Does pressure affect oxygen levels?

General Discussion on any topic relating to CPAP and/or Sleep Apnea.
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SleepyRose
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Does pressure affect oxygen levels?

Post by SleepyRose » Tue Mar 24, 2009 9:09 am

This is probably a stupid question but my doc wants me to do a home O2 sat thing. The DME person whos bringing the stuff said that if my O2 is low theyll adjust my pressure.

I didnt think pressure had anything to do with blood oxygen. I guess the whole CPAP thing does but how does the pressure affect it?

My pressure now is 9.5 and its perfect for keeping my AHI consistantly below 5 so why rock the boat ?

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Julie
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Re: Does pressure affect oxygen levels?

Post by Julie » Tue Mar 24, 2009 9:37 am

Because while the pressure may keep your AHI below 5, there may still be room for improvement, and/or the MD feels that a higher pressure may allow more 02 to be delivered via Cpap (though not "as" 02 from an actual 02 tank, of course, as you would have if you had COPD). You should at least see what the results are, especially as there may be other medical reasons (conditions) which could impact you indirectly even if your 9.5 pressure seems ok to you now.

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TSSleepy
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Location: Portland, Oregon

Re: Does pressure affect oxygen levels?

Post by TSSleepy » Tue Mar 24, 2009 10:05 am

It will be good to see what the results are! Everybody is different, but I can describe to you what an AHI of five would mean for me.

My AHI is under 1 now, but I still desaturate down under 90%, very briefly once or twice a night.

If my AHI was 5, and I slept 8 hours, that would be 40 events per night >10 seconds. For my particular case, I have many more events in REM sleep and my REM stages get longer/stronger (and more apnea-ridden) as the night goes on.

So with an AHI of 5, the last REM stage of my night might be 40 minutes and have 20+ events in it (for an AHI of 30, during those 40 minutes). And my oxygen saturation would likely go down into the mid-80's. My excessive sleepiness would be gone, but I'd probably still wake up feeling out of it and headachey from the O2 desaturation.

Is that kind of thing happening to you? No clue! But wearing a pulse oximeter clip on your finger is a very simple/easy way to check how things are going, and well worth doing in my opinion.

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terry123
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Location: Texas

Re: Does pressure affect oxygen levels?

Post by terry123 » Wed Mar 25, 2009 9:08 pm

I used a recording oximeter on my husband to convince him to have a sleep study. He agreed after seeing the results which spent a lot of time under 90. He started on the Cpap first and the o2 sats improved significantly, but still having a lot of desaturations during the night. He is also on oxygen at night now and his 02 Sats are great.