Central Apnea, switched from BiPAP to CPAP?

[wubisnotanabbreviation]

I was diagnosed with CA about 2 1/2 years ago, and prescribed bipap treatment. After a couple of weeks things got very comfortable and I my AHI was consistently below 1.0. Then a few months ago my relationship with my machine went sour, and I couldn't understand why (http://www.apneaboard.com/forums/Thread-...-the-rails).

I finally had another sleep study, and it went surprisingly well. At my follow up appointment, I learned that I had slept 6 hours, had 4 separate REM cycles, with zero events. Wow! Perfect score! Then, my doctor told me that what worked so nicely was CPAP at a pressure of 6.0. I was expecting to hear ASV, not this.

My machine was set to this configuration about 2 weeks ago. I've been trying to give this configuration a fair chance, but I am still frequently having the sensation that there is too much pressure for comfortable exhalation. I have essentially perfected a breathing pattern of in through my nose, out either by nose or mouth. This seems wrong but defensible. My results have been erratic, but my average for the past week is below 2.0 (helped by a 0 I posted last night) - higher than it was during my "honeymoon period" but still considered "treated".

In my first sleep study, CPAP made things worse. What could have changed to make it the preferred solution now? Can anyone help me understand what is going on here?

[Boodmaster]

That doesn’t sound right, but I mean, it’s possible of course. You could just not have had any CA at the time of the test. But fwiw I’d probably consider another test.

[Sleeprider]

In your last thread, your settings were 9/3 and all apnea wewe being detected as OA.  At that time the consensus advice on the forum was higher EPAP and less PS.  That is exactly what CPAP at 6.0 represents.  I think we would have found a similar result if you had implemented our suggestions.  For central apnea, CPAP pressure generally works best, and if that fails, then the move to bilevel without a backup rate is generally worse.

I predict that CPAP will result in a lower AHI than bilevel, but if the central apnea diagnosis is correct, then results may be inconsistent in the long run.  Whether the event rate or sleep disruption end up at a level that justifies ASV remains to be seen, but doesn't look likely at this point as you actually had reasonably good results, even when your settings were extremely adverse for CA like in this chart.