ResMed Airsense 11 - Central vs. Obstructive

[FlowRider]

I'm a new CPAP user and just found this board - it's a great resource!

How does the Resmed AirSense 11 determine if an event is central or obstructive?  In general, how accurate is that determination?  

I'm especially interested because my in-clinic sleep studies had very different results: the diagnostic study indicated ALL apneas were central while the titration indicated ALL apneas were obstructive.  For what it's worth, my initial home study (Watermark ARES) indicated only obstructive events. So far, after a week of use, OSCAR tells me the AirSense 11 believes nearly all are central (CA index = 3.51 and OA index = .13).

[Crimson Nape]

Hi FlowRider! -
Resmed induces a waveform in the air they have termed Forced Oscillation Technique (FOT). This is something like a sonar signal. The Resmed will send out this wave of air looking for a return. If the waveform bounces back, then the event is classified as an obstruction (OA). If the waveform is not returned, then it is considered a Clear or Central event (CA). While technically a Clear and a Central event are different, an EEG is required to determine the difference. For this type of event on a CPAP, a CA is considered a breathing cessation without an obstruction being detected.

- Red

[Gideon]

Please post your OSCAR daily charts and both your diagnostic and titration sleep studies

Thanks
It is with data that we can best comment

[FlowRider]

Crimson Nape - Thanks for the explanation of ResMed's approach to identify obstructions through a reflected signal. Interesting technique!

Gideon (and perhaps others) - Attached is a representative day from OSCAR, my diagnostic report, and my titration report. Apologize for the wide presentation of the reports - I needed to convert .pdf to .jpg for upload.  

   

   

   

[SarcasticDave94]

I guess the PSG diagnostic was first shown, it mentions 7 Central and zero Obstructive, plus 44 Hypopnea. No Centrals reported in the titration.

Maybe the variable CA status may end up being treatment emergent, however due to the 7 in the PSG, you may have a lower threshold for Centrals susceptibility.

OK onto OSCAR. Try a reduced EPR and no Ramp. Both can contribute to pressure swings, which creates the environment CA like to make themselves present in some patients.

[Gideon]

I suspect arousal/breath holding and a bit of obstructive but without seeing the breath-by-breath charts (3-4 minute view) I'm guessing.

[FlowRider]

SarcasticDave94 - Thanks for the suggestions!

Gideon (and perhaps others) - Attached are three zoomed in examples of central apnea events identified by my AirSense 11.  Do you think they are, in fact, CAs?

           

[SarcasticDave94]

You're welcome.

I'll let others better than myself read zoomed charts. I'm not at all experienced with it. Never had to do much with fine details on mine.

Best wishes you'll get better tuned therapy soon. I'll be around somewhere, possibly break room with coffee.