How Many Centrals Are Too "Many"

[MDee]

I am still in my first 30 days of biPap. MY AHI is around 2-3 each night. Right now my OA/Hypo combined is around 1. The rest is Central. I figure I need at least one month (or 2) to get the settings right and my body adjusts. But when I have adjusted and if I am still not feeling rested, and if the Centrals still make up more of my AHI than OA/Hypo, do I revisit? During diagnostic testing my CA AHI was at or near 5, so an average of 2 is still much better than without any biPap. And the machine has done wonders in lowering my combined OA/Hypo down from 50 AHI to 1.

[LSAT]

I would guess that if you have more than 20-25 a night...and a high AHI...it's too many for the average user. ...

[Jay Aitchsee]

Don't worry about a small number of centrals. Most centrals reported by machine probably wouldn't be scored under PSG conditions. "Centrals" (holding your breath) often accompany brief arousals due to disturbance, turning over in bed, waking, etc. Since the machine doesn't have any way to tell if your were awake, it scores them as "centrals". A CAI under 5 would not normally be of concern.

[tmoody]

Take a look at http://www.carolinasleepsociety.org/doc ... of_asv.pdf and go to page 34, where it gives a definition of central sleep apnea:

AHI>5
Centrals >50% of apneas
Centrals or hypos >5/hour
Symptoms of disrupted sleep

Those conditions are conjunctive; they all have to be satisfied. It gives one perspective on how many centrals are too many, which is the point at which central sleep apnea is defined to be present. Below that threshold, I guess they're just considered stray centrals.

[jnk...]

A stray one here and there ain't no biggie. But it isn't always a matter of number. It can be telling when they occur in clusters, one right after another, in a breathing pattern resembling waveform overshoot and undershoot, in close succession. (Wait, was that repetitively repetitious and redundant?) That is the sort of thing that can sometimes benefit from specialized forms of PAP to get around a sort of side-effect of PAP that some people have, if it doesn't resolve itself over time on straight CPAP.

[SewTired]

I am still in my first 30 days of biPap. MY AHI is around 2-3 each night. Right now my OA/Hypo combined is around 1. The rest is Central. I figure I need at least one month (or 2) to get the settings right and my body adjusts. But when I have adjusted and if I am still not feeling rested, and if the Centrals still make up more of my AHI than OA/Hypo, do I revisit? During diagnostic testing my CA AHI was at or near 5, so an average of 2 is still much better than without any biPap. And the machine has done wonders in lowering my combined OA/Hypo down from 50 AHI to 1.

If AHI is low and you are getting fewer than 15 centrals a night, shouldn't be a problem. Keep in mind that turning over can result in a 'central' flag. I found that the centrals decreased a lot after a month or two. If they keep increasing, then that's a flag to talk to your doc.

[MDee]

This is all very helpful. I am getting between 15-20 per night (so far).I don't roll over in my sleep (bad shoulders). They tend to cluster. I'll keep monitoring them. Right now I am trying to recover from the "you need a wide mask" expedition. So much air leaked into my eyes a few nights ago, I am still having to add artificial tears throughout the day.

2jnk: to see the breathing pattern, where do I look on the Sleepyhead graph? Insp/Ex Time?

[jnk...]

I am not a SleepyHead user, but my understanding is that graphs can be zoomed, as shown in this thread:

viewtopic.php?f=1&t=108899&p=1038813#p1038628

[lilly747]

Right now my OA/Hypo combined is around 1. The rest is Central. I figure I need at least one month (or 2) to get the settings right and my body adjusts. But when I have adjusted and if I am still not feeling rested, and if the Centrals still make up more of my AHI than OA/Hypo, do I revisit? During diagnostic testing my CA AHI was at or near 5, so an average of 2 is still much better than without any biPap.

Hi DMee,

I had the same experience. But, after 2 or 3 months I did go from 17.0 CAs per Hour to about only 0.4 CAs per Hour.

THEN, a month ago I decided I needed more PS just because it felt good...big mistake. I ONLY raised my PS 0.4cm...my CAs went from 3 a night to 75 one night and avg of 25. I put my PS back 2 weeks ago but my CAs have not come back down yet.

This morning I had an AHI of 3, ALL CAs. All I can suggest is watch yours over time....I sure am watching mine right now....good luck...

[MDee]

@jnk, that did the trick (also, the post you linked to was interesting as I too have a connective tissue disorder that can (rarely) cause Central Apnea).

Anyhow, here is what a sample cluster of CAs look like. No idea what I am seeing, but the average duration is ...15 seconds? I think that is what the number inside the parens is (15), (17), (24) etc.

[robysue]

They tend to cluster.

Do they tend to cluster during periods when you know you are likely awake or semi-awake? If so, they may be nothing more than normal sleep transition centrals that would not be scored on an in-lab PSG.

Right now I am trying to recover from the "you need a wide mask" expedition. So much air leaked into my eyes a few nights ago, I am still having to add artificial tears throughout the day.

Is the eye misery making you more restless at night?

@jnk, that did the trick (also, the post you linked to was interesting as I too have a connective tissue disorder that can (rarely) cause Central Apnea).

Is the sleep doc aware of the connective tissue disorder? Is the doc who treats you for the connective tissue disorder aware that you are now on PAP therapy for OSA? If not, you do need to make sure both docs know what's going on with both conditions.

Anyhow, here is what a sample cluster of CAs look like. No idea what I am seeing, but the average duration is ...15 seconds? I think that is what the number inside the parens is (15), (17), (24) etc.

Yep, the number in the parenthesis is the estimated time of the duration of the event. It comes from the machine's data.

For what it's worth, those centrals do not look like the beginning of an overshoot and undershoot cycle. They may be sleep transition central associated with an arousal of some sort. Or not.

But overall, the number of them per night is not (yet) large enough to be a serious concern.

Finally, as lilly747 observed, some people are very sensitive to the PS number. PS = IPAP - EPAP, and your PS = 4 is not particularly large, but if you can exhale comfortably with your current settings, you might try reducing PS = 3.5 or PS = 3 and see if there are fewer CAs scored.

[MDee]

They tend to cluster.

Do they tend to cluster during periods when you know you are likely awake or semi-awake? If so, they may be nothing more than normal sleep transition centrals that would not be scored on an in-lab PSG.

I tend to discount the ones at the start and at the end, focusing on the ones when I know I am asleep. So for the example I used, it brings it down from 21 to 15.

Right now I am trying to recover from the "you need a wide mask" expedition. So much air leaked into my eyes a few nights ago, I am still having to add artificial tears throughout the day.

Is the eye misery making you more restless at night?

I excluded info from the night with the wide mask.

@jnk, that did the trick (also, the post you linked to was interesting as I too have a connective tissue disorder that can (rarely) cause Central Apnea).

Is the sleep doc aware of the connective tissue disorder? Is the doc who treats you for the connective tissue disorder aware that you are now on PAP therapy for OSA? If not, you do need to make sure both docs know what's going on with both conditions.

Most doctors do not understand the genetic condition and tend to discount it or ignore it. It is an uphill battle to get them to take it into consideration. There are no docs who treat the connective tissue disorder so you have to work with existing medical professionals who maybe heard about it once in passing in medical school. My primary MD is aware but has no experience in handling it or sleep apnea (she at least listens). The sleep doctor is aware, but tends to ignore it.

Anyhow, here is what a sample cluster of CAs look like. No idea what I am seeing, but the average duration is ...15 seconds? I think that is what the number inside the parens is (15), (17), (24) etc.

Yep, the number in the parenthesis is the estimated time of the duration of the event. It comes from the machine's data.

For what it's worth, those centrals do not look like the beginning of an overshoot and undershoot cycle. They may be sleep transition central associated with an arousal of some sort. Or not.

But overall, the number of them per night is not (yet) large enough to be a serious concern.

Finally, as lilly747 observed, some people are very sensitive to the PS number. PS = IPAP - EPAP, and your PS = 4 is not particularly large, but if you can exhale comfortably with your current settings, you might try reducing PS = 3.5 or PS = 3 and see if there are fewer CAs scored.

This is good to know and I will keep working on getting more comfortable with the biPap. I had planned to increase the IPA slowly to deal with aerophagia first and then tackle this next. The mask fitting testing took up most of last week.

[jnk...]

@ Robysue: Thanks.

[Goofproof]

One that lasts over 6 minutes, it only takes one of those. Time spent in Apnea is seldom mention but very important. Sleep Apnea generally kills you slowly, time spent in Apnea tills me how fast it's killing me. Jim