Comparing Notes from Bipap to Cpap?

[lhpangler]

Hello everyone,
I need someone to "read me in" on auto CPAP's. I have been a successful bipap user, but I have an aunt using a Resmed, Elite II, CPAP on auto set. I am trying to help her follow the holy grail of reducing AHI's to 0. My simple life's view is increase or adjust pressure until AHI's drop.

So now comes the CPAP on Auto. It has a min/max pressure setting. Right now it is set at 5/10. Machine say average pressure is around 8-9. AHI's are about 6. It seems to me that changing the min or max really won't matter in the average is not near the max. Upping the settings by ,5 won't really matter.

Any suggestions would be welcomed as I have no experience with a CPAP. On idea I had was to take the machine off auto and start to pick a constant setting.

TIA,
LHP

[Xney]

There's three things I would keep in mind (generally) for adjusting the APAP:

1) You can have a big range early on to "dial in" the therapy, but you want to end up with more like a 6cm range of pressures, such as 6-12cm, at the end

2) The minimum, and whether it should be bumped, has to be determined by looking at the data from the night. You want to see if the machine is spending a decent amount of time at the minimum or does it always jump to a higher pressure and stay there.

For example, you have a range of 6-12cm. After 20 minutes, events start happening, and the machine goes to 8 or 9cm, and spends most of the night at that range. In that case, 6cm is too low for the bottom range - you'd want to bump that to 7cm or 8cm.

3) The maximum should be determined by the 90%/95% number, not the average. You want that 90/95% plus about 1cm or so (for most nights)

If the average is near the top of the range, you probably need higher pressures in general.

[Xney]

Also, AHI of 0 is unrealistic as a goal. A good goal is to get it first below 5, and then something like 2-3 or lower.

[lhpangler]

Thanks for your reply. It was helpful.
I'll have to look around to see if the Elite II interface will tell me 90/95%. As for me and my bibap, my ahi's are about .8 to 1.0. Have a great day.

[Pugsy]

Actually changing the minimum would very likely reduce that AHI if they are obstructive apneas .
Minimum sort of gives us a sort of starting point for keeping the airway held open. If it is a bit too low it takes a little too long to get to the ideal pressure to prevent the stubborn events. The machine can't go from 5 to 9 in a blink of an eye. None of the APAPs will do that. Give it a little better head start with a little more minimum and it has a better chance of getting to where it needs to be to prevent those stubborn events that need a little more pressure.
Sometimes something as little as a 1 cm increase in minimum pressure will produce rather dramatic results.

That said...I don't know what Bilevel machine you were using...but a word about the S8 machines...for some people the Hyponeas were rather aggressively scored and more difficult to bring down with minor pressure changes.
This was the way the whole S8 models went about things...cpap or apap.
It may be difficult to compare your bilevel AHI to an APAP AHI when comparing different brands of machines and/or different models.

ResMed machines show 95% pressure on the LCD screen.
Respirionics machines show 90% pressure on the LCD screen.
Both are just numbers where the machine says you were AT OR BELOW that particular number. People tend to forget the or below part and think that 95% is the "ideal" pressure...it may or may not be.

[Thoughtful User]

Dear forum,

I understand that many users think that they can titrate themselves. And in most cases the logic of self titration make a lot of sense. However, you might want to keep in mind that if you are actually increasing pressure and you don't see AHI go down (which I assume you are reading this index from the machine,) very likely the nature of the AHI is central and not obstructive, in which case, you should only try the lowest pressure that reduced your AHI. More over, it has been reported in literature that overtitration may lead to central apneas, and there is even a controversy that states that overtitration may be the cause of the famous complex-sleep apneas.

My suggestion is, stop playing with the machine and go and visit a sleep specialist that can customize the treatment that you need.

BTW, I am not a doctor, but I am reading some actions that can be potentially harmful.

[Xney]

A sleep study with titration would definitely be preferred. But it may not be an option.

A sleep specialist looking over the same data and making recommendations is frankly not that different than experienced members here looking at it. Sounds wrong, but that's just how it is sometimes.