Difference between central and obstructive Hypopnea???

Had another take home sleep test. This one showed a proportional higher count of Hypopnea events per hour (18), 2.5 Central Apneas and 1.0 Obstructive.
Having read that Hyponea's can be central or obstructive, may I assume that in my case they are likely central due to my higher central ratio within the apneas's?
Would the total AHI be 20.5 centrals?

Interstingly, at my CPAP mashine the amont of central 'apneas' were greater (7).

Okay... I am confussed!!

Hi -- hopefully someone smarter than me will come along and answer your question more fully! In the meantime, I can help you with a couple things.

First, the calculation of AHI: AHI = Obstructive Apnea Index + Central Apnea Index + Hypopnea Index. So, in your case, where those numbers are 1.0, 2.5, and 18.0, your AHI Is 21.5.

That central apnea number you mentioned on your CPAP -- is that your total number over the course of your night, or your index (which would be the total number divided by the number of hours)? Index would be most helpful.

Sometimes people have more central apneas when they are on CPAP therapy. You can read about it more at the following links, courtesy of board member -SWS who has helped me immensely
http://www.rtmagazine.com/issues/articl ... -11_03.asp
http://www.chestnet.org/accp/pccsu/comp ... a?page=0,3

And to invoke his knowledge again, I'd asked him about trying to figure out whether my hypopneas were central or obstructive in nature in another thread a couple months ago. Here are a couple relevant quotes:

-SWS wrote: We can't know whether those hypopneas are central, obstructive, or both types. The bad news is that CompSAS can be a challenge for a skilled technician to properly titrate in a lab with full PSG instrumentation. Unfortunately there aren't many useful conclusions amateurs on a message board can or should draw given your data----other than your complex SDB is a challenge to treat.

-SWS wrote:

BrianinTN wrote: If regular CPAP eliminated most OAs and left very few hypopneass with a bunch of CAs, doesn't that suggest that the hypopneas I'm seeing now on the BiPAP S/T are central rather than obstructive in nature?

Great question... But unfortunately there's STILL not enough information to deductively reason central hypopneas vs obstructive hypopneas:

1) your obstructive and central components can each be highly variable, and
2) obstructive apneas that are under-addressed with insufficient pressure can easily convert to residual obstructive hypopneas

That latter point is why it takes more CPAP pressure during NPSG titration to clear obstructive hypopneas than apneas. It's also why BiLevel titration protocol calls for obstructive apneas to be cleared with lower EPAP, but for hypopneas to be addressed with higher IPAP...

Hopefully this is enough to get you started and hasn't made things more confusing rather than less!

arburtus
I'll just add that its not ONLY central and obstructive apneas that are in the AHI. There are also hyponeas.
wiki/index.php/Hypopnea
Most machines can accurately detect obstructive apnea and hyponea events but are less accurate with respect to tagging central apneas. So, I would not worry too much about seeing a few centrals in you AHI on your home machine. But if you are worried, there is only one way to accurately diagnose central apneas and that is with a polysomnography study in a real sleep lab.
http://en.wikipedia.org/wiki/Polysomnography
There needs to be lack of effort as measured by chest and belly bands and these have to correlate with flow measurements and brain wave traces. A take home test cannot do this accurately.

Edited to make it clear my remark was for arburtus and not directed at BrianinTN.

arburtus wrote:Had another take home sleep test. This one showed a proportional higher count of Hypopnea events per hour (18), 2.5 Central Apneas and 1.0 Obstructive.
Having read that Hyponea's can be central or obstructive, may I assume that in my case they are likely central due to my higher central ratio within the apneas's?
Would the total AHI be 20.5 centrals?

Interstingly, at my CPAP mashine the amont of central 'apneas' were greater (7).

Okay... I am confussed!!

Hypopneas could be obstructive or central. There are only few machines that can distinguish between them. One of the problems in home tests is that there is no technician to verify Central apneas by watching if you're attempting to breathe or not. At your home test do you also wrap straps around your chest and belly?

If you have 18 Hypopneas and 1.0 Obstructive then the AHI would show 19 because Central apneas are not included.

Overall, to suspect a Central Apnea syndrome you need at least 10 central apneas and hypopneas per hour with Oxygen desaturations, 50% or more of all events to be central rather than obstructive and also some kind of ailment. But, 40% of healthy individuals may have up to 5 central apneas per hour of sleep.

Central apnea are included in the AHI.

"Apnea" is a word meaning "not breathing". It does not refer to the cause of the breathing stop, nor does the total AHI. Your AHI is simply an idicator of the number of time your breathing was totally (apnea), or patially (hypopnea) stopped.

This is from an American Academy of Sleep Medicine AASM document:
http://www.aasmnet.org/resources/factsh ... papnea.pdf

A common measurement of sleep apnea is the apnea-hypopnea index (AHI). This is an average that represents the combined number of apneas and hypopneas that occur per hour of sleep.

BrianTN thinks clearly, and has aquired much reliable knowledge during his relatively short time on this board. You will do well to pay attention to anything he says.

What is the best way to apply therapy for increasing Central apneas just as Hypopneas and Obstructive Apneas are going down? I'm leery of increasing pressure as I think that will increase leaking and Obstructive apneas. My pressure on BiLevel (APAP) is 5.6 low and 9.6 high. At that pressure, my OSA was 1.0, Hypopnea 2.5, and CA 15.4.

Bob Difley wrote:What is the best way to apply therapy for increasing Central apneas just as Hypopneas and Obstructive Apneas are going down? I'm leery of increasing pressure as I think that will increase leaking and Obstructive apneas. My pressure on BiLevel (APAP) is 5.6 low and 9.6 high. At that pressure, my OSA was 1.0, Hypopnea 2.5, and CA 15.4.

You need to make your doctor aware of what is going on with the centrals/CAs.
You can't fix them with more pressure with your machine (not even counting the chance of making leaks worse) and more pressure could maybe even make them worse.
Exactly which machine are you using...is it a Respironics BiPap? Are you using BiFlex exhale relief? If you are you might try turning it off and see if the CAs reduce with no BiFlex (exhale relief).

Bob Difley wrote:What is the best way to apply therapy for increasing Central apneas just as Hypopneas and Obstructive Apneas are going down? I'm leery of increasing pressure as I think that will increase leaking and Obstructive apneas. My pressure on BiLevel (APAP) is 5.6 low and 9.6 high. At that pressure, my OSA was 1.0, Hypopnea 2.5, and CA 15.4.

Bob, try cutting your pressure support by 1-cm. At 9.6/5.6 give a try to 8.6/5.6. It might clear that CAI right up.

Sleeprider wrote:

Bob Difley wrote:What is the best way to apply therapy for increasing Central apneas just as Hypopneas and Obstructive Apneas are going down? I'm leery of increasing pressure as I think that will increase leaking and Obstructive apneas. My pressure on BiLevel (APAP) is 5.6 low and 9.6 high. At that pressure, my OSA was 1.0, Hypopnea 2.5, and CA 15.4.

Bob, try cutting your pressure support by 1-cm. At 9.6/5.6 give a try to 8.6/5.6. It might clear that CAI right up.

Pugsy wrote:

Bob Difley wrote:What is the best way to apply therapy for increasing Central apneas just as Hypopneas and Obstructive Apneas are going down? I'm leery of increasing pressure as I think that will increase leaking and Obstructive apneas. My pressure on BiLevel (APAP) is 5.6 low and 9.6 high. At that pressure, my OSA was 1.0, Hypopnea 2.5, and CA 15.4.

You need to make your doctor aware of what is going on with the central/CAs.
You can't fix them with more pressure with your machine (not even counting the chance of making leaks worse) and more pressure could maybe even make them worse.
Exactly which machine are you using...is it a Respironics BiPap? Are you using BiFlex exhale relief? If you are you might try turning it off and see if the CAs reduce with no BiFlex (exhale relief).

I'm using a ResMed APAP with nasal pillows. Where do I find BiFlex exhale relief?

Bob Difley wrote: I'm using a ResMed APAP with nasal pillows. Where do I find BiFlex exhale relief?

You don't. ResMed machines don't have BiFlex...BiFlex is only available on Respironics bilevel machines.
Exactly which ResMed model are you using...APAPs aren't bilevel and have EPR exhale relief.
ResMed bilevel machines don't offer specific exhale relief like the EPR or Flex relief of the Respironics machines.
ResMed didn't add any additional exhale relief with their bilevel machines because the pressure support function is normally sufficient exhale relief along with the Easy Breathe technology they use.

My pressure on BiLevel (APAP) is 5.6 low and 9.6 high

Did you mean that you are using an apap machine with the minimum of 5.6 and it can go to 9.6 if it needs to
or are you using an auto bilevel machine and you have 5.6 on exhale and 9.6 on inhale?

There seems to be some confusion here as to exactly what you are using...if you can give us the exact model name we can then figure out what your options are for exhale relief (if you have any).