Switched to ASV - AHI is great, but still feel like I'm not sleeping well

[Sassbeek]

Hey all,

Wanted to post to see if there's something obvious I'm missing here. Brief history of how we got here

- Original sleeptest shows AHI of 26/hr, plus 20/hr RERAs. AHI is mostly hypopnea with some centrals, no obstructive
- Given an APAP
- Tried alot of different settings, kept running into issues. AHI was averaging between 3-6, usually 50/50 hypopnea and central (or slight majority central), would occasionally have 1-2 obstructive events a night (Possibly just machine mislabeling?). Higher pressures seemed to make things better, but aerophagia meant I could only go so high before sleep would be ruined by constantly waking to stomach pain. EPR to maximum raised this ceiling a bit
- Showing mild Cheyes Stokes in this time, think it was ~8% of the time

- Sleep doctor recommended BiPAP, but wasn't sure if that or ASV would be better given central apneas and evidence of cheynes-stokes, so recommended I got an ASV since you can effectively turn that into a BiPAP to save me potentially having to get two more machines
- Have gone with my initial ASV settings, which are just giving it a wide spectrum to work with.

EPAP min 6, max 15
PS min 2, max 19
iPAP max 25

So I've been on ASV now for around 3 weeks and now my AHI is basically eliminated. Most nights it's 0.0, it's only been over 0.3 twice. But, my sleep still feels really bad. I'm consciously waking up alot during the night, and wake up feeling tired. It definitely feels better than on APAP where my sleep felt *awful*, but still doesn't feel great.

Last nights sleep attached, it's pretty typical.

Does anyone see any obvious tweaks to make here? If not, should I just keep it up and see if I adapt and it's too early to worry? Lastly, is there merit to trying to see what happens in a BiPAP mode with a constant epap and ipap? Do I just have non sleep apnea related issues impacting my sleep?

Apologies if I'm missing anything, happy to provide more as needed

[Sleeprider]

All charts are of the same therapy session, and any one of them would have been sufficient. I have some ideas on how we might improve this. This session is based on EPAP min 6, EPAP max 15.0, PS min 2.0 and PS max 19.0. It seems pretty clear you can limit EPAP max to 8.0 and PS max to 12.0. I think you may need a higher PS min of 3.0 to 4.0, but let's get a zoomed view of what is going on at about 02:12 where we see the flow limits and snores occurring. I suspect flow limitation that might benefit from higher PS. With the ASV, you need to let your breathing settle before masking up. Your sleep session starts with slow, deep breathing resulting in very high vent rates which is used by the ASV as a target. This resulted in extended hyperventilation being forced by the machine. Just relax and let things settle down before masking, or use a ramp time and that will go away. My impression is that you don't need ASV and might have done better with a Vauto bilevel.

[Sassbeek]

All charts are of the same therapy session, and any one of them would have been sufficient.  I have some ideas on how we might improve this. This session is based on EPAP min 6, EPAP max 15.0, PS min 2.0 and PS max 19.0.  It seems pretty clear you can limit EPAP max to 8.0 and PS max to 12.0. I think you may need a higher PS min of 3.0 to 4.0, but let's get a zoomed view of what is going on at about 02:12 where we see the flow limits and snores occurring. I suspect flow limitation that might benefit from higher PS.  With the ASV, you need to let your breathing settle before masking up. Your sleep session starts with slow, deep breathing resulting in very high vent rates which is used by the ASV as a target. This resulted in extended hyperventilation being forced by the machine.  Just relax and let things settle down before masking, or use a ramp time and that will go away.   My impression is that you don't need ASV and might have done better with a Vauto bilevel.

Thanks so much for the indepth reply, can't express my gratitude enough for the work you do here and apologies for triple attachment, was trying to capture all relevant data points in the screenshot!

Attached is around the 2:12 mark, see anything interesting there? Happy to screenshot anywhere else if needed

I can for sure change those settings. What should I be looking for when masking up, just breathing slower? Or should I just do as you said, 15 minute ramp and that'll sort it out?

Was definitely hoping to not hear yet another machine may be better, but it is what it is if that's the case. Will try my best to make this work but am open to switching if I've exhausted all possibilities

[Sleeprider]

Your zoomed chart shows periodic higher flow often preceeded by a flow limited or even a possible snore breath. What I don't see is the mask pressure that might have given some insight to those variations in terms of machine response. If you can capture that flow rate segment again, but include mask pressure, breath rate, insp time and tidal volume, it would be more useful.

[Sassbeek]

Your zoomed chart shows periodic higher flow often preceeded by a flow limited or even a possible snore breath. What I don't see is the mask pressure that might have given some insight to those variations in terms of machine response.  If you can capture that flow rate segment again, but include mask pressure, breath rate, insp time and tidal volume, it would be more useful.

Think I got them all here, let me know if not or if you need more.

Thanks again!

[Sleeprider]

If you don't mind some experimentation, based on very limited information, I'm going to suggest we try some settings that seem to address your needs. I'd like your to change EPAP min 6.0, EPAP max 8.0, PS min to 3.0, PS max to 8.0. This is as close as I can get to bilevel with a higher minimum PS, however you will still get limited ASV pressure support when minute vent or respiration rate falls below your moving target. Remember not to mask up until your respiration has settled after going to bed.

[Sassbeek]

If you don't mind some experimentation, based on very limited information, I'm going to suggest we try some settings that seem to address your needs.  I'd like your to change EPAP min 6.0, EPAP max 8.0, PS min to 3.0, PS max to 8.0.  This is as close as I can get to bilevel with a higher minimum PS, however you will still get limited ASV pressure support when minute vent or respiration rate falls below your moving target.  Remember not to mask up until your respiration has settled after going to bed.

100% up for any experimentation! Will try this and report back

One quick one, is there something with my breathing I should be more focused on? Like making sure I'm breathing faster or slower than I was last night? Or just get into bed, sit there for 5 minutes, relax and stick it on without over thinking?

[Sleeprider]

Your breathing rate will usually get shallower and slightly faster. You sure don't want to mask up when you're just done exerting yourself. It should settle enough in 3 to 5 minutes. Look at the flow rate graph when you first dropped into bed and started your last session, and don't do that. Your ASV learned that as a target rate and tried to maintain it for the first 15 minutes.

[Sassbeek]

So here's my next night with those settings changed, not sure if my initial breathing is still an issue? I tried to lay in bed for 5 minutes before adding my mask, if that's no good maybe I can try ramp as you suggested or just start in 'mask fit' mode which quietly switches to treatment mode if you leave it on for enough time?

See anything here? Definitely feel like I didn't have a great night sleep, but it's only a one off so happy to wait or if there's something else I should tweak

Also happy to provide any more context if needed (Initial sleep study, other nights sleep etc). Also happy to zoom in anywhere

[Sleeprider]

Well this is much better from the perspective we have 8-hour of therapy vs 1.75 in the previous chart. There is no significant difference in AHI or respiratory statistics. I don't see any evidence of central apnea and if sleep is being disrupted, it is due to the varying PS through the night. I still think you are on the wrong machine and the Vauto would have been a lot more comfortable to deal with whatever you are trying to resolve. I assume your diagnosis is obstructive sleep apnea and I am unclear why you thought ASV would be better. Unfortunately, with the Resmed ASV, you either get CPAP or ASV. There is no option to make this machine mimic the therapy on a Vauto or VPAP-S. The good news in you have a machine worth more than a simple bilevel, and if you choose to do a swap with someone like Supplier #2, you should come out with some surplus funds.