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00:59 AHI = 40.0; at 01:00 AHI = 1.0
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PsychoMike Offline

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Post: #11
RE: 00:59 AHI = 40.0; at 01:00 AHI = 1.0
The chart that shows the drop is the "instantaneous" AHI/hr chart, not your overall AHI number. In ResScan it can be quite confusing. Sleepster's analogy for the car speed is quite appropriate....in the hour from 00:00-00:59 you had 40 events, in the 01:00-01:59 you had one...your AHI "speed" for the 1st hour is 40, your AHI "speed" in the second hour is only 1. Your average/overall AHI "speed" looks like it will be somewhere <10.

The chart isn't useless, but it doesn't give a good overall picture. It is saying that during the period from 00:00-00:59, your apnea is not being controlled well at all....you're having some pretty big apnea event and lots of them. The rest of the time it seems to be pretty well controlled. Perhaps in that stage of sleep, you're more prone to apnea events and the current set-up you are using (constant pressure at 14 cm H2O) is not dealing with them well.

I would suggest that if you are having many of those 40 event / hr hours, then perhaps you need something that will bump the pressure for you to help control them better (Autoset, perhaps)....your pressure graph looks like you are running in a constant pressure mode. Something to definitely discuss with your DME or sleep doc.
(This post was last modified: 07-06-2014 05:44 PM by PsychoMike.)
07-06-2014 05:44 PM
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justMongo Offline

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Post: #12
RE: 00:59 AHI = 40.0; at 01:00 AHI = 1.0
As discussed here, AHI is convoluted. By definition, AHI is the average apnea-hypoapnea per hour. It really only has meaning when the sum of all events for a nights sleep are divided by the hours slept. That AHI plotted versus time is nonsense in my opinion.

As for the graphs presented in the OP -- you're way off from optimal therapy. That huge cluster is scored as OA and correlates with flow limitation. In my amateur opinion, you need more pressure. Again IMO -- you would be well served with an auto machine.

INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
07-06-2014 05:48 PM
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zonk Offline

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Post: #13
RE: 00:59 AHI = 40.0; at 01:00 AHI = 1.0
(07-06-2014 05:20 PM)jcarerra Wrote:  Is it a point here that my data as shown is incorrect?
(I don't mean is "awful," but 'that it cannot be that way period.')
If this is a pattern, you,re advised to see your sleep doctor, the doc knows your medical history and can devise the best treatment options for you

Edit: with so many events, you might want consider getting an oximeter
(This post was last modified: 07-06-2014 06:07 PM by zonk.)
07-06-2014 06:03 PM
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jcarerra Offline

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Post: #14
RE: 00:59 AHI = 40.0; at 01:00 AHI = 1.0
Well, that was informative and very helpful. I see my error--that I did not even know there was such a thing as "hourly" AHI. I simply had the impression that AHI was a total number of events divided by the total time.

Indeed , I had argued elsewhere that a whole night's overall AHI as reported by the machine and widely used--could be a satisfactory number even though there were extremely bad periods that needed to e "looked at" but were 'hidden' in the night-long AHI average. So... looking at the night's overall AHI could be misleading.

I stand by that...as I have nights where overall average AHI is reported at satisfactory level near or under 5, yet I have a 45min to hour cluster (not usually as bad as the one shown, but "bad)." And if one were to look at the AHI number, one could conclude "your therapy is working OK."

But you have clarified that the graph is plotting an HOURLY "AHI" which is not an average at all but simply a sequence of single hour values.

Oh, I have an oximeter CMS D50 Plus, and have finally gotten the data to import. Lowest number was 84, Avg low 93.4.
(This post was last modified: 07-06-2014 06:44 PM by jcarerra.)
07-06-2014 06:41 PM
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Sleepster Offline
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Post: #15
RE: 00:59 AHI = 40.0; at 01:00 AHI = 1.0
(07-06-2014 05:31 PM)vsheline Wrote:  The hourly AHI is a running accumulation of the total number of As and Hs since the beginning of the hour. The hourly total gets reset to zero at the beginning of each hour.

Wow! That's a pretty lame way of doing it. I think SleepyHead calculates it differently.

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INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
07-06-2014 07:12 PM
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archangle Offline
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Post: #16
RE: 00:59 AHI = 40.0; at 01:00 AHI = 1.0
Gee, I never noticed ResScan did it that way. That's lame. SleepyHead displays a running total over the past hour.

"Real" AHI as used in treatment is usually the nightly average apnea/hypopneas per hour over your sleep time. "Hourly" AHI is less useful in general, but has some uses. "Hourly AHI" as they show it there is sort of only useful at the last reading within the clock hour. i.e. the 11:59, 12:59, 01:59, etc. readings. The way SleepyHead does it is better, but "THE" AHI reading of interest is still mostly the nightly average.

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07-07-2014 06:40 AM
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jcarerra Offline

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Post: #17
RE: 00:59 AHI = 40.0; at 01:00 AHI = 1.0
(07-07-2014 06:40 AM)archangle Wrote:  ..."Real" AHI as used in treatment is usually the nightly average apnea/hypopneas per hour over your sleep time. "Hourly" AHI is less useful in general, but has some uses. "Hourly AHI" as they show it there is sort of only useful at the last reading within the clock hour. i.e. the 11:59, 12:59, 01:59, etc. readings. The way SleepyHead does it is better, but "THE" AHI reading of interest is still mostly the nightly average.

"THE" AHI ...

You sleep 8 hours.
From 3-4am, you have 40 events.
none the rest of the night.

Your "THE" AHI is 40/8 = 5.0

So, "you're OK."

I say NO!!! you are not ok, even though your AHI says you are. I say that those 40 during one hour are a problem that needs to be looked at--but the AHI average HIDES the fact that there is a problem.

This is not some far-out scenario that never happens;
it exactly describes what often happens with me.
07-07-2014 07:53 AM
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archangle Offline
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Post: #18
RE: 00:59 AHI = 40.0; at 01:00 AHI = 1.0
(07-07-2014 07:53 AM)jcarerra Wrote:  "THE" AHI ...

You sleep 8 hours.
From 3-4am, you have 40 events.
none the rest of the night.

Your "THE" AHI is 40/8 = 5.0

So, "you're OK."

I say NO!!! you are not ok, even though your AHI says you are. I say that those 40 during one hour are a problem that needs to be looked at--but the AHI average HIDES the fact that there is a problem.

This is not some far-out scenario that never happens;
it exactly describes what often happens with me.

It's "THE" AHI in terms of the way the medical community seems to look at it. I won't say it's right, but there's some degree of sense in that idea. The cumulative effect of one hour of 40 AHI may be roughly equivalent to the cumulative effect of 4 hours of 10AHI.

However, AHI is a bit of a rule of thumb anyway. AHI doesn't take into account the duration or completeness of the apnea. An 11 second apnea counts the same as a 120 second apnea, but I'll bet the effects on your body are more severe for the later.

AHI is sort of a quick and dirty look. Proper treatment often requires a more in depth look. Unfortunately, many doctors only look at AHI. Heck lots of them only look at 4 hours a night usage.

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07-07-2014 08:23 AM
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justMongo Offline

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Post: #19
RE: 00:59 AHI = 40.0; at 01:00 AHI = 1.0
(07-07-2014 07:53 AM)jcarerra Wrote:  "THE" AHI ...

You sleep 8 hours.
From 3-4am, you have 40 events.
none the rest of the night.

Your "THE" AHI is 40/8 = 5.0

So, "you're OK."

I say NO!!! you are not ok, even though your AHI says you are. I say that those 40 during one hour are a problem that needs to be looked at--but the AHI average HIDES the fact that there is a problem.

This is not some far-out scenario that never happens;
it exactly describes what often happens with me.

that's why we read our data -- because AHI isn't the full picture.

INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
07-07-2014 10:45 AM
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robysue Offline
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Post: #20
RE: 00:59 AHI = 40.0; at 01:00 AHI = 1.0
(07-07-2014 07:53 AM)jcarerra Wrote:  
(07-07-2014 06:40 AM)archangle Wrote:  ..."Real" AHI as used in treatment is usually the nightly average apnea/hypopneas per hour over your sleep time. "Hourly" AHI is less useful in general, but has some uses. "Hourly AHI" as they show it there is sort of only useful at the last reading within the clock hour. i.e. the 11:59, 12:59, 01:59, etc. readings. The way SleepyHead does it is better, but "THE" AHI reading of interest is still mostly the nightly average.

"THE" AHI ...

You sleep 8 hours.
From 3-4am, you have 40 events.
none the rest of the night.

Your "THE" AHI is 40/8 = 5.0

So, "you're OK."

I say NO!!! you are not ok, even though your AHI says you are. I say that those 40 during one hour are a problem that needs to be looked at--but the AHI average HIDES the fact that there is a problem.

This is not some far-out scenario that never happens;
it exactly describes what often happens with me.
As with many things, outlier data can do all kinds of interesting things.

So to revisit in the scenario posted: An 8-hour night of sleep with 40 events that all occur in 1-hour.

Yes, the overall AHI = 5 (borderline "ok") and but the "AHI for 3-4 am" is 40 (way bad). But the person also GOT 7 hours of presumably high quality sleep both before and after the bad hour on this bad night, so it's not like the person has a AHI = 40 for the whole night either: A person who's diagnostic AHI = 40 is getting 8 hours sleep with an average of 40 events/hour, or 320 events all night long. And no good sleep.

And so an important question to ask when dealing with really nasty clusters of events is: Does this kind of a pattern occur rarely or frequently?

If this 40-event hour is the only bad hour in a month of PAPing, it's not really all that important: Almost all the sleep is good-to-excellent and PAP is working at its current settings.

But hour-long clusters of 30+ events occur on several nights every week for a month or more, that does indicate that something's not working as well as it should.

And jcarerra writes:
Quote:This is not some far-out scenario that never happens;
it exactly describes what often happens with me
So clearly jcarrea should be more worried about this kind of a cluster than I am: I've had a few clusters of 20+ events in 3 1/2 years of PAP, and they're well separated in time and are usually connected to the flu. Jcarrea, on the other hand sees enough of these clusters to say they often happen to him.

In my case, there's no point in bringing in Daily data that shows one of these clusters and asking: What's wrong? What should we do about this?

In Jcarrea's case, I think it's critically important to bring in a hard copy of several days of data that show this kind of cluster and directly ask the doc: What's wrong? What should we do about this?

But I don't think it is reasonable to expect a doc to automatically look beyond the overall long term AHI if the patient is not making some effort to indicate there's something wrong.

The main reason sleep docs focus on the overall, long term AHI is simply time: It's just plain too much trouble to go digging into the nightly data for the dozens of patients you see each day or the hundreds you see each month. So looking at one basic number (AHI) is a bit of a survival technique: It lets you get patients in and out more quickly. I'm not saying I agree with this rationale, but I do acknowledge that it's an important reason that docs are a lot less interested in our data than we are.

But there's another more valid reason for focusing on the long term AHI for the typical OSA patient: We're all going to have some good nights and some bad nights. And a few very bad nights. But a few bad nights here and there is NOT usually an indication that something is "wrong" and must be fixed. In other words, if we're getting enough apnea-free sleep on the vast majority of nights, there's not much that tweaking of the PAP settings can do in terms of addressing continuing patient complaints of daytime fatigue and sleepiness. Not all bad sleep is related to OSA and non-optimal PAP therapy.

But again, in Jcarrea's case, the clusters are not confined to a few bad nights "here and there", and so it's worth hitting the doc over the head with the Detailed Daily data and bringing up the issue of what to do to fix the problem.

Final note: I'm not a big advocate of simply telling people like jcarrea: The data says you need to increase your pressure. Hour long clusters of events are NOT common once someone is on PAP. REM-cycles don't last that long. And when the clusters of events really do last 30-60 minutes or more each night, there's a real possibility that part of the problem may be pressure-induce centrals even if the machine scored events are labeled as Hs or OAs. And teasing apart PAPers who are having pressure-induced unstable breathing and centrals from PAPers who just are inadequately titrated and need more pressure is beyond my expertise as a knowledgeable patient.

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07-07-2014 11:19 AM
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