AHI down from 68 to 0.69 on my first night? Something feels off.

[nisegami]

Hey all. I did an in-lab sleep study* in June where my overall AHI was 67.9. From the moment I got my results, I've had some concerns that it might overstated because during the study I slept mostly on my back and side whereas at home I sleep on my stomach**. One of the reasons I thought this might be the case was because on my back during the study I remember waking up gasping multiple times whereas I have never had that experience at home.

*it was their first time using the particular machine, but they are an experienced lab

**I have since read that chin tucking is a bigger factor, but the point stands

I expressed this to my doc and he showed me a breakdown of my positional data during the study which showed my RDI on my side as 52.7 and my RDI while supine as 105.5. This was enough to convince me that I was probably also experiencing sleep apnea while sleeping on my stomach. There were some challenges but I got my AirSense 10 yesterday and set it up for the night. I had some challenges getting through the night and I distinctly remember briefly waking up several times. This morning I loaded my data into OSCAR and it showed 5 events across 7 hours of sleep, which is orders of magnitude lower than during my sleep study. I did certainly feel more rested than usual, but given how frequently I woke up this AHI figure seems much lower than I expected.  

From what I can tell, the AirSense 10 algorithms for picking up on apneas is solid, though it may discount apneas that are almost but not quite 10s long. So there may have been a few of those, but it's not enough to explain the huge disparity, is it?

Basically I'm trying to reconcile the massive gap in these numbers. From what I can tell, sub-1 AHI is not something everyone reaches even after years of treatment, let alone their first night with a mask that isn't quite right. I've attached what I think are the relevant parts of my original report and my first night's report from OSCAR. Is there a chance I never had sleep apnea to begin with with my usual sleeping position? Any thoughts? 

Also, OSCAR is incredible and I am thankful to have it and you all to help with this journey <3

[Gideon]

Entirely possible!!!
Please post a screenshot, use F12 (PC) or equivalent to take it, or View/Screenshot from OSCARs menus as that includes some minor (temp) formatting to maximize the info presented.

What I still see is possibly many arousals (the spikes in the flow rate) It will take a 2-3 minute view looking at and around those spikes to be sure.
And you FL chart indicates that your events are not fully resolved.

Your min pressure is set at 4 and many of us feel that that is too low for many. That and EPR is the best tool at your disposal to manage those flow limits.
I doubt you will see much difference in AHI other that this may have been that exceptionally good day, but the the below changes you may feel better.

Because your AHI is so good I'll suggest the min pressure that will allow the full use of EPR
Set Min Pressure=7
Set EPR =2, FullTime (NOT Ramp only)

try these the repost and be very critical of how you feel and answer the question of which settings "feel" better, yes it is very subjective, and why.

[Sleepster]

There were some challenges but I got my AirSense 10 yesterday and set it up for the night. I had some challenges getting through the night and I distinctly remember briefly waking up several times. This morning I loaded my data into OSCAR and it showed 5 events across 7 hours of sleep, which is orders of magnitude lower than during my sleep study. I did certainly feel more rested than usual, but given how frequently I woke up this AHI figure seems much lower than I expected.  

First of all, congratulations on being able to tolerate the CPAP machine on your first night. That alone is a great accomplishment. Stick with it.

There may be no correlation between your AHI and the number of times you woke up. The AHI measures how well your airway splint is maintained. The frequent awakenings (also known as fragmented sleep) may be due to the fact that the hose, the mask, and the pressurized air are all new and they are disturbing your sleep. That will pass as you adapt.

And by the way, once you get acclimated to CPAP therapy I recommend turning off the ramp. If that causes discomfort you can always turn it back on, but usually it is a feature needed only by beginners.

[nisegami]

Entirely possible!!!
Please post a screenshot, use F12 (PC) or equivalent to take it, or View/Screenshot from OSCARs menus as that includes some minor (temp) formatting to maximize the info presented.

The screenshot feature refuses to save on my machine unfortunately, but I did take a regular screenshot if that helps. I haven't found any reports of similar issues online, so it seems like a me problem.

Your min pressure is set at 4 and many of us feel that that is too low for many.  That and EPR is the best tool at your disposal to manage those flow limits.
I doubt you will see much difference in AHI other that this may have been that exceptionally good day, but the the below changes you may feel better.

Because your AHI is so good I'll suggest the min pressure that will allow the full use of EPR
Set Min Pressure=7
Set EPR =2, FullTime (NOT Ramp only)

try these the repost and be very critical of how you feel and answer the question of which settings "feel" better, yes it is very subjective, and why.

I agree with your recommendations based on what I've read. Will give it a try, thanks!

First of all, congratulations on being able to tolerate the CPAP machine on your first night. That alone is a great accomplishment. Stick with it.

There may be no correlation between your AHI and the number of times you woke up. The AHI measures how well your airway splint is maintained. The frequent awakenings (also known as fragmented sleep) may be due to the fact that the hose, the mask, and the pressurized air are all new and they are disturbing your sleep. That will pass as you adapt.

And by the way, once you get acclimated to CPAP therapy I recommend turning off the ramp. If that causes discomfort you can always turn it back on, but usually it is a feature needed only by beginners.

Thanks! I intend to stick with it, thought I already think I need to get a heated tube and a different mask. My initial thought was that my awakenings were due to discomfort, but when I saw how few apneas I had my mind jumped to them being related. If it is just the experience being new, then hopeuflly I acclimate as you sugggest. Note taken about ramp, will probably leave it on tonight and revaluate tomorrow.

[Gideon]

Auto ramp is prob ok but start it at 7.

Better if you can go without the ramp so once you get used to it try ramp off

Thanks for the screenshot that covers what the auto formatting does.