ResMed apnea type CA/OA recognition problem

[palerider]

Well, I'm done with trying to help someone who's rolling their eyes at every comment.

I'll leave that to others.

Cheers and good luck.

I'm sorry, I didn't mean to offend you. I probably mistakenly used this emotion. It was supposed to mean that I was wondering about...

Eyerolls are typically used to convey "what is this stupidity I'm hearing?" or something to that effect.

I generally avoid emoticons because I don't know what they mean.

[Jay Aitchsee]

Please include Flow Limitations in the next set of charts you post.
Thanks

[pcstud]

Please include Flow Limitations in the next set of charts you post.
Thanks

Same day. I don't see anything interesting here.

[Jay Aitchsee]

It would be helpful if you posted an overview which included these charts in the future so we can see what's going on.
Events
Flow rate
Pressure
Flow Limitation
Leaks

I asked for your Flow Limitation chart to be included to see if Flow Limitations were driving your pressure up. I cut and pasted your charts together so we could see.
The answer appears to be, not so much. A couple increases are driven by FL, one by hypopnea, and the rest by OA. These OA without preceding FL are interesting. How about posting a couple shots about 5 minutes in duration centered on the Flow Rate surrounding those apneas like the one at 2:30 and the one around 4:00.

flowlimit.JPG

This chart would seem to suggest a higher pressure was needed around 7:00, but the machine was limited by Pmax. In reference to our previous conversation, some people find increasing pressure and/or pressure fluctuations disturbing, which could be the driver of those CA. Again, it would be helpful to see all the charts posted together to gain better insight as to what's going on. As I said earlier, I suspect you might be awake or semi awake after 7:00 during those CA. If the Flow Rate chart were included, it might give us a clue.

[pcstud]

I hope this will help

[Jay Aitchsee]

OK, so here's my opinion:

Each of the events or chain of events depicted in the examples above begin with what looks like a disturbance indicating a possible arousal. These disturbances occur at 2:21:00, 04:03:18 and 07:03:58. Also associated with each disturbance and event is a small amount of leakage which could indicate mouth breathing or mask slippage and could confound the result. There are no Flow Limitations associated with any disturbance or event.

I believe these events are occurring during a time of disturbed sleep and arousal and would not be classified as "real" apneas in a lab setting. However, CPAP machines will raise the pressure after an Obstructive Apnea is detected, regardless of sleep stage, awake or not. In the above examples, I believe the machine has raised the pressure unnecessarily and a reasonable course of action would be to limit Pmax.


Others may disagree.


(A graphic overview of the whole night followed by expanded graphics for select periods would be helpful in future posts)

[Pugsy]

The machine can't tell if a person is asleep or not...it can't tell if the reduction in airflow that it perceives as an OA is related to an arousal/awakening at all. It will respond to awake flagged events just like if we were asleep because it doesn't have any way of separately the 2.

I agree with Jay...pretty much all the flagged stuff looks like post arousal breathing flags...not asleep so not real.

I have seen this happen with my own reports on more than one occasion. Heck, one night I had an AHI of 3.4 and there was a nice mixture of centrals, OAs and hyponeas. Pressure increased for the OAs as we would expect. Only thing...every single one of those flag events in all categories weren't real asleep events. All were arousal related and so blatantly awake breathing related not even iffy.
Didn't surprise me...I knew I didn't sleep well that night because of pain issues worse than usual. I did a lot of remembered tossing and turning....AHI was high for me but none of them was even real...not a single one.

We may or may not remember the arousal/awakening...but it can still happen. For me I remembered just having a crappy night's sleep due to pain. I figured some of the events would be arousal related...it was a surprise to me to find out every single one was arousal related. My sleep apnea therapy was spot on with no events related to apnea at all...I just had a bad night due to back pain.
The machine still did its normal thing because it has zero way to tell if we are awake or asleep.

[pcstud]

@Jay Aitchsee @ Pugsy

Your opinion is in accordance with my original assumption - obstructive apnea events are misdiagnosed but it is not the fault of the machine as I expected; I did not associate it with arousal but thought it was central apnea.I didn't know the arousal looks the same as the apnea on the graphs. This is new to me.

What you are saying is very good news, because it means that I do not have central or obstructive apnea at this pressure. As I expected.

The interesting thing is, I don't have that kind of experience/problems with Dreamstation. Recently I also tested PrismaLAB (a very interesting German device!) and there my AHI dropped even to zero. No one similar events. Is it possible that other manufacturers recognize arousals? Or did they just appear to me after changing the machine?

Thank you for your time guys!

[Pugsy]

No...there are no brands or manufacturers of cpap/apap machines that can recognize awake vs asleep breathing.
None of them will. Maybe someday they will but not now.
If you didn't have this issue with the DreamStation brand it was just a coincidence.
I have seen false flagging happen on Respironics machines as well...they aren't any better at distinguishing awake vs asleep than ResMed or anyone else.

This is a flow rate graph from an Encore report ...Respironics machine.
Pretty much every single flagged event here is arousal related...this person didn't even have OSA (per an in lab sleep study)...he just has crappy sleep from a truck load of spontaneous arousals.
He has more arousal related breathing than asleep breathing.
Asleep breathing the nice smooth equal breaths...the arousal breathing is irregular and all over the place...and his AHI was around 5 per the machine with a nice mixture of all categories of events....none of them were real.

[Jas_williams]

Machines classify events with different criteria without full understanding on the scoring used it is difficult to say why one machine scores one way or another scores another. All we really know is an indication of what the particular machine you used thought the night was like. Don’t get hung up on the numbers, look at the treatment and how you feel and if you were awake or not when the events were scored. Anything under 2 AHI is good if you still feel tired it may not be sleep apnoea causing your issues, look else where.