APAP - Elevated pressure while awake?

[chris94546]

OK, so the parameters I set on my Airsense 10 were pressure range 4.4 to 8, with EPR set at 2. Therefore, according to what I have read with EPR 2 my actual pressure range would be 4 to 6 (as machine will not go lower than 4). So this afternoon as a test I took a 20 minute rest on my bed with cpap at these settings. I was fully awake the entire time, but very relaxed. Well 10 minutes in the machine crept up to the highest setting allowable with my presets, that being 8. Theorhetically, if someone without apnea did exactly what I did, what would typically be the highest the machine would go, and why did my pressure go up to 8 (6 factoring in EPR) while I was awake (totally normal breathing with full in/exhallations).

[Lucid]

I find it uncomfortable to try to breathe through the machine, tubing, and mask in that few seconds before the machine reaches its minimum pressure setting.  I also wake up immediately if the electricity goes off.  So I think there's some minimum pressure level needed just to compensate for the difficulty of breathing through all that gear, even for someone without sleep apnea.  Maybe it's 4, or maybe it's 6.

[Dr.Bob]

This could be a machine defect. Respironics machines can develop a defect in which they incorrectly sense "vibratory snore" - including while you're awake and breathing normally. They bump the pressure up as a result of this false sensing. See https://www.acpjournals.org/doi/full/10.....2022.0145  for specifics.

I wasn't aware of similar problems with ResMed machines, which I think is what you have, right? Can you look at an upload in OSCAR and see what it's showing? There should be some events to which it's responding, leading to the rise in pressure.

I'd be happy to work with you to figure this out. As the author of the article I linked to, I have quite an interest in machine defects. Good luck!

[staceyburke]

You do not know how EPR works.  EPR (exhale pressure relief) subtracts from the Min pressure during exhale.  In other words Min 7 and EPR 3 would give you an inhale of 7 and an exhale of 4.   Min 7 - 3 Epr = 4 exhale.  However all cpap machines can go only as low as 4 - that is the lowest pressure that the machine will go no matter what you do.  So lets give a example of Min 4.5 and EPR 3 - Min 4.5 minus 3 Epr would be 4 because that is the lowest it can go.  EPR does nothing with the Max Number.

Resmed uses Flow limits to raise pressure...  So If you have flow limits the pressure goes up to stop the flow limits from becoming O and H events.  Flow limits, Obstructive, and Hypopnea (FL, O, H events) are the same thing - Apnea.  They are classifications of the same thing - Apnea.  I have how apnea is categorized in my signature at the bottom of the post.

IF you need help with any settings - we need to see data from OSCAR graphs.  When you post them make sure you put the following in the screenshot.  Event Flags, Pressure, Flow Rate, Leak Rate, Flow Limits....

[Grandpapa-G]

For most people, whether they have sleep apnea or not, will register apneas or flow limits if they use a cpap machine while awake. This will almost always drive your pressure up to the max setting. Your breathing pattern while asleep can very different than when you are awake.

[Dr.Bob]

For most people, whether they have sleep apnea or not, will register apneas or flow limits if they use a cpap machine while awake. This will almost always drive your pressure up to the max setting. Your breathing pattern while asleep can very different than when you are awake.

What makes you say that most people have apneas while awake? I haven’t heard that before and it seems counterintuitive. 

Thanks for replying.

[Crimson Nape]

When awake, our breathing pattern is erratic and easily exceeds the time limit used to determine an apnea. When we sleep, our breathing pattern becomes more rhythmic.

- Red

[Sleeprider]

Best guess is your pressure is set too low and you end up using reparatory effort to obtain the flow rate you require. This causes flatting of the inspiratory wave which is interpreted by the machine as flow limitation, causing pressure to increase in accordance with the algorithm. I would suggest a minimum pressure of 6.0 maximum pressure 9.0 with EPR 3 to provide a range of 6/4 to 9/7 (inhale/exhale). Why are you trying such low pressure?

[Dr.Bob]

When awake, our breathing pattern is erratic and easily exceeds the time limit used to determine an apnea.  When we sleep, our breathing pattern becomes more rhythmic.

- Red

Thanks! Very interesting