Long time CPAP user still fatigued

[SarcasticDave94]

Oh no! AHI 0.09. You just missed it.

Now for the real test. Was it good sleep?

[enigmatic]

If only the low AHI and 'good sleep' correlated.  I'm expecting to hear it's a miracle you're cured!

Not too great sleep. Still tired, but night was clearly fragmented with wakeups trying to acclimate this new alien parasite-- going to try to give it time.

Starting to feel like a better gold standard would be to have no 'awake' (level 3) states on watch sleep states. More awakes = worse sleep.
It really does add color to the picture. For anyone interested to learn about apple watch 8-9, there's a good reviewer by the name of the quantified scientist
on youtube. He typically rates apple watch highest (and he compares a lot of other competitors, quantitatively not just qualitatively). I tried lots of other devices that were garbage for various reasons. I find the apple watch to be the
real deal, or close as we can get to PSG.

[Jay51]

There is a technique called blowing back at an ASV machine to get it to decrease pressure.  If you are awakened or troubled by high pressure do a quick purposeful exhale and inhale.  That is supposed to reset the pressure lower to min PS.  It shows the ASV algorithm you are breathing on your own again.

[enigmatic]

There is a technique called blowing back at an ASV machine to get it to decrease pressure.  If you are awakened or troubled by high pressure do a quick purposeful exhale and inhale.  That is supposed to reset the pressure lower to min PS.  It shows the ASV algorithm you are breathing on your own again.

Interesting, thanks. I would think pulling off the mask would do the same, but sounds like a good reset flag if I could remember during the night. I was doing the opposite, very slowly and somewhat forcefully attempting to train it back to the right (comfortable or smooth) rates.

[Bhante]

Oh no! AHI 0.09. You just missed it.

Now for the real test. Was it good sleep?

Well, that's what it comes down to, isn't it? Also note the total time in apnea 13 seconds, just one central apnea, I don't see that that 13 seconds in itself is going to kill you. 

That's a LOT of sleep. Even allowing for wake time - I didn't try estimating how long but can't be much more than an hour give or take. (Actually, so little wake time seems quite good to me for a first time considering what you were being subjected to!) And tired after all that?

If it was me I'd be racing to cut that IMAX right down, but that's just my bias so take that with a pinch of salt.

I expect you have tried paging through the whole night's data in high res so that you can see every breath? What does it look like?

[Bhante]

On the CO2 measurement, I'm wondering, DOES IT REALLY MATTER? Just being the devils advocate, but since you have SPO2 (OK not every night but infinitely more than CO2), you have tidal volume, and you have breathing rate. That really ought to give you all the information you need regarding hypoventilation. What more could CO2 possibly add?

If you can tease it out of OSCAR, the ideal would be total expiration time x total expiration volume + total inspiration time x total inspiration volume, as a graph for every breath over the whole night (strictly you would want smoothing to be useful, eg average over every 20 breaths), and then compare that graph over the whole night with SPO2. That will really be a true plot of hyper/normal/hypoventilation over time. If you can get tidal volume and breath time on a breath by breath basis from OSCAR, then you could do it by exporting data to excel. You might want to add sleep stage to the comparison, as the metabolic rate changes according to alertness and sleep stage especially REM sleep.

@Jay51, on the question of whether CO2 measurement has any significance whatsoever, it would be interesting to plot hyp(o)ventilation over time together with both SPO2 and CO2 (where you have it) and see if there is a perfect correlation. If it is a perfect correlation then you can just ignore CO2.

The only thing you would lack, with a graph of hyp(o)ventilation against time plus SPO2, would be a graph of metabolic need for oxygen over time, but to some extent you have some indication of that with SPO2 and sleep stage.

[StuartC]

[quote pid='489289' dateline='1697193889']
on the question of whether CO2 measurement has any significance whatsoever, it would be interesting to plot hyp(o)ventilation over time together with both SPO2 and CO2 (where you have it) and see if there is a perfect correlation. If it is a perfect correlation then you can just ignore CO2.
[/quote]

I can only speak for me based on a sleep study.  Good SpO2, high CO2.  So no perfect correlation.  CO2 measurement is significant, as far as I can tell.

[Jay51]

               


   


I can see the logic in your thinking Bhante.  Here are 2 capnography home sleep studies.  The 1st one I actually passed, but I didn't sleep long enough.  The most important numbers are:  % of time greater than or equal to 45 mm/HG (22% on this particular study).  This indicates time in hypoventilation (exhaling too great a % of Co2).    Next most important number is % of time less than or equal to 35 mm/HG.  This indicates time in hyperventilation.  The time between 35 and 45 is normal.  I wake up around 1pm and start hyperventilating, but my spo2 remains about the same it looks like to me.  I spend significant time in hypoventilation also, but my spo2 remains relatively stable.  The one large spike down in spo2 is an artifact. 

The 2nd one I failed miserably.  66% of the time hypoventilating.  I guess I have experienced the same thing as Stuart - Good spo2 but high Co2 at times.  Also, I had documented hyperventilation and good spo2 also at the same time.  For reference, RT told me a person can spend up to 25% of the sleep time hypoventilating and be considered normal.  Above 25% confirms a hypoventilation diagnosis.  Oh, and the 6 large spikes down in Spo2 were artifacts were the sensor moved on my finger.

[SarcasticDave94]

Yes blowback on the ASV is a thing and I've used it basically to tell the ASV to back off I'm breathing and not dead.

[enigmatic]

   
   
Thanks for all the input @all.

@Bhante I could certainly do what you suggested, have to think more about significance. Would the formulas you suggest not mimic the shape of flow rate? Not sure what I'm supposed to see. Do you have any visual examples/links to look at?
Also, I'm not certain if each of those variables is sampled equally (timewise), not sure if it matters though, as I'd use 1 sec intervals anyways. Even though many of the RESMED signals are subsampled much faster than 1sec, I think the machine only writes synchronized samples out at 1 sec to the card. I also don't see any insp/exp volume on oscar, for your equation (only time)- are they both tidal volume? Are those volume variables available? The breathing signals (zoomed flow rates) honestly look pretty darn smooth, most of the time (second figure is single apnea event and breathing signals surrounding). A lot better than APAP did. Yesterday, had a lot more energy as the day wore on.

@Jay 51, when I went to get my machine I did indeed see a portable SPO2/Capnography device next to a patient bed. So, they are certainly aware of it. Guess my Dr. doesn't believe it's worth looking into. And have a feeling this new device will delay that. I have a feeling if ASV solves it, maybe no reason to look further -- not sure, would have been nice to know for a fact.

@Jay51 and Bhante
If Jay could provide the raw data, I could put together Bhantes signal. Maybe we can all learn from it. But unfortunately, if you are gathering the data from ASV machine, I suspect the hypoventilation would not be present or minimized due to the machine (isn't that one purpose?), Bhante thoughts? Again, it would be great to have a link to show what I should expect to see regarding identifying hypo/hyper/normal behavior.

Now here's something interesting. They insisted large was right nasal pillow size. So last night, I started out with that hissing and sounds like leaking and fighting pressures, after about 20 minutes, I said heck with it, I'm trying medium. Put it on -- all those issues vanished.
It was back like smoothly inhaling exhaling, no leaky sounds - no weird machine forcing me to inhale earlier than I want. On the other hand median TV dropped to 440. Almost as if larger size supported larger air volume and TV -- no evidence though (and I'm sure most vendors would dismiss that conjecture).

Night was still very choppy with awakes (literally hour or two in mid am), but charts all look really good, I think. Still tired this morning. Will see how day goes.  I suspect they never did any overnight remote titration, but let the machine auto titrate by using auto mode. I sure don't see any differences in pressure formula since I turned it on.