Centrals in relation to Obstructives?

[cindjo717]

I was wondering what the percentage of centrals in relation to the obstructives should be? I have heard it mentioned that centrals are not so good and am not sure how to tell when it's too many. Thanks.

[jnk]

I was wondering what the percentage of centrals in relation to the obstructives should be? I have heard it mentioned that centrals are not so good and am not sure how to tell when it's too many. Thanks.

Not a direct answer on the percentage, but a nice summary of the overall issue, in my opinion:

'Normal persons tend to have transient central apneas during the transition from awake to sleep, due to normal sleep related changes in the brain’s control of breathing: that is, there is, less "drive" to breathe, and in specific, a sleep-related need for increased levels of carbon dioxide (CO2) to cause the central nervous system to signal the muscles of breathing to contract, and, in fact, breathe. It is normal for a person to have one or several of these events until sleep becomes more continuous. "Post-sigh" apneas are common during the sleep period when a person arouses; the person reflexively takes a large breath (sigh) or two, which abruptly decreases the carbon dioxide levels, followed by rapid transition back into sleep, with the onset of a central apnea due to the lack of enough carbon dioxide levels to drive the breathing effort. Just as with the first attempts to transition into sleep, this is a normal breathing response to cycling between sleep and awake states. While such "transitional" apneas are most likely associated with drowsiness and light sleep (non rapid-eye movement, or NREM), erratic breathing and intermittent central apneas are seen commonly in rapid-eye movement (REM) sleep. Therefore, a certain amount of central apneas may occur throughout a night of sleep that are considered normal responses; such cases are not associated with any underlying abnormality of the central nervous system or breathing apparatus, and are not known to cause any major harm to the person who displays such activity. Such "normal" apneas may be associated with the person coming to a full awakening with a feeling that she/he stopped breathing, possibly resulting in a feeling of fear, anxiety, or panic which may be associated with a racing heartbeat, and sweating. However, if central apneas occur repetitively, generally in the range of five times per hour of sleep, an abnormal situation is considered to exist, and the person is considered to have "central sleep apnea." . . . The frequency of apneas, however, is not the only criterion for deeming these events abnormal or significantly harmful; the length of events and degree of decrease in oxygen blood levels is also of importance in determining the potential harm and the treatment necesary, as is the clinical condition in which the apnea occurs.'

-- Robert C. Basner, M.D., Director, Columbia University Cardiopulmonary Sleep and Ventilatory Disorders Center; Director, Pulmonary Diagnostic Unit. Columbia University College of Physicians and Surgeons, New York, N.Y.

http://knol.google.com/k/central-sleep-apnea#

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[Pugsy]

How many are you seeing? Are they happening all night long or are they happening when you first go to sleep or wake up...or during the night if you wake up for some reason?

Most of mine are random..with some clusters mainly when I am just waking up which I know aren't real.
As long as they remain under 5 an hour and I can't explain them away with sleep onset...I wouldn't give them more than a shrug of the shoulders.

Some nights I have zero CAs...some nights I have random CAs...some nights I see clusters of them and I might have a CA index of 3 or 4 or more. For me it isn't so much a set number but more of the pattern which I might be concerned with. I don't recall ever seeing a % guideline as to a relation between CA vs OA.
Some nights all I have are CAs...some nights all I have are OAs.

I think people hear "central" and panic and immediately think of it as being horrible and think the worst because people who have a predominance of centrals possibly can possibly have some significant underlying health condition and don't stop to think that the presence of a few centrals (even if they are the real deal and not the machine mislabeling something) doesn't necessarily mean that an ugly condition is present. One has to look at the whole picture and not just a single numerical value.

[teknomom]

I keep reading that transitional centrals aren't "real". For me they are very real and make up almost all my centrals. I have periods of over and hour at bedtime and in the morning and several shorter periods during the night when cycles of transitional centrals keep me from going back to sleep (and caused serious desaturations without my ASV). I understand that just one or two centrals during transition isn't a worry for most people, but it is a very serious problem for those of us with primary central apnea. I get tired of seeing it dismissed as not "real!

[JohnBFisher]

I keep reading that transitional centrals aren't "real". For me they are very real and make up almost all my centrals. I have periods of over and hour at bedtime and in the morning and several shorter periods during the night when cycles of transitional centrals keep me from going back to sleep (and caused serious desaturations without my ASV). I understand that just one or two centrals during transition isn't a worry for most people, but it is a very serious problem for those of us with primary central apnea. I get tired of seeing it dismissed as not "real!

Ditto! Though I do have centrals throughout the night, I stop breathing for so long during the transition phase that the "Auto Off" feature on my BiLevel unit would turn off my BiLevel unit. And it would do that time and time and time again ... Though it was just noted as a "transitional central" on the sleep study, it was a HUGE problem for me. You see, in order for the "Auto Off" feature to take effect, it meant that I had to stop breathing for more and one minute at a time. So, while they are normally, not a big deal for some of us, it is a *huge* problem.

Still, our experience with transitional central apneas is fairly rare.

[archangle]

I was wondering what the percentage of centrals in relation to the obstructives should be? I have heard it mentioned that centrals are not so good and am not sure how to tell when it's too many. Thanks.

Centrals and obstructive apnea are probably equally harmful to you. It's a lot harder to make centrals go away with CPAP. CPAP may cause centrals. It may take a more complicated machine such as an ASV to treat central apnea.

If you have central apnea without CPAP, that's probably indicative of some more serious underlying condition. If you develop centrals while under CPAP pressure, that might or might not indicate an underlying problem. It does mean you may be harder to treat.

Be sure to not panic just because your CPAP machine says "central apnea." Make sure someone who is competent looks at your results, including flow waveforms. It's not an apnea unless you have an O2 desat or an EEG arousal, which the machine can't see. If the duration of the "central apnea" is low enough, it may not be harmful at all.

[archangle]

Ditto! Though I do have centrals throughout the night, I stop breathing for so long during the transition phase that the "Auto Off" feature on my BiLevel unit would turn off my BiLevel unit. And it would do that time and time and time again ... Though it was just noted as a "transitional central" on the sleep study, it was a HUGE problem for me. You see, in order for the "Auto Off" feature to take effect, it meant that I had to stop breathing for more and one minute at a time. So, while they are normally, not a big deal for some of us, it is a *huge* problem.

I can understand turning the machine off if the machine is no longer connected and is blowing large amounts of air, but it should be obvious that the machine is still connected to a patient who isn't breathing.

What were they thinking? "He's dead, so we'll shut down so we don't waste electricity?"

[Mr Bill]

Ditto! Though I do have centrals throughout the night, I stop breathing for so long during the transition phase that the "Auto Off" feature on my BiLevel unit would turn off my BiLevel unit. And it would do that time and time and time again ... Though it was just noted as a "transitional central" on the sleep study, it was a HUGE problem for me. You see, in order for the "Auto Off" feature to take effect, it meant that I had to stop breathing for more and one minute at a time. So, while they are normally, not a big deal for some of us, it is a *huge* problem.

I can understand turning the machine off if the machine is no longer connected and is blowing large amounts of air, but it should be obvious that the machine is still connected to a patient who isn't breathing.

What were they thinking? "He's dead, so we'll shut down so we don't waste electricity?"

I guess the assumption is, for a bilevel unit, that the patient does not have CSA or they would be using an ASV so if no breath, they have taken it off. AFAIK ASV's do not have an auto-off feature.

What I find interesting is that I log pretty much zero OA's and very few CA's but lots of hyponeas especially when patient triggered breath percentage drops. So, my machine compensates for CA's starting... by intervening. And, I guess since it intervened, no CA occurred but only a hyponea.

Do any of us ASV users get CA's logged with any frequency? John?

[JohnBFisher]

...What I find interesting is that I log pretty much zero OA's and very few CA's but lots of hyponeas especially when patient triggered breath percentage drops. So, my machine compensates for CA's starting... by intervening. And, I guess since it intervened, no CA occurred but only a hyponea.

Do any of us ASV users get CA's logged with any frequency? John?

In my case the CA events were with an older unit that did not well distinguish between not wearing it and wearing it. Essentially it just knew that the user had not switched to inhalation from exhalation (or the other way around). So, if no breathing, the mask must not be on the user ... at least that seems to be the thinking of the engineers.

I sure don't get a lot of CAs with my ASV unit. Some are logged. But it's normally after a VERY stressful day when my symptoms are a lot worse. My sleep is also then pretty bad. I use "Auto" for the backup rate to allow the machine to try to guess when I am going to breathe again. It helps allow me to breathe a little more naturally, which is not always at 10 or 12 breaths per minute.

Further, I find the Respironics ASV unit seems to encourage more patient triggered breathing. As I've noted before, the Resmed unit feels a lot "tighter" to my breathing pattern. When that pattern changes it tries to shove me back into that pattern. That's not normal, so can be disruptive. The Respironics unit allows more leeway to see if you will breathe. While more normal, it seems to allow a few more apneas than the Resmed unit.

Hope that helps.

[TmjTerri]

I went to my sleep doctor in 2010 about this very issue. I was on my vpap and during the night I would wake up and my machine would be completely off.This happened many times during the night! My sleep doctors RT had NO idea why this was happening so she gave me a different machine. So did the machine turn off because I stopped breathing? I am a bit confused by this now. I am really wondering now if my sleep doctor does not know what they are doing. Weird!

[JohnBFisher]

... during the night I would wake up and my machine would be completely off.This happened many times during the night! My sleep doctors RT had NO idea why this was happening so she gave me a different machine. So did the machine turn off because I stopped breathing? I am a bit confused by this now. ...

Well, did the problem go away with the new machine? If it did, then the problem was with the old machine. If the problem remained, then it's likely the problem had more to do with you than the machine. Did your RT and/or doctor ask to see the data from your machine? That would have helped them better understand the frequency and timing of the events. My doctor wants to see data that I dump from my unit.

In my case, I could show how it would turn off just as I was falling asleep. I pointed out that it happened over and over and over and over ... and that it was/is pure torture for me. Almost everyone has some central apneas during the transition from wakefulness to sleep. But most people don't stop breathing for more than a minute at a time. With that, he went back to the detailed report and noted my central events at the transition from wakefulness to sleep and noted the duration. That and a letter of medical necessity was enough to get me an ASV unit.

So, in short the answer is .... It depends! I doubt that your RT and doctor were completely clueless. That type of problem does occur. But central sleep apnea is fairly rare (rarer than a machine that acts up). So, they might not think to check central apneas as an issue.

[teknomom]

Do any of us ASV users get CA's logged with any frequency? John?

@ Mr. Bill, I hardly have any CA events - almost all hypopneas, most at the "low point" of periodic breathing. Zero OAs most nights.