Pulse Oximeters in CPap machines.

Why have the Pap manufacturers not incorporated a pulse oximetry into home use CPaP machines?

The American Academy of Sleep Medicine ( accrediting society of >11,000 sleep professionals) has a specific guideline for identifying a hypopnea event, specifically:

The recommended hypopnea definition (H3A) in the current version of the AASM Scoring Manual defines a hypopnea in adults based on a ≥ 30% drop in airflow for ≥ 10 seconds associated with an arousal OR a ≥ 3% oxygen desaturation.(May 1, 2022)

It would be difficult for the current machines (e.g. Resmed and Respironics) algorithms to accurately identify arousals (PSG seems to do this by way of EEG monitoring), however it would be very easy for PaP manufactuers to incorporate oximeters, especially wireless, into the machines and subsequently use that information in the algorithms to identify hypopnea events.

It would lead to improved accuracy of HI , or a least be nearly compliant with AASM guides.

Under the current situation (ignoring desaturations) and only using change in air-flow criteria, current Pap devices may well be reporting (or over-reporting) inaccurate results.

dataq1 wrote: ↑

Thu Nov 10, 2022 11:12 pm

Why have the Pap manufacturers not incorporated a pulse oximetry into home use CPaP machines?

The American Academy of Sleep Medicine ( accrediting society of >11,000 sleep professionals) has a specific guideline for identifying a hypopnea event, specifically:

The recommended hypopnea definition (H3A) in the current version of the AASM Scoring Manual defines a hypopnea in adults based on a ≥ 30% drop in airflow for ≥ 10 seconds associated with an arousal OR a ≥ 3% oxygen desaturation.(May 1, 2022)

It would be difficult for the current machines (e.g. Resmed and Respironics) algorithms to accurately identify arousals (PSG seems to do this by way of EEG monitoring), however it would be very easy for PaP manufactuers to incorporate oximeters, especially wireless, into the machines and subsequently use that information in the algorithms to identify hypopnea events.

It would lead to improved accuracy of HI , or a least be nearly compliant with AASM guides.

Under the current situation (ignoring desaturations) and only using change in air-flow criteria, current Pap devices may well be reporting (or over-reporting) inaccurate results.

I see two problems with your idea:

1) Expecting people to remember to put on some kind of wireless oximeter night after night is a bit much. Moreover, what is the machine going to do if/when that oximeter slips out of position and is no longer measuring the O2 saturation correctly? (This happened to me repeatedly on one of my in-lab PSGs, and eventually the sleep tech decided to tape the dang sensor (which was too large) to my finger.

2) If a machine only scores an H if your proposed integrated oximeter scores a corresponding 3% O2 desat, then you will miss all hypopneas that have a ≥ 30% drop in airflow for ≥ 10 seconds which are associated with arousals, but don't have a corresponding O2 desat. In my particular case, that would mean no or almost no hypopneas would be scored for the simple reason that on my diagnostic tests, all my hypopneas were scored because they had a ≥ 30% drop in airflow for ≥ 10 seconds associated with an arousal, but did not have a corresponding desat.

In other words, your proposal to change the way CPAPs score hypopneas would lead to under reporting of the true treated AHI in people who have hypopneas with arousals rather than hypopneas with O2 desats.

And under reporting the true treated AHI could very well lead to people believing their OSA is well managed when in fact it is not.

robysue1 wrote: ↑

Fri Nov 11, 2022 12:51 am

above

Pleased to converse with you about this....

1) Expecting people to remember to put on some kind of wireless oximeter night after night is a bit much. Moreover, what is the machine going to do if/when that oximeter slips out of position and is no longer measuring the O2 saturation correctly? (This happened to me repeatedly on one of my in-lab PSGs, and eventually the sleep tech decided to tape the dang sensor (which was too large) to my finger.

The only expectation would be for those folks who want to utilize an oximetery channel. For those patients who do not want/need to have oximetery feedback there would be no need to strap on the oximeter. (I agree that wired oximeters can be a problem as the wiring tends to get tangled in bed sheets or the pulled out of position. I was recently hospitalized and was being O2 monitored, And as might be anticipated the finger oximeter would fall off. Eventually the night nurse came and replaced it with a oximeter on a strap with no wires at all, and placed it on my wrist like a smart watch. Good to go! - Actually it was that experience that got me thinking about it's application to cpap)

If a machine only scores an H if your proposed integrated oximeter scores a corresponding 3% O2 desat, then you will miss all hypopneas that have a ≥ 30% drop in airflow for ≥ 10 seconds which are associated with arousals, but don't have a corresponding O2 desat. In my particular case, that would mean no or almost no hypopneas would be scored for the simple reason that on my diagnostic tests, all my hypopneas were scored because they had a ≥ 30% drop in airflow for ≥ 10 seconds associated with an arousal, but did not have a corresponding desat.

In other words, your proposal to change the way CPAPs score hypopneas would lead to under reporting of the true treated AHI in people who have hypopneas with arousals rather than hypopneas with O2 desats.

And under reporting the true treated AHI could very well lead to people believing their OSA is well managed when in fact it is not.

That is the crux of the matter. What standard should be applied.... that of the AASM or the equipment manufacturer?

You can be confident that if your sleep study was performed at an accredited lab, it was eventually scored according to AASM standards.
Now, you and I go out and purchase a CPaP machine, they don't score with the same standard. Leaving you and I unable to compare - because we are not using the same "yardsticks" - lab AHI scores and at-home AHI scores.

Which system reports the "true" hypopnea --- it seems to depend on the standard one wishes to employ.


Thanks for your time,

dataq1 wrote: ↑

Fri Nov 11, 2022 10:15 am

That is the crux of the matter. What standard should be applied.... that of the AASM or the equipment manufacturer?

Since it is not reasonable for a CPAP machine to score hypopneas under either of the AASM criteria (H3a or H4) and since both of the AASM criteria require a decrease in airflow that can be measured by the machine, it is reasonable to have the machines score hypopneas using just airflow. The caveat is that the user (or sleep doc) looking at the data from a CPAP needs to understand that the data is a bit "dirty" in the sense that the machine can measure neither O2 desats (without additional equipment) nor arousals. Hence it is reasonable to believe that for most patients, the machine scored AHI will likely include some false "positives"---i.e. things in the breathing pattern that get flagged as Hs (or OAs or CAs) that would not be flagged on an in-lab NPSG. But since a real hypopnea (under either H3a or H4) requires a measurable decrease in airflow, the number of false "negatives"---i.e. real events that are not scored by the machine---should be relatively few and far between. This means the treated "AHI", as reported by the machine, does give you a decent upper bound on the true AHI (as computed on a PSG under either H3a or H4). And if that upper bound is less than 5, then the true AHI is also less than 5.

You can be confident that if your sleep study was performed at an accredited lab, it was eventually scored according to AASM standards.

But the question is still: Which AASM standard was used to score the hypopneas on that PSG that was conducted at an accredited lab?

Medicare demands a 4% desat for a hypopnea to be scored, which is rule H4 in the AASM criteria for scoring a hypopnea. My diagnostic sleep test(s) were both performed in accredited labs. Both labs used H3a, the AASM standard that allows a hypopnea to be scored with an associated arousal, to score my sleep tests and all of my hyponeas were "hyponeas with arousal". So all of my hypopneas on those PSGs do not count if the test is scored using H4, so under H4, my AHI is 3.5 (so Medicare would say I don't need an xPAP). But under H3a, the AASM standard that was used to score both of my diagnostic in-lab PSG sleep studies, my AHI was 23 on the first diagnostic study and 19 on the second. In other words, I have two diagnostic PSG done in accredited labs that were scored by one of the two AASM approved criteria that shows I have moderate OSA and need xPAP. But if those same NPSGs had been scored by the other AASM approved criteria, I would have been told I don't have OSA at all.

And that's a real problem that catches real people. Sure, the vast majority of people undergoing an in-lab NPSG who have at least moderate OSA are likely to have an AHI > 15 regardless of which way the hypopneas are scored. But a few of us will slip through the cracks if hypopneas with arousal are defined as "non-events" because there was no O2 desat.

In other words, the problem is that even the professionals have not agreed on which standard to score hypopneas because the professionals have not yet agreed on whether repeated >= 30% reductions in flow rate with corresponding arousals is as damaging to a person's sleep and health as repeated >= 30% reductions in flow rate with corresponding desats are.

Now, you and I go out and purchase a CPaP machine, they don't score with the same standard. Leaving you and I unable to compare - because we are not using the same "yardsticks" - lab AHI scores and at-home AHI scores.

Because there are two distinct AASM standards for scoring hypopneas, you can't even compare AHI scores from NPSGs done in different accredited labs. As I said before:

• Under H3a, my diagnostic AHIs are 23 and 19 and I have moderate OSA and I get an xPAP.
• Under H4, my diagnostic AHIs are 3.5 and 3.0 and I have no OSA and I don't get an xPAP.

And this is on the exact same set of data: The choice of the AASM standard used to score the hypopneas determines whether I have moderate OSA nor no OSA. And the choice of the AASM standard used to score the hypopneas determines whether my insurance will or will not pay for an xPAP machine.

Which system reports the "true" hypopnea --- it seems to depend on the standard one wishes to employ.

That's true of the two different AASM standards. Which one is a "true" hypopnea? Does a "true" hypopnea require a 4% O2 desat? It does if you are using H4 in order to satisfy Medicare, but it doesn't if your are using H3A because you believe that hypopneas with arousal are as destructive of sleep quality and overall health as hypopneas with O2 desats are.

My point is that since the AASM doesn't even agree on one standard, there's no point in worrying too much about the fact that xPAP machines are likely to overreport all sleep disordered breathing events, including OAs and CAs as well as Hs, simply because an xPAP cannot tell when you are awake and when you are asleep: The AHI numbers off the xPAP are going to give you a good upper bound on the actual number of real (true) events, and if that upper bound for the AHI is below 5, then the real (true) AHI---regardless of whether the hypopneas are scored under H4 or H3a---will also be under 5

I understand what you are saying, but there is ONE recommended standard (H3A) and ONE alternate standard (H4A). Yes?

The major difference between the two (other than the degree of desaturation), is that the H4A standard does not rely on arousals at all.

Since the home machines currently have no reliable method for detecting arousals, the simplest standard for at-home machines to adopt is the H4 standard.

But current at home machines can't really adopt either standard because they lack the capability of detecting any desaturations at all.

BTW, If oximetry were built into at home machines, it could be a simple matter to select the threshold desaturation (3 or 4%) in machine setup.


Relative to Medicare: Medicare (and likely the other insurers) rely on the sleep study results (that maybe either H3 or H4), not the on-going day-to-day home results. Since I'm addressing home results, Medicare position on H4 versus H3 has no bearing.

dataq1 wrote: ↑

Fri Nov 11, 2022 12:42 pm

I understand what you are saying, but there is ONE recommended standard (H3A) and ONE alternate standard (H4A). Yes?

But Medicare, the biggest insurer of folks with OSA does NOT accept standard H4a. And hence standard H4a is still a AASM approved standard for scoring hypopneas. And yes, there are still labs out there that use H4a to score hypopneas on PSGs. And many AASM approved home sleep studies also use H4a to score hypopneas.

You seem to think that somehow the fact that H4a is an "alternate" means it is not a valid standard. But it is still a valid AASM approved standard.

Whether the AASM should push back against Medicare and inform them that in the collective eyes of the AASM, hypopneas scored under H3a are just as significant and just as bad as those scored under H4a and that Medicare ought to accept the collective opinions of the medical experts is another question altogether. But the fact that the AASM has not pushed back on Medicare's insistence that the only hypopneas that count are those with 4% O2 desats means that there are folks in the AASM who either believe H4a is the "right" definition of a hypopnea or there are folks in the AASM who don't really care which definition is used.

The major difference between the two (other than the degree of desaturation), is that the H4A standard does not rely on arousals at all.

And that's my main problem with H4a: If you happen to arouse before the desats happen, under H4a you can wind up being declared as "normal" because none of your hypopneas with arousal (which count under H3a) count under H4a. That's how you get someone like me: Under H3a, I have moderate OSA because my diagnostic PSGs in an accredited labs came up with H3a scored AHIs of 23 and 19. But if those PSGs had been scored under H4a, I would have been diagnosed as not having apnea at all because my H4a scored AHIs would have been 3.5 and 3.0.

In other words, the fact that the AASM still sanctions scoring PSGs under H4a means that there is not yet an overwhelming consensus that hypopneas with arousal (and no O2 desat) are "real" hypopneas that are as serious as those hypopneas scored under H4a.

Since the home machines currently have no reliable method for detecting arousals, the simplest standard for at-home machines to adopt is the H4 standard.

I disagree. Having a home CPAP machine adopt the H4 standard means that if a person's OSA is primarily caused by hyponeas with arousal and the machine's pressure is set too low to prevent those H3a hypopneas with arousal from happening, the person may well wind up with a machine reported AHI = 0.0 night after night, but in reality the number of their H3a hypopneas with arousal remain significantly high because the person actually needs more pressure to treat them than the current pressure settings allow.

And what would happen in that case? The patient can be fully compliant with xPAP, their "treated AHI" would be close to 0 (because they don't have any hypopneas with desats to begin with and the home machine is not scoring them under your scenario), but their real AHI (under H3a) remains essentially unchanged because the machine is not set high enough to prevent the H3a hypopneas with arousal from happening. So the person continues to arouse many, many times for each hour of sleep; their sleep is still badly fragmented; and they still suffer all the daytime symptoms that convinced them to get a sleep test in the first place.

In other words, making a home CPAP machine use standard H4a will result in the machine under reporting the true number of events in every patient who has a significant problem with H3a hypopneas that are scored because of the arousals. That can lead to under treatment of the person's OSA because the machine scored H4a AHI will not score all those H3a hypopneas with arousal that are scored if the machine is using only the wave flow to score hypopneas.

In other words, when a machine uses only the wave flow to score hypopneas, it will count both H4a and H3a hypopneas, along with some false events that occur when the patient is awake.

Using your idea of having a machine use oximeter data to score only H4 hypopneas means the machine will miss every single H3a hypopnea "with arousal" that does not have a corresponding deast. Your idea might eliminate a few false positives---i.e. "scoring non-events as events", but it's going to also create a situation with a heck of a lot of false negatives---i.e. not scoring real hypopneas that would be scored under H3a because the person was asleep, but had an arousal before the desat occurred.

Statistically speaking, over reporting the treated AHI by counting 'non-real' events is better for the patients than under reporting created by routinely not scoring one whole category of event---i.e. not scoring H3a hypopneas with arousal that do not involve an O2 desat.

But current at home machines can't really adopt either standard because they lack the capability of detecting any desaturations at all.

Both standards are based on flow rate. The machines can measure flow rate. By flagging any period of a >=30% reduction in flow that lasts at least 10 seconds as a "hypopnea", every real hypopnea (under either H3a or H4a) will be counted. Yes, there will be some "false positives" thrown in. But that is not just because the oximeter data is missing. Just as important, perhaps more important, the EEG data is missing. The machines cannot tell when we're awake and when we're asleep. So anything that looks like sleep disordered breathing (including OAs and CAs as well as Hs) gets scored---even if we're wide awake with our eyes open.

But that's not a problem: The real treated AHI, based on both oximeter and EEG data, as scored on a PSG in an accredited lab will be less than or equal to the AHI calculated by the machine when it scores events based solely on flow rate. So if the machine's AHI is consistently low enough, we can correctly conclude the real, treated AHI is also low enough.

If you make the machine discount every >=30% flow reduction that lasts for at least 10 seconds just because there is not a corresponding (3% or 4%) O2 desat in a built-in oximeter, then every real 3Ha hypopnea that has an arousal, but no corresponding desat will not be scored by the machine. In other words, for people with a lot of hypopneas with arousal, you wind up under counting the events. And now the machine's AHI is worthless because the machine's AHI could well be a lower bound on the true status of your treated OSA rather than an upper bound. In other words, for people like me, the machine's AHI could be significantly lower than 5 while the real treated AHI might remain virtually unchanged if the pressure is not set sufficiently high enough to keep the hypopneas with arousal (but no desats) from happening while the person is asleep with the mask on your face.

BTW, If oximetry were built into at home machines, it could be a simple matter to select the threshold desaturation (3 or 4%) in machine setup.

That still will lead to a situation where H3a hypopneas with arousal but no corresponding O2 desat are not counted. And that means you are under counting the number of real hypopneas.

Relative to Medicare: Medicare (and likely the other insurers) rely on the sleep study results (that maybe either H3 or H4), not the on-going day-to-day home results. Since I'm addressing home results, Medicare position on H4 versus H3 has no bearing.

And I'm telling you that your ideas would mean that for a person like myself, there would be no way to tell if the machine is treating my apnea. If the only events that the machine flags are "hypopneas with a 3% or 4% (your choice) desat" then every one of my hypopneas that still occur while I'm using the machine would not be counted. In other words, in theory I could have a CPAP reporting an AHI = 0.0 while still having 15-20 hypopneas with arousal per hour. In other words I could have 15-20 places in each hour of sleep where there is A >= 30 reduction in flow for 10 seconds or more with a corresponding arousal, but no O2 desat while using the machine, and your machine would not count a single one of those in its AHI because not a single one of them had an O2 desat of 3%.

robysue1 wrote: ↑

Fri Nov 11, 2022 2:07 pm

above

I can't address all you've written right now, but I did want to clarify the recommended definition versus an acceptable alternative.
See: https://jcsm.aasm.org/doi/10.5664/jcsm. ... %20adults.

I am relying on the definitions (given in Table 1) specifically:

H3a is the Recommended hypopnea definition based on a ≥ 30% reduction in airflow for ≥ 10 seconds associated with a ≥ 3% decrease in the oxygen saturation or an arousal

H4* is the Acceptable hypopnea definition based on a ≥ 30% reduction in airflow for ≥ 10 seconds associated with a ≥ 4% decrease in the oxygen saturation

* - Definition utilized by Medicare

Both definitions rely on desaturation. H3a is an either/or (either desat or arousal).

Going out on a limb, I suspect that AASM is referring to an arousal immediately following a reduction in airflow, rather than an arousal that precedes a reduction in airflow.
The issue there is that some (maybe many arousals) are not respiratory arousals but are called spontaneous arousals. These non-respiratory arousals (mini-awakenings, "Most of us experience mini-awakenings without even noticing them—up to 20 times per hour". - per John Hopkins. This falls into the category of sleep-wake junk.

On the other hand, if you are awakened or aroused (for example gasping) immediately following a reduced air flow epoch, it ought to be reflected in preceding desaturation. YMMV...
good discussion,

dataq1 wrote: ↑

Fri Nov 11, 2022 3:15 pm

I can't address all you've written right now, but I did want to clarify the recommended definition versus an acceptable alternative.
See: https://jcsm.aasm.org/doi/10.5664/jcsm. ... %20adults.

I am relying on the definitions (given in Table 1) specifically:

H3a is the Recommended hypopnea definition based on a ≥ 30% reduction in airflow for ≥ 10 seconds associated with a ≥ 3% decrease in the oxygen saturation or an arousal

H4* is the Acceptable hypopnea definition based on a ≥ 30% reduction in airflow for ≥ 10 seconds associated with a ≥ 4% decrease in the oxygen saturation

* - Definition utilized by Medicare

Both definitions rely on desaturation. H3a is an either/or (either desat or arousal).

As you state, H3a is an EITHER/OR: If either condition is met, a hypopnea will scored. An H3a hypopnea does not require an arousal. Likewise, an H3a hypopnea does not require an O2 desat. It requires one of the the two things to happen.

If a person has a >= 30% reduction in flow for at least 10 seconds AND there is an arousal, then a hypopnea will be scored if the event happens when the person is asleep. Loosely, that's what a "hypopnea with arousal" means---there was an arousal before an O2 desat could occur. And H3a treats these events as real hypopneas even though there is no corresponding desat.

That means H3a does NOT demand an arousal.

H3a does not demand an arousal. H3a also does not demand a 3% O2 desat. H3a demands that either an arousal happens or a 3% O2 desat happens (or both could happen).

In other words, there are three types of events that can be scored as a hypopnea under H3B on a PSG:

1. a >= 30% reduction in flow lasting at least 10 seconds with both a corresponding 3% O2 desat and an EEG arousal.
2. a >= 30% reduction in flow lasting at least 10 seconds with a 3% O2 desat, but without an EEG arousal.
3. a >= 30% reduction in flow lasting at least 10 seconds with an EEG arousal, but without a 3% O2 desat.

Your way of having a home machine score hypopneas would mean no hypopnea in category 3 would be scored. That means for people whose main problem are hypopneas in category 3 would consistently have their hypopneas not flagged by the machine when they occur. That leads to an under count of real events, which is far more significant in terms of determining the efficacy of therapy than counting some false negative events in the total.

And that's why your idea of saying that home machines should use oximeter data that shows a 3% or 4% desat before scoring a hypopnea is simply wrong-headed: Your criteria for home machine scoring of hypopneas means that a whole lot of real hypopneas under H3a that have an arousal, but don't have the O2 desat would not be flagged by the machine as a hypopnea.

I honestly appreciate your feedback, and thankful that we can have this discussion.

I'd like to head off to bed, but perhaps I can clarify something. I did not mean to say or imply, "... your idea of saying that home machines should use oximeter data"... If you took it that way I apologize, for that was not my intent. Rather, I'm suggesting that home machines could use oximeter data, that it would be helpful to provide a bit more clarity to an event, or even oxygen saturation trending throughout a sleep session. The pros and cons of incorporating desaturation in the event algorithm, should be discussed by the experts to arrive at a beneficial consensus - just as you have raised a potential con.

Having said that, perhaps you could clarify for my benefit what a H3B criteria is, as I did not see that in the list of definitions published in the AASM paper.

Meanwhile I'd like to understand how common is a 30% airflow reduction without an desaturation reaction. Perhaps you might know.

off to sleep now.

.
https://imgur.com/a/VNrqWG5

Data and Roby,
Since this thread touches on both oximeter use and arousals, I'll throw in my experience. I use the Wellue ring each night. Initially, I got it because I have a very low heart rate which my doctors say for me it is normal. I go down to 36 numerous times during the month, and regularly I'm below 40. The ring has given me insight into other issues besides AHI, heart rate,and blood saturation. Arousals can be a major problem preventing good sleep for some. I average 17-19 arousals per 7.5 hours of sleep, or about 2.5 per hour, which is considered normal. I would say more than 90% of the arousals I have are caused by movement, shifting position while sleeping. They all tend to follow the same logical sequence, movement, heart rate increase, arousal. Here's a chart from last night. If you follow the green cursor line down to movement, you'll see the sequence I described above. Last night I had 18 of these, 17 being a shift in position and one was spontaneous, ie. the was no movement. None of them woke me up that I know of and I felt like I had a pretty good nights sleep. The more information, the better. There is nothing earth shaking about wearing a ring at night, but it does help explain this and a lot more for me.
Thumper.

How many arousals during sleep is normal?
To state the obvious, spontaneous arousals are arousals not related to respiratory events, limb movements, snoring, etc. If you are over 60 years old you may have as many as 27 arousal per hour. Young and middle aged adults average around 15 arousal per hour.

Home Sleep Test | Jelic Center
https://www.drjelic.com › maxillofacial-procedures › hom..

Thumper1947 wrote: ↑

Sat Nov 12, 2022 7:01 am

If you are over 60 years old you may have as many as 27 arousal per hour.

What does that mean, "you may"?

Cause "normally", "you won't".

Rubicon wrote: ↑

Sat Nov 12, 2022 7:51 am

Thumper1947 wrote: ↑

Sat Nov 12, 2022 7:01 am

If you are over 60 years old you may have as many as 27 arousal per hour.

What does that mean, "you may"?

Cause "normally", "you won't".

@ Rubicon,
within the context of the full statement, I suspect the author is saying that while younger people normally have an average of 15 non-respiratory triggered arousals per hour, that as people age that frequency may increase to "as many as 27 per hour".

That the author is specific in his statement of numbers, suggests that there is some clinical data to establish normalcy for younger patients, as well as some incidental data for patients over 60 (but not enough over 60 data to suggest normalcy for that age cohort.

What is of significance is that the author is specifically referring to non-respiratory triggered arousals.

I have read other researchers that have associated non-respiratory (cortical) arousals with the brain transitioning between sleep stages. If that is accurate, then "normal" sleep patterns (shifting between sleep stages) would give rise to many such arousals in the "normal" sleep session.

Centennial1 wrote: ↑

Sat Nov 12, 2022 10:47 am

That the author is specific in his statement of numbers, suggests that there is some clinical data to establish normalcy for younger patients, as well as some incidental data for patients over 60 (but not enough over 60 data to suggest normalcy for that age cohort.

Great!

Like what?

Cause the "author" (and not really an author, he's some guy selling crap) is tossing out a pretty big meatball saying/suggesting/implying/fabricating that AI 27 is normal in 60+ year old patients.

Rubicon wrote: ↑

Sat Nov 12, 2022 10:57 am

@Rubicon
Actually he is NOT saying that 27 (non-respiration triggered) arousals is "normal", he actually said that "If you are over 60 years old you MAY have as many as 27 arousal per hour" (emphasis added).

I think it's a sure thing that if all cpaps had built-in oximeters,
there would be whole threads discussing how to disable them.
(((Especially if there was a wireless connection involved.)))
[OMG!!! RADIO WAVES!!!
Does anyone recall that LIGHT,
including visible and infrared, are in the EM spectrum?