Variations in AHI

[Catnapper]

I have been using cpap therapy for over 12 years. After the first 7 or 8 months, I found the solution for me, the right machine, the right mask and the right pressure. For years my AHI (according to my data and my doctor) stayed in the very low numbers. My AHI for 6 months would be between 0.4 and 0.6. Not too shabby.

Lately, all has changed. I might have a night with 0.1 AHI followed by a night with 3.6 AHI. I don't change anything so far as I know. Can anyone suggest some answers for why this might happen or what to do about it? I realize that 3.6 would be considered OK, but my concern comes from what might be causing the change.

Thanks.

Catnapper - Joanie

[Pugsy]

Joanie...Happy New Year.

What I would do first is make sure that the flagged apneas are real and not related to false positive flags from SWJ.

Not long ago I had a night with an AHI of nearly 4 and I went in and looked at each event flagged and not a single one of them was the real deal. They were all SWJ stuff. I just had a bad night in terms of back pain and remembered doing a lot of tossing and turning.

If you don't know how to figure out how to distinguish real events from false positive flags...watch the videos here.
http://freecpapadvice.com/sleepyhead-free-software

If they are indeed real for the most part then we start looking at other potential culprits.

[Catnapper]

Thanks Pugsy. Happy New Year to you too.

The first video did not like my computer, so I need to solve that problem before I can learn to evaluate the events. I think it will be interesting to do, so I will work on that when I can. Nice to know the software does all that. Maybe I don't have a problem after all.

I got a new machine in August, and have had a different mask than the one that did so well. That could also have caused some changes, don't you think?

Once I can evaluate the events, will I be able to adjust the causes?

Catnapper - Joanie

[Julie]

A new mask can definitely change results, esp. if you've gained or lost even a little weight as your face changes quickly at those times.

[Pugsy]

Once I can evaluate the events, will I be able to adjust the causes?

Hopefully. It's not always so easy to fix a problem even when you know what the problem is. Doesn't mean we won't try though.

And yes...a mask change can also impact results in multiple ways...might cause more arousals and thus cause more SWJ and might cause the pressure needs to be altered if the events are real and not SWJ.

The videos show how to zoom in and see the breathing up close and help you figure out real vs not real.
I do have a short version explanation in a thread somewhere that I did not long ago.
Let me see if I can go find it.

[Pugsy]

Well crap...I have bits and pieces of how to distinguish stuff all over the place and nothing in one nice easy to find place.
I really need to do a tutorial of my own and make it easy to find but just don't have the time or energy.

Found these...should get you started anyway. The video shows some easy tricks for how to scroll through the entire night easily and quickly looking at the flow rate zoomed in....basically zoom in to the level you want and then use the right and left arrows on the keyboard to smoothly move along with the examination. I do it sometimes just to count arousal breathing episodes that might not even have any flags associated with them.

Real asleep flagged event.


Not zoomed in much but arousal breathing before the flag so a post arousal flagged event.


Same here...post arousal flagged events...not asleep...so not real. This person actually doesn't have OSA (per an in lab study) and 95% of his flagged events weren't real..they were post arousal. He has some really crappy sleep issues and sleep maintenance insomnia issues unrelated to OSA or sleep disordered breathing. CPAP can't fix it.


An example of asleep breathing circled...the other stuff...post arousal. Again crappy sleep quality.

and this

It's nice when they are clear cut and easy to evaluate like these 2. 99.99 % sure I was asleep.


Or this one which is SWJ breathing near the flagged hyponea and the red circled area is asleep breathing.


Unfortunately we don't always get nice clear cut easy to spot to evaluate.

.this flagged event isn't real. There was arousal breathing prior to the flagged event.



Or here from a different machine's software....all these flagged events aren't real. They are all post arousal.

[Catnapper]

Thanks, Pugsy. Those examples help a bunch. I have a busy day today, but should be able to do some evaluating tomorrow. I will guess that I don't have many real events. I have an auto-bi-pap that probably takes care of things very well.

Catnapper - Joanie