APAP Reading higher pressure than set for

soulrhythm · Post by **soulrhythm** » Wed Dec 05, 2007 6:55 am

For the last few nights I have narrowed my APAP pressure from 10 to 12, but my 95% pressure has come back 12.4 and 12.2. How can that be?

Actually I have another question too: My AHI consistently jumps around quite a bit. It ranges from 1.9 to 4.7. It is under 5, so I am not too concerned, and it is all in my HI's, so that is ok too (my AI averages 0.1 and only fluxuates between 0.0 and about 0.3). I am wondering however , why the HI's fluxuate so much. Is that common? Is it because I have a Resmed machine that tracks Hypopneas higher than others?

Thanks, in advance, for your input.

JIM

Slinky · Post by **Slinky** » Wed Dec 05, 2007 7:08 am

What is your Leak rate showing? The displayed leak rate on your LCD screen is also the 95th percentile of the night. These newer machines are capable of compensating quite nicely for a high leak rate and I'd venture a guess that your Leak rate is quite high and contributing to the higher pressure.

There is also the possibility that those hypopneas are apnea-wanna-bes that were prevented from occurring.

rested gal · Post by **rested gal** » Wed Dec 05, 2007 7:31 am

Soul, every resmed machine I've used has reported a higher (almost double) number for the Hypopnea Index than any Respironics or Puritan Bennett machine I've used. That's with exactly the same setup of pressure, mask, separate humidifier, and whether C-Flex (in Respironics machines) was on or off.

That doesn't mean the resmed machine is over-reporting, or that the other brands are under-reporting. It's simply the way each manufacturer has designed their machines to report a certain degree of flow limitation. In other words, each manufacturer has its own definition of how limited the flow must be, and for how long, before it is no longer deemed a "flow limitation" and is called "hypopnea."

Guest · Post by **Guest** » Wed Dec 05, 2007 7:34 am

My leak rates are consistenly under .2. Occassionaly, I will have a .3 or .4, but not very often.

soulrhythm · Post by **soulrhythm** » Wed Dec 05, 2007 7:37 am

Your info on the Hypopneas makes some sense, but I'm still confused why the 95% pressure be higher than I had the machine set for? Am wondering if maybe it is because 10-12 is so narrow?

track · Post by **track** » Wed Dec 05, 2007 7:39 am

I have never been able to get my HI below 2..maybe it's because I too have a resmed machine. Who knows...but I am not worrying about it.
Fluctuations in AHI are normal for me...a lot of it depends on how much I sleep on my back or how long I sleep or if I have one or 2 drinks in the evening....more means higher AHI and less means lower AHI but never below and AHI of 2.

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rested gal · Post by **rested gal** » Wed Dec 05, 2007 8:04 am

soulrhythm wrote:I'm still confused why the 95% pressure be higher than I had the machine set for? Am wondering if maybe it is because 10-12 is so narrow?

I don't know. Other than that it would interesting to know, I'd not think that a half cm variation from a setting would matter at all treatment-wise. For curiosity's sake, it would be interesting to know why.

My guess would be that none of these machines are going to be absolutely 100% precise right down to tenths of a cm about what pressure they actually blow and/or what pressure they actually report. The specs in the manual for any brand probably state something like +/- 1 cm for what the blower might do. But I don't know.

track wrote:I have never been able to get my HI below 2..maybe it's because I too have a resmed machine. Who knows...but I am not worrying about it.

I thnk you're right not to worry about that, track. I didn't worry about it either since I felt exactly the same -- well rested -- after using any xpap machine. Personally, I'd consider an HI of 2 with a resmed machine to be the equivalent of getting a "zero" HI with Puritan Bennett and Respironics machines.

GumbyCT · Post by **GumbyCT** » Wed Dec 05, 2007 8:43 am

soulrhythm wrote:For the last few nights I have narrowed my APAP pressure from 10 to 12, but my 95% pressure has come back 12.4 and 12.2. How can that be?

I think it has to do with sleeping during math class. But I am not the math expert so we'll have to wait until Jules gets back to find out for sure.

Word problems are always a problem when not enuff info is given -specifically what the pressures were before and how many days? Meaning how many data points are you averaging?

Many scenarios come to mind but let's say for ex. if your press. avg for 30 days was 15cm? What would a pressure of 11cm for 2 more days cause the avg to be?

Get the idea?

rested gal · Post by **rested gal** » Wed Dec 05, 2007 9:12 am

GumbyCT wrote:Word problems are always a problem when not enuff info is given -specifically what the pressures were before and how many days? Meaning how many data points are you averaging?

Many scenarios come to mind but let's say for ex. if your press. avg for 30 days was 15cm? What would a pressure of 11cm for 2 more days cause the avg to be?

I much prefer word problems to math problems, or techie problems.

Since soulrhythm is using a resmed machine and those machines can give "daily, weekly, monthly" data in the LCD window on the machine, I took the 12.4 and 12.2 to be several "one night" results he was looking at. For just the "previous night." Not an average over several days. I've assumed wrong before, though, so maybe he was talking about a weekly average. I took it as the overnight pressure number.

Respironics missed the boat when they put just weekly and monthly averages into their "Show AHI/Leak" feature. resmed's way of presenting that window info is much better, imho...showing Daily/Weekly/Monthly results, and breaking down the AHI into AI and HI.

GumbyCT · Post by **GumbyCT** » Wed Dec 05, 2007 9:24 am

rested gal wrote:Respironics missed the boat when they put just weekly and monthly averages into their "Show AHI/Leak" feature.

mine is a Respironics but I am not familiar with how any of them do their math. Tho I am almost certain it's not very good.

I simply gave an example of "how" it could happen cuz I to have often wondered the same thing.

To compound "MY Problem"- my sleep doc thinks that Encore is 100% accurate. Go figure. Think she was sleeping during the "Ability to Reason" Lecture?

Slinky · Post by **Slinky** » Wed Dec 05, 2007 10:16 am

IF wishes were horses ..., right, RG? Or even if Resmed and Respironics would just LISTEN to the PATIENTS, the END-USERS and .... ah well.

You wish Respironics would adopt Resmed's way of presenting the LCD screen info, showing Daily/Weekly/Monthly results, and breaking down the AHI into AI and HI.

And "I" wish Resmed would adopt Respironics' Daily Events Per Hour chart. I wonder if they will EVER get it RIGHT!

*sigh*

soulrhythm · Post by **soulrhythm** » Wed Dec 05, 2007 11:09 am

Rested Gal... You are right...it was several daily reports I was looking at. My APAP max was set to 12, but the readings we 12.2 and 12.4. YOu may be right on wondering how exact they are in the tenths.

With my Hi's, I know it is not a big deal. I am under 5 and my AI's are very consistent at 0.0 to 0.3 (a great score!). I am just curious why one day my HI is a 1.9 and the next it can go up to 4.7 (with no change in other areas: leak rate, etc).

rested gal · Post by **rested gal** » Wed Dec 05, 2007 11:38 am

soulrhythm wrote:I am just curious why one day my HI is a 1.9 and the next it can go up to 4.7 (with no change in other areas: leak rate, etc).

Dunno. Maybe some more congestion on some nights, or mask getting shoved sideways a little pushing the nostrils more partially closed for a few minutes, or a change in head position pulling the chin back more toward the chest at times on some nights, or...gosh, anything!

I guess I just figure it's normal to have varying numbers of hypopneas, more so than apneas. With any brand of machine.

soulrhythm · Post by **soulrhythm** » Wed Dec 05, 2007 11:50 am

Yeah, that makes sense. I am probably just obsessing trying to hit a "perfect number that does not exist.

APAP Reading higher pressure than set for

APAP Reading higher pressure than set for

Re: APAP Reading higher pressure than set for

Re: APAP Reading higher pressure than set for

Re: APAP Reading higher pressure than set for

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Additional Comments: Strictly a side sleeper