Optimal minimum pressure

[jakobankerhansen]

I recently (last week that is :-) ) changed to a Resmed Airsense 10 Autoset CPAP from a Philips Dreamstation.
 
So far the change has worked out well, and I have already experienced small things, that I prefer on the new machine.
 
Now I am dialing it in, and my focus right now is on the optimal "minimum pressure setting"...
 
I have been thinking about what the "minimum pressure setting" is really about. Please correct me, if my assumptions are wrong, and please help me to get to the optimal settings for me.
 
When my treated AHI is well below 5, my assumption is, that the Auto CPAP will stay on the minimum pressure setting for most of the time ?
 
... Although the statistics on my machine after five days of usage says 10.9 with a minimum pressure setting of 4!
 
Standard setting on the machine for minimum pressure was 4. But what I feel is, that when I in my awake state breathe through my nasal mask at this setting, it feels as if I can't get enough air. It is as if my own breathing can suck with a higher pressure, than what the machine delivers. And my guess is, that if this also occurs during sleep, it will be quite a strugglefull experience.
 
Increasing the minimum pressure setting to 8.4 (from 4) lead to a much more relaxed breathing experience in my awake state.
 
Am I correct to assume, that the minimum pressure setting is both a minimum pressure, but it is also a maximum pressure, as long as the machine doesn't experience any apneas...? And if the minimum pressure setting delivers less air volume than what is consumed from suction from breathing, it would lead to a struggle ?
 
… Or are my assumptions wrong… They would be wrong, if the reality is, that a pressure of 4 delivers plenty more air, than what is preferred by a normal sized male person ?
 
… My assumptions would also be wrong, if the sensors of the machine (even without apneas) can sense, that normal breathing needs more air, and hence immediately increase the pressure…
 
What is up and what is down. And what is the normal optimal "minimum pressure setting", for a normal sized male with health lungs…?

Thanks in advance :-)

[cathyf]

Am I correct to assume, that the minimum pressure setting is both a minimum pressure, but it is also a maximum pressure, as long as the machine doesn't experience any apneas...? And if the minimum pressure setting delivers less air volume than what is consumed from suction from breathing, it would lead to a struggle ?

Well, first of all, any pressure that the machine delivers is added on to just the air pressure in the room. So, yes, at a pressure of 4 I'm definitely feeling like I want more, but it's certainly a higher pressure than if I were just lying there with no machine.

And on a resmed machine it reacts to flow limitations as well as apneas. If I set pressures to 4-20 I can peg an Autoset10 to 13 or 14 just from the flow limits and have an AHI of 0.0.

[SarcasticDave94]

Start using the free report tool OSCAR. We can tell you better with data. Typical though, if you're using EPR ResMed's exhale pressure relief, somewhat similar to Respironics Flex, you'll need 6 Min pressure if you want EPR 2 to work fully.

Min. Pressure 4 is for children only. No I'm not kidding.

Again let's see an OSCAR chart.

[Gideon]

Pressures on a ResMed.
I'm going to talk in terms of a BiLevel, but I'll bring it back to CPAP terms.

EPAP, this is Exhale pressure and is the 'low' pressure of a breathing cycle. We want EPAP to be at a level that stops most OA events.
PS or Pressure Support, EPR on theResMed, Flex is NOT equivalent. PS is actually the difference between Inhale and Exhale Pressures. That is all it is, but it is used to treat hypopneas, flow limits, RERAs, and UARS. P (and EPR is increased to better treat these events)

EPR is subtracted from the inhale pressure so Assuming an EPR =2 the Min pressure should not be less than 6 = Machine Min (4) + EPR (2).

Mode: Auto
Min Pressure = 6
EPR = 2 Fulltime
Max Pressure = 20 It shouldn't matter simply because it shouldn't go that high, if it does we will restrict it then. You just need enough room for pressure to rise.

If you post a copy of a typical DS1 night we can get it closer, but do expect to need to change the above.