[Pressure] Best settings for my machine?

[Chuck]

Zonk - Thanks for the link - I'll study all these pages more later today.
I wish the linked pages explained C-Flex better. I can't figure out what C-Flex+ actually does and what effects it might have on my therapy. Just as in my copy of the clinician manual, it's mostly squiggly line graphs without labels.

Can anybody explain the difference between the C-Flex and the C-Flex Plus features? The manual (I have both the professional and user manuals) doesn't explain it well.

Philips Respironics Flex Family

[SuperSleeper]

Hi Chuck, welcome to Apnea Board!

C-Flex is a type of "exhalation pressure relief"... it simply lowers the pressure a bit as you breathe out... you can read more about it on our Wiki, here:

http://www.apneaboard.com/wiki/index.php...ure_relief

[PaulaO2]

There isn't a significant difference between the two. C-Flex seems to be the slightly older version of algorithm to detect and respond to exhalation. C-Flex+ is the newer version, doing the same thing but with a different algorithm.

What they do is they detect when you breath out and slightly lower the pressure, making it easier to breathe out and be more comfortable. ResMed's version is called EPR (exhale pressure relief). They're all just for comfort and not for treatment.

[PaulaO2]

C-Flex pressure relief technology makes sleep therapy more comfortable by reducing pressure at the beginning of exhalation and returning to therapeutic pressure just before inhalation. The level of pressure relief varies based on the patient’s expiratory flow and which of the three C-Flex settings has been selected.

The real brains behind C-Flex is our patented Digital Auto-Trak & Sensitivity. Digital Auto-Trak is a highly sensitive algorithm that tracks each breath and detects the onset of inspiration and expiration – even in the presence of mask leak. It then responds by triggering C-Flex to provide an adaptive pressure relief right when the patient needs it. And delivering the right level of pressure relief when patients need it makes therapy more natural – and more comfortable.

C-Flex+ is our newest enhancement to comfort relief for our advanced CPAP units (REMstar Pro and Auto) when in fixed CPAP mode. Like C-Flex, C-Flex+ provides flow-based pressure relief at the beginning of exhalation. Like A-Flex, C-Flex+ softens the pressure transition from inhalation to exhalation to provide additional comfort in fixed-CPAP mode.

There's also A-Flex and Bi-Flex which work with autoPAP and Bi-Paps.

[SuperSleeper]

There isn't a significant difference between the two. C-Flex seems to be the slightly older version of algorithm to detect and respond to exhalation. C-Flex+ is the newer version, doing the same thing but with a different algorithm.

I think you're basically correct, Paula. While there may be some slight algorithm change from C-Flex to C-Flex+, (there's really no way to know for sure), it could very well be that they made some very small insignificant change, and are now promoting it as a "new better feature" for marketing purposes.

That's the problem with these technologies... it's all proprietary and the keys are guarded safely by the manufacturers, so we're really not sure what the difference is between the two "technologies", if there is any at all.

We just have to take their word for what each feature does.

[greatunclebill]

There isn't a significant difference between the two. C-Flex seems to be the slightly older version of algorithm to detect and respond to exhalation. C-Flex+ is the newer version, doing the same thing but with a different algorithm.

I think you're basically correct, Paula. While there may be some slight algorithm change from C-Flex to C-Flex+, (there's really no way to know for sure), it could very well be that they made some very small insignificant change, and are now promoting it as a "new better feature" for marketing purposes.

That's the problem with these technologies... it's all proprietary and the keys are guarded safely by the manufacturers, so we're really not sure what the difference is between the two "technologies", if there is any at all.

We just have to take their word for what each feature does.

i understood all along that my generation 2 respironics cpap with c-flex provided relief only on exhale. not on inhale and i never felt it on inhale. now i'm reading here and there in posts, people mentioning c-flex providing relief on inhale and exhale somewhat similar to a-flex. my thought is that they added inhalation relief and called it c-flex+.

[PaulaO2]

You are correct.

C-Flex is about adjusting the flow when it detected the user breathing out then increasing it back when the exhale ended. It seems to be exhale dependent.

C-Flex+ seems to have added the inhale but only in that it smooths the transition on inhale as well as the beginning of exhale. They added that part from the A-flex.

Frankly, I don't see what the difference is other than in quality. They both lower the pressure on exhale and they both raise it when the exhale ends (or inhale begins). C-Flex+ allegedly makes that transition smoother. It's all about branding.

Either way, using it or not using it would not truly make a difference in treatment except to encourage compliance for those who like the exhale relief.

[greatunclebill]

Either way, using it or not using it would not truly make a difference in treatment except to encourage compliance for those who like the exhale relief.

this may have nothing to do with the actual c/a-flex part of it and be more apap vs cpap. at a pressure of 12, even with the c-flex i was totally non-compliant because i couldn't breathe against the pressure. the 12 in, 12 out, even stepped down to 9 was just too much for me with my lung issues which are asthma/copd. when i got the apap and it was set 8-12, it was easy to tolerate on a-flex3 which would be blowing out against 5 in normal breathing.

[Chuck]

All very good replies; thanks so much.
Here's my C-Flex + paranoia: Let's say I have a central apnea. According to SleepyHead software, I had at least 2 of them last night.
If C-Flex + tries to adjust to my breathing rhythm, but I've stopped breathing, then ... does it go ahead and increase the pressure as if for inhalation? Or does the machine wait for me to begin inspiration before increasing pressure? And if the 2nd case is true, then does that mean my CPAP simply stops blowing until my brain finally decides to breathe?
I tried C-Flex + last night, and it was the worst night yet. I suspect my paranoia described above is possibly why.
I'm going with C-Flex (no +) tonight, as my understanding of it is that it only lowers pressure for exhalation, with no pressure relief during inspiration. This is all based on my best guesses at what's going on.
The advantage of C-Flex+ from the aerophagia point of view is that there is much less air blowing into your gullet, which means you swallow less, therefore less bloating. And indeed I am much less bloated today (just exhausted).
I also checked my SleepyHead record. My worst nights were back in August when I was mucking with the machine and I turned on C-Flex +. Something about my apnea doesn't like C-Flex +.

[PaulaO2]

They say they base it on a 'natural breathing rhythm', whatever that is. A lot of people don't like ResMed's EPR system as it doesn't match or detect their rhythm.

Two central events a night is not bad at all! The AHI is the number of apneas (stop breathing) added to the number of hyponeas (shallow breathing) divided by the number of hours. It's an average. So if you have an AHI of 4 and slept 8hrs, that'd be 32 events that night.