understand about gold is, although they put themselves forward as a medical organization, 100% of the people in the gold committee are getting significant amounts of money from the pharmaceutical industry. And so just be aware of that. Key thing is that they, so the standard of, the state of the art at the time this happened was to use the lower limit of normal to identify obstructive disease. They decided that was oh so difficult for primary care people and God help you mid-levels to understand. The word is going to create, 0.7 is the cutoff. And the number of people that I get that come in and say, this person has COPD because their ratio is 0.69 would make me want to puke. Because every one of the mid-level providers has been taught that that's the way you diagnose COPD. Now the key thing to know is that an FEV1 or FEC ratio of 0.7 alone doesn't diagnose anything. Now I will give them credit after 10 years of telling us that 0.7 was the magic number. In the fall of 2023, the gold committee said, oh, yeah, you should probably use the lower limit of normal to make the diagnosis. So they did finally admit that. Although I will admit I may have felt that a little bit, because I twice was on national teleconferences, and I would ask that question. Why did you do that? And then they would always hem and haw and not quite answer the question. But they did finally change it in the fall of 2023. So we're making slow progress. Just to give you the reason I think they did this. So these are the ratios using NHANES for, I don't remember how tall a person is, doesn't, but this is a male of some height or another. I don't think I put on the bottom, it doesn't matter. So there's my 0.7 cutoff according to the gold committee, right? So you've got two problems. First problem is the people in that box, this is somebody who's younger than 40. The magic, the age here, if you look very carefully, is 40 where the line crosses 0.7. So you've got all these people in the green box that have lung disease and the gold criteria would miss, but there's not that many of them. So not that much of interest to the pharmaceutical, I'm sorry, the gold committee. However, the people in that gold box, we've got all these people who are having, they're a little bit older, they probably got Medicare, which doesn't negotiate drug prices, and they've got an FEC, a ratio that is above the lower limit of normal, yet meets their gold criteria for giving them a drug. And if you read their recommendations for people, if you've ever done primary care, you kind of start with a little albuterol, maybe add a steroid, that's kind of the way you would normally start. That's not a choice in gold. There are zero non-trade drugs on their table of recommendations. It's all, we're gonna start, you want a two or three drug thing that's $700 a month, that's the recommendation to start a person. So every single older person, they can get into this yellow box, is big bucks in their income. Just be aware. And I don't know how many people, every mid-level provider I've talked to falls into this trap, and a lot of physicians do. Because the gold people are super effective at marketing this, and if you go to a conference, they've got some of the best lunches. They were at Baltimore, at the AOA thing in Baltimore, they had a lunch that I went to, and I'm like, this makes no sense. And I went and learned about it, and I'm like, this doesn't make any sense. A little about serial spirometry, since we're talking about the occupational setting. Unlike here in conservation, where we do follow change over time in the individual, most barometry programs don't bother. It's between the normal range, we're good. But my question is, is it okay to go from 120% predicted to 81% predicted without doing anything? Probably not, so that's why serial spirometry may make sense. ACOM has a method to do this. I like to follow the change in percent predicted. You can also follow the actual volumes, and then you have to do more math to get it so it works right. This is complex, that's too complex for me. The nice thing about following the percent predicted, model one, is that it's already taken care of. The system database is taking care of the fact that they're older now. Whereas if I do it with actual volumes, I have to subtract the right amount from their FEC and their FEV1 for the delta in age that has occurred since their last test. And I have to keep doing that, which is not impossible, but difficult. NIOSH recommends that they've looked into variability over time. They recommend if you're gonna use, 9% was what they found to be a significant change, but it ignores variability in the test. So they've come back to say that a 15% decrease is clinically significant and should be investigated. And that could be, the recommendation official is for FEV1, but I would argue it probably also applies to FEC, depending on what the exposure is that you're tracking people for. Has anybody ever used Spirola? Really? Wow, you're the first person I've ever met that's actually used Spirola. I don't know if that's what you're expecting. So Spirola, it's fine. Spirola, just so you know, this is no longer supported. Like, you're on your own. But NIOSH stopped supporting that about a year or two ago. The problem was that it was a single machine system. Like, there's one computer that's got all the Spirola data on it. And if that computer crashes, you're done. They were trying to get it, they were looking into the idea of making it like a web-based thing, or whatever we call it now, a cloud-based. Yeah, that was their plan, but they feared that was gonna cost them like half a million dollars, and then they didn't do that. So if you're using Spirola, it will keep working, but it's no longer supported. That's Spirograph. Very close, though. Okay. In ATS, in 2022, they added a new thing for us to be confused about, and it took me a while to figure out what the hell they were talking about. It's something called FEV1Q. This is actually the way they recommend tracking people over time. So FEV1Q, take their FEV1. Then if they're a boy, you divide it by 0.5 liters, and if they're a girl, you divide it by 0.4, which is apparently the 1% level of living person spirometry. The problem, this has been studied, okay? The cool thing is it predicts death. The lower the number is, the closer you are to dead. Not real hard to figure out. If you can't breathe as well, you're gonna die sooner. I got that, okay? That's all this number's ever been tested for. The problem with this recommendation to follow it over time is what's normal? What's a normal change? How much is normal change over the years? Because since we're using actual values, I expect them to go down. I mean, I guess when you get to zero, or 0.1, you're probably pretty nearly dead, but that's not our working population. I have no, they recommended this. It just says use FEV1Q. I haven't a clue how you're supposed to do this, but it is the current recommendation from ATS. It just makes no sense. Some cautions for serial spirometry. The first few tests, there's a learning curve, because we're asking you this weird maneuver when you use spirometry. The first couple tests are a little weird. If you go look at any of the studies done on serial spirometry, they typically ignore the first three maneuvers, and then start with the fourth one. Because the first three, there's a lot of variability in the first couple. Be very careful early. I think the graph of the transition. Early in a work life, be very careful. The changes will be difficult to interpret, and we'll look at that graph, I think, next. And you need to be aware of where the knee is in the predicted equation that you're using. Hope that's on my next screen. It is. So, for example, if you're using Newton 76, their knee is at the age of 24. And it's really between 24 and 25, because it doesn't curve again here. It's someplace in the middle where the knee occurs. If you look at, if you're using NHANES, which is the purple one, you can see that has a knee at about 20, or a little less than 20. And CREPO has no knee. It just ignored it, and they just continue to line off into space. So I guess when you're 15, you're supposed to have the largest lungs, but that's not physiologic. These are more physiologic. The GLI, this is what you get. These are linear equations. The purple and the chartreuse are purple lines. The gold is the thing with multiple splines, whatever that means. That's how they did their math. And so you get a nice curve, because the physiology, it's not like everybody's lungs get bigger until they're 24, and then suddenly the lungs are getting smaller. There's gonna be a transition. And that's a little bit younger for women. So if I do the same thing for women, it would be shifted to the left a little bit, because women's bodies get done getting bigger, younger than men's bodies do. A little bit of stuff from the last technical standard. So this is the weird stuff that was mixed in with their standards. They wouldn't encourage, they were using spirometry and lung testing to identify physiology, not make diagnoses. However, we mostly use them for clinical diagnoses. Kind of like in the AMA guide, you say, don't use this to compensate people. There is no other use for that book other than compensating people. Just be aware, it's something they said that you can't really do. And they do emphasize being cautious right around the cutoff numbers, because use your physician skill to say this is, at 0.01 liters below the cutoff, they're probably still normal. They recommend using the Z-score to assess severity, which we'll talk about in just a second. Bronchodilator response changed significantly. And it's mostly the way you do your math. So two things have happened. One is you can have a bronchodilator response for FEV1 or FEC. Used to be you could only have it for FEV1. FEC wasn't a choice. And then what happens is you have to look at, you compare the change when you gave bronchodilator and compare it to how many milliliters did it go up? Or how many fractional liters? And then you compare it to their predicted equation for that person. You don't have to look at the 200 milliliters anymore. That's gone. It used to be 12% and 200 milliliters. That's all changed. And the problem was if you went from 40% to 53%, that wouldn't be that many, especially an older person, that might not be that much actual volume change. That's why they required the 200 milliliters. And now if you compare it back to the predicted value, the math is really different. Most labs, this is, I actually think this is an improvement. Most labs aren't smart enough to do this yet. So you have to do this math by yourself. Every time I get spirometry results back that are not like stone cold normal, I get out my calculator and figure out what it really is. But it's not always the same. So I'm going to show the math. So it's their post in liters, myosoprene liters divided by the predicted in liters for that person. So this person had a 200 milliliter change divided by three liters that was predicted and that would be a 7% change. This is the chart for classifying things. I don't wanna get lost in this one. But this talks about what happens to the, using lung volumes, how I can predict their status. So it's a good reference. I don't wanna get lost in this one. I do wanna talk for a second about the z-squares and severity. So what you'll see here is mild is anything greater than, I'm sorry, mild is, nothing wrong is 1.645 and anything going higher, closer to infinity, positive infinity than that. And then they've got down to two and a half is mild, down to four is moderate, and anything worse than four, minus four is considered severe. And the reason they did that was because we used to use the 0.7, I'm sorry, we used to use the FEV1 to FEC ratio. Sorry again. We used to use FEV1 percent predicted to estimate severity, okay? And the problem is that means that I've got different values that are okay based on the age of the person. So if I've got my female, she'd be in the normal range, but before we would have called it mild impairment because we were using the FEV1 by itself. And the younger the person is, the less they align. I don't wanna get lost in this too much either, but it changes the way you think about the severity. And we also went from having five severities of badness to three, which is probably better. Any questions? So what's the positive for the denominator response to be greater than 10%? It would be a 10% improvement in either FVC or FEV1, and that's 10% of the predicted value. So if the predicted value is four liters, right? Doesn't, no, we're not, that's the change in the math. The old way we used to compare them to themselves. Yeah, I know. We used to compare somebody, their pre to their post and look for a 12% change. And now we compare it to the predicted equation. And you have to do it for both because some people with restrictive disease may improve with bronchodilator. They may go, their FVC may get better and they may benefit from that. One of the big things that these guys are trying to do, and I get this, right? They're trying to make this clinically useful. So if somebody had an FVC that improved with bronchodilator, they should be offered bronchodilator medications because it'll make their disease better. And that's what this is all about. Because the insurance company would say, he doesn't meet ATS criteria for reversibility. We won't pay for his medicines. Yeah, that's great to explain that. One of them drove that, yeah. Yeah, because there was no way to get medicine for somebody that had restrictive disease. So that was one of the problems. We could get it for obstructive, but not for restrictive. And at least in my, the patients that I see, a lot of them have restrictive disease. And the way it works for my black lung patients is if, because the federal government is still in like 1975. So it's still, the cutoff is if anything is, if either the FEV1 or the FVC is below 80% predicted, then we give bronchodilator. Now if they are, so if their FVC was down and their FVC improves, but the FEV1 doesn't change very much, they've got a positive, it would help them, but the insurance company wouldn't pay for it because it didn't meet ATS criteria. And now that the criteria has changed, we can provide care for people that have restrictive lung disease that happen to be bronchodilator responsive. And that's the big improvement. Any other questions? And for people playing at home, following this talk, I've got two additional slides that are just for reference. One is all the reference stuff that I talked about here. And then the second one is where to get lower limit of normal data if you need that. Thank you very much. Thank you.

spirometry

Dr. Wernz

testing recommendations

interpretation challenges

occupational medicine

obstructive patterns

restrictive patterns

lung volumes

GLI Global Initiative

bronchodilator response