New CPAP user, a few questions

[Steerpike58]

Very nice !
And in case I didn't mention it before, a graphic representation of AHI components can also be seen by selecting the "Overview Tab" on your OSCAR report.

To your question: The home PAP machines do not react to Clear Airway events. In fact, for some people, the pressure applied in reaction to obstructive and hypopnic events may, for some people, increase the frequency of clear airway events. This is called treatment-emergent CSA and seems to occur in 10-15% of the population of folks who are being treated for obstructive apnea by positive pressure CPaP/APaP. You can Google "treatment emergent CSA".

Relative to the efficacy of C/Apap with respect to treating obstructive and near obstructive events, you have to compare against your untreated values (sleep study). That is why it is so important (IMO) that your sleep study results are reliable and representative of your "normal and usual" (untreated) sleep experience.

Hope this helps.

Yeah, I really wish I had more confidence in the original 'sleep study', the results of which I posted earlier - repeated here ...

This was based on only 1 night, with terrible sleep due to unfamiliar heavy device on my wrist / finger, and complete lack of detail! Just one big 'AHI' number, nothing about CA, OA, etc. Looking at it again, it seems they are inferring everything from just Oxygen saturation.

I suppose one could very loosely infer that, if 'total' AHI was 30.3 during the test (untreated), and now we are seeing an average of 10 CAs, that the untreated OA/UA/H number was about 20. And if the OA/UA/H number is now around 4, then we're seeing a reduction in the order of 16 for OA/UA/H due to the CPAP. But that seems like a lot of assumptions!

As an aside, what's the general consensus on devices such as Apple's iWatch, and other mainstream 'monitoring' devices? A couple of recent articles suggest they aren't too bad! https://pubmed.ncbi.nlm.nih.gov/33378539/ and https://www.sleepfoundation.org/best-sleep-trackers are two such articles.

[ozij]

[...] I really wish I had more confidence in the original 'sleep study', the results of which I posted earlier - repeated here ...

This was based on only 1 night, with terrible sleep due to unfamiliar heavy device on my wrist / finger, and complete lack of detail!

Sleep studies are always based on one night, sometimes even a half night. During a PSG you have may devices connected to many parts of your body.

Just one big 'AHI' number, nothing about CA, OA, etc. Looking at it again, it seems they are inferring everything from just Oxygen saturation.

That's an incorrect inference. They're inferring you breathing interruptions from their effect on you peripheral arterial pulse. They are also measuring how these breathing interruptions are correlated to oxygen desaturations. And whether those interruption occur when you're awake or asleep.

I suppose one could very loosely infer that, if 'total' AHI was 30.3 during the test (untreated), and now we are seeing an average of 10 CAs, that the untreated OA/UA/H number was about 20. And if the OA/UA/H number is now around 4, then we're seeing a reduction in the order of 16 for OA/UA/H due to the CPAP. But that seems like a lot of assumptions!

It is. A lot of mathematical assumptions not based on factual reality.
Do you see where it says "Indices are calculated using technically valid seep time of 6 hrs 14 mins"? Unlike a CPAP machine, a WatchPAT does know when you're asleep and when you're awake. It was It was developed for that, and was shown to be sufficiently reliable for that. The total time recording time is reported as 8 hrs 46 mins. Of which -according to this report - you were awake about 25.06% of the time. Breathing irregularities when you're awake are simply not relevant to understanding how you breathe when you're asleep and are not counted. The comment about the oxygen desaturations means: if there's a breathing disruption with an oxygen desaturation of less than 3, we don't count it as an apnea.
Which is not to say breathing interruptions may not drive you out of sleep even if you're not desaturating according to this criterion.
So what your sleep study says is: When you were asleep, you had 30.6 breathing interruptions leading to an oxygen desaturation of 3% or more.

As an aside, what's the general consensus on devices such as Apple's iWatch, and other mainstream 'monitoring' devices? A couple of recent articles suggest they aren't too bad! https://pubmed.ncbi.nlm.nih.gov/33378539/ and https://www.sleepfoundation.org/best-sleep-trackers are two such articles.

Reliable general info can be found in research.

In order to have a valid distinction between Obstructive Apneas and Central Apneas, your sleep study has to be done with chest and abdominal effort belts, in addition to a device that identifies your sleep.

Many of the more recently published papers focus on cheaper ways of identifying and treating sleep apnea. Including a "lets get people on APAP and see what happens".

It used to be people were called into a sleep lab (strange environment) for a full night of monitored sleep and then - if diagnosed with sleep disordered breathing, they were called again for a titration of positive air pressure study. And given a machine based on one night's titration. This was far more expensive that a home sleep study and an APAP. And people complained the didn't sleep well in the lab, the monitoroing devices bothered them.... etc. With a WatchPat, you're at least sleeping in your own bed.

[zonker]

Unlike a CPAP machine, a WatchPAT does know when you're asleep and when you're awake. It was It was developed for that, and was shown to be sufficiently reliable for that.

thank you for teaching me something today.

[Steerpike58]

...Unlike a CPAP machine, a WatchPAT does know when you're asleep and when you're awake. It was It was developed for that, and was shown to be sufficiently reliable for that....

Thanks for your detailed response, which makes a lot of sense. I especially appreciate your insight into the relative costs of different approaches, and why 'give them an APAP to try' makes some sense.

I have just one question about your comment above; I looked up the WatchPat device online, and it comes with a finger sensor and (optionally) a chest (heart?) monitor - a second wire. However, 'my' WatchPAT device didn't have the chest sensor, it only had the finger sensor. So - do you know what you get / don't get with/without the chest sensor component?

My general concern with all this is that I don't seem to have a baseline condition to measure against.

Thanks again.

[ozij]

The sensors for chest and abdomen (don't know if WatchPAT has the latter) are there to sense whether your chest and abdomen are moving when your breathing stops. They are what is needed to distinguish obstructive apneas from central.
When your airway is obstructed, you struggle to breathe - your chest and abdomen are trying to get air into your lungs.
When you simply stop breathing your airway is unobstructed, you don't struggle, your muscles aren't moving.
Resdmed's video: Understanding Sleep Disordered Breathing
I don't know why your WatchPat didn't have that sensor. Maybe, once again a cost issue?

My general concern with all this is that I don't seem to have a baseline condition to measure against.

You do have at least a partial baseline condition to measure against: While you slept, you had slightly more than 30 significant breathing interruptions per hour.
You clearly have sleep disodered breathing that has to treated.

[Steerpike58]

So here's my latest chart. This represents by far the longest contiguous period I've managed to 'sleep' uninterrupted with the CPAP device - 5 hours. Not good, but 'progress' (at around 8am I woke up, went to the bathroom, and then slept through to 10am without the mask).

And here is my home-made chart of progress:

I have no idea what those 'Cheyne Stokes ...' events are; they seem to strike at random every few days. Things seem to have improved since I lowered max pressure down to 12; I'm still getting blow-by into my eyes and hearing 'trumpet' sounds from the chin area occasionally, even after tightening the mask to an uncomfortable level. But I'm not getting much aerophagia. Clearly 'Clear Airway' issues are the most predominant. I'm thinking of turning off EPR again; I tried it just once and hated it, so I'm reluctant to try again but - some suggestions are that EPR can raise CA events. Or maybe I could try reducing EPR to 1?

[Pugsy]

maybe I could try reducing EPR to 1?

Worth trying. Sometimes as little as 1 cm reduction can make dramatic results.
I have a friend who was able to reduce central index (per hour) from 15 to essentially 0 with a 1 cm reduction.

Bear in mind that reducing or eliminating EPR won't help if EPR isn't causing the centrals.

[Steerpike58]

maybe I could try reducing EPR to 1?

Worth trying. Sometimes as little as 1 cm reduction can make dramatic results.
I have a friend who was able to reduce central index (per hour) from 15 to essentially 0 with a 1 cm reduction.

Bear in mind that reducing or eliminating EPR won't help if EPR isn't causing the centrals.

It occurred to me, staring at my excel spreadsheet chart, that it would give the impression that the first week was the best week - after all, the overall AHI was in the 5-10 range for several days, something hardly seen since. However - that's in part because the actual session time (time wearing the mask) was very short, and I was woken during the night several times (so yes, the machine was 'effective' in reducing AHI, but also kept waking me). So I added three more rows to my spreadsheet - Duration, Sessions, and Max Session. Duration is the total time with CPAP; Sessions is the number of distinct periods measured (and correlates to 'wake ups'); max session is the longest single session.
Here's the new chart:

Looking at 'max session' (green row), I can see that not only was last night the longest single session (5:09), but the previous night was the second longest - 4:09. So I think reducing max pressure has been a benefit in terms of allowing me to sleep longer. I think I'll drop EPR to 1 tonight and let that run for a couple of days, and perhaps reduce pressure by 1 more unit after that.

[ozij]

You would benefit from keeping track of your 50% pressure as well.
That's the pressure at which, or above which you spend 50% of your time (statistically known as the median).
When your minimum pressure is too low to keep your airway clear, you have events (including flow limitations) that drive the pressure up.
On your machine, the algorithm only waits 20 minutes for stable breathing before it starts dropping the pressure - the pressure drops too low, it gets driven up quickly - possibly too high, stays there for 20 minutes, and son on. Now you have a roller coaster of changing pressures.

Keeping track of the effect changes have on your median pressure will teach you a lot.

[Steerpike58]

You would benefit from keeping track of your 50% pressure as well.
That's the pressure at which, or above which you spend 50% of your time (statistically known as the median).
When your minimum pressure is too low to keep your airway clear, you have events (including flow limitations) that drive the pressure up.
On your machine, the algorithm only waits 20 minutes for stable breathing before it starts dropping the pressure - the pressure drops too low, it gets driven up quickly - possibly too high, stays there for 20 minutes, and son on. Now you have a roller coaster of changing pressures.

Keeping track of the effect changes have on your median pressure will teach you a lot.

Would that be this measurement, shown in OSCAR:


Generally, I presume there's little downside to increasing the minimum pressure upwards from 8, if I 'feel' ok with it as a 'starting' pressure?

[ozij]

Yes, that's the one.

[Steerpike58]

maybe I could try reducing EPR to 1?

Worth trying. Sometimes as little as 1 cm reduction can make dramatic results.
I have a friend who was able to reduce central index (per hour) from 15 to essentially 0 with a 1 cm reduction.

Bear in mind that reducing or eliminating EPR won't help if EPR isn't causing the centrals.

I reduced EPR from 2 to 1 and it was a disaster; I felt like I couldn't exhale, and I had noticeable aerophagia. My AHI jumped to 26.3, with CA's at 19.17. So - back to 2 it is! Tomorrow I'll up the lower pressure from 8 to 9, based on observations of where the median pressure has been.

[Pugsy]

You know if it were me I wouldn't worry about those centrals until I was damn sure those weren't awake/arousal centrals simply false positives from poor sleep quality.

Now when you can say you sleep soundly all night without any issues and the centrals amount to over 5 per hour......then we maybe have a different discussion.

We gotta get the sleep quality much improved first....then we start worrying about the results we are getting.
If you aren't asleep....it doesn't matter what gets flagged.

I am fairly certain some of your centrals are SWJ sleep/wake/junk false positives....not all of them but some.
Get comfortable and do whatever it takes to get you to sleep and stay asleep.

[Steerpike58]

You know if it were me I wouldn't worry about those centrals until I was damn sure those weren't awake/arousal centrals simply false positives from poor sleep quality.

Now when you can say you sleep soundly all night without any issues and the centrals amount to over 5 per hour......then we maybe have a different discussion.

We gotta get the sleep quality much improved first....then we start worrying about the results we are getting.
If you aren't asleep....it doesn't matter what gets flagged.

I am fairly certain some of your centrals are SWJ sleep/wake/junk false positives....not all of them but some.
Get comfortable and do whatever it takes to get you to sleep and stay asleep.

That sounds great ... I've been wanting to improve my sleep quality for at least 10 years now. I gave up alcohol, gave up caffeine, tried many 'herbal remedies', sleeping pills, etc and nothing seems to work. When I finally had the sleep study last month and embarked on this path (CPAP) I was hopeful but as of now, I'm still not sure what to do next. Specifically with my CPAP, what would you suggest? I'm going to try increasing the min pressure next by 1, but not sure what else to try. I also need to explore a better fitting full-face mask but I don't have my next appointment till the end of the month (they are backed up). I was moderately encouraged by my results two nights ago, with the 'long' (for me) session with the mask. FWIW, I'm skinny (150 lbs) and very active, hiking around 4 miles a day, and I attempt to eat a healthy diet. I recently developed 'nocturia' (night-time peeing) but that's calmed down a bit (I've cut-back on liquids in the evening). I'm not on any recurring meds. Thanks!

[ozij]

I recently developed 'nocturia' (night-time peeing)[...]

One of the know symptoms of sleep apnea...