ResMed vs. Respironics Question

[UARSsufferer]

Hi all,

I'm a new user (about three months), about to settle on a machine, and I have a question about some odd results I'm having. I was using an S9 elite CPAP machine and getting almost exclusively centrals (AHI ~3 - 6 over a two week period). This is odd, because for the first two and half months I was on a Respironics APAP trial machine and experienced very few centrals per night. A few nights ago I switched to a System One CPAP and now I'm having almost exclusively Hypopneas again, with very few centrals (AHI ~3). I don't think that anything else has changed, so I'm wondering if this could be related to the machines. My questions are:
- is it possible that the machines work slightly differently, leading to different results (similar AHI, but centrals vs. hypopneas)?
- is it possible that this is due in part to the way the machines score breathing events? (I'm having the same events, but they're defined differently by each machine)?
- any other ideas?

More generally, has anyone found that they respond in a significantly different way to one machine or the other? (As opposed to just preferring one or the other).

Both machines are the latest models: S9 Elite CPAP with EPR and PR System One REMstar Pro CPAP with AutoIQ, with the pressure set at 8, and the Pilairo Q mask, and a Respironics chin strap. I'm looking at the data provided by SleepyHead.

[Pugsy]

The Auto IQ is NOT the latest model at all...but that shouldn't be the cause of the discrepancy. That model was discontinued well over 2 years ago.
The 2 brands do use different algorithms but I don't think that one brand would call the same thing hyponea with one brand and central with another...the airway being open or not should be the same with either brand.

There are minor differences in the even category definitions but that's mainly with the amount of reduction for OA or hyponea and not the patency of the airway.
Like 40% vs 50% for hyponea designation (I think 40...but I know just 10% difference).

The newest models are the 60 series machines with the heated hose.
PR System One 60 series machines...the closest thing to your machine would be the PR S1 60 series Pro model 460 as it has limited APAP mode capabilities...just like the Auto IQ had limited APAP mode capabilities.

The Respironics machines (from my past experience) do seem a little more sensitive and in general my AHI would be a bit higher with it than with the S9 that I used for a while.
But it wasn't because of "centrals"

I wonder if your centrals are real centrals or awake/semi awake breathing centrals..
Or did you see a pattern to the centrals with the S9 like a cluster at about the time you would be falling asleep?
Or did you see them during a time where you were most likely awake?

[UARSsufferer]

My mistake - i've got the 60 series machine, with full data.

I can't see a pattern to the centrals - they seems spread out evenly throughout the night, or at least fairly evenly spread out over a part of the night (a few of hours). I'm not conscious of waking up or stirring more often.

The odd thing, to me at least, is that I played with the pressure on the S9 and brought it as low as 5 (from 10). This did reduce the centrals (from a high of 45 per night, to ~12), and the hypopneas stayed away (1 or 2 a night). But as soon as I went to the Respironics machine I was having 12-20 hypopneas per night, and only 5-10 centrals (at pressures of 6 and then 8 ).

[Pugsy]

Hypopnea

An hypopnea is indicated if there is approximately 40% reduction in airflow for a duration of between 10 and 60 seconds, compared to the average airflow over an extended period of several minutes. Following a reduction in airflow, the therapy device must see two recovery breaths in order to label the event as a potential hypopnea. (Respironics detection is 40% reduction and ResMed detection is 50% reduction)


The reduction in air flow doesn't have to be as much to get a flag with the Respironics machine...only has to be 40%
So it is entirely possible that the PR S1 is flagging stuff that the S9 is ignoring.

Example....Reduction in flow is maybe 45%...gets a flag with the PR S1 but doesn't with the S9 because it needs a 50% reduction.


Similar situation with centrals...clear airway apnea events...
only it's ResMed that has the lower % of reduction to earn an event flag so it would not be unexpected to see it flag more apneas than the PR S1 and that includes both the clear airway and obstructive events.


Apnea

An apnea is indicated if there is an 80%/75% (Respironics/ResMed) reduction in airflow for 10 seconds compared to the average airflow over an extended period of several minutes or if there is no airflow detected for 10 seconds.

Apnea/Clear Airway Apnea Detection the the Respironics System One.. An apnea is detected when there is an 80% reduction in airflow from a baseline for at least 10 seconds if there is no airflow detected for 10 seconds. During the apnea, one or more pressure test pulses are delivered by the device. The device evaluates the response of the patient to the test pulse(s) and assesses whether the apnea has occurred while the patient has a clear airway or an obstructed airway. The airway is determined to be clear if the pressure test pulse generates a significant amount of flow; otherwise the airway is determined to be obstructed.

Apnea Detection guidelines per ResMed machines..Apnea...When the respiratory flow decreases by more than 75% for at least 10 seconds.

[UARSsufferer]

Thanks for that information Pugsy - that's really helpful. What I take away from your description is that my scores could be an artifact of the difference between the measures that each machine uses. I just happen to have a number of breathing events that fall into this borderline.

[Pugsy]

Yep...some "close" in duration...a few in that little window where the criteria is just a little different.

If trying to decide which machine to buy at the end of your trial..
If you couldn't see the AHI...do you sleep better or feel better with one over the other?
Features you like better with one or the other?

Did you try Encore to see if you liked that software?

[UARSsufferer]

If I couldn't see the AHI I would chose the ResMed machine - I find it's EPR much more comfortable than the Respironics Flex system. In fact I experience mild aerophagia with the Respironics machine. Because I was diagnosed with UARS I was initially going to chose the Respironics machine because it flags RERAs, but I have so few that I don't think it matters.

On a related matter, I find that many mornings I don't 'know' how I feel or slept until I check my data. I rarely feel refreshed in the morning, and suspect most days that I feel roughly the same, but if I have a low score I 'feel' like I had a better sleep, and if my score is a little higher, I 'feel' like I had a bad sleep (even if the difference is minimal). I may start checking the data on a weekly basis - it seems easy to get caught up on the numbers. Can anyone else relate?

[Pugsy]

I may start checking the data on a weekly basis - it seems easy to get caught up on the numbers. Can anyone else relate?

Yes, lots of people can relate.
It's why I often recommend that (especially newbies) wait until evening to check their "numbers".
Sort of eliminate creating a self fulfilling prophecy. If it doesn't look as good as we wanted..we feel crappy the rest of the day and we don't know if we would have felt crappy anyway.

UARS people...the regular "numbers" aren't going to likely show you much anyway. From what I have read UARS related stuff doesn't often show up in the regularly gathered data...
Maybe the RERAs or Flow limitations (which FL BTW won't show up at all if not in an auto adjusting pressure mode on Respironics machine) to some extent but not an absolute.
Typical AHI values that get reported aren't good tools to use for evaluation and instead people have to go on how they feel and that's hard for people to do.
We tend to be a numbers oriented society in terms of evaluating medical stuff...normal lab values is a good example.
We want to measure the effectiveness of our therapy with a "number" because we do it with lab stuff..unfortunately when it comes to evaluating sleep stuff it just isn't that simple.

There's just so much more to getting good sleep and feeling better than a nice low AHI.