Central Apnea - Pressure doesn't rise ???

[ShelleyH]

Hello. . .

I'm noticing from the data from my S9 VPAP machine that when a CA occurs that the pressure doesn't actually increase either before or after. My data card is still at the DME provider (our local hospital) trying to be read I guess or they are still waiting on the software update. Of course, I went and bought another one and have not lost any data or time recording and still have a combination of CAs and OAs and very few hyponeas. The pressure does adjust during the Obstructive Apneas. There is a slight delay in the adjustment.

So, is it my correct understanding that the S9 VPAP Auto does not help with Central Apneas and that I would need the ASV machine? Actually, I might hear back from my neurosurgeon that it is an affect from my instability and surgery may be on the horizon but until I know that. . .I'm wondering if this machine does anything for Central Apneas.

Thanks for information.

[jamiswolf]

By no means am I an expert at this, but since increased pressure won't treat a central apnea...then why would they design a machine to do that? (And just to clarify...I'm not referring to the increased pressure triggered by an ASV machine to initiate a breath).

If the preponderance of your apneas are central, then a machine with a timed back-up rate is what's needed. Or that's my understanding.
Jamis

[JohnBFisher]

... So, is it my correct understanding that the S9 VPAP Auto does not help with Central Apneas and that I would need the ASV machine? Actually, I might hear back from my neurosurgeon that it is an affect from my instability and surgery may be on the horizon but until I know that. . .I'm wondering if this machine does anything for Central Apneas. ...

Nope. The lack of pressure change is one way your unit deals with a central apnea - it does not even try to increase the pressure, since that might only make things worse.

I do not know you specifics, but since you have a neurosurgeon involved, I assume you have some neurological problems that might increase the number of central apneas. Many sleep doctors will first try CPAP, then BiPAP, in the hope that improved airflow will reduce central apneas. And in a large number of cases (I am guessing, but I think it is > 50%) that is exactly what happens. But if not, then alternative therapies, such as an ASV machine might be needed.

Hope that helps.

[ShelleyH]

So, I did understand it correctly. The pressure doesn't rise to impact a CA event. Maybe I needed to just ask that.

Yes, I do have other issues which is why they are looking at the Sleep Apnea again (originally diagnosed in 2009 with OSA) but Craniocervical Instability can change sleep apnea issues and bring on or start up Central Apneas.

The 2nd sleep study was not a complete study. The titration portion was not done due to me not being able to sleep soon enough, long enough. Doc decided to just prescribe BIPAP machine and give it a try so all the CA stuff is new for me. Yes, I'm informing them of these events.

[jamiswolf]

Shelly,
Yes, we sort of came at your question backward. Truthfully about all your machine can do with central (clear airwaqy) apneas is to count them.

Good luck with your Doctors appt.
Jamis

[JohnBFisher]

So, I did understand it correctly. The pressure doesn't rise to impact a CA event. Maybe I needed to just ask that.

Yes, I do have other issues which is why they are looking at the Sleep Apnea again (originally diagnosed in 2009 with OSA) but Craniocervical Instability can change sleep apnea issues and bring on or start up Central Apneas.

The 2nd sleep study was not a complete study. The titration portion was not done due to me not being able to sleep soon enough, long enough. Doc decided to just prescribe BIPAP machine and give it a try so all the CA stuff is new for me. Yes, I'm informing them of these events.

ShelleyH, sounds as if you you will need to do some reading:

Links to Central Apnea discussions
viewtopic.php?p=22702

Rested Gal keeps this list of links to Central Apnea discussions and various resources. Since your issue is neurological related, don't let the discussion about heart issues worry you. In your case, it would be a failure of the brain stem to properly initiate breathing.

A little bit of background here ... As you know, obstructive sleep apnea (OSA) occurs when the airway collapses. Usually it's the soft palette and/or tongue that falls into the airway. This blocks the airway and causes the snoring and snorting sounds that is so typical of OSA. The body continues to try to breathe. Thus, there is diaphragm movement. But no air flows. This usually results in the body needed to arouse from a deeper level of sleep to a lighter level to allow the obstruction to be cleared.

Unlike OSA, there is NO effort to breathe. The normal respiratory drive simply diminishes until an apnea occurs. It can be accompanied by "periodic breathing" which typically shows a waxing and waning. However, it might be more like what I tend to experience. I tend to simply breathe more and more shallowly until I simply stop breathing.

Most CPAP devices are designed to (1) recognize a central (or clear airway) apnea and (2) do *NOT* change the pressure upward. Some will auto PAP devices decrease the pressure when a central apnea occurs, on the presumption that increased pressure might trigger a central apnea.

Some people who experience central apneas during the use of a CPAP (or APAP) devices may not experience them when they use a BiPAP device. That is, by having a lower exhalation pressure than the inhalation pressure it causes fewer central apneas (in general). It appears your doctor decided to try that route in the assumption this might reduce your central apnea issues.

However, *IF* you have enough central apneas, you might need to use an ASV (adaptive servo-ventilator) device. This is a combination of a BiPAP device and a ventilator. You see, most central apneas occur as a result of a continuous undershoot / overshoot cycle. For some reason your body fails to breathe deeply enough. This allows CO2 to build up in your blood stream. This is the undershoot side of the cycle. Rather than expelling the CO2 it builds up until the body finally responds. In so doing, it tends to overdo the exhalation of CO2. The body tends to hyperventilate (just a little bit). But it's enough to blow off more CO2 than it should. This is the overshoot side of the cycle. And since it blew off too much CO2, the respiratory drive decreases, another apnea occurs and then the CO2 starts to build to higher levels than it should ... And back we go, round and round and round ...

To help break this cycle, an ASV unit senses when your breathing volume will not meet the average from a sliding three minute window. That is, it takes the average for the past three minutes and determines if you will reach that average. If not, it increases the pressure enough to help ventilate you. That's the ventilator part of the unit. When you are breathing normally on your own it will act much more like a BiPAP device.

Not everyone needs something like an ASV device. You have to have central apneas occur frequently enough that they must be addressed. Clearly this is a concern of your doctors based on your medical history. However, they will tend to be cautious about use of devices. They will start with something like a BiPAP device and then move forward. In fact, if you get an ASV unit, you would need to be titrated with one of those devices.

I hope that helps provide some background that you will find useful.

[ShelleyH]

Thank you for taking the time to post all that helpful information. I have kept reading on CA as much as possible. If my NS decides that the instability and previous brain stem issues are the cause, surgery to correct the instability will happen.
Thanks again for the links.