Episode 2: ...MANY MOVING PARTS...

Empowered Sleep Apnea: THE PODCAST
Episode 2: ...MANY MOVING PARTS...
All content © 2022 Empowered Sleep Apnea, LLC
www.EmpoweredSleepApnea.com

A full transcript of this episode (including a copy of the cartoon in-line with the text--SO RAD!) is available by clicking HERE.

Doesn't matter how you got here, you can't swim home!

Robert sure has washed up on the Isle of Sleep Apnea (I Love Sleep Apnea--tee hee!), but he's starting to find his way around!

In this entertaining SECOND episode of Empowered Sleep Apnea: THE PODCAST, Dave and Ellen tackle the MANY MOVING PARTS of Sleep Apnea. Who knew? There are two different flavors! Obstructive AND Central...different elements are important for different people!

Helping Robert get his head ready for the big discussion to come--at the FIVE REASONS MONUMENT (and Coffee Hut!), Dave and Ellen break down the language of Sleep Apnea, getting into the nitty-gritty about apneas, hypopneas, and RERAs (oh my!) :)

The cartoon featured in this episode is entitled A Simple Question, Part 1, and can be viewed by clicking HERE.

Our Website: https://www.empoweredsleepapnea.com
Official Blog: "Dave's Notes" : https://www.empoweredsleepapnea.com/daves-notes

To go to the BookBaby bookstore and view the BOOK, click HERE!

Transcript

Empowered Sleep Apnea: THE PODCAST
Episode 2: MANY MOVING PARTS
All content © 2022 Empowered Sleep Apnea, LLC 

00:00. Book Promotion

Empowered Sleep Apnea: The Book is now available, in both the hardback, which is just beautiful and really showcases the art nicely, but also in e-Book form, for Apple iBook and Kindle. Are you tired of guessing? Try on some Empowerment for yourself. We’ve got just your size. Want more information? Good! Go to www.EmpoweredSleepApnea.com and click the tab that says BOOK.

…and hey!...many thanks!

00:30 Opening Comments

Empowered Sleep Apnea is an educational podcast, which is a bit different from a medical advice show. Medical decision-making can be complex, and even EMPOWERED patients need a partner. So: play it smart, and make sure you discuss your case with your personal healthcare provider before making any changes to your medical treatment plan.

And now: ON WITH THE SHOW!

00:53 Episode 2: MANY MOVING PARTS

EMPOWERED SLEEP APNEA. Episode 2: …MANY MOVING PARTS…

Driving back to the Sleep Clinic to drop off his Home Sleep Apnea Testing kit, Robert could feel his anxiety coming back. 

Until recently, he hadn’t ever been to the doctor, and always felt like he was perfectly healthy. Then: just after turning 50, he is found to have Atrial Fibrillation, which was causing only minimal symptoms. 

But, because there’s a strong association between Atrial Fibrillation and Sleep Apnea, his cardiologist did a screening test, and had him wear an oximetry probe on his finger when he slept.

The picture that came back didn’t need a degree in rocket-science to figure out that something was wrong! Across the whole recording, the oxygen level bounced up and down…zig-zagging across the page, like a child’s drawing of a lawn that badly needed mowing.

At first, Robert didn’t understand why a Cardiology appointment would lead to a Sleep Clinic visit. And at first, he felt really defensive and hostile toward the notion of Everyone Just Trying Top Sell Him More Expensive Things, that he didn’t think he needed. 

When Robert explored his situation with his doctor, and they discussed the notion of “Sleep Satisfaction,” he realized that there may be more of a problem than he thought.

It started as a simple YES or NO question: Are you satisfied with your sleep? And, at first, Robert said that everything was FINE. 

SO, MEANS YOU SLEEP THROUGH THE NIGHT WITHOUT DIFFICULTY, AND YOU DON’T FEEL SLEEPY DURING THE DAY? The doctor answered.

Well, it turns out, the answer to that was a DEAD NO!

After exploring some of the things that he had been experiencing, it was clear Robert had been having problems. His Sleep Satisfaction was actually fairly poor! He often had difficulty getting to sleep. His sleep was perceived to be poor-quality and light-stage, with frequent perceived awakenings, in order to urinate.

Moreover, he experienced nasal congestion nearly every morning, and was really unable to sit still for any duration of time without dozing off. His wife rolls her eyes at him, because he can never make it through the movies at night.

The doctor explained that the first step of the Empowered Sleep Apnea method is to understand the Five Reasons To Treat. And the first of the Five Reasons to Treat is that Sleep Apnea carries RISK.

RISK FOR WHAT?

Well, RISK for early demise!

The doctor went on to explain that not all Sleep Apnea is the same. There’s different types, and they mean different things. He explained that a Sleep Study would help sort this out.

The week passed quickly, and now, here Robert was, dropping off the equipment he had worn the night before. 

It wasn’t as bad as he had expected. The equipment was easy enough to put on, and they said that he could otherwise sleep in any position that he wanted. 

The equipment he wore was straightforward enough. There was a cannula under his nose, that looked sort of like one of those oxygen cannulas he’d seen on patients in the Emergency Room 

(THAT NIGHT HE BROKE HIS ANKLE)

only this thing didn’t give him oxygen (the technician explained) but was going to detect air going in and out of him, measuring his functional breathing.

Around his chest and abdomen were belts that were stretchy. These measured his efforts to breathe. The technician told him that during Central Apneas, these belts show no movement at all. 

When the airway is NOT obstructed, they move together. 

And if the person is breathing against a CLOSED airway (this is called an “Obstructive Apnea”), she told him, the abdominal and thoracic effort bands will be out of phase with each other, see-sawing back and forth, as the person tries in vain to pull air into their lungs. 

On his finger was an oximeter, similar to the screening oximeter he wore, when the Cardiologist ordered it.

And, pinned to his shirt was a box, about the size of an old Sony Walkman. The technician told him that this thing had a microphone and a position-sensor built into it, so it’d be possible to document snoring AND the position of sleep he was in. 

He managed to get to sleep with the contraption in place, and only had to reposition the cannula twice.

As usual, he was up about four times to urinate, which made him wonder how anyone was going to get any useful information out of the test.

All, told, though, he thinks he slept for about four hours, and he was getting anxious to learn about the results. 

The following Monday, after checking the Patient Portal every day for a week, he felt his heart jump as he logged on. The results were in! 

He moved the cursor over to the result, until the cursor changed, indicating he could click to open it. 

He hesitated, feeling that sick feeling of anxiety. When he looked at the results, what was he going to see?

He opened his sleep study report to find acronyms, numbers, and another Oximetry graph that again looked like a bad drawing of a neglected lawn. 

In the doctor’s IMPRESSION it said: Severe mixed Sleep Apnea. Recommend patient return to clinic to discuss next steps...

He felt his hands shaking as he dialed the Sleep Clinic. Severe? What does that mean?

He punched his way through the telephone tree to select the option that allowed him to make an appointment. He felt woozy. He felt sick.  Sheila could hear his voice from the next room as he spoke to the receptionist, with increasing agitation. 

“When? Whaddya mean WHEN?! AS SOON AS POSSIBLE!”

7:06 CUE MAJESTIC THEME MUSIC/Welcome

DAVE: Welcome back to Empowered Sleep Apnea, a Podcast where you learn about Sleep Apnea through the power of Stories, from a patient-centered perspective. I am Dr. David McCarty, and I am here with Dr. Ellen Stothard... 

ELLEN: …Hi Dave!

DAVE: Hi Ellen, it’s great to see you again in the studio. 

ELLEN: Yeah! I am feeling the emotion from this story, that is for sure! It’s just…pulsing…it’s hypnotic...

08:01: Robert’s Trajectory So Far

DAVE: In Episode 1, we left him…slightly calmed down, right?

ELLEN: Yeah…I feel like he was, he was…”OK, there’s a trajectory here!”

DAVE: Yeah. But he came in really angry because he didn’t know why he was there. And, finally we got to the bottom of his narrative, and he understood, kind of the things that brought him there in the first place…understood WHY he was there…

Now, he’s got ahold of the sleep study [report], and he’s starting to panic.

He got the information off the portal. This is the way things happen sometimes, is you get the information before you have a chance to talk to someone about it. And now he is finding that he is really wanting some information.

ELLEN: I…I listened to the way the story describes the tech talking to him and giving him all this information, and the tech doesn’t really explain all of it…she just says what’s happening. And so I heard these words, like obstructive and central and all these different things…thoracic, abdominal… and I was, like, putting on my patient hat, and thinking: Man, there’s a lot of vocabulary here!

DAVE: It’s a lot to take in!

A lot of people just shut down.

09:02. Robert’s Hostility, Revisited

You know I think one of the things I’m learning from this exercise where we’re talking our way through this, and we’re learning from the cartoons that I’m drawing along the way, is that part of what I needed to understand as a physician was that the anger and the hostility and some of the lashing out that we see in a character like Robert…that all is a form of suffering.

ELLEN: Suffering...

DAVE: Isn’t it? 

ELLEN: Yeah. Can you tell me a little bit more about what you see that kind of indicates that to you?

DAVE: Well, it’s obviously displaying intense discomfort.

ELLEN: Yeah.

DAVE: You know, in my family, we have a term called Sudden Overwhelming Intolerance. I saw a guy the day before yesterday at a traffic light; I was waiting to go straight; he was waiting to turn left. 

And so we were both sitting there with our Red Lights. 

ELLEN: Mm. Hmm.

DAVE: He had a Red Arrow, and I had a Red Light. And this is a really…LONG…red light.

ELLEN: (laughs)

DAVE: I mean. Just ridiculously long. And you know, the other street is usually really busy, but there’s no one on it. So we’re just sitting there, quietly, no traffic, at our Red Lights.

And I’m watching this man. And I watch his face start to twitch. 

ELLEN: Mmmmmmm.

DAVE: And then I watch him nod to himself, and then he just takes off!

(cue sound effect of Car peeling out)

Just runs the Red Light. And of course…

ELLEN (laughing): …a second later…

DAVE (laughing):…five seconds later it turns green. But he- You know, he’d just had enough. 

ELLEN: Yeah…

DAVE: It was just…he reached that point. 

ELLEN: Yep.

DAVE: …and I think Robert…is there. 

ELLEN: Now that you describe that in such detail, I can definitely identify some places in my life where that’s happened. 

DAVE: Yeah, I mean, we’ve all been there. We’ve all been there. And I think that, you know…he’s- he’s worried. Now he sees these words “Severe” …and he’s read a little bit, but he doesn’t know anything yet…and he just wants to ask a couple of questions!

ELLEN: Yeah!

DAVE: And, and…right now h- h- he-…seeing all these numbers, he’s kinda terrified. 

11:01 What Robert Needs to Know

I think what we need to do…is we need to prepare Robert for his journey to the first step which is the FIVE REASONS TO TREAT…

You remember the-uh- Isle of Sleep Apnea MAP?

ELLEN: Yes!

DAVE: Wh- Where would Robert be, right now? Do you s’pose?

ELLEN: So…I- I mean he’s still in his Bay of Narrative a little bit 

DAVE: Yeah! He’s kinda washed up there isn’t he?

ELLEN: Yeah.

DAVE: …and he’s- he’s still sort of getting his head together on his journey to the, the -um…

ELLEN: …the FIVE REASONS TO TREAT MONUMENT!

DAVE: …and COFFEE HUT! 

ELLEN: Yes.

DAVE: …so he’s not there yet. He’s not ready to be there yet. Because, in order to talk about the first step of that Monument, which is called RISK, we have to understand the terms. You know, we can’t talk Central-Obstructive if we don’t even know what these terms mean.

I’ve got sort of an idea that there’s a vocabulary lesson that we need to get through. We need to help Robert understand this. 

So, for this exercise, I need you to advocate for Robert.

ELLEN: OK.

DAVE: OK, so…pretend that you don’t know any of these terms at all…

ELLEN: …OK...

DAVE: …and that you are mystified by this and you’re caught up in Robert’s turmoil. 

ELLEN. I’m in his shoes.

DAVE: You’re in his shoes! This is patient-centered stuff! We need to go through this so you understand, ‘cuz you’re a- you’re a detail person, you know?

ELLEN: Yes.

DAVE: You wanna know what these terms mean. So I call this form of suffering that Robert is…you know, this turmoil that he feels in the pit of his stomach, that’s making him lash out…

…he would never yell at a bank teller…you know?...he would never yell at the person at the library because his book wasn’t there…this is something different!

This is something that is stirring him into hostility. That’s a form of suffering. I call that suffering The Suffering of Ignorance. 

Because he doesn’t know.

ELLEN: He doesn’t know! And he’s lashing out, as a reaction.

DAVE: Right.

 ELLEN: Without even knowing WHY he’s lashing out, probably.

13:22 This Week’s Cartoon: A Simple Question, Part 1

DAVE: That’s right. That’s right. Before we get into what Robert needs to know, I- I wanna get into this week’s cartoon.

ELLEN: OK!

DAVE: So, uh, and I wanna do it early ‘cuz it’s also…it gets into this idea of…the frustration…and the suffering…of ignorance. 

ELLEN: Yeah! So…this week’s cartoon is kind of The Experience Through the Patient’s Eyes, right? As they’re being thrust into this world of providers who are caring for Sleep Apnea 

DAVE: Yeah. It’s really kinda wild out there, in the real world…it’s almost you’re kind of walking down Hollywood Boulevard, and you see all these different marquis…the patient doesn’t know what to do!

ELLEN: Sometimes I wish this was a visual show so you could see how high my eyebrows are…

DAVE: (laughs)

DAVE: T- To make this cartoon, um- I was feeling something inside, and I wasn’t quite sure what it was. I- I was feeling anxiety on the part of the patient. That’s what kinda got me there, and it wasn’t until after it was drawn that I kinda realized what this was about…

ELLEN: …yeah…that- so- it kinda came full circle to kinda show you the image after you had created this feeling in your mind…kinda back to that Vulcan Mind-Meld situation…

DAVE: Yeah! Yeah! Yeah! I mean- I think I get to learn something about this process, by looking at the cartoons that I drew the day before…

ELLEN: Yeah! Absolutely. Well, I think this one’s really fantastic for this episode…

…so this is a black and white drawing…and it really feels like there’s some DARK LINES and some LIGHT LINES; I can see this image of him walking through his life, just like PERISCOPES—SIDE TO SIDE, and LOOKING AT ALL THESE DIFFERENT PEOPLE, who are…basically with their hand out saying “No I’ll fix you, I’ll fix you. I know what’s best,” and…you know, including the guy from the Book Club…

DAVE: (laughs) …his crazy friend, who’s giving him this offhand advice…

ELLEN: Yeah, everybody’s out there and- and-…this is a side note, but…when people come to you with their suffering or their medical questions, they don’t always want you to TELL THEM what the answer is…

…they need to be asked more questions, as opposed to everyone telling them what’s true—who are they to believe?

DAVE: Mmm Hmm. Mmm Hmm.

ELLEN: Yeah. And so we end with…you know…a really shocking kinda visual, of Robert here with this target on his chest.

DAVE: …and, of course, in the cartoon, it’s Claudio…but, y’know this could be Robert…

…what I’m saying here, and what I was able to verbalize after putting this cartoon in conjuncture with Robert’s story, was that these are both examples of The Suffering of Ignorance. 

ELLEN: Absolutely, I can one hundred percent see that. And it must be really hard for patients out there, who don’t know who’s telling what truth…because I can look at these and go Mmm mmm mmm …but that’s what we need to know! How do you use Your Words to ask the questions to find the answers that you need to know?

DAVE: Yeah! Yeah! And I say that the answer is that the patient needs to be given some agency, and that requires education.

So, the salve…the cure for The Suffering of Ignorance is, of course…

DAVE and ELLEN (together): …knowledge!...

DAVE: Yeah.

ELLEN: Yeah.

DAVE: Knowledge. And knowledge is EMPOWERMENT.

So that’s what we’re gonna do today. And we’re gonna start with some vocabulary. This is a mixed Sleep Apnea syndrome, so…what does that mean?

ELLEN: Well…aren’t you supposed to tell me, I’m Robert! (laughs)

DAVE: (laughs) …so Robert! What do you think of yourself!

ELLEN: Well, it’s really interesting, so he’s got some big…they’re not even big words, is the thing, but they’re scary. So it’s MIXED, and it’s SEVERE. What does that mean?

So…

DAVE: OK.

ELLEN: Two different parts, right?

DAVE: So let’s- let’s break it down. So when it’s mixed, that means that there is BOTH obstructive and central things going on.

ELLEN: So, are there only obstructive and central and mixed? Are those the only options? Tell me a little bit more about that.

DAVE: Yeah, so for the purpose of this part of the conversation, we’re gonna break it down into two flavors of Sleep Apnea. It makes it easier to understand.

So, the two flavors are: Obstructive Sleep Apnea and Central Sleep Apnea.

And one of the important teaching points is that it’s very hard to separate them. And often, you really can’t. We do so for the purpose of trying to keep things understood, and understandable. But these syndromes often overlap. 

ELLEN: Yes. OK. 

DAVE: Let’s talk about obstructive vs central first.

ELLEN: That sounds good.

DAVE: OK.

So: obstructive events. So, AN EVENT. An EVENT is an episode that lasts…usually ten to twenty seconds.

18:23 Obstructive Events

DAVE: So: obstructive EVENTs. So, an EVENT. An EVENT is an episode that lasts…usually ten to twenty seconds…

ELLEN: …OK…

DAVE: …where the breathing is impaired. 

ELLEN: OK. So it’s an episode…an occurrence…a situation where—while you’re asleep—your breath is impaired. You’re not able to take oxygen into your lungs.

DAVE: You just don’t get as much air as you should.

ELLEN: OK…

DAVE: …and so it causes things to go a little haywire.

ELLEN: OK.

DAVE: OK. So that’s what an EVENT is. Now: EVENTS can either be OBSTRUCTIVE or CENTRAL. So let’s talk ab ut OBSTRUCTIVE events.

ELLEN: OK.

DAVE: So, an OBSTRUCTIVE EVENT happens when a person is sucking air in…towards their lungs…and the equipment at the back of the throat gets sucked together, so that it impedes the flow of air…

ELLEN: …it creates an OBSTRUCTION!

DAVE: Exactly! It creates an OBSTRUCTION to flow! If that OBSTRUCTION is more-or-less COMPLETE, where the person is sitting there really struggling to breathe, and it’s like they have a cork in their airway, in that case you’ll see their abdominal and their thoracic areas going up and down like a see-saw!

THAT’S CALLED PARADOXING!

ELLEN: So, there’s these two different bands as part of the test that was described.

DAVE: Yup. Yup…

ELLEN:…in the intro…that: one is higher up…

DAVE: …one’s around the chest…

ELLEN: Yep…and one’s around…

DAVE: …the belly…

ELLEN: …yep…and so…if the person—you can imagine this even—if there’s an obstruction in there…trying to breathe in…and their chest is bouncing…

DAVE: Yep.

ELLEN: …but nothing’s going in…

DAVE: …and so, when they’re tryin to suck in, their chest will kinda suck in, and the belly will go out, and then vice-[versa]—it goes back and forth…

ELLEN: …that see-sawing…

DAVE: …yeah, it goes see-sawing back and forth, that’s right.

ELLEN: OK, OK.

DAVE: …so that’s an obstructive APNEA. Usually in medical terms Ahhh [the short “A” sound at the beginning of APNEA] means “NOT”. 

A-SYSTOLIC means that you’re not having systole, which means your heart has stopped. So if you are A-Pneic—“PNEA” means “breathing” 

ELLEN: OK!

DAVE: Alright, so if you have an Apnea that’s obstructive, that means that the airway is blocked off. HYPOpnea…

ELLEN: Oooo! HYPO! Less than!

DAVE: Yeah. Lower than, UNDER. HYPOPNEA means that the airway is KINDA BLOCKED. 

ELLEN: OK. So it’s not a full apnea... 

DAVE: Yeah. Not a- Not a full blockage. So…imagine maybe…like…the straw gets kinda squinched up when you’re trying to suck it? 

[MILKSHAKE!]

 ELLEN: Mmm Hmm.

DAVE: …and you can’t get that shake through ‘cuz it’s kinda sucking…a little bit closed…but you’re getting a little bit?

[MILKSHAKE.  MILK. SHAKE.]

ELLEN: Yep.

DAVE: OK. So if that’s the way breath is going for several breaths in a row, you might drop your oxygen; it might cause you to be uncomfortable and WAKE UP…OK?...Having that relative obstruction…that UPPER AIRWAY RESISTANCE…that is a form of disruption…to both oxygen levels and to sleep stability.

ELLEN: Yes! And I think that’s an important thing to highlight. Because it’s not only about the oxygen, but it’s also about the sleep stability. 

DAVE: An obstructive event doesn’t have to be complete, we’ve just learned. A HYPOPNEA? Well, how do we define that? And, actually: the way we define it is really important. (laughs)

ELLEN: Yes. Yes, and this is something that I will say, honestly, coming from the research side of things, I didn’t appreciate that, when I was coming into the clinical world.  That it IS important—which yardstick…which measuring stick…where we draw the line. 

DAVE: Absolutely. A hypopnea, classically defined, means that you have evidence of a flow-limitation event…so on an airflow trace, normally good-looking, healthy airflow looks more or less like a Sine Wave. 

When a sleep study is done, there is a little device underneath the nose, and that is measuring air going in and out. 

ELLEN: OK.

DAVE: And when that is done…smoothly and normally, that tracing looks almost like a Sine Wave. 

ELLEN: Yeah! Yeah!

DAVE: It looks perfect. Up and down. Nice and smooth, ups and downs. When you start to see something called Upper Airway Resistance, the upper contour of it gets flattened, and it starts to get a little floppy, and it almost looks like Bart Simpson’s haircut. 

(laughing)

…so it…it zig-zags…

ELLEN: OK

DAVE: That’s called an upper airway resistance pattern. And so you can kinda see evidence of this harsh air-draw  that has a limitation there. 

ELLEN: OK

DAVE: …and when those flow limitation events are cyclic, meaning that they limit down, look like Bart Simpson, and then they recover, and look like a Sine Wave again, those are called “Cyclic Flow Limitation Events.” 

ELLEN: OK.

DAVE: OK? That’s what Obstructive pathology is all about.

ELLEN: OK.

DAVE: So, the question is the MAGNITUDE of the flow-limitation event…how much does it drop?...and…does it do something else? Does it cause a drop in oxygen? Does it cause a micro-arousal from sleep?

ELLEN: So, it’s not actually what’s happening [meaning: COLLAPSE OF THE AIRWAY] that’s causing the issues, it’s—again—what’s it impacting?

DAVE: Yeah, that’s right. Classically defined, with all that in mind, a HYPOPNEA is a 30% drop in flow, accompanied by a 4% drop in oxygen. 

ELLEN: OK. Let’s break that down. So, so we’ve got a drop in flow, so you just explained—

DAVE: That’s that “Bart Simpson” airflow limitation event.

ELLEN: Exactly.

DAVE: If that is followed by…

ELLEN: …a decrease in oxygen saturations…

DAVE: …measured by the finger-probe…

ELLEN: …OK…

DAVE: …and, if that’s 4% [or more], then that is the classic definition of a hypopnea.

ELLEN: So…maybe this is not a question that I need to ask, but…why 4%?

ANNOUNCER: Well, it turns out, the definition of hypopnea has always caused disagreements. Even as late as the 1980’s, you’d see significant variability from lab to lab, in how hypopneas were defined. In the late 1980’s, two major research studies got underway that would help us understand RISK with Sleep Apnea: The Sleep Heart Health Study and the Wisconsin Sleep Cohort. These two studies are the largest population-based observational studies to prospectively (meaning: in real time) follow a fixed group of people forward as they age, finding out who lives, who dies, what important diseases occurred, and relating these occurrences to the presence and severity of Sleep Apnea.  

These studies would teach us that Sleep Apnea carries a clear signal for worsening survival, and that signal tracks with a metric called the Apnea-Hypopnea Index, or “AHI”. The AHI is the number of apneas and hypopneas per hour. These two important studies defined their hypopneas using the 4% desaturation criterion. 

ELLEN: …and that’s important to remember, because if we stick with this bar at 4%, it indicates a certain level of severity, right?

DAVE: Correct.

ELLEN: …because, here, it’s “Okay, you meet the criteria? One check!” And so if we change the criteria…

DAVE: …and make it easier, then your scores are going to seemingly be worse. 

ELLEN: Yes.

DAVE: …but that’s not what those data show.

ELLEN: Yes.

DAVE: So we need to be real clear on which criterion we’re using. So that’s the 4% criterion. That’s the criterion that Medicare and Medicaid still adhere to. So: when they’re talking about “qualifying” for a device, they’re talking about a score that is obtained using the 4% rule. 

Hypopneas are kind of confusing…’cuz there’s more than one definition…the American Academy of Sleep Medicine recognizes that lesser degrees of desaturations and arousals from sleep regardless of oxygen saturations are both important. Because those both are associated with other adverse outcomes.

The definition of hypopnea according to the AASM (American Academy of Sleep Medicine) is that it can cause a 3% desaturation, or an arousal from sleep, as long as we’ve got that 30% drop in [air]flow. 

ELLEN: OK, so it still has the 30% drop in flow, but it changes to the 3% decrease…

DAVE: …or an arousal!

ELLEN: …or an arousal! So it can be one of the two!

DAVE: …ostensibly, you can have a 1% oxygen desaturation—or none at all!—but if the flow limitation event causes a microarousal from sleep, which is an EEG [electroencephalogram—“brain waves”] finding…

ELLEN: …yes…

DAVE: …that will be scored as a HYPOPNEA!

ELLEN: …ok, so that’s where we’re looking at the brain waves that the person has experienced during sleep and we’re seeing that they are transitioning because of this flow limitation. Because they are not taking the air in appropriately, they are waking up. So: they are transitioning from a stage of sleep to wakefulness, and we can see this from their brain waves.

DAVE: …right! We can actually see their sleep being disrupted…

ELLEN: …yeah!

DAVE: …it doesn’t have to be caused by the oxygen drop.

ELLEN: …yes, OK.

DAVE: …and that’s something that I think people have a hard time getting their hands around. 

ELLEN: …OK…

DAVE: …it’s not all about the oxygen. So there’s something else about having to struggle against a semi-closed airway is uncomfortable…and it feels yucky…and, at some point, it drives this response that rouses you up enough to clear the airway.

ELLEN: …yeah, and this is a pretty controversial thing in our world, right? Because we talk about this…the Apnea Hypopnea Index, which characterizes the amount of events that you have, this has been our North Star. 

DAVE: Yes.

ELLEN: …you know? That’s how we characterize everything, in the clinical Sleep Apnea world.

DAVE: It’s the index that we have seen map to mortality. So it maps to something extremely real, and extremely hard. The higher the AHI goes, the more likely you are to Leave This Earth!

…we’ll get to that in a minute. But: There’s a lot of problems with it. 

ELLEN: Yes. 

DAVE: …and there’s a lot of non-linearity to it…

ELLEN: …yes…and there’s a lot of looking at other things, like arousal and how it correlates, and how these things all relate to each other, in terms of the mortality, and the health, and the quality of the sleep….

DAVE: Yes. 

I don’t know about you, but I believe that there will be a BIG DATA solution to this conundrum. 

ELLEN: Oooo! Now we’re getting off a little into the interesting stuff!

DAVE: …multiple- multiple different indices combined, is gonna be how this one gets figured out…

OK! So we’ve learned about apneas and hypopneas of the obstructive flavor, what about RERAs? Have you heard of that?

ELLEN: Yes! I have!

DAVE: You have! But Robert hasn’t!

ELLEN: Oh, yeah, of course not!

DAVE: So a RERA is a Respiratory Effort Related Arousal. 

ELLEN: OK? Kinda similar to what we were talking about before, with the flow limitation…

DAVE: Yup! 

ELLEN: So, can you explain how they might be different?

DAVE: So, a RERA is different from a hypopnea just by matter of degree. Basically the way the manual describes it is anything that kinda looks like a flow limitation event that looks like it caused an arousal from sleep, but DOESN’T meet the criteria a “hypopnea” can be scored a RERA.

ELLEN: Ok, so if it has less than a 30% flow limitation…

DAVE: …yup…

ELLEN: …and it’s tagged to an arousal from sleep…

DAVE: …yup, then you can call it a RERA. Some labs don’t score RERAs anymore, because it seems a little redundant, since arousals are built  to the new AASM definition—newish I should say, it’s not NEW anymore—the AASM criteria that allows arousals to be worked into the hypopnea definition. 

You know, I think the reason we’re making this point on this episode is NEXT episode, we’re gonna talk about the FIVE REASONS TO TREAT…and the hardest one to talk about of all…is RISK.

…and how we discuss RISK is based upon how we define hypopneas, because THAT impacts how we define the Apnea Hypopnea Index. 

30:00 Central Apneas

DAVE: Put that on the table for now...

ELLEN: OK.

DAVE: We are now moving to…Central Apneas…

ELLEN: OK.

DAVE: Central apnea physiology. 

ELLEN: …so we’ve moved to the other side of this mixed…

DAVE: …yeah, this…I’m putting this coin out on the table, flippin’ it across…

ELLEN: …OK…OK…

DAVE: [in a carnival barker voice]…we got on one side we got obstructive events, obstructive events here-here-here-here…

ELLEN: (laughs)

DAVE: …turn it over on the other side, we got CENTRAL EVENTS…

ELLEN: OK.

DAVE: …and I’m- I’m doing that for a reason, because it seems like they are binary, like it’s one OR the other…and the point that I’m gonna make on this program…is that they are often interlapping…

(record scratching sound effect)

DAVE: (laughs)

ELLEN: Interlapping?

DAVE: That’s a made-up word, isn’t it?

ELLEN: (laughs)

DAVE: They often overlap with each other…

ELLEN: …yeah, but I like interlapping almost, because it’s TRUE…it’s more descriptive of what’s actually happening…

DAVE: So…a central EVENT…means…that the person quits TRYING to breathe…maybe it’s just reduced effort…maybe it’s absent effort…for a few breath cycles duration…and because of that, there is something that happens, afterwards. 

It causes perturbation. It causes instability. 

OK? So because of this pause, what you get in response is a…drop in oxygen…or, you know…another arousal, or something like that. So you see evidence that it’s physiologically provocative. 

That’s what central apnea physiology events are.  

ELLEN: I think we need to break that down for a second. So…we’re talking about central apnea physiology…so…WHY is it called CENTRAL? First of all. Because “obstructive” was very descriptive. 

DAVE: Right! It was the cork in the bottle, right? 

Central.

“Central” means that it is caused by an oscillation in the DRIVE to breathe. Which is generated by the brain. So—hence: “central.” 

ELLEN: Yes. And I think that’s important for remembering the difference between the two. So you can really imagine that cork in the bottle or the collapsing straw—or whatever…and understanding that “central” means “brain”…

DAVE: …yes…

ELLEN: …is not something that comes naturally. 

DAVE: …and…and…people kinda file it away…and it’s so foreign…and I’ve heard people say this: “Well, obstructive, I know what THAT is, but CENTRAL—that’s the BRAIN, right?”

…and it’s almost as if the level of complexity—that’s a BRAIN PROBLEM THAT I DON’T HAVE—because I would KNOW if I had a Brain Problem…

ELLEN: Oh, interesting!

DAVE: …so it’s kinda filed away in that—THAT’s something OTHER people have…so YES, it is caused by an oscillation of the respiratory control centers in the brainstem…but…it is not something that is FOREIGN. Because ALL OF US…every single one of us…yes, even YOU listeners!

ELLEN: (laughs)

DAVE: …if you put us at a high enough elevation, we will exhibit central apnea physiology. 

ELLEN: OK. I’ll bite. Why is that?

DAVE: …that’s called High Altitude Periodic Breathing…and it’s just and example of this physiology being driven mad by the effects of altitude. 

So…central apnea physiology happens for a number of different reasons. One of them has to do with this concept known as loop gain.  

Loop Gain is the idea that if you perturb the system…let’s say you drop oxygen, or—more importantly—raise the CO2 level—what does the system do in response? How REACTIVE to that perturbation is this system?

ELLEN: Ok, so kinda like it’s twitchiness, right?…

DAVE: Yeah! Yeah! Yeah! Exactly! So—if you have a twitchy furnace…

ELLEN: OK…

DAVE: …and maybe your house goes from way too hot to way too cold…

ELLEN: …yeah…

DAVE: …OK, so you’re like: Geez, why it it so FREEZING in here? And then the thing kicks on, and all of a sudden it’s ninety-five degrees!

ELLEN: Mmm Hmm! It’s one or the other, in those old buildings…

DAVE: That would be sort of a high loop gain situation—it goes on, and it doesn’t turn off in time…or maybe…it goes on too robustly…in an elevated loop gain situation, where there is elevated responsivity to shifts in carbon dioxide, people will sort of over-correct…

…and what happens in sleep is there will be transitions between Sleep and Wake. And there are different set points for carbon dioxide in the blood stream for the Waking Brain compared to the Sleeping Brain. 

And if the tendency is to over-correct during a microarousal, then person essentially hyperventilates for three breaths, and then falls back to sleep, and the drive to breathe is GONE, for a short while.

ELLEN: OK.

DAVE: …you’re trying to adjust. 

ELLEN: Having trouble adjusting to different set points is…is challenging.

DAVE: …that’s exactly right! So, the respiratory responsiveness to CO2 is part of that drive for central apneas…

ANNOUNCER:  …a major contributor to LOOP GAIN is, believe it or not! THE HEART! As we age, cardiac function tends to decline. And the time it takes for blood to circulate around the system (this is called the circulation time) INCREASES. 

 With our furnace analogy, it would be as if the temperature sensor was located a LONG way away from the furnace. So: the message to turn off the heat always arrives a little too late, and the house bounces between being TOO HOT and TOO COLD! 

With central apnea physiology, the extra stimulation of breathing that happens with arousals leads to pauses or reduced effort to breathe, once sleep resumes. 

This creates instability.

This means that central apneas can occur as a DIRECT RESULT of sleep fragmentation itself! Therefore, any condition that causes you to have arousals from sleep can create an unstable central sleep apnea pattern, if the LOOP GAIN is high enough!

This is why Central Sleep Apnea is so confusing!

DAVE: …”any source of arousals from sleep!” Now this is the crazy thing! This is why central apnea physiology is built into ALL OF US. 

ELLEN: …so this is the mixed part that we’re going to come to.

DAVE: Well, yes…because mixed means that you’re doing BOTH. So in Robert’s case, he has both things happening. So this is a puzzle! This is a conundrum. 

ELLEN: (laughs)

DAVE: When you tell someone they have some central sleep apnea…part of their thing…what they’re gonna think is…oh that’s the brain thing…Oh, I got something wrong with my brain…Oh my gosh!

And then they’ll pick up Google-pedia, and they’ll find out that central sleep apnea is linked to brain damage, it’s linked to strokes, and it’s linked to heart failure*…and the next thing you know, you’ve got a panicking patient on your hands.

[*important point: these conditions can lead to central sleep apnea, not vice-versa!]

What I wanna do here is explain that there’s a LOT of sliders here…a lot of volume knobs that contribute to central apnea physiology, and…I guess it’s not fair, but that’s life!...we collect more of that risk [for central apnea physiology] as we get older.

…we know that too many arousals from sleep can lead to daytime impairment.

ELLEN: Yes, because they disrupt the sleep, because…we haven’t quite talked about this yet, but sleep occurs in a pattern, such that you go from the lighter to deeper stages, and back up to awakenings, and if you get awoken out of the deeper stages, you can’t get all of your balance of stages that you need. And we’ll talk about that in the future…

DAVE: …of course we will, of course we will…but the basic idea is that sleep is kind of a metabolic cleaning service…

ELLEN: Mmm Hmm…

DAVE: …and a neurologic cleaning service, and…if you interrupt the maid too many times, the job doesn’t get done, in the time allotted.

ELLEN: …I have never heard that…as an example, but I love it! 

I think that that’s a really good description of why we care about these disorders, because they’re disrupting your sleep and kind of impeding the job getting done.

37:17 The Many Moving Parts of Obstructive Sleep Apnea

ELLEN: So we’ve talked about the obstructive, we’ve now talked a lot about the central—do you feel like you’ve described everything you need to, here?

DAVE: I think so. You know, I feel like Robert is gonna want to…he’s looking at himself in the mirror and he’s like: Why do I have Obstructive Sleep Apnea, doc? You know? Because, he’s skinny! And everybody’s working from the same playbook that says you have to be heavy to have Sleep Apnea. 

Now, I think we’re a little more sophisticated nowadays. I think people understand that you don’t have to be heavy to have Sleep Apnea, but a lot of people still hear that. And they believe it.

So, most people wanna know where it comes from. 

So, let’s just go through it! 

It starts with the nose…and it basically ends at the belly. 

ELLEN: Yep.

DAVE: So…anything that can cause nasal obstruction. 

ELLEN: Definitely.

DAVE: Examples of nasal obstructive syndromes include nasal septal deviation, turbinate hypertrophy, valvular collapse, and polyps. So all of those things can cause the nose to feel like it’s difficult to breathe through. 

ELLEN: So, those are things that we’re not necessarily gonna define, but people would know if they had them…

DAVE: They might? These are conditions that make it difficult to get airflow through the nose. And, and so listeners who feel that that’s a problem, they might find themselves breathing with their mouths open a lot; it might interfere with exercise, and they might notice it interfering with sleep! 

The nasal airspace is part of the problem, because when you try to suck air through a limited nasal airspace, you’re basically pulling air through a resistor! And as you try to suck air into the thorax, through that resistor, the back of your throat is the floppy part of the straw. 

ELLEN: Mmmm. And so then you get that collapsing, like if you’re trying to suck that MilkShake!

[MILK! SHAKE!]

DAVE: That’s right. And if you don’t do that, if you just CAN’T breathe through your nose, then 

when you’re sleeping you’re gonna open your mouth. 

And, opening the mouth, remember that the mandible is a hinge joint. The hinge is located right up by your ears.

ELLEN: …and your mandible is your jawbone…

DAVE: …is your jawbone, yeah! And when you open your mouth, that jawbone swings backward, and the tongue actually becomes more backward-positioned….so, you kinda LOSE with open-mouth breathing. You know, it allows you to bypass the nose while you’re awake, but when you sleep it sets you up for obstruction.

Soft-tissue structures, back of the throat. The uvula. Tongue. And Tonsils and adenoids back there. So: all of these structures can be part of the obstructive mass…and…sometimes…are an indication for surgery. And we’ll talk about that in a later episode. 

ELLEN: There’s some structures of the face, right? That’ll affect this as well… 

DAVE: Right! So, a narrow facial structure. And a small and backward-set jawbone. In the old days, there was a typical sort of adenoid facies is what the pediatricians used to call it. From the children who grew up mouth-breathing, so they had these very narrow faces, with these kinda small jaws and this open mouth, and these kinda very sad expression, because they always had these big bags under their eyes. 

But that’s the basic idea is that the narrower the face, and the smaller the jaw, the more you’re setting up that airway to have a problem. 

ELLEN: Very interesting.

DAVE: So now we get down to the neck. We’re thinkin’…the dichotomy here is Swan versus Bulldog. So the swan neck person has a long slender neck….is less at risk. The shorter, stockier build…Bulldog build…the shorter neck sets the structures of the upper airway to be relatively lax. So instead of being stretched taut by the swan neck, they’re a rubber band that’s in the relaxed position. So those soft-tissue structures are more likely to collapse when they’re…when sleep comes.

ELLEN: Additionally, it can be that there is extra mass on there. 

DAVE: Could do, too, as well. Of course, extra heaviness, meaning: adipose tissue, fat. And extra muscle could all be adding to the stress there…

ELLEN: Yeah, because it’s not necessarily people that are…overweight, but people who have larger builds, that are muscular…

DAVE: …yep…

ELLEN: …face these challenges as well.

DAVE: …moving down past the neck, we get to the thoracic area. So…as we age, our lungs age. Our lungs become less capable of doing their job. And that’s true for every year, every time we revolve around this great sun of ours, we lose a little bit of pulmonary function. 

And so, at some point, you may get to a place in your pulmonary decompensation that comes with mortality, that you start to have enough desaturations with events, that it starts to matter.

So, aging will bring about more laxity of the upper airway…and it brings about more problems, maintaining oxygen saturations in the lungs. 

We get to the abdomen, and we get to abdominal obesity. And, what I mean by that is when you gain weight in your tummy region, that’s the most likely to impair pulmonary mechanics. So think about it as: if you’ve got forty or fifty extra pounds right there under your diaphragm. When you’re lying down and trying to passively breathe? That diaphragm doesn’t really wanna go places. And so the lungs spend a lot of time not fully expanded. 

ELLEN: Yeah, you can think about…if you’re ever playing with your nieces, nephews, kids, whoever…and then they’re laying on your stomach…

DAVE: (laughs) That ‘s exactly right! Yeah! You can simulate this for yourself with a big Rottweiler or a toddler!

ELLEN: Yes! Exactly!

DAVE: (laughs)

ELLEN: Just layin’ all over you; I’ve got friends’ kids who do that to me…it makes it harder to take a good deep breath.

DAVE: it sure does! It sure does. And then, of course, the arousal threshold matters in Obstructive Sleep Apnea, too. So, whatever’s goin’ on upstairs, up in the Upper Airway, if it causes you to have an arousal from sleep, that’s gonna make it more…problematic.

So, you know, your score may be low in terms of apneas and hypopneas, but if you have a lot of flow limitation events, and you wake up with them—those would be RERAs—that can still be an important problem for you! Even though you don’t really have a lot of those oxygen dropping events.

ELLEN: Mmm Hmm. So you’re not fitting that criteria necessarily of “severity” in the AHI.

DAVE: Right Right.

ELLEN: But you have these other physiological things that are going on that are truly affecting your sleep, and your quality of your sleep experience.  

DAVE: Yep. That’s right. So…before we finish out this discussion, Robert’s gonna want to know:  what’s the AHI, and what’s the RDI [respiratory disturbance index]. 

OK? Because those are two common abbreviations that are thrown around, that talk about severity of Sleep Apnea. 

So I wanna make sure everybody knows what those are. 

ELLEN: And, so they talk about the severity of both obstructive and central, they bring it back together…

DAVE: They do, they do. And this is why it can be confusing! Because ultimately, the event index is going to be reported as a SINGLE index. So you’ll get a single report for the AHI, which is the Apnea Hypopnea Index…and all you gotta do for this is you count up the number of apneas and the number of hypopneas (whether they’re obstructive or central), you add ‘em all up, and put ‘em over the number of hours.

ELLEN: So you divide by the number of hours, so you’re getting—

DAVE: …divide by the number of hours…

ELLEN: …an average per hour…

DAVE: …per hour….

ELLEN: …that’s the index…

DAVE: …Technically per hour of sleep. OK, for a home sleep apnea test, they sort of estimate that, but on a lab based study, they’ll actually parse it out by when the patient was sleeping by EEG criteria. 

ELLEN: …the criteria of their brain waves…

DAVE: …brain waves, exactly…so when the patient was awake, that’s thrown out of that analysis. 

ELLEN: OK. But we don’t have the brainwaves on the home sleep apnea test.

DAVE: That’s right, so they estimate total sleep time a little differently there. 

The bottom line is: apneas and hypopneas per hour is the A.H.I. Pertinent to this discussion, and pertinent to the next episode…is we’re gonna want to know: how many of those were obstructive, and how many were central? 

‘Cuz we’re gonna find out next time that the way we discuss RISK is different, depending on which flavor we’re talking about.

ELLEN: OK, so Robert had mixed. 

DAVE: He had mixed. And so his…for the listeners, if you’re keeping score at home…Robert’s AHI was 36 per hour. 22% of his events were judged to be central in mechanism. 

ELLEN: OK.

DAVE: What we can say with that is thatt he’s got both obstructive and central physiology…it looks like obstructive is the most prominent. But, you know…one in five events was judged to be a central event. 

So, we’re going to have to help Robert understand WHAT that means, now we understand what it is. 

ELLEN: Yeah. And we also mentioned that there was another…the RDI…that we need to talk about as well…

DAVE: …absolutely…

In the event that your sleep lab scores RERAs…now RERAs really can’t be scored, technically, on a home sleep study, because you can’t really score an arousal –it’s not been agreed upon—but, in a lab, of course, you can…in a lab-based study, you have the EEG, you have the brain waves, so you can score arousals. 

So if your lab scores RERAs, then they may report an RDI. in addition to the AHI. So the RDI is the Respiratory Disturbance Index…and that includes ALL of the above—apneas, hypopneas, and RERAs.

ELLEN: So it’s uh, it’s got a little extra information in there.

DAVE: Well, you know, there may be somebody who has an AHI of one per hour, so…ostensibly, not worrisome…and they’ve got…seventeen RERAs per hour. So their RDI in that situation would be 18 per hour, their AHI would be one per hour.

In the International Classification of Sleep Disorders, third edition, the American Academy of Sleep Medicine has specific criteria for the diagnosis of Sleep Apnea. 

And their criteria are:

…if you have FIVE obstructive events per hour, in the setting of certain symptoms—and they list them in the book—things like snoring, difficulty sleeping, daytime sleepiness, mood disorders, or some sort of problem like hypertension or an arrhythmia…

…FIVE EVENTS PER HOUR…that includes RERAs…

ELLEN: Ok…

DAVE: …OK, so…you could have five RERAs per hour, no apneas no hypopneas, and…depression… that would meet the diagnostic criteria for Obstructive Sleep Apnea! According to the ICSD3.

If you have 15 obstructive events per hour…including RERAs…including RERAS…regardless of your other problems or symptoms…you’ve earned yourself that “Gold Star”!

ELLEN: Interesting, interesting. So this is, kind of, we’ve talked about how the line has maybe moved a little bit because we’ve changed our understanding of what is really going on…

DAVE: …I think that the hope here is that we can make treatment available to anyone who needs it! 

ELLEN: And so this kind of comes back to why you’re doing this?

DAVE: Yes. So—”needs it” depends on the FIVE REASONS TO TREAT. 

ELLEN: Exactly.

DAVE: So that’s why patients are very well advised to come to the plate with an understanding of why they’re here…and that’s EMPOWERMENT. That’s the opposite of the Anxiety of Ignorance. 

ELLEN: Absolutely. That’s awesome, that’s awesome. So I feel like, if I were Robert, I would understand my mixed Sleep Apnea at this point, with aspects of obstructive and central.

DAVE: Right? We’ve learned the moving parts of obstructive versus central.

ELLEN: Mmm Hmm. And I would understand also what my AHI means—the number that was presented to me…

DAVE: Yep

ELLEN: …what that means for me—not necessarily in my RISK or other—

DAVE: Right? We haven’t talked about RISK yet, but we just know physically what we’re saying…OK?

ELLEN: Yes. So, it’s a little less scary now…and…I’m understanding a little bit more maybe thinking about WHY I need to be treated, what kind of treatment would come for me, you know? So I’m thinking of myself sort of in that Hallway [like in today’s cartoon], the hallway of the doctors, saying “I’ll treat you this way, I’ll treat you that way…” 

DAVE: Yes! Yeah! So that’s kind where…a lot of people start the journey…is that everybody’s kinda grabbin’ at them from the sidelines, and many people are there before we’ve even had the discussion that we had today! That’s a scary place to be!

ELLEN: So, maybe not so washed up on the Bay of Narrative anymore!

 DAVE: No we-, we’re kinda amblin’ along the trail…maybe we should re-name this the Trail of Vocabulary…

ELLEN: Yeah…I can kinda see the Coffee Hut…from where I’m at…

DAVE: …in the hazy mirage in the distance…

Ellen: (laughs)

 49:27 Cue Majestic Theme Music, Ending Credits

Empowered Sleep Apnea is an educational production of Empowered Sleep Apnea, LLC. The show was written and performed by David E McCarty MD FAASM and Ellen Stothard PhD.

All sounds on this production were made by the performers, or were cobbled together from public domain sounds we found lying around the house…

The theme song the week was performed by Someone Else’s Problem.

Cartoons this week supplied by a thin man in a black suit, who drove away saying "SHHHHH!"

Dr. McCarty’s endless quest for answers enhanced by meandering. Dr. Stothard’s positive outlook this week  supported by Science.

Tune in next time, when Robert discovers that the geography of the Isle of Sleep Apnea is not exactly…stable, a white rabbit beckoning him to travel to the mysterious and iconic FIVE REASONS MONUMENT. You…shouldn’t miss it…

And now…coming up next…your Sleep Medicine Dad Joke.

50:42 Sleep Medicine Dad Joke

Dad: Ok, alright….I’m killin’ it.

Not-Dad: You are killin’ it! You’re killin’ it!

Dad: Alright…KNOCK KNOCK…

Not-Dad: well, who’s there?

Dad: Interrupting Sleep Doctor…

Not-Dad: Well, interrupting Sleep Doc-

Dad: YOU HAVE SLEEP APNEA! Get it?  Interrupting? Ha!

Not-Dad: I got it, interrupting Sleep Doctor, I get it!

END PROGRAM