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Please help me interpret my data. What could cause low O2? - Printable Version

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Please help me interpret my data. What could cause low O2? - MurphMurph - 08-03-2022

Hi all,

Like many people on this forum I am really suffering and am unsure of how to proceed. Desperate for some relief :/

At this stage I am not sure what to try next and any help would be greatly appreciated!

I'm a 32 year old male, healthy weight, diagnosed with mild to moderate OSA via overnight sleep study. The study showed an AHI of about 15.

I am using a ResMed AirSense10 and have been experimenting with different pressure settings.

From looking at my OSCAR data (see below) I think all of the metrics look fine:
  • Low AHI
  • Low RDI
  • Flow I think looks normal? I'm not sure.
  • There is some flow limitation, but not consistent. I'm not sure if I'm reading that chart correctly.
But even with those metrics I feel awful. Headache, very tired. My best guess is that this is due to low oxygen levels while I sleep.

I live at roughly 1 mile elevation in Colorado. Wearing a pulse oximeter while awake for about 30 minutes shows an average O2 level of about 94% with a min of 91%.

Wearing the oximeter at night, with a pressure setting of 6.0-7.4 or even 7.4 (no auto-set) sometimes resulted in good O2 levels throughout the night: average of 93% one time even 94% (same as waking O2) with a min of 89% or 90%.

But sometimes these settings will result in much lower levels, maybe an average of 92% with mins 86% or 87%.

So that's all of the info I have. What do you think?

Am I correctly interpreting the OSCAR data as saying I don't have a flow limitation problem?

Is there a reason my O2 levels would vary so much with the same settings? Am I possibly not getting enough air, and therefore should increase pressure?

I'm going to experiment with a higher max pressure plus EPR, starting at 1 and going up to maybe 3 or so to see if any of those adjustments make a difference.

Thank you in advance!

- Murph

PS - Sometimes I get aerophagia, but that also is not consistent. I've used a 7.4 setting a handful of times and it's about 50/50 if I experience it. Last night I tried a max pressure of 8.0 and only experienced minimal aerophagia. Not sure if that's a helpful clue.


[attachment=43697]
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RE: Please help me interpret my data. What could cause low O2? - staceyburke - 08-03-2022

You are at the top of your pressure all night long and you flow limits are very high 

I would suggest you raise the max to 12. 

Turn on the EPR to full time

EPR 3

Let’s see how that works for a night and post tomorrow.


RE: Please help me interpret my data. What could cause low O2? - MurphMurph - 08-04-2022

Hi Stacey,

Thank you for the quick reply! OK I will try a higher pressure and EPR.

How should I interpret the flow limitation graph? What is a "high" value?

- Murph


RE: Please help me interpret my data. What could cause low O2? - staceyburke - 08-04-2022

Flow limits are apnea only smaller. In my signature I have how O, H, and flow limits are classified. 

What is high - any that interrupt or interfere w with sleep.


RE: Please help me interpret my data. What could cause low O2? - MurphMurph - 08-05-2022

Hi Stacey,

Max pressure of 12 and EPR of 3 did seem to reduce my flow limitations some and I'm spending much less time at max pressure (see OSCAR screenshot below).

O2 levels were OK: average of 93%, min of 87%, spent about 95% of the time above 91%.

I'm going to try a slightly higher max pressure, maybe 12.4 or 12.8, to see if it can further reduce the flow limitations.

I'm also wondering if there may be a positional element here where I'm more flow limited while sleeping on my back. Subjectively it seems like when I roll onto my back the pressure increases almost immediately, although I'm not sure if that's true throughout the night.

Thanks again for your help! Do you have any further advice?

- Murph

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RE: Please help me interpret my data. What could cause low O2? - staceyburke - 08-05-2022

I would raise the min instead of the max by 1. Raising the max should not help. Lists go to min 9 and post tomorrow.


RE: Please help me interpret my data. What could cause low O2? - MurphMurph - 08-05-2022

Sounds good will do!


RE: Please help me interpret my data. What could cause low O2? - MurphMurph - 08-06-2022

Hey Stacey,

Worse results with min pressure at 9 unfortunately :/. A lot of central apneas (possibly as a result of the higher pressure?), average SpO2 of 92% with a min of 85% (thankfully only went down that low briefly).

Interestingly the flow limitation isn't noticeably different either. I have a deviated septum and enlarged turbinates, which the ENT was skeptical of as a major factor in my sleep issues. But I'm now wondering if the flow limitations are largely from that...

What do you suggest? The best O2 reading I've ever had was at a fixed pressure of 7.4, no EPR. Maybe my min pressure should be closer to that?

- Murph

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RE: Please help me interpret my data. What could cause low O2? - staceyburke - 08-06-2022

the centrals you have had iare treatment induced - the cpap is removing more CO2 from your body and you will be having the centrals until your body gets use to the new levels.  But to help that lets move the EPR to 2 and see if that decreases the centrals.

One thing that make centrals hard to work with is they are very inconsistent...  One day you have almost none and the next day with the same settings there are quite a few.  So one day does not make a pattern.


RE: Please help me interpret my data. What could cause low O2? - MurphMurph - 08-06-2022

OK I'll give that a shot, thanks for the guidance

- Murph