Causes of Unknown Apnoea events?

[Ratchick]

Sure... here you go. 

1) The time I fell asleep without my mask a couple of weeks ago and woke up feeling like I'd been kicked in the head by a horse.

   

2) Two nights ago with EPR on full time at 1cmH2O.

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3) Last night, with EPR off again.

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It's absolutely down to desats. Horrible desats that nobody but me seems to take seriously.

[Geer1]

Do the lower SPO2 values always correlate with CA's or is it also low at times that OSCAR data looks normal? Have you tested your awake SPO2 to see how it compares?

Hypoxemia is usually considered anything under 92% (or 88% in COPD). You meet either criteria the majority of the night. For an example during covid our local hospitals started having a shortage of oxygen and there was a memo sent out that doctors were to stop targeting 95% with oxygen therapy and instead target the lowest tolerable which they stated is around 90% for most patients.

One way to word it differently to doctors is to use the word hypoxic rather than desaturations. Desaturations are usually momentary drops. Hypoxic means your oxygen levels are low enough physical damage due to oxygen depravation. Saying you are hypoxic the majority of the night should raise eyebrows. If it doesn't I would be seeing a different doctor.

[Ratchick]

Yep, they know this. I've had several 24/48 hour cardiac, blood pressure, etc monitors, as well as my sleep study, they're WELL aware of this, and I've shown people this info before as well. When I'm awake, my average is usually about low-mid-90s, so a little low maybe, but not super bad I had some initial tests done regarding lung function but apparently those were fine. But I will track it longer term and see what it says. It's definitely not in the range that it is at night, that's for sure.

I know that this is at a level where most people would be in hospital on oxygen, and I genuinely don't know why my doctors don't seem to give a damn. Your guess is as good as mine, to be honest. 

I do sometimes have nights where I spend much less time in hypoxia territory (usually when it's an overall bad night and I'm waking up ALL the damn time or can't sleep). But it's always linked yes. Is it linked to my chart? I would say so. It can be blatantly obvious, like this:

   

Other times, my sats don't recover quite so much, depending on the length of the apneas and the frequency of them, plus how effective my breathing is between those breaths... But yeah. It's always pretty easy to match up the pattern of the SpO2 chart and my CPAP data. Not just CAs but also flow restrictions etc, or even areas that are almost-apneas but aren't quite long enough to be tagged (or otherwise not "normal" breathing etc).

[Geer1]

I was curious if it fell for other reasons as well but seems to be mostly tied to the central apneas. You definitely need ASV at a minimum (or potentially try an oxygen bleed, that is an option mentioned on uptodate which is a doctors version of wikipedia). If they won't write a prescription for anything then they need to order a titration study imo.

Keep pushing your doctors. I would focus on discussing the Resmed titration protocol info and trying to prove that the machine you are on currently doesn't treat your apnea or hypoxia either in theory (based on this Resmed literature) or in reality (based on recorded AHI and oximetry). Force them to take extra steps (prescription for ASV, order titration study or referral to a different sleep doctor). Here is another UK version resource by Resmed recommending ASV for central apnea.

https://www.resmed.co.uk/healthcare-prof...s-for-csa/

If I was in the same position and doctors weren't willing to take the next steps I would bluntly tell them they are not doing their job and that the central apnea and hypoxia need to be treated. If your doctor is a complete knob and you don't mind potentially ruining the relationship I would threaten to file a malpractice suit with your documented data proving your untreated apnea and hypoxia, that should get some attention and if he tells you to screw off then I probably would file a case because you have one...

If you can't convince a doctor then private purchase is the only option but you are looking at $1600 for a used ASV or $2150 for an unused one (secondwindcpap USD prices) unless you can stumble upon a cheap used version locally (sometimes can find on local FB/Craislist or whatever it is you guys use over there).

Edit: The only thing that could potentially be in your doctors advantage is duration of treatment etc. I see you only joined here in March. I assumed you have been dealing with this for a while but if it has only been 2 months or not even on CPAP then they could argue they were collecting data (and potentially following some protocol although I can't find NHS protocol for central apnea treatment online).

[Ratchick]

I was initially diagnosed a decade ago, though was never given any therapy back then (and I have no idea what my actual sleep study showed from back then, either), but I started on APAP/CPAP at the beginning of February after my second sleep study. Even then the doctor really didn't seem that convinced it would make much of a difference but insisted I stay on it regardless. The problem is actually getting hold of the doctor again and not the sleep clinic or his secretary. Very frustrating. Come Monday, more chasing, more emails, more charts.

And just to demonstrate that a) it's not as simple as opioid-induced apnea and b) the futility of trying to figure out anything about central apnea from one day, here's the overview of last night, where I should have been most affected by my medication.

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The previous week's AHIs were in the 30s and 40s and my average is ~29. 
Go figure.

[Crimson Nape]

Based off that graph, you are definitely an ASV candidate. Wow!!!

[Ratchick]

That chart is the best night I've had since I started by a LONG shot  (I've had a few more that are around that level of AHI but only when I've been waking up for unrelated reasons or struggling to sleep in the first place). This was a week ago and isn't even close to being my worst.

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[cathyf]

I'm confused, ratchick -- are all of the shaded regions large leaks?

[Geer1]

Can you post some zoomed in examples of the periods of high flow limitation. I find it interesting that these periods correlate with some of your best/most consistent SPO2.

Cathyf, the light grey appears to be periods of SPO2 Drop.

[Ratchick]

Cathy - no, they're not large leaks, they're O2 drops. I've set up my OSCAR to show SpO2 drops as a blue "span" rather than a flag, because it's easier to see the coincidence of drops with the CPAP data, as well as makes it easier to highlight all of the other flags.

   

Geer!: I've wondered the same thing myself. But it happens every. Single. Time. If I'm asleep and not having many events, you can pretty much guarantee I'm having a lot of FLs. I'll go grab some zoomed-in shots now.