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oxygen or AHI more important
oxygen or AHI more important
I have a hard to solve dilemma with CPAP.  Most of our machines do not report oxygen levels, and we tend to focus on AHI.  BUT when they do the sleep study they want to keep oxy level above 88 or 90.  I have a new recording oximeter with wrist strap and finger cuff that works amazingly well.  I have been using every night and compare to OSCAR report and Resmed MyAir.  The results seem to conflict sometimes.

I've been experimenting with changing pressure.  One thing for certain, if i raise pressures above 10, i get crazy leaks and i've tried every mask and every hint.  Only way to stop leaks at higher pressure is tighten mask.  Then i wake up with dented face, and sore nose.  MYAIR really scores me low when i have leaks, but my AHI can be 1.0 or less

I can set my pressures too low, like 6 min and 7.5 and everybody loves me (no leaks, excellent AHI)  BUT oxyimeter no like.  Plenty of dips below 88.  Maybe i am rambling and lost most of you already, but it's difficult to find the happy middle.  Is it crazy for me to assume if i can set everything where i get good oxygen, above 90 all night, that i can not worry so much about AHI and/or leaks?  I can set pressures to 7-9 and oxy is near perfect, but AHI raises to 3 or 4, and MyAir scolds me about leaks.  

We all seem to struggle with finding the perfect mask, comfortable and no leaks.  That is also frustrating.
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RE: oxygen or AHI more important
Top of my head, general reply (Charts are lacking)

Increase EPR. I'd increase it to 3, This increases the efficiency of the air exchange and thus can reduce Oxygen desats.
Your min pressure with an autoset should be at least 4+EPR so with EPR= 3 min should be at least min = 4 + EPR = 4 + 3 = 7
Gideon - Project Manager and Lead Tester for OSCAR - Open Source CPAP Analysis Reporter

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RE: oxygen or AHI more important
Do you know the components of your AHI: obstructive apnea/central apnea/hypopnea? The information could be useful.

It sounds as though you might benefit from experimenting further with other nasal pillow masks. That's a drag when you've already experimented a lot, but it could be worth it. Have you gained or lost weight? Gotten new wrinkles (speaking as one who has her fair share of those)?

You could get the best advice if you downloaded Oscar and posted a chart or two. Any chance you could do that?
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RE: oxygen or AHI more important
The components of the AHI are important. Centrals/Obstructive/Hypopnea all suggest differing solutions.
Also Apneas aren't the only thing that can cause desats...Afib can cause desats as well.(I'd guess other issues as well but I only know about Afib-with an AHI of zero I still have an ODI of ten). For me small changes can make a big difference. Min pressure of 8.2 gives me an AHI < 1(a mix of OA,CA and Hypopneas) and good oxygen. A slight increase to a min pressure of 8.4 gives me an AHI of 3-4(all centrals).
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RE: oxygen or AHI more important
Your desats are measured during a sleep lab because they want to know how greatly the deficit is likely to affect you AT A GIVEN RATE OF HYPOPNEAS AND OBSTRUCTIONS.  Your insurance might not be so keen to cough up $1200 if you show an AHI of 12, but your saturations never fall below 94.

Additionally, they are measured, or at least monitored, to determine the response when you are given 4,6,8,10,12,14,...cms of H2O in treatment.  If you desat to 88 regularly with a pressure of only 6 cm, but immediately improve and maintain sats to 94 at 8cm, and even better to 97+ at 9cm, they know where to peg you.
Contrite, and wiser.
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RE: oxygen or AHI more important
Thanks for all the input and suggestions.  I guess this is a process of making small changes and watching the results in order to dial every thing in.  I am attaching Oscar results for one of my better nights.  Also attaching my new oximeter results.  One nice thing it shows oxygen less than 90% was only 12 seconds.

At this pressure, it looks like i still have significant leaks but i'm not so sure that i need to worry so much about leaks if my AHI and oxy are both good.

Attached Files Thumbnail(s)
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RE: oxygen or AHI more important
Are you using the 'with Arms' headgear with your Dreamwear? I found the Philips Dreamwear 'with arms' headgear helped me with leaks over the standard Resmed P30i headgear...the headgear did better staying in place with 'with arms'.
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RE: oxygen or AHI more important
Drgrimes, could we get you to reformat your chart please? Turn off the AHI graph, it's not really useful. We need to see event flags, flow rate, pressure, flow limitations and leak rate. Also, turn off the pie chart - it covers up other useful information.  The instructions for formatting are here.

Your AHI on the chart you gave us is very good but the pressure is trying to go higher, which suggests you might have flow limitations. Although the leaks are not good, they probably aren't making an enormous difference. Resmed machines allow large leaks up to 30% of the time before giving you the red frowny face Angry However I believe you should continue to work on reducing the leaks. Your max pressure of 9.0 is not abnormally high and shouldn't cause excessive leaking - it's just a matter of finding the set-up that works best for you. The one in your avatar looks suitably robust!

Which model oximeter do you have? Some models are compatible with OSCAR, allowing the oxi trace to be included in the Oscar chart, which can be very helpful.

A final comment - ignore the MyAir scores - they seem to be based on some false underlying assumptions and are aimed more at jollying you along than providing useful information.
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RE: oxygen or AHI more important
ok i think i've got Oscar arranged properly.  I have switched (need to update profile) from Philips dreamwear to Resmed AirFit N30i.  I have tried almost everything and this one works best for me.

The oximeter is Viatom, off Amazon, but does not seem to integrate with Oscar.  One thing i like about it, is that it vibrates when you drop below level.

I am mostly experimenting with changes in pressure, but i have a fair amount of leak, but when i raise the pressure to above 10 the leaks get really worse.  I've tried tightening the mask but then i get dents on my face and sore nose.

I really appreciate all the help and suggestions.

Attached Files Thumbnail(s)
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RE: oxygen or AHI more important
Your EPR is currently set at 2, as Bonjour stated increase that to 3. Higher EPR helps induce more flow which should help improve oxygen level.

The leaks due to increasing pressure may be due to mask leaks or they may be due to mouth leaks. You could try taping mouth to see if that stops or reduces leaks to confirm which is the issue. If it is the mask and you haven't tried the P30i I would recommend it, all you need is a cushion and it will just clip into the headgear you have. The P30i seals much easier than the N30i if you have the right size and the headgear can be much looser/more comfortable, at least that was my experience with the two.

If it is mouth breathing taping, chin strap or cervical collar might help avoid it.
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