Gobsmacked-- had sleep study, and now I don't have apnea anymore?!?

[cathyf]

I was diagnosed with apnea in spring 2014, got a then 1st-generation AirSense10 which I started using on Oct 10, 2014. My sleep study showed oxygen went down to 80%. My AHI was 45 REM and 9 nonREM, with 77 hypopneas (34 non-REM, 43 REM) and 14 OAs (9 nonREM, 5 REM).

Back then I weighed 267lbs. I started losing weight in mid-January 2015, and over the next 16 months I lost 125lbs.

Now since there are lots of "experts" who say that apnea is caused by obesity, I did do a couple of little experiments in 2017 after the weight loss to see if lowering the pressures caused events to bump up, and it sure did. With pressures around 9-14 my AHI was consistently under one. If I dropped the pressures I would have good days and bad days, with bad days up at 6-7-8 or so. I stopped experimenting after that and focused on mask fit.

It's now been 6 years, and so I started worrying about my machine breaking down, so I discussed getting a new machine with my PA. I've always been able to see that my machine chases flow limitations all night no matter where I set my pressures. A recent experiment that I tried was setting my pressures to 14min/20max. I had all the same FLs as my usual 9/14, and the machine would chase the pressure up to 16/17/18. But at 9/14 when the machine had to stop at 14 I would have the FLs, but not apneas or hypopneas. So basically I decided that I should ask for a for-her A10 because the modern ones all look for things having to do with FLs that the original model doesn't look at.

So the PA says sure let's schedule you a sleep study.

The sleep study was pretty awful -- the first night in six years that I slept without my APAP. I felt like I didn't get any sleep at all. When I left at 5am I was dizzy, felt like crap -- just like my old untreated apnea days. So I did more research on machines.

Then a week-and-a-half later my PA calls me and tells me that the sleep study showed that I don't have apnea anymore. My oxygen only went down to 94%, and I had some scattered events.

I was totally shocked by this. My PA said that she would give me a referral to have an actual appointment with the neurologist.

I then started to do some experiments. I set my pressures to min7-max8. And had only a couple of isolated events for 5 days. And then I had this night:

Isolated ugly night

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That first wakeup was me waking up with nasty reflux (which I have occasionally) and glancing at my machine and seeing that it said I had an AHI of over 15 for the two hours that I had been asleep so far. Went back to sleep, and by morning it was an AHI of 7.42. When I looked at my data in OSCAR I could see that there were those 2 ugly clusters. (The UserFlag1 is 20% for 10 seconds and UserFlag2 is 35% for 10 seconds.) The first one is ~45 minutes, the second one is ~40 minutes. The close-ups are what you would expect, which is a mixture of almost-events and events for a pretty ugly scenario. I also wear a Fitbit, and I can see that during those clusters my heart rate was climbing up to the 80s -- normally my resting heart rate is below 70.

I then lowered my pressures further to 5/6 to continue experimenting. I had another night a week later (two days ago) where I had an ugly cluster that lasted ~30 minutes, but the bottom line is that the other 14 days out of 16 I looked like a person without apnea!

So what the heck do I do now? I have no idea what made those two ugly nights different from the 14 no-apnea nights. I have no idea what is happening when I'm asleep because I'm asleep!!!

If I use the machine and read the data, I can see what happened. But if I take the "congratulations you don't have sleep apnea anymore put your machine away" advice, then if the apnea returns I will have no idea that it's happening!

Two more screenshots... First is the overview of my entire 6 years of use

Overview of my whole history

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and the overview of my last month. (Sleep study was Nov 11).

My last month

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If I can get an appointment with this neurologist, what should I ask him?

I'm really lost here... I thought I knew what I was doing, and now I find out that I don't know anything at all!

[Julie]

Yes you do, you didn't just take the doctor's word that your apnea's gone... good for you!

Someone with more experience reading those charts should be along soon...

Congrats on the weight loss!

And BTW, it's now thought apnea's responsible for weight gain, not the other way around.

[kteague]

...Back then I weighed 267lbs. I started losing weight in mid-January 2015, and over the next 16 months I lost 125lbs...

...The sleep study was pretty awful -- the first night in six years that I slept without my APAP. I felt like I didn't get any sleep at all. When I left at 5am I was dizzy, felt like crap -- just like my old untreated apnea days. So I did more research on machines. Then a week-and-a-half later my PA calls me and tells me that the sleep study showed that I don't have apnea anymore. My oxygen only went down to 94%, and I had some scattered events...

First of all, a HUGE congratulations on the weight loss. Just a bit jealous, but happy for you nonetheless.

Did you get a copy of the sleep study report? Based on your description of the night, if it were me I'd want to go over the details to see if their conclusion had enough meaningful data behind it to accept that the absence of events was actually due to an absence of the condition. For instance, how much sleep? What proportion of sleep stages - very much deep and REM sleep? How many wakeups? There are some people who have to get way into their sleep before having events. Frequent wakeups can give a misleading conclusion in these situations. Did they capture supine sleep? Supine while in REM? You want to be sure they saw your probable worst case scenario.

Please let us know how this pans out. It would be lovely if your hard work was rewarded by resolving your sleep apnea. I commend you for your diligence in wanting to be very sure.

[chunkyfrog]

You have heard about files getting switched in the doctor's office . . .
Obviously, it had to happen, at least once.
Maybe it happened again.
I am wondering if your doctor is in a HMO--and he may feel immune to malpractice suits.
The business model often places profit over patient.
You may be stuck financing your own cpap expenses until you can clear this mess up.

[Pugsy]

First of all you need to figure out if you were really asleep or not when the clusters of apnea events happened.
Go here and watch the videos and learn to spot asleep breathing vs awake/arousal breathing.
While they are talking mainly about central apneas...it can be any apnea event or hyponea that can be a false positive flagging.
http://freecpapadvice.com/sleepyhead-free-software
If you aren't asleep then they aren't real.

As for the flow limitations....any chance you are experiencing any nasal congestion?

[chunkyfrog]

Any time a doctor/DME suggests a redundant sleep study,
I would check with insurance to see if it's really needed for coverage.
I guess the upside to getting my fat back is that those ignorant quacks don't question my diagnosis.

[greatunclebill]

I'm not a fan of neurologists & ent's and apnea. find a board certified pulmonologist that specializes in sleep apnea. pulmonologists are better schooled in the lungs and airway. that's their only job.

[Okie bipap]

They may understand lungs, but some of them do not understand Medicare. When I was in the hospital in 2014, the doctor doing the morning rounds was a pulmonologist. He scheduled me for a sleep study based on what the nurses saw when I slept. After doing two sleep studies, he tried to order a machine for me. Medicare refused to approve the the machine because he had not documented a face to face meeting where sleep apnea was discussed prior to the first sleep study. As a result, I had to go through two more sleep studies in order to get my machine. The sleep clinic we use is ran by a pulmonologist, but the only person we normally interface with is a nurse practitioner. I do see a pulmonologist every six months for my asthma and allergies.

[cathyf]

First of all you need to figure out if you were really asleep or not when the clusters of apnea events happened.
...
As for the flow limitations....any chance you are experiencing any nasal congestion?

Actually I'm pretty sure that they are real. I know from experience that the machine sees flow limitations more-or-less constantly while asleep, and none at all when I'm awake, so it's really obvious whether I'm asleep or awake. It's not nasal congestion per se -- if I'm lying awake with insomnia I can breathe fine with my mouth closed. As soon as I get sleepy my nose closes up and in order to breathe I have to either open my mouth or wake back up. This happens early on in my progression from awake to asleep. I do occasionally see an isolated event during a time period that I know that I was awake, and those I will chalk up to sleep/wake junk.

Here's a my day from Nov 25th. This was a couple of days after they told me that I don't have sleep apnea, and this is one of those 14 days of non-events that look like maybe they are right. I've got the pressures set to 7/8.

11/25 all night

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Here's a closeup of me falling asleep

mask on 2:24, asleep 2:44

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Pretty obvious when I'm awake vs asleep!

Here's that solitary 3:30am hypopnea

3:30am hypopnea

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I think I was asleep and it was real, but it was an isolated event.

Looking at that graph of my uneventful night -- and I think that this is pretty typical -- I would call that someone who is right on the edge of having events, but not actually going over that edge most nights. Two nights later I went over the cliff for two distinct periods of 45 minutes and 40 minutes long.

Back when I was first diagnosed it was clear that I was a frequent flier over that cliff, and I should sleep with a CPAP. Now they are calling me "cured" but I'm pretty leery -- 40-45 minutes of real events is long enough to cause significant stress to the whole body. We've all heard of all of the dangers of untreated apnea, and when something is going on in looks pretty scary to me!

[Julie]

It looks, apart from anything else, like your min. pressure wants to go higher but is being blocked by the low max setting... haven't read back all of your notes, but is there a reason it's that low (vs e.g. the usual of 20)?

[Pugsy]

That lone hyponea.....see the irregular breathing immediately in front of it??? That's arousal breathing...you weren't asleep.

Don't be surprised if you don't remember it though...we don't remember arousals or awakenings unless we are awake long enough to form a memory.

Now your flow limitations...and the fact the machine wants to go killing them with more pressure does point to some sort of airway reduction in air flow if we can't blame nasal congestion.
The sleep lab probably didn't monitor minor flow limitations but the apap mode will try to kill them because it means the airway is at least trying to collapse.

You may be border line in terms of meeting criteria for OSA diagnosis...maybe sometimes you might meet it and sometimes you don't.
Might be related to sleeping position or maybe even REM stage sleep or maybe both.

[cathyf]

It looks, apart from anything else, like your min. pressure wants to go higher but is being blocked by the low max setting... haven't read back all of your notes, but is there a reason it's that low (vs e.g. the usual of 20)?

This is me trying to do my own "sleep study" of not letting the machine react and seeing what happens without it. Since they have told me I don't need a CPAP anymore I want to see what happens if I don't have the machine raising pressures.

This is me doing the opposite experiment -- I've run my pressures at 7/14 for years, and I can see that it zooms up to 14 as soon as I fall asleep. Two months ago I tried the experiment of setting my minimum pressure to 14 and max at 20. My thought being that if pressure would really fix the FLs then it wouldn't get off 14.

chasing flow limitations

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But look at that -- the experts say I don't need a CPAP at all, while the A10 algorithm goes and chases those Flow limitations all the way up to 20!

Here's what I see with a max pressure of 14

a typical night with max pressure of 14

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It's clearly thinking that I need 14 and wants more. But I'm not having events even though I'm not letting it go past 14.