AHI of 0.0 is possible and sustainable but takes effort!

[torontoCPAPguy]

viewtopic/t54059/Posting-SCREENSHOTS-as ... sible.html

This is the third night, albeit not in a row, of AHI=0.0
I just wish I could find the original reports to show the newbies what a mess I was in before getting on this forum, getting educated and NOT being afraid to experiment with masks, pressures, adjustments. I was so tired last night that I was asleep when I hit the pillow. No water in the humidifer, dead tired, no mask adjustments, no nothing! And to wake up to this graphic representation was unbelievable.

I attribute my success to finding the right pressure range through experimentation (don't be afraid); the right mask and the right adjustment for low leakage; etc. I KNOW I spent half the night with my face smooshed into the pillow I was so exhausted. The results shown are unbelievable. AHI=0.00

So newbies... it takes time. Educate yourself. Ask questions and persist. Experiment. It is indeed possible to get to AHI=0.00 with perserverence.

[who]

"[An estimated, non-NPSG] AHI of 0.0 [as scored and reported by an S9 home machine] is possible [according to the way AHI is estimated and reported by an S9] and sustainable [for S9 users, according to the way the machine chooses to measure and record its own estimates] but takes effort [, though no more effort than it takes any user of any machine to get good therapy, regardless of how much useful information is, or is not, easily obtainable directly from the screen of the machine chosen by the user]!"

[Velbor]

"[An estimated, non-NPSG] AHI of 0.0 [as scored and reported by an S9 home machine] is possible [according to the way AHI is estimated and reported by an S9] and sustainable [for S9 users, according to the way the machine chooses to measure and record its own estimates] but takes effort [, though no more effort than it takes any user of any machine to get good therapy, regardless of how much useful information is, or is not, easily obtainable directly from the screen of the machine chosen by the user]!"

Nor is an AHI of 0.0 clinically necessary, nor necessarily any better or more desirable than an AHI of 5.0 or perhaps even 10.0.

[torontoCPAPguy]

"[An estimated, non-NPSG] AHI of 0.0 [as scored and reported by an S9 home machine] is possible [according to the way AHI is estimated and reported by an S9] and sustainable [for S9 users, according to the way the machine chooses to measure and record its own estimates] but takes effort [, though no more effort than it takes any user of any machine to get good therapy, regardless of how much useful information is, or is not, easily obtainable directly from the screen of the machine chosen by the user]!"

Nor is an AHI of 0.0 clinically necessary, nor necessarily any better or more desirable than an AHI of 5.0 or perhaps even 10.0.

OK. I'm still learning here. Why would an AHI of 10.0 be more desirable than an AHI of 0.0?
What does non-NPSG mean?
Is the report of the S9 significantly less accurate than other methods of measuring?
Asides from continuous visits to the sleep clinic or MD how would one obtain good therapy without data from one's machine?
Please clarify as I thought that the object of the effort was, in fact, to get one's AHI to as low a level as possible.

Like I say, still learning and going on what I am reading and being told on the forum.

Thanks.

[KC5cychris]

stiring the pot

if you feel good cpapguy, that is what matters. I know I can tell when I wake up if My AHI is higher that 4.0

[needanap]

Congratulations on your 0. I'm still trying, but haven't gotten less than 2. But I think it's amazing how every night can be so different. Some nights I sleep so well, and other nights I yank the thing off around 3 AM, wide awake and trying to quiet my mind. It's been so humid in western NY for weeks, so that's what I'm blaming. Also, those darn hot flashes, although Cpap has slowed them down. Amazing!

[torontoCPAPguy]

Truth is that even with the 0.0's I am not FULLY refreshed but certainly feeling a WHOLE lot better than I was when I was awakening in cold sweats during the night due to hypopneas jacking up my blood pressure in my sleep. And like I say, I'm no MD but I have got to figure that the lower one's AHI the better? Or am I mistaken in that assumption?

[echo]

My opinion is, the lower the better. Even a machine-reported AHI of 10, if accompanied by desats and arousals (which we don't know unless a pulseox or home psg is used), means that once every 6 minutes you are having one or both events, That does sound clinically relevant to me, sorry Velbor.

[deerslayer]

Fortunately i am one of the lucky few that can sleep 8hrs+ without a bathroom break. my normal AHI is under 2 & some times under 1. other than leak data what i concern myself most is not only time in apnea but-- (length of apneas) . Thanks to James Skinner's analyzer software i am able to do so....James you are the man !

[torontoCPAPguy]

My opinion is, the lower the better. Even a machine-reported AHI of 10, if accompanied by desats and arousals (which we don't know unless a pulseox or home psg is used), means that once every 6 minutes you are having one or both events, That does sound clinically relevant to me, sorry Velbor.

This is getting interesting. Desats = blood oxygen saturation low? Arousals due to what? Sorry, just thinking out loud because THAT was pretty much my issue along with OSA. My breathing would get very shallow and I would awaken in a cold sweat.... but are we talking full awakenings or just coming out of L3 or REM? And you are right, of course, these things are indeed clinically relevant and don't show up on the data that the standard S9 Auto (for instance) produces, although the S9 Auto will graph hypopneas. My clusters of hypopneas would directly co-relate to low blood oxygen saturation, which I assume are the desats you refer to. And indeed they would cause 'arousals' albeit generally not full arousals but bringing me out of, or more to the point, preventing me from getting down into L3 and REM sleep. I never had a dream. The machine reported AHI #, viewing apnea and hypopnea events and the other data is valuable IMHO but (of course) does not paint the full picture. We have gone so far as to purchase a recording oximeter and a hospital grade recording blood pressure system (and THAT will for sure wake you up if you put it on automatic.... I used it by leaving the cuff on and connected and simply pressing the button if I awakened at night so that I had SOMETHING to relate to blood oxygen saturation, etc.) All I can tell you is that with an AHI of 0.0, for ME, my SO2 and BP are under control and I am sleeping as well as I have in years. I am wondering out loud if SO2 (blood oxygen saturation) can drop low with the ensuing BP high WITHOUT apnea and hypopnea events taking place? (Of course it can... silly question... emphysema, etc.)

In any event, I agree that desats and arousals are clinically relevant - but am thinking out loud that the lower the AHI the better nontheless and we are dealing with two seperate issues if this is the situation, no?

Thanks for jumping in. Discussion is the best teacher.

[who]

OK. I'm still learning here.

As are we all. And no one here is trying to rain on your parade. You are no doubt getting good therapy. The responses to your fine post are simply an attempt to keep any new ones from panicking, or being discouraged, if their machine counts home-machine-estimated AHI differently from the way your machine does.

Why would an AHI of 10.0 be more desirable than an AHI of 0.0?

That is not quite what Velbor said. The point is that it is possible that a person whose machine is reporting a higher AHI based on the way that person's machine scores events may be getting therapy equal to, or better than, another person using a machine that counts events differently. Neither machine is reporting events with the same accuracy that a nocturnal polysomnography (NPSG) is capable of reporting. Home machines report estimates based on very different ways of labeling events.

Is the report of the S9 significantly less accurate than other methods of measuring?

No. At least, not compared to other home machines. The info from the screen may reach 0.0 on one machine before another model of machine would, in theory. That isn't good or bad on its own. It is just something to be aware of. Numbers cannot be compared between brands at face value, and in this case, between different series of machines within the same brand.

Asides from continuous visits to the sleep clinic or MD how would one obtain good therapy without data from one's machine?

Data is important, and you are using it well. The idea, just as you say, is to get the numbers as low as possible within reason but not to lose sight of how one feels. No one is criticizing your use of data.

ResMed has changed how it reports data. Some prefer the new way; some prefer the old way. Either way, you are to be commended for using the data and taking charge of your therapy to make it as good as possible.

Velbor is known for (among other things) clarifying differences in the ways brands describe the way they report estimates of AHI. So, hopefully ResMed will eventually clarify the specifics of what has changed in how S9s establish a baseline from which it measures changes in breathing that it chooses to label as hypopneas and apneas. Then I hope that Velbor can add that info to his proverbial chart of clarification of home-machine AHI scoring.

[Velbor]

Why would an AHI of 10.0 be more desirable than an AHI of 0.0?

An AHI of 10.0 would not be more desirable than 0.0. My point was that 0.0 is not necessarily a more desirable goal than 10.0. Diagnostic criteria for Sleep Apnea includes an AHI of over 5.0 (or without other symptoms, over 15.0). "Normal" people without sleep apnea have apneic periods, which are simply not clinically significant.

What does non-NPSG mean?

Not certain of the N, but PSG is polysomnogram, the "gold standard". Determination of an apnea or hypopnea involves not only information about airflow, but also blood oxygen saturation (and thoracic and abdominal breathing muscular effort to determine the origin). Home CPAP machines make their determinations based on airflow analysis only.

Is the report of the S9 significantly less accurate than other methods of measuring?

Different machines use different "rules" or "definitions" for airflow-based designations of apnea or hypopnea. With the S9, ResMed reportedly "relaxed" their older and stricter S7 and S8 definitions, in an effort to more closely approximate PSG values (and the numbers produced by competitor machines). It is not "less accurate"; it just follows its own definitions, which are not standardized.

Aside from continuous visits to the sleep clinic or MD how would one obtain good therapy without data from one's machine?

As others have already pointed out, how you feel (with or without standardized metrics such as the Epworth sleepiness scale) is important. But subjective feeling can be misleading, and data (from CPAP, or CPAP with software, and perhaps periodic repeat polysomnograms) is always desirable and often useful.

Please clarify as I thought that the object of the effort was, in fact, to get one's AHI to as low a level as possible.

Yes, that is ONE of the goals. Also important is time in apnea; arguably, long apneas will lower blood oxygenation more significantly than lots of brief apneas, though those may produce more "arousals". Sleep apnea is a multi-factoral condition, and reducing it to a single number is a bit too simplistic. Which brings us back to my objection that while an AHI of 0.0 may be possible and perhaps sustainable, it may not be worth the effort! Velbor

[who]

Velbor, do you have the other half of this amulet?

[torontoCPAPguy]

Fascinating and the best explanation of things that I have read to date. And I had no idea that ResMed had changed their algorithm(s) for calculating AHI, etc. It was my impression all these months that the apnea and hypopnea events and the calculation of AHI were based on solid formulas and data and not something that a manufacturer could simply play with. What an awakening! Thank you. This fits in with the "instantaneous" improvements experienced according to the data presented by the S9 Auto! (Truth is I had a feeling that it might be too good to be true as I am old enough to know that whatever appears too good to be true usually is too good to be true.)

This is more like an uncalibrated torque wrench thing.... where you can see variations in results but the results are not 'finite'.

Now. Where does one get one of these polysomnigraphical thingy's? I don't have one yet.

[jdm2857]

Toronto, if I remember correctly you have a pair of S8 AutoSet IIs sitting around. If you feel up to some experimenting, you could switch back to one of them (set up the same as your S9) and see what results you get. That would yield a bit more enlightenment about the differences between the S8 and S9 AutoSets.