ASV: Hypopnea Index Remains High

I've been on my new PR BiPAP autoSV Advanced for about 10 days now. (Those of you who have followed my other threads know that over the last year I've been fighting to get on the "right" machine, starting first with a CPAP a year ago and then a BiPAP S/T a couple months ago.) I've definitely been more tired after using the ASV (and more prone to take naps) than when I wasn't on any machine at all, so I was eager to finally get the smart card reader that arrived today.

The data confirms that my AHI is still a bit on the high side -- an average just under 8, with of course a lot of nightly variation in it. I was hoping to get some opinions from all of you based on the data. My settings are pretty standard: Min EPAP 4, Max EPAP 15, Min PS 0, Max PS 15, Max Pressure 30, Backup rate auto, Flex setting 2.

Apologies for the dump of screenshots from Encore below.

As I understand it, your AHIs comprise mostly of Hypopneas. In my case by using my APAP, one way to resolve the nature of Hypoapneas, i.e. if Obstructive or Central, is to raise the inspiration pressure somewhat gradually. This should resolve the Obstructive Hypo, leave the Centrals Hypo, and the total Hypopneas should diminish.

Brian, I agree with avi123. It appears most of your AHI score is due to hypopneas. You probably should talk with your sleep doctor about this. It might be you need a slightly higher EPAP pressure to help keep your airway open. But as is true with anyone with an ASV unit, there is a lot to consider (such as, higher pressure can trigger more central apneas). In such cases, it is always advisable to discuss the details with your doctor.

Yes, this is correct. This was unfortunately my problem with the BiPAP S/T as well.

BrianinTN wrote: My settings are pretty standard: Min EPAP 4, Max EPAP 15, Min PS 0, Max PS 15, Max Pressure 30, Backup rate auto, Flex setting 2.

My guess is running the autoSV on straight auto mode, as indicated by your current settings, isn't an effective modality to address your hypopnea. You could trial Min PS 3, tonight. You may also entertain Max Pressure 25.

This is the second time things looked amazing in the lab but not quite so hot at home.

I understand the argument behind increasing min PS (somewhat, anyway), but what's gained by lowering the max pressure to 25? From the graphs, it never gets close to that high as it is.

BrianinTN wrote:but what's gained by lowering the max pressure to 25? From the graphs, it never gets close to that high as it is.

Your device will run more efficiently and provide longer device life at lower Max Pressure. You could happily set Max Pressure 20. People on this board love to run there devices at the highest possible Max Pressure. It tears these machines up, as has been demonstrated many times with run-away pressures and burnt-out machines, by many forum users. Running your device at Max Pressure 30 is almost as dumb as the person who set your device parameters to run on 'Auto'.

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BrianinTN wrote:As for tinkering with min PS, should I start lower (say at 2), or is 3 a better place to start for a particular reason?

I agree with you. I'm guessing you could start at Min PS 1 for tonight. Perhaps raise Min PS progressively by 1cmH2O each subsequent night and observe what happens with the hypopneas. It's a start..

BrianinTN wrote:Flex setting 2.

Turn Flex off. At your low pressures you need flex like you need a hole-in-the-head.

OK. Believe it or not, they titrated me at 20/16 on the BiPAP.

BrianinTN wrote:OK. Believe it or not, they titrated me at 20/16 on the BiPAP.

The best part of having an ASV device with your own data capability is that you can retire your sleep doctor, forever.

Please note that "StillAnotherGuesS" is a

very very

new poster. S/He is not the poster known as "StillAnotherGuesT".

StillAnotherGuesS wrote:

BrianinTN wrote:but what's gained by lowering the max pressure to 25? From the graphs, it never gets close to that high as it is.

Your device will run more efficiently and provide longer device life at lower Max Pressure. You could happily set Max Pressure 20. People on this board love to run there devices at the highest possible Max Pressure. It tears these machines up, as has been demonstrated many times with run-away pressures and burnt-out machines, by many forum users. Running your device at Max Pressure 30 is almost as dumb as the person who set your device parameters to run on 'Auto'.

If the machine does not get to the higher pressure, it won't get "burned out". I would never trust a poster who registered 2 weeks ago on statements about what "has been demonstrated many times" or about "many forum users".

As a matter of fact, I would automatically distrust any posting by a poster who chooses a name so similar to a well known well respected other poster on the forum.


Caveat emptor.

Thank you for saying everything you did, ozij.

The "Guess" person may think it was funny to register the name he/she did, but it's not.

Not funny. Not good advice. And not the poster known and respected here as "StillAnotherGuest."

I have used the Fisher & Paykel #432 full face, as you do, for a few weeks and had high leak rates with it like you (above 30 L/min). I think that the solid foam under the Silicone cushion caused it. So I changed to full face #431 (without the foam), in medium size, and it works much better. The leak dropped to below 10 L/min. But I keep the headgear straps quite tight. Especially, the lower ones. I can slide my index finger between the strap and my cheek easily but not my thumb. After switching the pressure ON, I adjust the mask by lifting it off my self severel times.