Hi everyone,

I’m new to CPAP and looking for some guidance, as my therapy doesn’t seem to be going in the right direction yet.

** Baseline sleep study (before CPAP) **

I was diagnosed with moderate obstructive sleep apnea on a home sleep study.

  • AHI: 21.9 / h

Event breakdown: - Obstructive apneas: 21 - Central apneas: 5 (~0.7/h, not clinically significant) - Hypopneas: 141 (dominant component)

Diagnosis: Moderate obstructive sleep apnea. No Cheyne–Stokes respiration reported

My OSA was mostly hypopneas, with very few central events.

** CPAP device and current settings **

  • Device: Löwenstein Prisma Smart
  • Mode: APAP
  • Min pressure: 5.0 cmH₂O
  • Max pressure: 14.0 cmH₂O
  • SoftPAP (pressure relief / pressure support): 4.0 cmH₂O
  • PSoftMin: 4.0 cmH₂O
  • PMaxOA: 13.0 cmH₂O
  • Ramp: Off

** Results on CPAP **

** Night with APAP 4–12 cmH₂O (before pressure increase) **

  • AHI: 13.4 / h
  • OA: ~4 / h
  • CA: ~2.4 / h
  • Hypopneas: ~7 / h
  • RERA: ~7 / h

Sleep felt more stable and better tolerated

** Night with APAP 5–14 cmH₂O (current) **

  • AHI: 33+ / h (worse than baseline)
  • OA: ~1–2 / h (well controlled)
  • CA: ~8 / h
  • Hypopneas: ~24 / h
  • RERA: ~14 / h

Cheyne–Stokes respiration appears (~2%), which I never had before CPAP

Additional observation: The machine ramps up very quickly to high pressure, even during short naps or very light sleep, and tends to stay near max pressure for long periods.

** My concern **

It looks like:

  • Obstruction is controlled
  • But CPAP is inducing central apneas and unstable breathing
  • Overall sleep is very fragmented and I feel worse than before treatment

This makes me suspect treatment-emergent central sleep apnea or over-ventilation due to aggressive APAP + high pressure support.

** What I’m hoping to get feedback on **

Does this pattern make sense early in CPAP therapy?

Could high pressure support (SoftPAP = 4) and a wide APAP range be driving the central apneas?

Would reducing pressure support and narrowing the pressure range (or trying fixed CPAP) be a better approach?

Thanks in advance for any insights — I’m trying to understand what direction makes the most sense before my next discussion with my provider.

Here is the link to my data: https://sleephq.com/public/teams/share_links/570c7d0b-ff0c-489b-a3c5-02b5de421b3b

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    parent

  • Try a lower pressure support. You could have high loop gain, and it is frequently made worse with higher pressure support. Too much CO2 gets blown off, your chemoreceptors go "aaaaaaa!" and then your breathing oscillates a bunch.

    Have flow rate and minute vent next to each other in OSCAR. Zoom in so you can see about 5 minutes across the whole screen. If MV looks like a sine wave and your breaths are waxing and waning in a way that follows the shape of MV, that's high loop gain. Especially if there isn't any indication of obstruction at the same time that this wobble gets going.

    Try to get your range a bit smaller and try a pressure relief of 1-2. Other people may have better ideas for overall range. I just woke up and am pulling a blank. The pain with HLG is that you frequently need higher pressure support to relieve flow limitations, but it also feeds into that wobble. You get to choose between fewer centrals but lots of flattened breaths or lots of centrals but prettier looking breathing when you're not oscillating over 30-60 seconds.

    Fair warning: if this doesn't get better in 6-8 weeks it's not "just" TECSA and you'll likely need ASV.

    Welcome to an extremely annoying club.

    parent
    parent root

    Whoooo that's wobbly.

    I'm way less familiar with that machine, admittedly. But generally, try to keep your max under 12-13 initially, unless you have really obvious obstruction that needs serious blasting. Try turning your minimum to 7 or so. Getting the range smaller should help at least a little bit.

    And yeah, when I was going through some similar stuff (though I never triggered CSR detection) pressure relief of 3 made the instability far more impressive than at 1. You will have to see how it feels yourself, but in my experience that sort of mad wobble disturbs sleep more than slightly increased flow limitations.

    ASV acts as essentially active noice cancelling for that wobble. The pressure support is constantly adjusting in finer increments to create a negative version of that MV wobble.

    parent root

    Just to clarify something about my machine, because there seems to be some confusion:

    On my Löwenstein Prisma (provider-locked unit), I do not have access to separate PSoft or PSoftMin values in the clinician menu.

    The only SoftPAP-related options available are:

    • SoftPAP: Off / Slight / Standard

    There are no numeric pressure support settings exposed (no PSoft, no PSoftMin), so I can’t directly set PS to 1–2 cmH₂O the way it’s done on some other devices.

    I’ve already reduced SoftPAP from Standard (max) to Slight, but OSCAR still shows the same generic PS values, which I understand may be a limitation of how Löwenstein data is interpreted rather than proof that nothing changed.

    If anyone here has experience with Prisma devices or provider-locked firmware, I’d appreciate confirmation on whether this is expected behavior and how best to fine-tune pressure support and overall stability given these constraints.

    parent root