Question re: APAP Maximums

[jduluoz92]

What is the point of limiting an Auto PAP below 20?

The machine will not go above what is needed to treat apneas. If you limit it below its capacity, it will potentially be unable to treat some apneas. Forgive me if this is a stupid question. Still new to this game. Working on dialing in my settings and curious why people suggest upper limits with APAP machines on this forum.

Thanks!

[kteague]

You are right in that the machine should go only as high as needed so having it open to 20 shouldn't be a problem. And it usually isn't, but based on my reading here, there can be exceptions. Some have talked of "runaway" pressure, or the machine chasing something you don't want it to chase, like maybe snores or a leak. Someone prone to painful air in their belly may have made a choice to tolerate an occasional event to avoid the belly air, so they limit how high their machine can go. Or a person prone to pressure induced centrals may have fine tuned their pressure to where it's enough to stop most events but not enough to cause centrals. Or a preferred mask may fit fine up to a certain pressure, then at some point interrupt sleep with leaks. Plenty of reasons to put a limit on the pressure range, but guessing to the majority it's a non-issue.

[LSAT]

What is the point of limiting an Auto PAP below 20?

The machine will not go above what is needed to treat apneas. If you limit it below its capacity, it will potentially be unable to treat some apneas. Forgive me if this is a stupid question. Still new to this game. Working on dialing in my settings and curious why people suggest upper limits with APAP machines on this forum.

Thanks!

You are right...limiting the max pressure serves no purpose unless a person's pressure occasionally goes high enough where they get aerophagia. In that case it may be prudent to sacrifice AHI in favor of comfort. Many APAP users don't understand the max pressure.

[Goofproof]

You are right in that the machine should go only as high as needed so having it open to 20 shouldn't be a problem. And it usually isn't, but based on my reading here, there can be exceptions. Some have talked of "runaway" pressure, or the machine chasing something you don't want it to chase, like maybe snores or a leak. Someone prone to painful air in their belly may have made a choice to tolerate an occasional event to avoid the belly air, so they limit how high their machine can go. Or a person prone to pressure induced centrals may have fine tuned their pressure to where it's enough to stop most events but not enough to cause centrals. Or a preferred mask may fit fine up to a certain pressure, then at some point interrupt sleep with leaks. Plenty of reasons to put a limit on the pressure range, but guessing to the majority it's a non-issue.

For the Majority, they are mis-informed as to the best way to set their APAP to find the best range for them a clue. This also applies to most Doctors, run and find a doctor that cares and knows what they are doing.

Some get by with a 4 to 20 cm setting, many waste valuable time with poor or no treatment by doing this, not counting the discouragement it causes.. 2 CM under and 2 CM over your doctors guess for your best CPAP pressure is a good place to start, then by using the full data collected by your APAP read by the software available you can get a idea of what you need to do to get the best treatment you can.

I also favor no using the Ramp feature unless you can't live without it. Also don't jump around making changes, one night does not a Trend make. Happy Papping! Jim

[chunkyfrog]

When my maximum was "wide open", runaway high pressure would frequently wake me in a panic.
When set at just a cm or so above my therapy pressure, I get to sleep without being disturbed,
and my AHI is quite acceptable with my CA's practically nil.
This worked fine with my S9 Autoset, so I use the same settings for my Airsense 10.

[ajack]

whether it's an internet myth or not? they also say the algorithm works better with the max also being reduced.
It's obvious that increasing the minimum to a bit under the median or average ,,,,,or 2cm under the 95% works better.

[kteague]

I see posts regarding the lower end of the pressure range. Didn't address that as it wasn't the question which was specific to the upper limit. FYI, I am of the opinion the vast majority of users have it wrong on the lower limit and that it very much does matter. Think too low of a start pressure on an auto is likely the most responsible cause of failure on APAP.

[D.H.]

You would consider setting the max lower than the machine capacity if any of the following occur:

• You doctor says so.
• You are having issues with leaks that are possible mouth breathing (might apply differently to FF mask).
• You are having “central” or “clear airway” events. Sometimes (not always), they can be caused by too much pressure.
• You are experiencing arousals or discomfort from the higher pressure.

[palerider]

they also say the algorithm works better with the max also being reduced.

"They" who? there's nothing in the documented algorithms to support that claim.