Data, at last!

[BleepingBeauty]

If you had a doctor willing to arrange a trial on AutoSV, those heavy apnea clusters are where you would at least hope the SV might normalize CompSAS related respiratory overshoot/undershoot.

I had hope...

You'd experimentally run autoSV applied right on top of that CPAP 12 CM H20 fixed pressure setting. So your doctor thinks an AutoSV experiment in an attempt to normalize those dense apnea clusters is an inherently dangerous experiment?

Apparently.

Let's recap that underlying logic: "It might be dangerous to try and remove those dangerous dense apnea clusters... best to let that kind of danger stand untreated. Besides, they're probably psychosomatic..."

Preachin' to the choir, my friend.

What is your sleeping altitude?

I live at about 4700 feet. First two sleep studies and the most recent one were done in Phoenix at about 1100 feet. Third study, at 5000 feet, was a CPAP titration; fourth study, also at 5000 feet, was an ASV titration - which the tech noted I "tolerated well."

[-SWS]

What is your sleeping altitude?

I live at about 4700 feet. First two sleep studies and the most recent one were done in Phoenix at about 1100 feet. Third study, at 5000 feet, was a CPAP titration; fourth study, also at 5000 feet, was an ASV titration - which the tech noted I "tolerated well."

Well, 4700 feet is pretty high. Allowing her to run nocturnal pulse oximetry for a few nights is probably a good idea (now that I'm done being highly annoyed at her ). If your intermittent problem is related to sleeping and breathing at high altitude, then you're probably experiencing high-altitude periodic breathing.

Sometimes an oxygen bleed addresses that. Other times added CO2 dead space is prescribed (less common). High-altitude periodic breathing is a type of respiratory overshoot/undershoot that servo ventilation can possibly correct as well. So at least it's encouraging that your doctor is willing to investigate whether altitude-related PB is at the heart of your problem. The symptoms of HAPB are pretty much the same as CompSAS---except a CPAP machine is required to differentiate that second case. HAPB can occur at high altitudes even without a CPAP machine, and CompSAS occurs because of a CPAP machine at any given altitude. Periodic breathing---oscillating between respiratory undershoot and overshoot--- can cause central apneas.

The absolute best cure for HAPB is to move to a lower altitude, however.

[ozij]

Bummer, about the doc, as Brenda said.

However, the data has hope in it.
Because if you compare this bad night chart with the first, good night chart, the difference in leak rate is mind boggling -- at least to my mind.

I noticed the higher leak rate (and obviously, the line isn't nearly as flat as it was earlier), but I didn't think it was so much higher that it was of concern. Maybe I'm wrong about that.

The doctor's comment, when looking at my printouts, was "Your leak rate looks fine." (My ex-doctor never once mentioned a high leak rate to me, either, even though the printouts from my auto trials showed leak rates in the 40s and 50s every single night. I never saw those until I was no longer his patient and got copies of my records.)

It's the "before and after" that I find impressive - much more leaky when the AI is a mess.

Quetsion for those with technical knowledge: Can high altitude mess up the machine's ability to compensate for leaks? (A bug, something the didn't thik of?)

I would also consider 12-13 range.

O.

You mean run the machine in true Auto mode, with 12 and 13 as min/max pressures? I'm kinda leery about running in Auto mode with this machine, since I know the Respironics algorithm didn't work well for me during four trial periods (although the range during those trials was much wider than one cm; most recent one ran from 7-14). I certainly respect your opinion, ozij, but I'd love to hear from a few others on this subject (like -SWS, Muffy, rested gal) before I attempt it.

Thanks.

I did mean 12 min 13 max, but actually thought first of 12.5 fixed as an option.

O.

[-SWS]

Can high altitude mess up the machine's ability to compensate for leaks? (A bug, something the didn't thik of?)

High-altitude can skew the detected pressure----albeit with high linearity. But off the top of my head I can't think of leak compensation circuitry itself being significantly skewed at high altitude with any significant degree of non-linearity.

You might recall that Bev also seemed overly sensitive to non-LL leaks in this monstrously long thread:
viewtopic.php?f=1&t=35298&st=0&sk=t&sd=a#p302701

A few patients seem much more inclined than the rest of the population to react disproportionately and adversely to very small stimuli, or perhaps in this case small leaks. I personally feel that's a function of sensitive physiology more than it would be unique machinery-skew---especially if it occurs on multiple machines for any given patient. I dare not use the term chaotic bifurcation, since I got razzed in the monstrous thread above. That's merely what I'm thinking out loud about episodic CompSAS, relative to what just may be very subtle triggers---such as small pressure-altering leaks in this case...

But I definitely think HAPB is a good thing for the doctor to check out.

[BleepingBeauty]

What is your sleeping altitude?

I live at about 4700 feet. First two sleep studies and the most recent one were done in Phoenix at about 1100 feet. Third study, at 5000 feet, was a CPAP titration; fourth study, also at 5000 feet, was an ASV titration - which the tech noted I "tolerated well."

Well, 4700 feet is pretty high. Allowing her to run nocturnal pulse oximetry for a few nights is probably a good idea (now that I'm done being highly annoyed at her ). If your intermittent problem is related to sleeping and breathing at high altitude, then you're probably experiencing high-altitude periodic breathing.

I was pleased that she advocated the oximetry trial. That was one of the questions I was going to ask her yesterday. But if I remember correctly, HAPB was discussed in my other thread; I think the consensus was that it usually occurs at much higher elevations. (Not saying it can't be a factor in my situation, though.) I'll be interested to see what the oximetry reveals, in any event.

Sometimes an oxygen bleed addresses that. Other times added CO2 dead space is prescribed (less common). High-altitude periodic breathing is a type of respiratory overshoot/undershoot that servo ventilation can possibly correct as well. So at least it's encouraging that your doctor is willing to investigate whether altitude-related PB is at the heart of your problem. The symptoms of HAPB are pretty much the same as CompSAS---except a CPAP machine is required to differentiate that second case. HAPB can occur at high altitudes even without a CPAP machine, and CompSAS occurs because of a CPAP machine at any given altitude. Periodic breathing---oscillating between respiratory undershoot and overshoot--- can cause central apneas.

This, I have to confess, I'm not so pleased about. Not that it might help, of course - just the thought of adding oxygen to the CPAP. It means I'll have to deal more often with my DME (which I try to avoid whenever possible), and it makes me feel like I'm falling apart instead of getting better. It's just one more thing to pile onto my treatment, such as it is. I wanna be one of those people who goes on the hose and feels better - if not instantly, then with time. And God knows I've given it a lot of time...

The absolute best cure for HAPB is to move to a lower altitude, however.

Well, if that's the diagnosis, that's what I'll do.

[ozij]

Guess I'll have to look for that term again...
Bev had exceptionally long apneas - but Bleeping Beauty, on two rather leaky recent nights has apneas clusters -- more or less at REM time, so I was thinking that maybe, under her specific altitude conditions, the machine wasn't really supplying enough pressure, despite its compensation ability.
Does that make sense, or do you consider it far fetched?

Of course, we don't know if those are central or obstructive apneas...

...I wonder how many of us are more sensitive to non- Large Leaks, despite what manufacturers say (or think).
I mean, some of us don't don't feel too well at all when our AHI is 4.2, so who's to say the same can't be true for leaks?

O.

[Pugsy]

Well.... I can only offer my meager thoughts for what they are worth. I experience much smaller clusters (compared to yours) and when they occur, I feel like crap. I wouldn't be surprised to find that my O2 levels drop significantly when I have several events back to back. Seeing yours now, I would bet my last dollar that there is a significant drop. I have also noticed that when I have a less than perfect leak (but not grossly huge) I can still get my clusters and they are much more pronounced than when I get the clusters with no leak to speak of.

Maybe your increased leak is just enough to let more events sneak through the door. Maybe a tighter leak rate (like your first nights) keeps the door closed better. It's not like you never had a good night because you had some great nights. Maybe a tiny increase in minimum pressure would allow the machine to compensate a little better when those events try to sneak in while you are working on your end to minimize the leakage. Maybe having a minimum and maximum pressure of 12-13 would give the machine a chance to close the door when needed if the leaks bounce around a bit.

[Pugsy]

Did you change your taping method recently? If so, how does that correlate with the increase in leaks?

[-SWS]

Guess I'll have to look for that term again...
Bev had exceptionally long apneas - but Bleeping Beauty, on two rather leaky recent nights has apneas clusters -- more or less at REM time, so I was thinking that maybe, under her specific altitude conditions, the machine wasn't really supplying enough pressure, despite its compensation ability.
Does that make sense, or do you consider it far fetched?

It does not sound like a far-fetched idea to consider to me, O. Regardless, right now I can't conjure up an explanation of how that can happen in either hard circuitry or algorithm---such that recorded pressure measurement stays so very linear when non-linear leaks are introduced. With only cursory analysis on my part it seems unlikely, though...

...I wonder how many of us are more sensitive to non- Large Leaks, despite what manufacturers say (or think).
I mean, some of us don't don't feel too well at all when our AHI is 4.2, so who's to say the same can't be true for leaks?

I'm convinced that the manufacturers define large leaks with respect to a CPAP machine's ability to effectively compensate pressure delivery. However, we also know that very many message board patients adamantly claim that small leaks disturb their sleep. My own hunch was always that last claim had more to do with sensory-related disturbances rather than briefly transient pressure or blood-gas related disturbances. But in the case of CompSAS inclined patients, I'm not so sure leak-related sensory disturbances are to blame.

Recall that Bev met current CompSAS diagnostic criteria with central emergence here:
viewtopic.php?f=1&t=35298&p=306443&#p306443

Long apneas were, indeed, a facet of her SDB presentation.

HAPB was discussed in my other thread; I think the consensus was that it usually occurs at much higher elevations. (Not saying it can't be a factor in my situation, though.) I'll be interested to see what the oximetry reveals, in any event.

I agree that HAPB usually occurs at even higher altitudes. Epidemiology in general tends to reveal bell-curve distributions across the population, however. And a typical bell-curve distribution probably means that some patients will start manifesting HAPB at nearly a mile high (your 4700 feet) versus most HAPB patients exclusively manifesting HAPB at higher altitudes.

BB, unfortunately you're in the realm of medical unlikelihood either way: episodic CompSAS or HAPB. And either way, I would at least want to trial the AutoSV in an attempt to normalize those episodes of dysregulation---whether they are episodically related to CompSAS or HAPB. The auto/adaptive servo-ventilation design endeavors to counteract oscillating respiratory overshoot and undershoot that manifests as periodic breathing and even central apneas/hyponeas.

Below is an example of the BiPAP autoSV running in CPAP mode until period breathing occurs. Then straight CPAP modality is automatically abandoned as the machine's IPAP delivery fluctuates, on-demand, to compensate for that respiratory undershoot and overshoot:

[ozij]

Pugsy, Good catch!
Very good point -- and BB did:

viewtopic/p381574/Tape-Question.html#p381574

I was just reading this post and thinking that no way would a free corner work for me - I'd have air rushing out in a minute; Have had, actually, when the tape worked off a bit.

O.

[BleepingBeauty]

Did you change your taping method recently? If so, how does that correlate with the increase in leaks?

Yes, and no. I wasn't taping previously. I was using my chinstrap (as I've been for the past seven months). I started taping night before last, with Catnap's posted method, and it's working for me. Can't say it's better or worse than what I was experiencing, leak-wise, with the chinstrap; overall, it's about the same. But it's more comfortable in the hotter weather than wearing the chinstrap.

The higher leak rates occurred while still using my chinstrap. The past two nights, using the X taping method, my leak rate has been 38.41 and 37.39; AHI has been 8.8 and 8.5 (far lower than the 24.0, 14.7 and 14.8 the three nights prior).

[BleepingBeauty]

I agree that HAPB usually occurs at even higher altitudes. Epidemiology in general tends to reveal bell-curve distributions across the population, however. And a typical bell-curve distribution probably means that some patients will start manifesting HAPB at nearly a mile high (your 4700 feet) versus most HAPB patients exclusively manifesting HAPB at higher altitudes.

BB, unfortunately you're in the realm of medical unlikelihood either way: episodic CompSAS or HAPB. And either way, I would at least want to trial the AutoSV in an attempt to normalize those episodes of dysregulation---whether they are episodically related to CompSAS or HAPB. The auto/adaptive servo-ventilation design endeavors to counteract oscillating respiratory overshoot and undershoot that manifests as periodic breathing and even central apneas/hyponeas.

So would I. But what I can I do if the doctor doesn't see the problem and won't prescribe it for me?

Below is an example of the BiPAP autoSV running in CPAP mode until period breathing occurs. Then straight CPAP modality is automatically abandoned as the machine's IPAP delivery fluctuates, on-demand, to compensate for that respiratory undershoot and overshoot:

FWIW, that flow graph looks much like what I saw on the raw data from my May sleep study that I was shown yesterday. Seemed to indicate that my breathing was even and steady, which is why the doctor is not convinced I have CompSAS.

[jules]

An analysis of the raw data might be fruitful. I know I don't know exactly what to look for but I know Muffy does.

I suspect the software is alternating between apnea and leak --- it will pick what it thinks is worse (well maybe Respironics programmed it that way but who knows) It won't show both events simultaneously in the raw data but when you look at the output, you have to remember that there are many readings that are lumped together in the graphs.

It is a matter of resolution - how many pixels wide the graphs is versus how many data points are being represented. The graphs are coping trends not minute by minute changes in the situation.

I suspect leaks are triggering all of this.

Are you using any kind of flex? I recently turned mine off at gumby's suggestion and have gotten a lot of my pockets of apneas (I get these too and could post some equally bad reports) to disappear. I don't know if this will last however.

[-SWS]

Seemed to indicate that my breathing was even and steady, which is why the doctor is not convinced I have CompSAS.

Well, what the doctor saw during the NPSG was probably exactly what she would have seen all those nights when your home-recorded AHI was around 2 or less.

However, your flow patterns during those home-recorded nights with unacceptable AHI spikes---and specifically during those very dense apnea clusters---are what the good doctor did NOT manage to see. As far as she's concerned, I don't have trigeminal neuralgia flareups either---since I am 100% symptom free at the moment.

Needless to say I'm damn glad she's not my neurologist.

[BleepingBeauty]

I suspect leaks are triggering all of this.

Are you using any kind of flex? I recently turned mine off at gumby's suggestion and have gotten a lot of my pockets of apneas (I get these too and could post some equally bad reports) to disappear. I don't know if this will last however.

No, I turned off the C-Flex completely on my old machine (it had been set on 3) about a month ago, and I haven't used either C-Flex or A-Flex on the new machine at all.