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.
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 +.
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.