Understanding Pressure Setting on ASV

[czara]

I would be ever so grateful if someone could please help me understand why my therapy has not been successful.

Hx: 75 y/o F, no hx of sleep apnea until after shoulder replacement surgery May 2017;  exhausted and could not recover from surgery.   Finally a heart specialist realized it was apnea, which had been undiagnosed for 2 yrs.

May 2019, in lab PSG showed 60 events/hr in supine position (which I must use r/t shoulder pain).  Began with Dream Machine CPAP.  Had high number of CSA I believed from high pressures Dr ordered (5-20).  I could not tolerate high pressures; (chest hurt and left me breathless throughout day.)  
 
New Dr advanced me to BIPAP.  The high pressures from BiPAP were intolerable so Dr. lowered to 5-10; but that seemed too low to treat apneas.  I continued BiPAP for 1 yr.  then Dr suggested I stop using BiPAP.   I was always tired, never felt rested and did not sleep well.
  
Two yrs later (Dec 2022) I had neck whiplash in deer collision (totaled car).  My apnea became very severe.  Another new Dr. in Sleep Medicine.  In-lab PSG (Ap '23), recommended Airsense CPAP.  Used Airsense for 6 wks but that was triggering high CSA.  Back for in-lab PSG 2 more times (May and June '23) before received Resmed Aircurve ASV.  I thought that would be the answer to my prayers.

Using ASV since July 2023, initially with pressure recommendations from Sleep Study: EPAP 5-11 cmH2O, pressure support 0-15 cm H2O per Dr orders.  Continued with restless sleep and ~ 10 AHI/hr.   Pressure was strong enough to push face mask (amara view) loose and cause a significant air leak.  After 3 wks. Dr. lowered pressures to:  EPAP 5-11 with PS 0-10 cm H2O.

What I perceived as strong pressures continued to cause air leaks, awakenings and SA.  After 4 wks Dr lowered pressures again on Sept 1.  Currently: EPAP 5-10, PS 0-8.  But I am still miserable and severely sleep-deprived.  This pressure reduction has not helped over the last 4 wks but seems to have gradually made things worse.  AHI last night at 19.   I can't sleep from all the awakenings.  And the pressures are quite a bit different from the last sleep study recommendations.

I have tried different mask set-ups and liners to no avail.

The ASV is supposed to automatically adjust to your breathing.  But I feel like it is fighting me; almost attacking me.  As I doze off to sleep with slow deep breaths, the ASV algorithm reads it as apnea and starts blasting me with pressure.  I am so sleep-deprived for over 10 months now that I am having difficulty thinking this through.  I have no physical or mental energy.

My Dr does not seem to know what to do now.  I don't understand much about the pressures on an ASV but I'm wondering if my pressure support begins too low at 0-10.  I don't know.  I've looked at the Resmed Sleep Reports.  It looks like the SA event happens and then the air leak, not the reverse, which is what I thought was happening.  I can't understand the graphs on OSCAR.

Any ideas would be appreciated.  And please share any information on how or where I can learn to understand how these pressure settings are affecting the machine and my sleep and what is most appropriate.

Thank you,
Carolyn

[Sleeprider]

Carolyn, we have many members that are successfully using ASV. Sometimes it requires adjustment in how to adapt to the machine, or control it, and sometimes a different mask can work. Our best bet to help you is to see your results in OSCAR, a free software that gives us details on your therapy efficacy, respiration and settings. The graphs will let us see how disruptions arise and helps guide us on how we might want to limit the machine's pressure settings. The reasons that individuals have problems with the ASV therapy vary a lot, so it really helps to narrow the possibilities with some graphs. You mention slow, deep breaths as you try to fall asleep, and this is one mode of failure, because the Resmed ASV learns your breathing rate and volume over a couple minutes, then tries to maintain that. Slow, deep breathing is not how we sleep! Our breath rate becomes shallower and more rapid. I'm certain if we look back at your results on CPAP and BPAP, your normal respiration is less than 400 mL tidal volume and about 15 breaths per minute. By using this slow deep breathing, I'm certain you are setting yourself up for disruption and failure. Post some charts, and let's try to get this optimized from both the machine settings, and user points of view.

For better understanding of your machine, read the ASV section of the Resmed Clinical Titration Guideline, I think on Page 28. https://document.resmed.com/en-us/docume...er_eng.pdf