S8 Autoset Questions

I have had a S8 Autoset loaner for ONE week and am NOT Happy with it so far.

My regular ( now broken) CPAP was the RemStar Auto M series with C flex...during the past 2 1/2 years, I was getting a AHI of less than 3 with a set range of 8 to 10 and using a FP 432 Full mask. (Avg pressure was 9.5)

With this S8, I am using the same settings and mask as the M series, BUT....my Efficacy readings for the week are significantly HIGHER!!

Readings are: Press 10, Leak .08 l/s, AHI 11.5, AI 1.4. HI 9.7 !!

Questions:
1) NO option on S8 menu for the FP 432 Mask ( tried Standard and Ultra as Mask setting with no noticable difference in Daily Result)
Can Mask selection Effect Efficacy results??
2) Are pressure range settings different between the two mfg algorithyms(sp)??
3) What changes in settings suggested before I return S8 next week and try to get a different Autopap.

Thanks in Advance

No, the "mask setting" on the S8 machine shouldn't really affect the efficacy results, since it's really just used by the machine to calculate the "leak rate", although I suppose if it was drastically different maybe it could? The idea is to match the leak rate represented by the ResMed mask selected in "mask setting" on the AutoSet II as closely as possible to the "exhaust flow" (aka "intentional leak rate") of the mask you're using. In theory, if the two numbers are the same and you have no leaks, then the machine-reported leak rate would be zero. That is the ultimate goal. Your leak rate of .08 l/sec is just fine. The leak rate shouldn't affect efficacy results until it gets around .4 l/sec (24 l/min).

You can find the "exhaust flow" for the F&P 432 mask in the brochure that came with the mask and you can also find that here: http://www.fphcare.com/userfiles/file/O ... ctions.pdf. Look at the Technical Specifications/Exhaust Flow Information chart. Find your machine pressure there, and right below that will be the flow rate.

Then, look at this chart, which shows the expected flow rates for the ResMed masks: http://www.resmed.com/assets/documents/ ... sa_eng.pdf. See which flow rate most closely matches your mask's "exhaust flow". On the second page you will see the equivalent settings for the machine. It looks to me like your closest match would be the Mirage Swift II mask, which uses the "Swift" mask setting on the S8 machine.

I have a few thoughts about why you're seeing such different results with the S8 AutoSet versus the RemStar Auto M. One thought is that Respironics' C-Flex and ResMed's EPR do work differently. ResMed machines actually drop pressure by that many cm H2O on exhale, while Respironics C-Flex works differently. You didn't mention if you were using C-Flex, what that setting was, and if you're using EPR on the AutoSet loaner (if it even has EPR).

Also, ResMed does tend to report events differently than Respironics. Many people notice that their hypopnea results are higher with the ResMed machines, which may simply be due to a difference in how the manufacturers define and respond to it. As far as I know, your set pressure range would be the same with both machines.

I'm just wondering if you notice a difference in the way you feel -- either better or worse. My other thought is that you've only had the loaner for a week. It can take me at least that long to get used to changes in my therapy.

Perhaps some others here will have some good suggestions for you, but I hope that helps to explain some things.

EPR and C flex set to "2".

Yes, I do not feel rested in the morning after same amount of rest (8 hrs).

Seem to feel a little groggy and irritable.

Bob

Hi Bob,

That is a very significant difference in AHI that you report between the two machines, for sure (Respironics AHI <3 vs. ResMed AHI 11.5). Whether that much of a difference would continue over a longer period of time, I don't know. There can be an adjustment period when we change anything to do with our therapy, and you may be a bit more distressed at bedtime without your familiar machine too.

Respironics and ResMed each have different algorithms, so it could be that your particular breathing pattern is more compatible with Respironics' method of operation.

Even though you have both EPR and C-Flex set to "2", they do work differently. Since the ResMed machine actually drops exhalation pressure down 2 cm H2O, perhaps you could try EPR on the ResMed machine set at "1" or even "off" and see if that makes any difference for you.

Rested Gal has suggested here that because the ResMed algorithm defines "hypopnea" differently than Respironics, you may get a more comparable AHI by cutting ResMed's HI in half. If we did that in your case, then your ResMed AHI would be 6.25. Still higher than Respironics, but perhaps some of the things mentioned above could account for some of that.

I hope you'll be able to sleep better soon! Please let us know what you discover.