s9 in auto - does it adjust to RERAs??

Does the S9 in auto mode adjust to catch RERAs or just hypopneas and apneas? thanks

Been a while since I had the S9 AutoSet, but if I recall correctly:

1) the S9 does not attempt to track RERAs; hence it can't directly respond to them.

2) the S9 does respond (by increasing pressure) to snoring, flow limitations and obstructive apneas. Not sure about hypopneas. And it (correctly) does not responded to clear air way apneas since they are much more likely to be central apneas.

Isn't a flow limitation the same as a RERA? In other words, if it is responding to a flow limitation then by default it is responding to a RERA?

tiredintenn wrote:Isn't a flow limitation the same as a RERA? In other words, if it is responding to a flow limitation then by default it is responding to a RERA?

Nope. Flow limitations and RERAs are related, but they are not the same.

A flow limitation is a partial collapse of the upper airway. FL are detected (in algorithms designed by the Resmed and PR engineers) by changes in the shape of the inspiratory part of the wave form that matches certain criteria. Flow limitations have been discussed at some length (among many other topics) on [url=viewtopic.php?f=1&t=62516&st=0&sk=t&sd=a&start=30]SleepingUgly's recent thread[/i] starting around page 3. Lots of useful charts particularly one from -SWS showing several different types of wave forms that are considered to be indicative of flow limitations.

A RERA is a respiratory effort related arousal: It is something that can (and often is) measured in the sleep lab using the EEG channel to verify that an arousal has indeed occurred where the flow data and the belt data are showing increased respiratory effort. PR claims that it's System One machines detect RERAs (and the Auto versions of those machines also respond to the detected RERAs as well as the detected FL). How PR's engineers programed the S1 to "detect" RERAs without an EEG is a proprietary secret---but the PR algorithm must be based on pattern recognition of what "recovery breaths" (during the arousal) are likely to look like in the flow wave.

OK - so if you were me with nothing but reras - 17/hr and were given an S9 auto would you titrate until the flow limitations were minimal? Would you then run in CPAP at the 95% pressure or keep it on APAP. thanks

tiredintenn wrote:OK - so if you were me with nothing but reras - 17/hr and were given an S9 auto would you titrate until the flow limitations were minimal? Would you then run in CPAP at the 95% pressure or keep it on APAP. thanks

Did you have a formal titration study done? If so, then I'd keep the machine at whatever was prescribed based on that study at least for a while and study the flow limitation graphs and track how I felt each morning in a sleep log of some sort. But that's just me and I'm not a doctor.

And at my next appointment with the doctor or his assistant, I'd ask some questions about what kind of data off of the S9 Autoset you should be looking at to verify that your pressure level is correct.

I'd also start by reading through this current thread about flow limitations: viewtopic/t62947/Help-Clueless-about-Fl ... tions.html