obstructive verses central

[ywp]

Been on a S9 apap for a couple years. At a pressure of 14 to 18. Had a AHI below 1 with about half obstructives and half hypos.

Went to a PR1 auto bipap. My AHI went up to 2 to 4. No obstuctives. All centrals with lots of flow limiting and hypo. Because it see them as centrals it does not want to raise the epap. Been using settings around 15 min epap to 20 max ipap with prressure support of 3 to 4. Tried lower and higher pressures.

My question is which machine do you beleive. Or beleive none of them? the newer PR seems to be more sensitive to detection and response to flow.

Any advise on settings? If I try fixed bipap. what settings. 90% levels. where should pressure support be.

The whole identification of central verses obstructives by these machines seem questionable?

[Otter]

Been using settings around 15 min epap to 20 max ipap with prressure support of 3 to 4. Tried lower and higher pressures.

What happened when you did that?

My question is which machine do you beleive. Or beleive none of them? the newer PR seems to be more sensitive to detection and response to flow.

The whole identification of central verses obstructives by these machines seem questionable?

Because the machines don't measure respiratory effort, all they can do is make an artificially intelligent guess based on flow data. I think they do a pretty good job for most people, but you may be one of the exceptions. Philips and Resmed use different methods to check your airway (one sends a single 2 cm pulse, while the other sends a rapid series of smaller pulses), and it may be that one is more accurate for you than the other. If you really want to get to the bottom of this, you could rent a home sleep study kit with myoelectric sensors and use that concurrently with each machine. If you decided to go that far, I'll be very interested in your results.

If after scouring a few nights of flow data you really think your AHI was lower with the S9 and the difference isn't just in how the two machines score events, then it seems to me that the S9 algorithm is a better match for you and you should go back to that. I'd both count scored events (rather than accept the AHI summary at face value) and look for events that would be scored by one machine but not by the other. Also be alert for waking centrals.

Though it doesn't really address what to believe about the type of apnea you have, the best guide to which machine supports your sleep better is how you feel.

[sister]

Good question! Which machine to believe? I just got a new S9 auto last week and now have an AHI of 0.2 to 0.8.
After using the S8 for over 5 years I never could get my AHI down, always ran in the 20's and 30's no matter what I tried.So really, which machine do you believe? I feel about the same!

[archangle]

Look at the flow waveforms with SleepyHead or other software and see how completely you're stopping breathing and for how long. Don't just look at the number of events, consider how serious they look. If they're borderline in terms of duration or completeness, it's not as worrying as long, complete apneas.