Understanding Sleep Study

[Centennial2]

I'll begin by apologizing if this has been covered elsewhere....
I'm trying to relate my wife OSCAR summary data to data she got from her sleep study, to confirm that her treatment is effective.
I think I've got a good handle on the OSCAR terms and conventions (apneawiki great help) but the terms used in her sleep study are less clear:


Just guessing here but are they saying there were 134 apneas and hypopneas during her 8.25 hours.  Is there a separate index for hypopneas or does this just lump apneas and hypopneas all together? 
What is a pRDI ?
Again guessing is ODI4% (128 events) supposed to be telling me that 128 times during the session her oxygen saturation dropped by 4% or more?

What the heck is a pAHIc4%.

Lastly what is a PAT amplitude, and why is it important? What, if any significance, is there that the PAT amplitude is so variable?



Thanks,
BE

[BoxcarPete]

Can't help you much with the PAT, but I can confirm for you that you pretty much got the others:

RDI = Respiratory Disturbance Index. This is always the highest because it includes apnea, hypopnea, and additional types of events that can disturb sleep.
AHI = Apnea-Hypopnea Index. This includes every event where breathing was restricted by 50-80% (hypopnea) or >80% (apnea) for ten seconds or longer.
ODI 4% should be a total of the number of those events where O2 was desaturated at least 4%.
AHIc4% I believe is referring to "central" apnea, where there is no effort to breathe, rather than an airway obstruction.

That last one, CSR, probably refers to Chyenne-Stokes Respiration, which is an abnormal breathing pattern that can be associated with heart failure, so it's good that she scored a zero there.

[robbob2112]

If you want help with seeing how effective your wife's treatment is you will need to post her Oscar data.

[Opus1]

Engineer, well we already have something in common. My engineering proclivity causes me to ask questions. So…
The percent reductions you mentioned, what is the ‘compared to quantity’?  I assume that there is a baseline value; but how is that baseline established?

As a simple example, is the baseline oxygen saturation the mean of all the all the o2 reading for the entire sleep session, or the mean of the O2 readings in the previous 10 seconds? Or something else?
Same kind of question relative to apneas or hypopneas.

In essence, what defines the baseline(s)?

[Centennial2]

Thanks for asking that, I'd like to know as well (even though I don't have an engineering degree !!!!)

[Expat31]

You may be interested in this video presentation.

To start with the doctor goes at breakneck speed, then slows down to a better pace.

You may want to pick and choose what interests you, and go backwards and forwards a few times.

Gives a good insight on some basic key elements:-

Understanding your sleep study

[Centennial2]

To Expat: Thanks for that link. However, compared with all the apparent absence of detail in my sleep study, it would seem that the Watchpat study is a dumbed down investigation. 
Maybe I’m not seeing it in my study but is there something that measures the effort needed to breath? Is there any way to see the ratio of apneas to hypopneas.?
According to this doctor in the video these things are necessary to understand the validity and seriousness of the overall AHI.

I’m also very interested in that question about the baselines and how they are determined.

[BoxcarPete]

To be honest, in my opinion there's nothing hidden in the subtleties of that report. That type of thing is for people in the mild range, like me. He didn't even mention sleep phase, but my test was an in-lab polysomnography, so I had brain wave data to confirm sleep phase. I had an AHI of 25 in REM, but 0 in non-REM sleep for an overall AHI of 5.8, which barely rates a mild diagnosis, but was shredding my brain due to the inability to complete a phase of REM uninterrupted.

Your wife's study shows over 130 events per hour, that's more than two per minute, lasting over ten seconds each. If you do the math that's a bare MINIMUM of 40% of the night with severely restricted airflow. Are you really going to change the way you approach the problem if it happens less frequently on the side than back? She could have fewer than a quarter of the events per hour in one position or another compared to the average and still rate a diagnosis of severe OSA.

I don't know about baseline, it might even be a medically accepted value for a person based on age-normalized typical values.

[Centennial2]

Your wife's study shows over 130 events per hour, that's more than two per minute, lasting over ten seconds each.

How did you get >130 events per hour ? She was told it was about 16 per hour.

[BoxcarPete]

Ha! Look at me, I've forgotten how to read. Ignore that whole post, I took one look at total events and then turned off my brain because nobody ever has 130 events/hr. That's insane, and I knew it was insane when I was typing that post and I went and posted it anyway without looking again.

If you don't have sleep position data, you don't have it. Back sleeping is like REM, sometimes worse, sometimes about the same, almost never better than side sleeping/nREM.