AHI < 1.0 now, but still tired? Is it UARS, RERA, arousals or FL in your FR peaks?

[cathyf]

2SB, I have a thread detailing my flailing and confusion over the last 6 months with the title "Maybe I have apnea, maybe not, are all sleep doc jerks?"

A big part of my problem is that when I started on this whole journey of diagnosis and treatment of sleep-disordered breathing six years ago, I formed a bunch of conclusions based upon what I was seeing in my data and experiences that turned out to be just wrong. And unlearning the wrong stuff surely adds more steps to the learning process!

One thing that I haven't been able to track down -- is there a primer here on "how to read a flow rate wave form" that tells you this part is inhaling, this part is exhaling, this is what the little shoulder thingy means (and what it's called, since "little shoulder thingy" probably isn't the scientific name ). Explains the anatomy of flow limitations, apneas, hypopneas, what's different in a central, why awake breathing looks like it does, etc?

I need to go dive in to the references that you've posted, but the more I read about UARS the more it sounds like me. The lifelong inability to breathe through my nose while asleep (or even drowsy). The amazing flow limits shown in my OSCAR/Sleepyhead data, but very few apneas or hypopneas. The fact that my APAP clearly chases FLs all night long and will boost the pressure to however high I'll let it go, but if I set the max low I don't get events. The positional apnea -- I've always hated sleeping on my back, but now realize that if I force myself to sleep on my back the obstructive apneas will come slamming one after the next. (On the 22nd of March I started the night on my back, and a few minutes in I started on a 28-minute span where I had 35 obstructive events, for a total of 12:48 of the 28 minutes in obstructive apnea. 45% of the time -- yikes! I wonder how low I desaturated?)

I also discovered that if I sleep in a cervical collar my AHI on my back basically goes away entirely.

I wore a fitbit during my sleep study last fall, and when I line up the fitbit's graph of sleep stages with what came out of all of the sleep-center monitors it lines up amazingly well. It misses lots of the awakenings, but as far seeing the transitions between light, deep and REM sleep it was right on each one. My fitbit is telling me that I don't get nearly enough deep sleep, and that my heart rate spends a lot of my sleep time well above resting heart rate levels. (And also my fitbit has been telling me that my resting heart rate is doing strange things. I got it for Christmas in 2015, and until the end of 2019 my resting heart rate bounced around in the 60s. Since then, it's been bouncing around in the 70s and even up into the 80s. I'm trying to figure out if that has anything to do with my lousy sleep as well...)

Anyway, I'm off to read more of these excellent links...

[cathyf]

A quick question...

The discussions of flow limitation as measured in sleep labs or even home tests like ApneaLink are all about using the nasal cannula and capturing the flow in and out of the nose. But I breathe through my mouth when asleep and have always used a full face mask, so my machine is measuring flow rate and flow limitations using the air flow in and out of both my nose and mouth.

How does this affect how events are detected with the machine vs in a sleep lab?

Something that I am just now appreciating... In my July 2014 sleep study, I had 14 Obstructive Apneas -- 9 NREM, 5 REM -- and 77 Hypopneas -- 34 NREM and 43 REM. My May 2014 ApneaLink screen had 65 Hypopneas and only one Apnea. But my 6-1/2 years of using my machine, my very-low AHI has shown 2-3 times as many apneas as hypopneas.

In fact, that's kind of a weird thing about what my machine data is showing: I have flow limits out the wazoo, which my machine spends the entire night chasing, but it doesn't actually detect very many hypopneas at all. I have recently figured out how to create an absolute sh*t-storm of apneas that pressure won't touch -- fall asleep on my back without wearing a cervical collar

[attachment=31268]

But that's all apneas and only a few scattered hypopneas.

Is this a difference between scoring mechanisms between machine and sleep lab?

And for us mouth-breathers, how does this singular focus on airflow in and out of our noses work if most of the air is moving in and out of our mouths?

[JoeyWallaby]

You've seen supine sleep aggravates your OSA, do you do anything to limit supine sleep?

[Sleeprider]

The soft cervical collar makes a big difference in stopping the shitstorm of apnea. Flow limitation can occur whether you breathe nasally or orally, and it's all about whether the upper airway is restricted for flow. Flow limitation is on a continuum, and whether it results in hypopnea or obstructive apnea depends on how hard your work to prevent self-strangulation. I have seen members that have very high flow limitation but low AHI, they don't sleep well, but you can see the effort. You just kink the hose and arouse repeatedly. At least you know how to prevent it.

[cathyf]

You've seen supine sleep aggravates your OSA, do you do anything to limit supine sleep?

Actually I discovered a week-and-a-half ago that if I sleep with a cervical collar ($15.49 on sale at Walgreen's) that I can sleep on my back and not have events. I first got a "normal" size (3.75 inches) and it was amazing. Since everything about my airway, head, face, etc. is very small, and the normal adult size collar is kind of uncomfortable, I also special ordered a 2.5 inch small size thinking that a smaller size would work better for me. But I found that the small size doesn't do much good at all -- it's really quite striking.

What is really amazing is that with the collar I can actually fall asleep with my mouth closed, and I think that is the first time EVER in my life. I've always been fine with breathing through my nose when awake, but once I got even drowsy I felt like I was suffocating/holding my breath and had to open my mouth to breathe. That's back or side -- I clearly chin tuck on my side, too, it's just not as bad as what's going on with supine.

I still have pretty significant flow limitations, but they don't progress to events.

[2SleepBetta]

cathyf:

I just now read your other two threads on FL metrics, sleep MDs, UARS and your route to benefits from adopting SleepRider's recommendations of pressure settings and a cervical collar. You have won, in a sense, the war on the limited front of insured medical "treatment", AHI<=5. Now full focus can be on improving how you feel there, given that you say you don't feel that much better rested now--largely because of other pain issues. You should feel somewhat better and have better-health prospects. But not yet. You are still having to "pull too much vaccum" and are likely, as others have pointed out, having  arousals preventing rest you need.

Before commenting further, I was struck by how I recently I experienced the truth of SR's comment in your thread, "  Positional apnea is not dependent upon supine sleeping because the mechanism is chin tucking." I recently find that being confirmed in my sleep. 

My "bio square" shows where I started from. My c-collar, P-10-pillows mask and chock (to stop supine sleep) recently got me to 12 months of 0.1AHI. Great, but I still see markely  reduced FL and variable earmarks of continuous  inspiratory flow limitation (IFL). Not nearly as serious, I believe, as yours have been. 

I found a good way, other than a holding slot in my chock, to mount my accelerometer against my back near lumbar L3 (so as to continue recording and knowing position and motion). So, as an experiment, I've been sleeping without the chock, which made turning over very difficult--to the point I would sleep on one side many nights through. I'd wake up with the low eye half swollen shut, it taking hours to normalize. Surprise! I still get 0.00 to 0.2 AHI on my back, rarely more, vs my start in the 50s. Why? Two things: che c-collar and, I believe, my use of ResMed P-10 nasal pillows. The 50 and higher AHIs, total time in apnea mid 30%'s, were with full face masks and lots of leakage-awakenings for this incorrigible mouth-breather (who, AS SUCH, "COULD NOT USE THE p10"). I tried tape and then eventually sealed my mouth with a cllnging, but not adhesive, mineral gel, Gel-E-Roll, from Silipos.

I finally get to my point: For various pain driven reasons, you reluctantly favor sleeping on your back, though you prefer not to. Your new PAP pressures and c-collar make it sane to do so now. My guess is that, aside from getting a bi-level machine like the AirCurve VAuto, the best new thing to try would be the P10 mask (possibly a different make, but I think it is ideal). Many users rely on tape, which I tried, but didn't like, to stop mouth breathing. Gel-E-Roll works well, but you need a separate device, an elastic band, to apply pressure on it to hold it in position pressing against your pre-pursed lips. Somewhere at AB I believe I posted pictures of the setup and, elsewhere, of the chock.

Justification for suggesting nasal pollows (or my loony imagination?) here: I think the air-tight sealed coupling of a nasal pillow to your nose (nares?), together with no (or minimal) mouth leakage will enhance and maintain steady retention of your airway's effective and critical cross sectional area when supine. Not informed in pneumatics, my sense is that with a full face mask there is more opportunity for variation and shortfall in the critical pressure needed inside the airway as we exhale or inhale through our mouth. Seemingly unrelated, as as any heart aspects are here, we know that our pulse waves travel through airway tissue and its and surrounding tissue and show up in tiny flow rate waves ("cardiogenic ballistic effect"), primarily near the end of expiratory flow (for me, anyway). Somehow our FR has a superimposed pulse wave and I am "supposing" our breathing regularity has a similar effect.

You make a lot of good observations that merit more and better response.

But, but for now, just one thing more regarding matters you raise in the thread on what flow limit (FL) numbers mean. I hope the following lightly edited quote from my post in Ameriki's recent thread will throw some light on the FL matter I, too, had a lot of trouble understanding. The trouble is because of the ambiguity of "flow limitation" in our sleep medicine context.  One use of the terms speaks to any kind of significant airflow restriction, the other use, FL, refers [for ResMed PAP machines and OSCAR] to a change in the volume of airflow that has flowed in over a set amount of time. The former (typically) is an "inspiratory-flow limitation" of any length of inflow, possibly nearly continuous and steady (as is yours, if not mine, now?), the latter, FL, is a specified reduction in total flow volume over a set time period vs a prior (I'll say) like or commensurate period. If highly restricted flow rate and volume is continuous, then no FL will be flagged. 

The edited quote:

"[The] unrounded upper tips ("M-tips") of [your] inspiratory upper half of the flow rate curve[:] Those indicate inspiratory flow limitations (IFL). I suspect those limitations are present in much of your sleep that night (if not always). Note that it is true that there are both IFL and machine flagged flow limits (FL) in your 2-minute view. The latter arise when near continuous IFL becomes critical and causes, somehow, the flow rate (and related flow volume) to vary enough in a short time interval for the machine to flag a FL.

"The M-shaped tips are prominent markers of IFL--which is related to flow limits[FL] our machines do flag, but different. A single FL reflects a certain number of seconds or breaths (I don't remember which) of breathing when the inflow of air dropped a certain percentage [in a preceding time period]. On the other hand, IFL is often a  continuous condition that can vary some over an extended time period and be episodic too. 

"For FL the machine flags, the concept is analogous to a plastic water hose that is kinked enough for a fixed number of seconds (say 12 seconds or 3 breaths) for water flow into a bucket to be reduced a certain amount (say 1 gallon or 3 liters). On the other hand, for IFL it is analogous to kinking, and keeping kinked, the hose for long stretches of time, maybe (for your {?) or my sleep) the whole night through. The latter condition in sleep requires your breathing muscles to work harder to draw in air, like sucking harder on a straw to get air. That tends to awaken many of us frequently, though we don't often remember that."

[cathyf]

I’ve actually got a whole bunch of long posts in me, since I got the results of my sleep study yesterday. 

And, again, I’m at “everything I thought I knew is wrong!”

My question at this point— I could post that over on the thread I started, but I think that it would be more valuable over here, because I think what I’m seeing is right on target with the flow limit deep dive that we’re doing here. (I could post a reply on that other thread saying to come over here)

I know that the rule is “keep your stuff together” but I think that over here is “together” in a different way. 

Summary what happened— my sleep test this time and my sleep test last November appear to be two different people, LOL! (Honest, it was me both times...) 

This time: 

- The lowest oxyhemoglobin desaturation (SpO2) related to a respiratory event was 86% associated with a 41 seconds obstructiveHypopnea.
- RDI supine was 13 per hour and lateral RDI 39 per hour of sleep.
During REM sleep- REM RDI was 42 per hour, NREM RDI 16 per hour, REM supine RDI 42 per hour, and NREM supine RDI was 16 per hour of sleep.

November:

- The lowest oxyhemoglobin desaturation (SpO2) related to a respiratory event was 92% associated with a 19 seconds obstructiveHypopnea.

- RDI supine was 26 per hour and lateral RDI 2 per hour of sleep.
During REM sleep: REM RDI was 3 per hour, NREM RDI 2 per hour, REM supine RDI 0 per hour, and NREM supine RDI was 4 per hour of sleep.

[Crimson Nape]

cathyf - This is 2SleepBetta's thread. If you feel that your topic is different enough from your original thread, then please start a new thread.

[Gideon]

Cathy, to prevent confusion, please post anything about your therapy in your own thread otherwise we will not know if the response is directed to you or the OP.
The Moderators here have the capability of moving your posts, and replies to you, over to your own thread.

[cathyf]

Cathy, to prevent confusion, please post anything about your therapy in your own thread otherwise we will not know if the response is directed to you or the OP.
The Moderators here have the capability of moving your posts, and replies to you, over to your own thread.

Fair enough— I will do so... I also have a lot of flow limit thoughts that I will put here— I’ll probably end up repeating myself, but I can definitely see how that will help to keep things coherent in each place.