Unclassified apneas

[nativedancer]

Don't mean to flail a dead horse, but I have considerable sinus drainage at night, and when I snort it back into my throat, perhaps that could account for the UA's and Hypops that appear on SH.

[eseedhouse]

Don't mean to flail a dead horse, but I have considerable sinus drainage at night, and when I snort it back into my throat, perhaps that could account for the UA's and Hypops that appear on SH.

Probably not unless your snort lasts for at least 10 seconds. Might be interpreted as a snore or a flow limitation in which case if you have an auto machine the pressure might go up. But it's not part of your AHI unless it lasts at least 10 seconds.

[nativedancer]

That's the problem: these apneas are neither CA nor OA, so what are they? Can we even define them as AHI?

[MobileBasset]

It seems as though your interest is high with respect to these UA events. Have you thought of looking at your data using ResScan in order to verify the ResMed display interpretation of them?

The Sleepyhead data seems to not show a correspondence with the definition of UA in the ResMed data management guide link posted in an earlier message. By that I mean the ResMed definition says a UA is registered during a large leak when the machine's ability to differentiate between a central and obstructive apnea is degraded, yet the Sleepyhead data does not show enough large leaks to account for your 42 UA.

How do you feel with all this going on? Your oxygen is very good, your CAs (and OAs) are zero on this night so it seems you are getting therapy. Do you think the events are disturbing your sleep, or is your interest purely academic?

[nativedancer]

Fairly academic, I guess. I just wonder what's going on. I do get plenty of rest, and don't have to get up much during the night, and most days I feel pretty good. And the Dr doesn't seem concerned. SH is sometimes an embarrassment of riches, eh?

[nativedancer]

I'm going to close the book on this unless and until I can discover a more useful method or pathway to examine the problem. Thanks, y'all. Maybe someday...

[PaytonA]

You might try asking Resmed if your VPAP st reports only UAs and if so, why.

[TyroneShoes]

That's the problem: these apneas are neither CA nor OA, so what are they? Can we even define them as AHI?

Well, no, I don't think we can. The classic definition of AHI is a summary index of the OA index, the CA index, and the hypop index. Some of the machines that are a bit beyond classic xPAP might want to include undefined or minor events in AHI, but I think that just muddies the waters, because then we have varying definitions, which is never good. Blurred lines.

RDI gets a pass, because RDI is essentially AHI plus an arousal index. That is helpful, more sophisticated than simple AHI, and not really much more difficult to understand. And it has a different name, as it should.

But we can't ignore these events either. I say take AHI for what it is worth (which isn't really all that much other than a general indicator), and if we want to take things up a level and deal with the more complicated combined apnea, or undefined apnea, or apneas shorter than 10 seconds (lots of those would still give me concerns even though AHI doesn't include them), then find a different way to measure and track that which has a different name so as to not be confused with what we consider AHI to be.

Its kind of like apneas are like states; official, with their own recognizable boundaries and laws, and all of these events in the nether region are still like unformed nascent territories, or provinces, where the understanding and the boundaries and rules aren't fully baked or even commonly understood yet.

After all, it is never black and white. An OA event is often not completely only OA, a CA event is often not completely just CA, and sometimes both things can happen at the same time. A combined event. But an xPAP can't really be that smart when reporting just AHI, because AHI sees these events as distinct, black and white events. The PSG study also has trouble determining just what category each event falls into, as well. It is what it is.

What is important is the question about whether an undefined event or an event that is too short to be flagged an apnea is medically problematic or not. That is the question I would like to see answered.

[PaytonA]

That's the problem: these apneas are neither CA nor OA, so what are they? Can we even define them as AHI?

Well, no, I don't think we can. The classic definition of AHI is a summary index of the OA index, the CA index, and the hypop index. Some of the machines that are a bit beyond classic xPAP might want to include undefined or minor events in AHI, but I think that just muddies the waters, because then we have varying definitions, which is never good. Blurred lines.

I must respectfully disagree. The "classic" definition of AHI is the number of apneas and hypopneas divided by the amount of time slept. It does not depend on being able to determine which type of apnea it is. As such, it seems to me, that the unclassified apneas *do* belong in the AHI and should be considered the same level of importance as any other apnea. It is just that we are left adrift considering how they should be treated.

Best Regards,

PaytonA

[DeepBreathing]

I agree with Payton on this. The AHI is the index of all apneas and hypopneas. Otherwise the AHI reading would be artificially low when the machine has problems identifying which is which. These are most definitely apneas, and of reasonably long duration. I've attached a blow up of part of Native Dancer's initial screen shot. There is no airflow for nearly a minute - that is an apnea, regardless of how it is classified.

[attachment=1584]

I go back to what I said in post #14 - it's likely that your machine does not attempt to classsify apneas. Some VPAPs (certainly the Adapt and quite possibly yours as well) don't have the FOT facility used to classify apneas. The backup rate kicks in to prevent central apneas, so by elimination any which still occur must be obstructive. I am pretty confident what you are seeing here are obstructive apneas and hypopneas. The only way to treat these is to raise the pressure.

If you raise your EPAP a couple of points, I think you will see a reduction in these apneas.