Central or Obstructive Apnea

Hi,

I am new to this forum and thank you for this wonderful opportunity to share experiences and knowledge on sleep apnea.

I was diagnosed with OSA around 3 months ago. My sleep test result was AHI = 26. There is no significant difference with respect to sleep position, i.e. my AHI does not decrease when I sleep on my side. I purchased a ResMed S9 Autoset with a nasal mask and have been consistently using it for around 2 months. I still have extreme difficulty in waking up in the morning and I still feel very tired when I wake up. But my daytime sleepiness has slightly improved.

I just discovered that I can get a detailed sleep report by pressing the info button and double check button of my S9 CPAP simultaneously; and I am suprised with the report I got. Here is the summary of the report (I am translating from Turkish so there might be slight difference in the terms):

Days: 25/30
Days>1 hour: 24/30
Average Usage: 6.8 hours
Hours Used: 170.7 hours
Pressure: 7.8
Leakage: 7 L/min.
AHI: 3.4
Total AI: 3.2
Central AI: 3.1

This means that out of 3.2 total AI, 3.1 is Central and only 0.1 is Obstructive. This is very confusing to me, as I was diagnosed with obstructive sleep apnea, not central. So, should I be using a BIPAP instead of CPAP? Is there a mistake with my diagnosis? Any comments would be greatly appreciated.

Thank you in advance..

CPAP pressure tends to be a plus factor for respiratory control system gain. Now data from a CPAP cannot actually discern the difference between an obstructive or central apnea as they have only the flow data and “pressure pulse” testing results to work with. Nonetheless it is possible that you are having some PAP induced central apneas.

So what to do to lower the respiratory control system gain:

1. Check your vitamin D3 levels and correct if below 50 or above 80. See The Vitamin D Counsel for details as to the proper assay. D3 just tends to make the respiratory control system run better.

2. Try to lessen the stress in your life. Stress is another “gain factor” where the respiratory control system is concerned.

3. Pursue metabolic health. If your cells work better everything works better. This means learning to eat well and move well. Dietitian, personal trainer, three years or so. As you move toward an active lifestyle I do believe you will find your respiratory control systems working better along with a whole bunch of other things as well.

opinio wrote:Hi,

I am new to this forum and thank you for this wonderful opportunity to share experiences and knowledge on sleep apnea.

I was diagnosed with OSA around 3 months ago. My sleep test result was AHI = 26. There is no significant difference with respect to sleep position, i.e. my AHI does not decrease when I sleep on my side. I purchased a ResMed S9 Autoset with a nasal mask and have been consistently using it for around 2 months. I still have extreme difficulty in waking up in the morning and I still feel very tired when I wake up. But my daytime sleepiness has slightly improved.

I just discovered that I can get a detailed sleep report by pressing the info button and double check button of my S9 CPAP simultaneously; and I am suprised with the report I got. Here is the summary of the report (I am translating from Turkish so there might be slight difference in the terms):

Days: 25/30
Days>1 hour: 24/30
Average Usage: 6.8 hours
Hours Used: 170.7 hours
Pressure: 7.8
Leakage: 7 L/min.
AHI: 3.4
Total AI: 3.2
Central AI: 3.1

This means that out of 3.2 total AI, 3.1 is Central and only 0.1 is Obstructive. This is very confusing to me, as I was diagnosed with obstructive sleep apnea, not central. So, should I be using a BIPAP instead of CPAP? Is there a mistake with my diagnosis? Any comments would be greatly appreciated.

Thank you in advance..

Almost everyone gets CAs. These are clear air apneas vs obstructive. They can occure when you are partially awake and hold your breath when you are restless in bed. Unless you have large numbers of CAs bunched together, you do not have Central Apnea.

Good diet, moderate exercise on a frequent basis, excellent sleep hygiene - these all help. Google "sleep hygiene" and read a few articles from established sources. Maybe cut out all caffeine (even chocolate) for ninety days and see how you feel.

It's also good to download the software and look at the timeline of the night. You can see how long your apneas are and at what times of night they occur. Long apneas and apneas occurring in bunches are of more concern. But the summary statistics you posted indicate relatively good CPAP therapy. That you are feeling poorly may have to do with items in my first paragraph.

The manufacturer's software is here - http://storage.resmed.com/software/ress ... an_4.3.exe

When you have time you might take a look at this little tutorial. While it is explaining software reporting terms...data is data no matter which machine or which software and I think I hit on centrals just a bit in the tutorial.
understanding your data viewtopic/t88983/Pugsys-PointersSleepyH ... nding.html

Some centrals is just part of normal nighttime sleep. It's normal to have what we call sleep onset centrals during sleep stage transition. It's normal to have an occasional central during the night.
Often the machine will flag awake/semi awake breathing irregularities as some sort of apnea event because the machine doesn't know if we are asleep or awake. Awake breathing is much more irregular than asleep breathing so the machine often will flag pauses in breathing while awake as some sort of apnea event and central flags are common.

Even if the centrals were all the real deal and not awake breathing by mistake flags...2 or 3 per hour isn't enough to get a central apnea diagnosis.
Use the software (links in my signature line) to see if you can spot some sort of pattern to the centrals. The LCD machine is just giving you an overall hourly average. For all we know you could have the bulk of them in the first hour and not much of any others the rest of the night...when that happens awake breathing is highly suspect.
So there's more to evaluating what is going on than just looking at an hourly average. Need to look at the software reports to get a clearer picture of what happens during the night.

I once woke up in the middle of the night with extreme nausea...lay there in bed thinking "do I need to make a mad dash to the bathroom to throw up or not"....well, I didn't make a mad dash and I just lay there for about 45 minutes fighting the nausea and eventually it went away and I fell back asleep. When I looked at that report....I had 45 minutes with a lot of central flags. Like 1 every 2 minutes...just for that time frame and I know I was awake. They stopped when I went back to sleep. It made my overall hourly average for the night a bit elevated for the central index...but it really wasn't any thing to be concerned about because I know I was awake during that time frame.

The reason that you see a small number of OSA's is that the ones that you see in your data are the ones not prevented by your cpap machine. Hard to say how many were prevented *smile*, since they didn't happen.

As far as centrals go, I'm in a similar position. I see very few OSA's in my data (those that are not caught by the machine), so the vast majority of events are CA's, which I didn't have when I had my sleep test. In other words, I'm seeing at least some of those because I'm using cpap *smile*. I generally have less than one of these per hour on the average, as Pugsy says, not enough for a diagnosis of central apnea. If my AHI goes up over 1, it's always additional centrals. It is kind of weird, though, seeing those centrals when there weren't any on one's sleep test, but that's the way it goes for some of us. Centrals can be caused by something as simple as holding your breath when rolling over in your sleep...As I recall, 10 seconds of not breathing is counted as a CA.

Anyways, sounds like you're doing fine...cpap is a work-in-progress for all of us *smile*.

I get central apneas, about 3.0-3.5 of my AHI. Sometimes there are the awake-sleep-sleep-awake transitions and sometimes they show up because you didn't take a breath within 10 seconds. Centrals are the toughest thing to figure out because you basically decide not to breath for more than 10 seconds; in severe cases it can be devastating and I think there are a lot of doctors are in denial about the impact of centrals.

Unless they start to get consistently above 5 and they are not the transitional ones, I wouldn't worry about it. If your central numbers start to go up and you feel worse and worse, then you may want to look into a machine that is specific to central apneas.

My suggestion is to get Rescan software and look at the details to see when they are happening and for how long, as has been suggested.

As for your sleep study, the only way to know if you had central apneas during your study is to see your study as an AHI of 26 includes obstructive, central, and hypopneas (shallow breathing).

Keep researching the capabilities of your Autoset. There are Resmed clinician manuals out there that so will know the exact capability of your machine. And this forum will give you as much if not more good information that you will find anywhere else. Everything is up to how much effort you want to put into understanding you apnea and the best therapy.

John

opinio wrote: Pressure: 7.8
AHI: 3.4
Total AI: 3.2
Central AI: 3.1

This means that out of 3.2 total AI, 3.1 is Central and only 0.1 is Obstructive. This is very confusing to me, as I was diagnosed with obstructive sleep apnea, not central. So, should I be using a BIPAP instead of CPAP? Is there a mistake with my diagnosis? Any comments would be greatly appreciated.

I was hoping someone would comment on "Central AI" not really being a central but instead are hypopnea events particularly when measured at low pressure (i.e., 8 cm H2O or lower). Mis-reporting CA is a limitation and an artifact of the machine's software. I've been informed, second hand, from a sleep specialist that these events are probably not centrals and are normally hypopneas where you may or may not be sleeping.

SleepWrangler wrote:
I was hoping someone would comment on "Central AI" not really being a central but instead are hypopnea events particularly when measured at low pressure (i.e., 8 cm H2O or lower). Mis-reporting CA is a limitation and an artifact of the machine's software. I've been informed, second hand, from a sleep specialist that these events are probably not centrals and are normally hypopneas where you may or may not be sleeping.

Does looking at the waveforms on the flow chart of ResScan shed any light on the exact nature of these events?

CowFish wrote:Does looking at the waveforms on the flow chart of ResScan shed any light on the exact nature of these events?

Good question. As a newbie I wonder if I should shut up or contribute and hope that it leads to something good. Here goes something ... or nothing.

What I see in the data is clusters of crescendo-diminuendo flow patterns and occasionally no breathing at all. Flow patterns look like a bead of pearls on a necklace, or pearls stuck together all in a row without pause. I am told the event classification of CA vs H is probably not all that relevant. This is the main point I wanted to communicate to OP. Where I take note are lengthy clusters of strange breathing most of which may not even be automatically scored. Normal breathing on my SleepyHead chart looks like a nice even sawtooth-like pattern and is not characterized by progressively deeper breathing as previously described.

At a macro level therapy is improving noticeably every ten days without any dial wingin, yet like OP, because of crescendo-diminuendo patterns I am still wondering if I have the correct machine and is it set to the proper settings. I'll put the strange breathing pattern in front of my doctor, or at the very least ask better questions about my sleep study, titration, and response to therapy. Sleep doctor meeting is scheduled this month.

I'll put the strange breathing pattern in front of my doctor

IMO that is a good thing to do.

Maybe you could also post some screenshots here for comments. (And I am curious to see what you are talking about.)

SleepWrangler wrote:I am told the event classification of CA vs H is probably not all that relevant.

Somewhere in the forum this has been discussed with links to Resmed's research and how it came up with feeling comfortable calling a central apnea event....they did some extensive testing and compared the machine's results to a live tech's manual scoring and the difference wasn't enough to be a problem. I don't have that research though...should have saved it but didn't.

Anyway...ResMed is comfortable calling it a central with the S9 machines...they wouldn't do it if they couldn't back up the claim.
Now if talking about the S8 algorithm and they way it does hyponeas..yeah, very likely have some centrals dumped in that basket.

What the S9 doesn't know is if a person is awake or asleep.

CowFish wrote:Maybe you could also post some screenshots here for comments. (And I am curious to see what you are talking about.)

Here is more brilliant information from Pugsy. I should just scrape all her posts from these forums into a book. A description of what I am talking about is best summarized in these two threads.

• viewtopic/t97106/First-Time-for-Periodi ... -show.html
  viewtopic/t96332/What-does-PB-look-like.html

The discussion of CA events and hypopnea is related to PB and CSR in my examples because that is what I see in my data graphs. Unfortunately I don't know if I am awake or sleeping but the frequency is high enough that odds dictate that I must be sleeping for some portion.

Pugsy wrote:

SleepWrangler wrote:I am told the event classification of CA vs H is probably not all that relevant.

Somewhere in the forum this has been discussed with links to Resmed's research and how it came up with feeling comfortable calling a central apnea event .... they did some extensive testing and compared the machine's results to a live tech's manual scoring and the difference wasn't enough to be a problem. I don't have that research though...should have saved it but didn't.

I found this using the keywords from your response.

• Central apneas or Hypopneas? viewtopic.php?f=1&t=74422&p=682914&hili ... ch#p682914
  Central Sleep Apnea Detection and the Enhanced AutoSet Algorithm: http://www.resmed.com/fr/assets/documen ... -paper.pdf

SleepWrangler wrote:I found this using the keywords from your response.

Central apneas or Hypopneas? viewtopic.php?f=1&t=74422&p=682914&hili ... ch#p682914
Central Sleep Apnea Detection and the Enhanced AutoSet Algorithm: http://www.resmed.com/fr/assets/documen ... -paper.pdf

Thank you. I don't have time to reread it right now but I think that is the discussion thread and research paper I was thinking of.
I did bookmark the links for later review though

Perhaps whomever it was who told you that the data from the S9 was unreliable hadn't seen the research or was thinking about S8 algorithm.
If the S9 calls it a central...it most likely is a central....now whether you were awake or not, that is a different story.
It's hard to tell for sure unless you happen to be awake for a period of time and remember it.
If you are having concerns about the pattern of breathing associated with an increased central apnea count time period...can you post an image of what you are seeing so that we can see what you are seeing.

I once had 17 centrals in 17 minutes...looked suspiciously like Cheyne-Stokes Respiration but not quite exactly like it.
Since it was an extremely rare occurrence and my overall central hourly average is almost always less than 1...I don't worry about random fluke extreme results. I can't swear that I wasn't awake or semi awake during that time frame. It was about an hour before my normal wake up time so it wouldn't have been impossible for there to be some semi awake breathing flags.

If you are consistently night after night seeing a large number of centrals and what appears to be CSRish breathing pattern...talk to your doctor.