First Night on ASV – Need Advice
Hi again everyone
I just completed my first night with asv and tbh I really hoped for a better result. I woke up really tired and groggy and felt way worse than normal. I looked through my data on Oscars and immediately knew my settings where off. Im therefore writing this post in hope of some experienced asv users can help me with my therapy/progress.
Background:
- Mild OSA/UARS.
- My biggest issue seems to be long periods of waxing and waning ventilation (likely high loop gain), often triggered after flow limitation/arousals.
- CPAP/BiPAP controls obstructive events fairly well but does very little for the unstable breathing.
BiPAP settings that I came from:
- EPAP 6
- PS 4 (IPAP 10)
Flow limitation improved only slightly compared with CPAP, but loop gain remained almost unchanged.
First ASV night:
- Fixed EPAP: 5.6
- PS min: 2.6
- PS max: 9
Results: https://sleephq.com/public/9034f7ec-9fbd-4b61-b914-08b8ea768e78
- Central apneas: essentially zero.
- However, flow limitation became noticeably worse during waxing/waning periods.
- I ended up with more hypopneas than on BiPAP.
- Subjectively I felt much worse.
Looking at OSCAR, the ASV algorithm is clearly changing pressure and trying to follow my minute ventilation, but it doesn't seem to stabilize the oscillations enough. It almost feels like once unstable breathing starts, my upper airway also becomes more unstable.
My questions are:
- Does this sound like poor initial titration rather than ASV simply not working?
- Would you consider increasing EPAP slightly if hypopneas appear during these periods, or would you leave EPAP alone and instead focus on the PS range?
- How do you decide on the optimal PS minimum? I understand ASV needs room to both increase and decrease pressure, so I don't want to set PS min unnecessarily high.
- Has anyone with UARS/high loop gain experienced that ASV required a lot of tuning before it became effective?
- When you titrate ASV, what metrics do you prioritize in OSCAR? Minute ventilation, IPAP behavior, flow limitation, respiratory rate, or something else?
For context, I'm also planning to try EERS once my equipment arrives, since acetazolamide (125 mg) had only a very small effect for me.
I'd really appreciate hearing from people who have successfully titrated ASV for unstable breathing rather than primarily central sleep apnea.
Thanks!