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[Diagnosis] Average AHI went from 1 to 4 - Why?
#1
Average AHI went from 1 to 4 - Why?
I have been using a ResMed S VPAP bilevel machine for the past 5 years set to 12/8 with the P10 nasal pillows. I don't sleep more than about an hour at a time, but overall AHI has been about 1 and I was pretty happy. Not perfect, but much more rested than before I started CPAP 5 years ago (was a zombie).

In December 2018 I saw a new sleep clinic about getting a new machine in the new year. Doc said your doing pretty good, with AHI about 1 but we can do better. I want you to try the Phillips Respironics Auto BiPAP (700X110). Auto set to start at 12/8. Using a new ResMed P10 nasal pillow mask and headgear.

I have been using the Phillips for the past 2 weeks (since 14 Jan 2019) and my AHI has increased with a very sharp increase in CAs reported as compared to the old ResMed data.
However I see that even using the ResMed I had an increase in AHI in December 2018. Not sure why, maybe sore nose from seasonal allergies and/or loose stretched out headgear on old P10 nasal pillows. 

As an experiment on 27January I used my old ResMed BiPAP 12/8 and got similar bad results to the new Phillips. Then last night I changed mode on my old ResMed BiPAP (was BiPAP 12/8) NOW CPAP mode with 8 IPAP with 6 EPAP comfort setting. AHI improved to 1.67 from 4.9 the previous day and breathing was more comfortable overall using the ResMed. This ResMed CPAP mode test approximately matches my ResMed results while in BiPAP 12/8 for the past year.

Yesterday I asked my CPAP Tech to look at my data and advise changes since I am not happy with the Phillips machine and/or its setup so far. Haven't heard back yet.

Please let me know what you think after you have a look at the attached:
 
3 month Overview:
     
ResMed S VPAP in Bi-PAP mode data before 13 Jan 2019 and 27 Jan 2019 and CPAP Mode 28 Jan 2019
Phillips DS Auto BiPAP 13 Jan to 26 Jan 2019

Daily data from: 
SleepyHead for Phillips Auto BiPAP 12/8 on 23 January,  
   

ResMed Bi-PAP 12/8 
   

ResMed CPAP 8/6 
   

Thanks, Steve
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#2
RE: Average AHI went from 1 to 4 - Why?
On the Philips, you can turn off VS2 and clean things up a bit. The Philips is set to auto BiPAP pressure with pretty wide-open pressure at 8.0 to 25 and PS 4.0 to 8.0. The charts show this has increased you IPAP and EPAP pressure as well as pressure support from time to time. This is probably responsible for most of the increase in CA events. In addition to the disruptive potential of changing pressure and pressure support, you have a fairly high leak rate which may also be a problem. The leak problems began with the Resmed back when the AHI first showed increases. Your AHI shows essentially no or very low OA, and increases are mainly with CA and H events with the Philips, and only CA in the Resmed associated with leaks and the disruption of changing machines. I could be wrong, but on the 28th it looks like you went with non-bilevel pressure and had a pretty good result and lower leaks.

If you're going to continue with the Philips BiPAP you need to tame the settings. I recommend EPAP 7.0 or 7.5 with IPAP max at 14.0 and PS 3.0 to 4.0. I really think you did fine on the S9 VPAP-S and if changing to an auto bilevel would have suggested an Aircurve 10 Vauto at 7.0 to 14.0 with PS 4 or less.
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#3
RE: Average AHI went from 1 to 4 - Why?
Thanks for your analysis and good guidance SleepRider. Much appreciated. 

You are correct. I changed mode on my non-automatic ResMed VPAP-S Bi-PAP machine to constant pressure CPAP mode 8 with PS of 2 last night, so IPAP was 8 and EPAP was 6. This provided better results than the previous night in BiPAP mode with IPAP 12 and EPAP 8. 

I don't think that the Auto Bi-Level machine is helping me as you pointed out. I will reduce and bound the pressures on the new Phillips DS Auto Bi-PAP machine as you suggest and will give it another try. Maybe even try an experiment setting it in constant pressure CPAP mode with a slight EPAP pressure reduction of 2 or 3. I don't seem to need an exhaust pressure reduction of 4.

Is it possible that the CA events I am seeing are due to me being awake?

What is the best way to automatically log my sleep state? Using one of those oximeter/heart rate monitors?

Cheers, Steve
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#4
RE: Average AHI went from 1 to 4 - Why?
Lacking a real EKG, I have found some of the fitness watches do a reasonable job of distinguishing light and heavier sleep periods.  It's not too scientific, but can give you an idea of whether you're sleeping well; however you probably know that by how you feel.  I definitely think the CA event rate is related to sleep disturbance, and that it traces to leaks, changes in pressure, stress etc.   I was wondering if you were due for a mask change, or if you had one when the leaks started to spike upward?

Quote:You are correct. I changed mode on my non-automatic ResMed VPAP-S Bi-PAP machine to constant pressure CPAP mode 8 with PS of 2 last night, so IPAP was 8 and EPAP was 6. This provided better results than the previous night in BiPAP mode with IPAP 12 and EPAP 8.

In CPAP mode we would call that a CPAP pressure of 8.0 with EPR of 2 resulting in pressure 8/6. If they were bilevel settings we would call that EPAP 6, PS 2, IPAP 8.  That looked pretty good!  It appears you can tolerate lower pressures and pressure support.
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#5
RE: Average AHI went from 1 to 4 - Why?
Thanks for the terminology lesson!

Yes I was due for a new nasal pillow mask and headgear when all the leaks started. 

I have also started experimenting with sleeping on my stomach for an hour a night to give my back some relief. Can't sleep on my sides due to arthritis in my shoulders.
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