ASV Minute-Ventilation spikes after REM—looking for fresh ideas

[BrunoV]

Hi everyone,
I ran a search but most threads I found ended without a clear resolution, so I’m hoping the collective wisdom here can help.

What’s happening

• Every night I see events in OSCAR where my Minute Ventilation (MV) suddenly jumps right after a REM phase (confirmed with the SleepScore app—its staging isn’t perfect, but the timestamps line up).
  
• The MV spike almost always wakes me up. This pattern has been going on for months.
  

What I’ve tried so far:

1. EERS (Expiratory Rebreathing Space)
Tried 12 in → 9 in → 5 in.
Each reduction helped a bit, but making an EERS < 5 in is tricky with the parts available in Brazil.

2. No-EERS setup -> Acetazolamide (125 mg bedtime)
Following ChatGPT’s advice, removed the 5 in EERS entirely.
Started 125 mg two weeks ago.
Noticeble imporvement in the first night only.

Current ASV settings
EPAP 4 fixed, PS 2–7 cmH₂O.
Stable but MV spikes persist. EPAP 4 always solves all my centrals. 

Next ideas (from ChatGPT)

1. Lower Pressure Support to 1–6 cmH₂O.
   
2. Add glycine (3 g) + L-theanine (200 mg) at bedtime.
   
3. If that fails, increase acetazolamide to 250 mg.
   

Questions for the group

1. Has anyone else had awakenings timed with MV spikes after REM—and found a fix?
   
2. Did lowering PS or tweaking EERS make a real difference for you?
   
3. Any success (or side-effects) with combining acetazolamide, glycine, or L-theanine for this issue?
   
4. Other avenues I should explore?
   

I’ve attached OSCAR screenshots from 2 events of the 4 events last night for reference.

Thanks in advance for any suggestions—happy to test incremental changes and report back.

[BrunoV]

update 26 june 
Oscar graph attached.

There were no awakenings today, but the overall sensation after waking up was worse.

MV awakenings - Better
Grogginess - worse
Memory -  worse
Mental speed  - worse

Code:

Date  |EPAP| PS |Medications          |EERS|ASV Time|DEEP| REM| MV-Awakening| Grogginess| Memory| Mental Speed
------|----|----|---------------------|----|--------|----|----|-------------|-----------|-------|--------------
06-25 | 4  |2-7 |Acetazolamide 125 mg | -  | 6:15   |120 | 60 | 4           | 4         | 8     | 7.5
06-26 | 4  |1-6 |Acetazolamide 125 mg | –  | 5:19   | 89 | 55 | 0           | 8         | 6     | 7
      |    |    |Glycine  2.5g        |    |        |    |    |             |           |       |
      |    |    |Theanine 200mg       |    |        |    |    |             |           |       |

[BrunoV]

update 27 june 
Oscar graph attached. 

Two MV awakenings today... same medications and ASV setting as yesterday. For some reason, when I get less REM sleep, I always wake up feeling better

MV awakenings - Worse 
Grogginess - Better
Memory - Better
Mental speed  - Same

Code:

Code:

Date  |EPAP| PS |Medications          |EERS|ASV Time|DEEP| REM| MV-Awakening| Grogginess| Memory| Mental Speed
------|----|----|---------------------|----|--------|----|----|-------------|-----------|-------|--------------
06-25 | 4  |2-7 |Acetazolamide 125 mg | -  | 6:15   |120 | 60 | 4           | 4         | 8     | 7.5
06-26 | 4  |1-6 |Acetazolamide 125 mg | –  | 5:19   | 89 | 55 | 0           | 8         | 6     | 7
      |    |    |Glycine  2.5g        |    |        |    |    |             |           |       |
      |    |    |Theanine 200mg       |    |        |    |    |             |           |       |
06-27 | 4  |1-6 |Acetazolamide 125 mg | –  | 4:53   | 87 | 12 | 2           | 4         | 7     | 7
      |    |    |Glycine  2.5g        |    |        |    |    |             |           |       |
      |    |    |Theanine 200mg       |    |        |    |    |             |           |       |

[SarcasticDave94]

Despite the fact ASV stands for Adaptive Servo Ventilator, it is not going to act like a true ventilator as it lacks any manually accessible timing functions. I don’t know if the ASV will be the best tool to shape Minute Vent or other breath parameters.

The only things you can edit are your Mode, EPAP, and PS when it comes to settings. For example, have you used ASV Auto Mode that gives an EPAP Min and Max, creating a range? Have you tried more than 4 EPAP and/or more than 1-6 PS? Beyond modifying these, the ASV allows no more settings to attempt an influence in breathing.

You may find the ASV isn’t the correct tool to shape breathing.

Edit: another aspect, are you certain you need ASV if you say EPAP 4 treats your Central Apnea? It's not really EPAP that normally addresses CA but a PS burst on top of a base EPAP. Yours won't do this either possibly with a limited PS range 1-6 or 2-7. This is sounding an odd setup for what I've seen in my own when I had ASV, and others treating Central Apnea.

[BrunoV]

Hi SarcasticDave!

Appreciate you weighing in. Here’s the quick history just so you know where I’m coming from:

Polysomnography (in-lab)

• AHI 17 overall, 0 centrals.
  
• REM AHI equivalent to 41; non-REM AHI was low.
  

CPAP – ResMed AirSense 10 AutoSet

• Tried almost every fixed setting between 4 – 12 cm and many auto ranges.
  
• Once EPAP went past 7 cm, centrals blossomed.
  

BiPAP S – ResMed AirCurve 10 S

• More control over IPAP/EPAP and trigger settings, but still plenty of centrals.
  

Older BiPAP ST – ResMed VPAP ST (pre-IVAPS / pre-EasyBreathe)

• The lack of EasyBreathe kept jolting me awake—rough experience.
  

Current unit – ResMed AirCurve 10 ASV

• Best so far; reins in those emergent centrals.
  
• I’ve run PS min/max, EPAP min/max, and many mixes—with and without EERS (5″, 7″, 9″, and none).
  

I’m not ruling out that the answer could still be a pressure tweak—I’ve just spent months chasing every setting I can think of across these machines. I keep detailed OSCAR notes for each experiment, so if you suspect a particular configuration might help, I can:

1. Pull up a night I’ve already logged with those settings, or
   
2. Run another test night exactly as you suggest and share the graphs.
   

Let me know which route seems more useful. Open to any fresh angle 

Thanks again!

[SarcasticDave94]

Ok, it seems like you had Central Apnea after introducing CPAP, in other words what we know as treatment emergent CA. Sound about right, to you?

How long have you been using CPAP and other machines? It is possible the CA have diminshed on their own with time, again assuming these were treatment emergent.

The machine missed thus far is the ResMed VAuto, which might have been enough to treat your level of Apnea while also avoiding the CA. It too might not affect Minute Vent or other breath aspects, as it is an Auto Bilevel.

If, however, you really need MV assist, that probably comes in with the ResMed ST-A, a between class CPAP-ventilator combo.