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[CPAP] BiPAP Machine Won't Switch to Inhale
Hi there, everyone.

I recently purchased a used Respironics BiPAP Auto M Series machine on Craigslist. It's my first bipap machine, and I'm having some trouble with it. I've been doing a lot of reading here and other places via Google to learn things about the machine, so I know how to get in to change settings, etc., but I still have a lot to learn.

The problem I'm having is that, no matter how I adjust the settings (biflex, rise, etc.), the machine almost always stays on the exhale pressure. Rarely, if I take a big breath with all my might, I can get it to switch to the inhale pressure, but then, if I try again, it usually doesn't work. I am a bit of a shallow breather, and I know the previous owner was a big guy, and probably had much bigger lung capacity than I do, so I don't know if that could be the issue. If it might be, is there a way to reset the breathing pattern / air displacement, so the machine would learn mine?

The bottom line is, I just don't know enough about bipap machines to know how to troubleshoot this problem. I've been googling around for answers for more than a week to no avail. I would deeply appreciate any help or information you guys might have.

== Details ==
Machine: Respironics BiPAP Auto M Series (used)
Mask: FlexiFit431 Full Face Mask

Mode: Bilevel Auto
Max IPAP: 20.0 cmH2O
Min EPAP: 6.0 cmH2O
Max Press Sup: 8.0 cmH2O
Bi-Flex: 3

Thank you!!
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Hi bethelight,
WELCOME! to the forum.!
Hang in there and someone who knows the ins & outs of the BIPAP machines will help you soon.
Best of luck.
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(07-19-2013, 09:57 PM)bethelight Wrote: Mode: Bilevel Auto
Max IPAP: 20.0 cmH2O
Min EPAP: 6.0 cmH2O
Max Press Sup: 8.0 cmH2O
Bi-Flex: 3

Hi bethelight, welcome to the forum!

The difference between inhale pressure and exhale pressure is called Pressure Support.

Your Max Press Sup has been set to 8. This means the machine will never automatically raise the Press Sup higher than this.

If the Press Sup is zero there will be no difference between inhale and exhale pressure (both EPAP and IPAP will be 6 when starting the machine).

If there a Minimum Press Sup setting, I suggest setting it to a comfortable starting amount, such as 1 or 2 (or whatever you are already accustomed to), and increasing it by 1 each night, until you find the amount of Minimum Press Sup you like best. I think many bi-level users prefer the minimum to be 4 or higher. (I prefer a minimum of 6, because I am prone to Central Apnea. If my Minimum Press Sup is not high enough my breathing will sometimes very gradually become ever more shallow, leading to hypopneas.)

Take care,
--- Vaughn
Membership in the Advisory Member group should not be understood as in any way implying medical expertise or qualification for advising Sleep Apnea patients concerning their treatment. The Advisory Member group provides advice and suggestions to Apnea Board administrators and staff on matters concerning Apnea Board operation and administrative policies - not on matters concerning treatment for Sleep Apnea. I think it is now too late to change the name of the group but I think Voting Member group would perhaps have been a more descriptive name for the group.
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I'd talk to a doctor or a respiratory therapist about this. It may be something with the machine. That said:

Do you know what your mask leak is? If the leak is too high, the machine may not be able to detect your exhalations.

How's your hose? I recently had trouble because the company sent me some very thin, cheap tubing which actually deformed just slightly in one spot. It was enough to dampen the pressure changes, keeping the machine from detecting my breathing.

Have you tried setting the machine to steady pressures? Instead of minimum and maximum, have a fixed IPAP (inhale pressure) and EPAP (exhale pressure). I don't know if that's right for you. I know I sleep better with steady pressures. But if the problem is that the machine isn't switching over to the expected EPAP, it may be worth seeing if giving it fixed numbers will make the difference.
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Thank you all for your responses!

vsheline, there isn't a Minimum Press Sup setting, unfortunately, but thank you for the suggestion!

pgw78, thanks! The machine is telling me the average leak is 0.7 L/min, but I only slept with this for about two hours one night (I wasn't getting enough air because the pressure was staying on the exhale minimum), and I've been messing with it, trying to get it working since then. The hose seems fine, but I'll look at it more closely in a bit.

I have tried setting it on steady Bilevel numbers instead of using Auto, but the problem remains.

Thanks again!
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