.

So does this machine speak to what her baseline oxygen saturation is while awake?

A "wild guess" can be made by looking at the periods of high SpO2. In the examples shown, maybe 95%...?

Of course this does not include driving. My SpO2 levels drop while driving longer distances. I actually have higher basal values while sleeping than I did while driving. I have since programed some breathing exercises in while driving to keep my O2 levels from dropping.

NotMuffy wrote: OK, I'll get the "real" waveforms to show the "roundness".

Can you also assess whether hypoventilatory tendencies contributed to any of her downward SpO2 trends?

secret agent girl wrote:If tonight is as bad, I'm not going to wait a week to change something...

If you're considering changing xPAP settings, keep in mind that if you intend to treat CompSAS with CPAP, it takes about a month to equilibrate. CompSAS really hates dial wingin".

TS,

NotMuffy wrote:...your prior S8 DLs really did not show a CompSAS pattern to speak of (AHI was well-controlled, with the exception of a couple days where it drifted up a bit).

the worst of which (and it really wasn't all that bad) was Day 1:



and bears strong resemblance to this Day 1.

TS2, "IMHO" this is (after application of low-level CPAP) entirely a sleep quality issue. Your sleep is bad before CPAP, you have adjusted to that, but now CPAP causes you to lose the delicate balance and you decompensate. At this point there needs to be a 200% effort into sleep hygiene and an attack on insomnia (maybe a little EO won't hurt, but I'd go with Nature's Gift: Lavender, Mandarin, Chamomile, or Sweet Marjoram, or a blend of all four called SleepEase).

-SWS wrote:Can you also assess whether hypoventilatory tendencies contributed to any of her downward SpO2 trends?

On the night of the study, I do not see anything that qualifies as a clinically significant downward trend.

TS3, application of CPAP results in a slight upward trend:




The monitored parameters in this NPSG do not lend themselves to assessment of hypoventilation. There's a thermistor and a PTAF, measuring temperature and flow, respectively. Upon application of CPAP, if an additional channel of volume were added, hypoventilation might be assessed, but the best way to measure that would be ETCO2 or TcpCO2 (since that's what one really wants to know).

TS4, I think that's an excellent point and deserves strong consideration. Body habitus may be a strong contributor. There's probably a low FRC and apnea threshold is easily disturbed.

OK, there's going to be a lot of techno-flash, but let me put this up first, to sort of set the tone (sympathetic tone, to be specific):



SDB can cause 3 potentially harmful things:

• Oxygen levels to drop
• Hemodynamic changes
• Disturbances in sleep continuity

Generally, AHI and leaks get all the press. Desaturations have been coming into play, and sleep quality gets some attention (but nowhere near enough IMO).

However, the concept of sympathetic activation is rarely considered. The above histogram is a bird's eye (1000 second) view on ambient (no CPAP). This demonstrates what heart rate does during SDB events, where there's an accompanying surge with every respiratory event, sometimes 20 BPM.

Try doing some exercise to get your heart rate up 20 BPM and you get the idea of the kind of stress that SDB can place on the cardiovascular system.

And this is not good stress, because it's often done with a low oxygen level.

Besides, this is supposed to be sleeping, not stressing.

And if we look at a trend view of the night:



you can see there's a significant pattern of Heart Rate Variability.

-SWS wrote:

HoseCrusher wrote:Basal SpO2 on this software refers to an average over the whole recording time.

Thanks... Do you know if the desaturated event values are averaged in or excluded from the basal score for this manufacturer?

HoseCrusher wrote:The desaturated events are averaged in.

Thanks again. I hope you don't mind my asking how you arrived at that information for this particular manufacturer. I assume the manufacturer documented " total recording-time average" as "basal" somewhere in literature, or perhaps you examined the data-structures/code?


Here's the reason I ask: The term "basal" most often refers to a "base for comparison". The manufacturer might have better termed what you described as "average SpO2" IMO rather than "basal SpO2"... As if the manufacturer cares what I think.

But in this earlier example "RE SpO2" values correctly do not skew the "base SpO2" values that are employed for medical comparison:

mean of 3 values before onset of RE

In the quote above we have few discrete values versus large-trend data, and thus it becomes numerically important to separate the two entities being compared. Whereas the oximeter manufacturer has a large-trend body of data, in which the sum total of RE values can be comparatively small or even negligible. However, you heuristically estimated roughly a 1% difference in your boxed data-exclusion example above---which exemplifies potential for significant numerical difference between those two data-processing methods.

However, that boxed data-exclusion method does not accurately extract the discrete RE events from the selected data area. Rather that method seems to grossly extract data areas comprised of both RE values and prior-event basal values within each user-defined box. By contrast, SAgirl spent 106 numerically-significant minutes in RE, distributed both inside and outside those four user-defined boxes.

If the term "basal" implies "base for comparison" I think the manufacturer might have more suitably used the term "average SpO2" instead of "basal SpO2". Again, many thanks for your input.

.

secret agent girl wrote: I will make myself be still long enough to get 5? 10? minutes of sitting and lying data. I may have to resort to Reading Fiction do accomplish that. Maybe I can recruit secret agent boy to provide some foot rubbies—do you think that would throw the readings off too much?

I like the fiction-reading and foot rubbies idea. But you can't sit still for more than 5 or 10 minutes of daytime data collection?

secret agent girl wrote:When I first got the CMS-50F, we saw SpO2 levels up to 98 and 99...now, only a few weeks later, neither of us can "make" it go over 95/96. I tried gently wiping out the inside of the finger thing, but it didn't help. How can I double-check that it's giving accurate readings? I'd rather do it sooner than wait until my SS on the 8th, where I would guess I can get them to help me out.

That change from 98/99 to 95/96 in a few weeks suggest that either you or the meter changed. If you are prone to something along the lines of asthma, bronchospasms, hypoventilation then: 1) the pulmonary condition is not necessarily exclusive to sleep, and 2) a 5 or 10 minute foot-rubbies data-collection period during the day might not capture the pulmonary issue. On the other hand, if foot-rubbing tickles--causing hyperventilation---then I think you'll be able to capture THAT pulmonary phenomenon.

THAT said, taking the meter into your doctor's office for a side-by-side comparison sounds like an excellent idea.

secret agent girl wrote:I swear I'm waking up during those early hours and feel myself holding my breath and the machine isn't "pushing" enough for me to take a breath.

Your description above sounds like what I "felt" during my own wake/sleep/wake/sleep central-apnea example I had linked earlier in your thread.

SWS, you and I are on the same page when it comes to a classical definition of basal.

I was able to have a chat with a programmer when I had some difficulties with a CMS-50E unit that was found to be defective. While his "English" was much better than my "Chinese," there was still a lack of understanding on my part. He finally told me to "play" with the .csv file that is generated with each recording and the summary data would become clear.

I ran a simple average on the SpO2 column and came close. I found that when I purged the file of all the 0 values where signal was lost, and then ran an average, I ended up with the exact number that is reported as basal SpO2.

By the way, the difficulty I was having was that upon resuming recording after a brief lost signal episode, the SpO2 values were extremely low, and then would bounce high. I believe there is some smoothing and something like a moving average done over 3 seconds, but it was taking over 2 minutes for the unit to settle down. Now I can understand how the signal can be messed up for a few seconds, but I didn't understand how that would carry over several minutes. I was told that I had a unit with a glitch in the code, and it was replaced. I was also advised to simply discard the data from the loss of signal point to about 1 minute afterward to end up with a more realistic picture of what is going on.

Note that this was not a loss of signal cause by simply pulling your finger out. I was looking at a marginal condition. I pulled my finger out just a little bit, like it was slipping off during sleep, until I was at the point where it was just at the point where signal was lost. When I wiggled my finger, it seems that contact is made and broken several times over a short period of time. Under this condition, the zero's in the moving average cause the value to drop rapidly. I never did get an answer to why the value would shoot up higher than it should, but it appears there is some checking algorithm that causes this.

.

secret agent girl wrote:“TS”
Someone please take pity and tell me what TS means. I get the gist from context, but details are nice, too.

Well what do you think it means?

secret agent girl wrote:“the little squiggly button next to the serial number”
Ah, unfortunately, only the 4 graphs already shown are listed. I suppose “the optional ResLink module” = $$$

Boy, an S9 would be real helpful right about now, but that's water under the bridge.

secret agent girl wrote:““the best way to measure [hypoventilation] would be ETCO2 or TcpCO2”
NotMuffy: Is it worth asking at the sleep lab if they’d do that--That is, would the info be useful to you?

Yes it would. Although CompSAS is largely an entity of hypocapnia (low CO2) perhaps your pCO2 is on the high side and makes your SaO2 a little more unstable than would otherwise be. BTW, a PFT might be helpful to shed light on that.

And once you broach the subject of ETCO2, maybe you could have them consider some enhanced expiratory rebreathing space.

secret agent girl wrote:““At this point there needs to be a 200% effort into sleep hygiene and an attack on insomnia (maybe a little EO won't hurt”
NotMuffy: I’ll check out the EO thing.

Lavender was shown by Goel et al to improve SWS. Use the angustifolia variety.

secret agent girl wrote:For the other two, “SH” and “I”, would Sound Sleep, Sound Mind be a good choice, or do you recommend something else?

I never read Barry. I think we put together a nice hygiene list somewhere for BleepingBeauty (or one/all of the trips).

secret agent girl wrote:Sorry!--and FRC is…?

Functional residual capacity.

secret agent girl wrote:“you can see there's a significant pattern of Heart Rate Variability.”
NotMuffy: Yeah, I see that and it’s kinda worrisome. Do you think it’s all/mostly in response to desats due to hypopneas due to sleep instability?

Respiratory events.

.

secret agent girl wrote:and turned on EPR cuz it felt like too much effort to breathe at the start of the night and I wanted to fall asleep quickly, instead of playing head games with myself and the machine.

I noticed you have EPR set for "full time." If the main reason you want to use EPR is only because of effort to breathe (I assume you mean effort to breathe out, not effort to inhale) when you first start the machine each night, you might try setting EPR for "ramp" only.

That means you'll also have to set a starting pressure for ramp, and a ramp "time" ... the amount of time you want ramp (and EPR during ramp) to be in effect. You'll also need to remember to push the ramp button after the machine starts up if you want to start out the night with EPR's pressure relief when you're exhaling.

If you wake up during the night and the pressure seems difficult (probably won't feel difficult by then) to breathe out against, you can always hit the ramp button to start "ramp with EPR" over again.