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[Pressure] Pressures over 20?
When I had my second night in the sleep lab (CPAP titration), the final report said that my apnea events were "abolished" at a pressure of 10 cm/H2O, hence this was the setting they gave me on my machine - set to a fixed pressure of 10. I had read up on machines before I got mine and when the DME called me to make the appointment to get the machine I asked if I had any say on the machine or features and he said that they pick the machine. I was actually pretty happy when I got there and saw that it was an AS10 Autoset, because I thought auto mode would be useful for the future and I was reading good things about that device. Kudos to them for that at least! Big Grin

I started using SleepyHead from day one (actually installed it before getting my machine) so I have been examining the charts every day. It didn't take long before it became clear to me based on AHIs that 10 was not cutting it. I don't know how they came up with that number. I realize some nights can be better or worse than others, but I find it hard to believe that all was magically cured at a pressure of 10 like the report suggested.

I have had the machine in auto mode for about a week and a half now and based on where it seemed to spend the most time, that is how I am at my current pressure range of 16-20. The thing is, I still can't seem to get an AHI below 2.x, and it is usually closer to 5 or 6 it seems. Also, the machine seems to hover between 17 and 20 and often holds around 19-20 for a while.

This is making me wonder if 20 is not even enough for me, and if that is the case I guess I'll need to do another study at some point. More importantly to me though... do they even make machines that go over 20? This seems to be the upper limit of many machines. Can I never expect to see AHIs less than 1 if my pressure is maxing out at 20 and I still have many apneas throughout my sleep? Sad

I am having occasional problems with leakage, which I know can increase AHIs and in some cases "hide" them since the machine may not know what's really going on. Honestly my two lowest scores below 3 were on nights with significant mask leakage which leads me to believe the AHI numbers may be erroneously low. But I have also had nights with pretty minimal leakage and at best I have had a 5 or 6 AHI on those nights.

For now I am looking into different mask sizes and am also going to try some nasal pillows, but I am really wondering about the pressure.
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(03-06-2015, 05:37 AM)TiredToo Wrote: ...do they even make machines that go over 20?"

Yes. My VPAP Auto Bilevel machine can go up to 25 cm-H2O.
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Can VPAPs run in normal APAP and CPAP modes as well? I don't know that I would need or want a VPAP.

I think I will spend more time watching the data before I pursue that possibility anyway, but it's good to hear that 20 isn't the max. I probably should also have mentioned that my AHIs are almost all obstructive. I rarely see any CAs and if I do it is one or two events the entire night, even at 20.
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(03-06-2015, 08:23 AM)TiredToo Wrote: Can VPAPs run in normal APAP and CPAP modes as well? I don't know that I would need or want a VPAP.

I think I will spend more time watching the data before I pursue that possibility anyway, but it's good to hear that 20 isn't the max. I probably should also have mentioned that my AHIs are almost all obstructive. I rarely see any CAs and if I do it is one or two events the entire night, even at 20.

My VPAP Auto has 3 modes. fixed CPAP, fixed bilevel "S" mode, and VPAP auto. It can run run like an Autoset by setting the PS (Pressure Support) to at or near zero.
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As long as the events you are treating with increased pressure are OA and H, and you see flow limitations or snores, you're probably on the right track. CA events are not treated with more pressure. Also, as you use higher pressures, bilevel pressures can become helpful and more comfortable.

What is your EPR set at? I have seen positive results at lower pressures from reducing EPR to 1 or zero.
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Initially EPR was set to 3 by the DME and I experimented with different settings but I've had it turned off now for a few days. I exhale fine against the higher pressures and before my study my wife told me numerous times that I stopped breathing often in my sleep. I asked her if it was after inhaling or exhaling and she said it usually seemed to be after an inhale then I would go for "what seemed like a minute" without breathing at all then I would suddenly let out a huge exhale. For this reason, and since looking at the charts, I felt it was best to keep the pressure up to prevent my airway from closing again before I could exhale.

Edit: Definitely seeing flow limitations and the pressure (if not already at 20) bumping up in response to them. I'd really like to go to a lower minimum if only to prevent some possible pressure-related leaks but my charts are telling me I need more pressure. With the minimum at 16 every "event" (FL & OA) seems to bump it to at least 18 so I am going to try 18-20 tonight and see what happens.
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Assuming the alogoritm for the 10 series is nearly the same as the 9 series, the machine will aggressively raise pressure in response to flow limitation, snore, and Obstructive apnea; but not to an open airway apnea (CA.) Moving up the "floor" pressure setting is useful for most. Some people are given machines set to 4-20. Starting at 4 means it has to bump up several times before it becomes effective. I doubt you'll see much difference between 16-20 and 18-20.

I have found an advantage to having a higher "floor" pressure is the abilty to get the mask adjusted for zero leak when I first start up. Usually I can go from night to night with the same strap adjustment -- until the head straps stretch or the mask cushion is near end of life.

TiredToo: Are you heavyset? Sleep position might be considered. We big fellows often need higher pressures when on our back; I try to sleep on my side.
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Us larger fellows? I did not know that you were so politically correct, Mongo.


You might be experiencing something that I have encountered. Look at your obstructive events and the pressure before the event. If there are some where the pressure did not increase until after the event, it seems to me to mean that there were no precursors to the event that the machine recognized. When I run auto ( my machine is an S9 VPAP Auto), I see a fair amount of this and my AHI is higher than when I run in straight bilevel mode. I am running in the same pressure area that you are. My inhalation pressure is 20 and my exhalation pressure is 16.

What Mongo suggested will probably help but if it does not, I suggest the following. Put your autoset in straight CPAP mode and set the pressure for 20. I would set the EPR to 3 or 2 but if you are comfortable with it turned off that is fine.

I would try Mongo's suggestion first. If it works well for you that is great. If not, you could try this suggestion. Hopefully, one of these suggestions will prove beneficial. If not, you may need to step up to an Aircurve. I would suggest the Aircurve Auto since it gives you the 3 operating modes that Mongo mentioned.

Good luck and let us know how it goes.

Best Regards,

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(03-06-2015, 01:03 PM)PaytonA Wrote: Us larger fellows? I did not know that you were so politically correct, Mongo.
My basic nature is not very PC. Having worked in a military/government/corporate culture has beaten it into me!
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I could definitely stand to lose some weight... I'm 6' and 205 lbs. I'm for the most part an average build but all of my excess weight goes to my belly and chest and I do have a somewhat thick neck. I am definitely worse on my back. I always start off on my side but how I end up is a different story. I've always been an "active" sleeper... I'm pretty much all over the bed throughout the night. Since starting the CPAP though, at least I don't thrash around like I used to - which was apparently during my long breathing pauses. What a surprise!

I looked at each day (about 3 weeks in so far) up close and I would say that the pressure almost always goes up slightly before the OA events (10-30 seconds prior) yet the events do still happen obviously. But there were a few times where the pressure appeared to go up just after. So I would conclude that in most cases there is a precursor to the OA events. What concerns me is that even when the pressure is still at 20 or close - say 19.2 - I still am seeing occasional new OA events. But 20 being max, where can I go from there? I've got some different mask types on the way and I am hoping a different type of mask may help but I don't know that it will.

I had been considering just setting it to a fixed 20 (or 20-20 in auto) but didn't think about turning EPR back on along with that. That sounds like a decent idea as an alternative to 18-20 with no EPR.

I've got it set to 18-20 for tonight already. If I remember later maybe I'll just set it to 20 and turn the EPR on. Either way I think around 20 is where I need to be... a far cry from the "10" the lab stated in the report.

I believe the AirCurve is a step above the Autoset, correct? I don't have any other machines to compare to, but I really like this AutoSet, and especially the ability to use a FlashAir WiFi card in it. I gave SleepMaster a try for that but after having some issues I just wrote my own program for it. I'll likely share it (just as an alternative... definitely not trying to steal his thunder) once I can post links.
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