What ASV adjustments affect hypopneas most?

[The Sheikh]

Hi Folks -

I'm looking for some suggestions....

I've been successful getting my central and obstructive apnea index down to near zero. However the hypopneas seem difficult to get a handle on. My PR Advanced SV ASV unit shows about 15-25 hypopnea events each night. This is not bad, but I'd like to tweak it in better if possible. Evidently my RESIDUAL Cheyne-Stokes breathing pattern may be causing it, I dunno.

At this point here are my settings - after months of trial and error, they are optimized so that CA, OSA, FL, VS and hypopneas, taken as a group, are at a minimum:

Pressure Max: 20
Epap min: 4
Epap max: 6
PS min: 4 (breathing pulse)
PS max 15
Breathing rate: Auto - averages about 13.8 bpm
Rise time: 2

I am wondering WHAT adjustment(s) may help to decrease the hypopnea events? I have not played with the backup breathing rate yet. I have had it set to "Auto."

I tried increasing the PS min breathing amplitude from 3,4 or 5 attempting to better stablize the hypopneas, but 3 or 4 seems to be best. If I go too high, the CA's start in and hypopneas get more frequent.

What effect will the breathing backup rate have on hypopneas, if any? I average about 13.8 for the last month set at auto. I wonder if running it on manual at a slower breathing rate might help?

Anyone have suggestions using these adjustments or any other method to decrease hypopneas?

BTW, I am sleeping well and my O2 remains above 93% all night, so this is more an exercise in just trying to get the hypopnea numbers to read better - more in line with the other indices.

Thanks.

Tom

[JohnBFisher]

EPAP min and PS Min makes the most difference with Hypopneas.

I would recommend against switching from AUTO for the Breaths Per Minute (BPM). You can seriously mess up your breathing (your CO2 and oxygen exchange) by getting the values wrong. That is especially true if you then adjust the rise time. Most healthy folks will just end up with a horrible night of sleep. But if you have central apneas you will wake up with one humdinger of a headache. We've had some folks try it here before and found "AUTO" was the best choice.

Hope that helps.

[The Sheikh]

EPAP min and PS Min makes the most difference with Hypopneas.

Hi John,

Thanks for the info.

Could you give me an idea of how higher or lower Epap min and PS min might affect the hypopneas?

From trial and error it appears that higher epap mins cause more hypopneas - but Epap min needs to be at a certain level to handle the OSA and flow restrictions.

Though, I am not clear on how the PS min breathing pulses affect everything. So far I find a 3-4 cm/h20 level is the highest I can run before the overall indices start to deteriorate. I would think a stronger PS min pulse (above 3-4) would help stabilize the breathing amplitude, but it seems to make the hypopnea index worse at the same time.

BTW, does the rise time setting (1-5) work when in BPM auto mode or just when in manual mode?

Tom

[StillAnotherGuess]

I am wondering WHAT adjustment(s) may help to decrease the hypopnea events?

Given your current EPAP settings your best chance to reduce hypopneas is to incrementally increase PS Min. And disable Rise Time. At EPAP Min 4, Rise Time is useless.

[JohnBFisher]

... Could you give me an idea of how higher or lower Epap min and PS min might affect the hypopneas? ...

Well, you've already found that increasing your EPAP does not help. So, I would go with an incremental increase of PS min to bump up the inhalation pressure. This should help keep your airway open a little bit better. But as you've already noted, you may have a very limited room for change.

Unfortunately, we all have to tinker with the settings (make one change .. measure the results for a week or so .. make another change .. repeat measurements .. etc ...). This is a clear case where one size does not fit all. In fact, with ASV therapy there is no one right answer. The answer is "whatever works best for you!".

I've used this approach several times and clearly end up with a result that can be easily defended when I discuss it with my doctor. He has no problems with this approach to determining what works best for me.

The Rise Time is only available if you do not have BPM set to AUTO. As I noted, changing that can make the unit more difficult to use and possibly result in very poor sleep. I would just leave your BPM setting in AUTO.

Hope that helps.

[johnthomasmacdonald]

how does asv therapy differ from cpap/bipap? - Both machines are shooting air aren't they? what's the fundamental difference?

[Xney]

how does asv therapy differ from cpap/bipap? - Both machines are shooting air aren't they? what's the fundamental difference?

The difference is ASV adjusts the pressures on each breath to maintain volumes and rates. BiPAP and auto-bipap will adjust pressures too, but they do it in response to events.

The ASV is a much more advanced machine

Also, an ASV will trigger a breath for you if you don't breathe, at some automatic rate or numerical rate, as a backup. In this, it functions more like a BiPAP/ST

[kugie]

I have similar issues. I finally have my average AHI below 5 by going to the BiPap ASV. My central apneas and obstructed apneas are now very low, near 0 most nights, but Hypopneas have gone up rendering my AHI of 3 - 5. I found in some Philips literature that said to have pressure support at 4 or above if hypopneas become dominant. I have tried many configurations, but I am prone to leakage at higher pressures and then central apneas again go up. It definitely takes trial and error. I am currently at PS of 5 and slightly lowered EPAP min to 8. Hypopneas have decreased but I now have a few more central apneas. AHI still 3-5. May be as good as it gets for me. I agree to leave BPM to auto. I tried figuring my natural bpm multiple times and different rise times were tried also. Always rendered poor sleep. I believe my bpm may change as I go into deep sleep or REM, so auto is the way to go. I will continue to slightly adjust epap min and ps. Maybe in 0.5 increments instead of whole units as I have. Then I must be patient and try the new settings at least a week before readjusting again.

[zonker]

I have similar issues.

it's better to start your own thread than to tag onto an older one. you'll likely get some response that way.

good luck!