CPAP and APAP Question

[lzicc]

I've been using my CPAP for 4 years now. My pressure is set to 12. Last week I turned the pressure down to 11 and my AHI from SleepyHead went down. I was averaging around 2 AHI when my pressure was 12 and now it is a little lower. Some nights as low as .48.

I asked my doctor if I could try a APAP to see if it is possible that my pressure needs lowered. I did lose some weight, so they gave me an APAP to use for 30 days. I used it last night and SleepyHead was telling me that my 95% average pressure was 15 and my AHI from last night was .88. That doesn't sound right to me. If I can keep my AHI well under 5 using a pressure of 11, why is the APAP saying my average pressure from last night was 15?

This is with the APAP variable pressure:


This is with CPAP fixed 11 Pressure:

[LSAT]

95% is NOT an average. It means that 95% of the time your pressure was at that number or LOWER.

[Pugsy]

Like LSAT said...95% numbers aren't the average or where you were at for 95% of the night....they are where you were at OR BELOW for 95 % of the time.
With no way to know how far below for how long at lower pressures. People often forget (or don't know about) the "or below" part of the definition.
95% numbers are easily skewed by relatively short periods of higher numbers be it pressure or even leak numbers.
Because they are easily skewed we can't always consider 95/90 % numbers as a definitive marker for evaluation of pressure needs or even leak results because we don't know how long it was at lower numbers.

Better to evaluate the graphs themselves to get a better idea where the pressures were running for the night.

[ChicagoGranny]

I've been using my CPAP for 4 years now.

Time to start thinking about getting your own APAP?

Although your current machine may last years longer, a good rule of thumb is to get a new machine every five years. After five years, the risk of failure of a CPAP machine is significantly higher, the technology of newer models is marginally better, and you can keep your older machine as an important backup machine.

[lzicc]

I do want to try to get an APAP. My current CPAP is 4 years old and I don't think my insurance will let me get another one til after 5 years and I don't know if they will let me get the APAP or not. I think after this 30 days trial, if my pressure does fluctuate allot during the night, they may consider it.

So if my pressure auto set to 15 95% of the time, wouldn't that mean that my pressure should be 15? I can post some of the graphs if that would help. I don't know how to screenshot them all in one shot though.

[Pugsy]

So if my pressure auto set to 15 95% of the time, wouldn't that mean that my pressure should be 15?

No....you still don't understand that the machine is NOT doing 15 for 95% of the time.
It's doing 15 or below for 95% of the night. For 5% of the night it is going over 15 .
The "or below" is very important.

95% numbers are really only significant when looked at for weeks and months...not nights.

Long term...the median pressure number is probably the one that I would look at if using cpap mode.

Some time ago when I was using apap I did a long term evaluation of 90/95% pressure numbers because some nights my 90/95% number was around 12 and some nights it was 18...with minimum being 10 cm.
Over 6 months it all averaged out to the 90/95% pressure numbers being in the 12 to 13 range...which was just about where the median average ended up being.
Some nights I would need higher pressures like 18 for 30 minutes of the night...and the 90/95% number would be up around 17...but I wasn't using that much pressure all night...only for maybe 30 minutes or so.

90/95% numbers are easily skewed higher by short periods of high numbers.

You do have a choice though....use 11 or 12 all night and get decent results or use 15 all night and get same decent results.

The times at 15 or 16 cm...could just maybe have been the machine responding to some snores or flow limitations that wouldn't be critical to let them slide with less pressure....or maybe they were related to sleeping position or even REM sleep.

[Pugsy]

Read this thread please. It provides additional explanation about 90/95% numbers along with a couple of reports that might show you what I mean about the numbers being skewed easily.

viewtopic.php?f=1&t=61734&st=0&sk=t&sd= ... holy+grail

It's old and the software shown is different but the basics are unchanged no matter what software is showing the numbers.

[ChicagoGranny]

I don't know if they will let me get the APAP or not.

Insurance companies pay by a billing code. CPAPs and APAPs use the same code. The insurance company doesn't distinguish between the two.

[avi123]

Are these your charts from 2015?

[lzicc]

Pugsy, thanks for clearing that up. I understand now. AVIL123, I believe that is mine. Here is a current graph.

[palerider]

I used it last night ... That doesn't sound right to me. If I can keep my AHI well under 5 using a pressure of 11, why is the APAP saying my average pressure from last night was 15?

when trying new things never make a decision based on a single nights sleep.

[lzicc]

Very true. I think I was hoping to wake up and see some really low pressure numbers. I also thought I would feel better after using the APAP. I actually felt more tired when I got up.

I used it last night ... That doesn't sound right to me. If I can keep my AHI well under 5 using a pressure of 11, why is the APAP saying my average pressure from last night was 15?

when trying new things never make a decision based on a single nights sleep.

[Pugsy]

Your body is used to experiencing a constant fixed pressure all night and now with apap the body is experiencing changing pressures all night...some are little changes and some are rather big changes. It takes a while to adjust to any new change.
Also some people simply find that the least little change in anything can disturb their overall sleep quality...so those changing pressures could maybe be disturbing your sleep at some level and that could maybe account for not feeling the good numbers.
So it could just be poor sleep quality from the "change" and with time you might get adjusted to apap full time and get back to feeling the good numbers....or maybe you are one of those people who find that the variations in pressure in auto adjusting mode causes the low level sleep disturbances (you may or may not even remember awakening).

I do see that they are using apap pretty much wide open which really isn't the optimal way to use it. Lots of variations and it's letting some snores, Flow limitations and RERAs slip past the defenses which could also account for maybe not sleeping so great.

I think you would do better if that minimum was increased so that the FLs, snores and RERAs were better reduced. They aren't a part of the AHI but they do mean that there's a good chance that sleep quality isn't optimal.

I would suggest increasing that minimum from 5 to maybe 9 or 10...that will better hold the airway open so the machine is doing more preventing and not so much fixing. It will lessen the roaming around of the pressures and could maybe even reduce the need for the machine to go higher.

FLs, snores and RERAs could be signs that the airway is trying to collapse a bit...
FLs and snores are 2 of the primary things that these machines will increase the pressure in an attempt to open up the airway better.

Oh...FLs are only flagged in apap mode...so the absence of FLs in your cpap mode reports doesn't mean anything...the machine simply doesn't flag them in cpap mode.

How long are you going to have this machine? I would increase the minimum and at least see what happens with a more optimal minimum setting. No need to do anything with the maximum at this time.

[ChicagoGranny]

when trying new things never make a decision based on a single nights sleep.

Even if your AHI went to 60?

[palerider]

when trying new things never make a decision based on a single nights sleep.

Even if your AHI went to 60?

stranger things have happened.