Dropping auto pressure with breathing on PRS1

[rhashimoto]

I have a PRS1 Auto set at 6-10. Sometimes when I wake up at night or early morning I'd like to be able to reset the pressure to make it a little quieter and have less venting air without having to reach for the ramp button. It seems like it must be possible to breathe in a manner to convince the machine to dial back the pressure since that's exactly what it's supposed to do, but I haven't found it through trial and error yet.

I've been reading viewtopic.php?f=1&t=76435&p=698078&hili ... se#p698078 on the algorithm the machine uses to decrease the pressure, and according to that I need to present a good "wave flow" when it decides to sample a lower pressure. I'm using Sleepyhead so I can see it sometimes sampling a lower pressure when I'm lying in bed right before I get up and consciously trying to breathe regularly and deeply, but it then brings the pressure back up so it apparently wasn't happy with the results of the sample.

What kind of "wave flow" is the machine looking for, and does anyone have tips on how to breathe in order to produce it?

Thanks!

[Mary Z]

How long have you been on CPAP? After a few weeks noise and venting should not be a problem. I think reaching for the ramp button will be a lot easier than to fool the machine into thinking you have a certain breathing pattern. Don't you want the machine to work the way it is designed? Hitting the ramp button more than twice during the night is counterproductive. If you want successful therapy let yourself get accustomed to the noise and venting. Most machines are very quiet. I can't imagine using the ramp feature because of noise. If venting is a problem you may need a new mask.
To repeat the most important points a pressure of 6-10 should be easy to deal with as far as noise, and let the machine work how it's designed, leave the ramp button alone after going to sleep. Good luck.

[Janknitz]

It takes quite a while for the algorithm to respond, so you'd have to be awake and controlling your breathing for quite a while before you'd notice a difference. I don't think it lowers pressure based on a single sampling. Much easier to just roll over and hit the ramp button.

If your pressure range is wide, you may be able to narrow it a bit, so that the increased pressure and noise doesn't wake you. If the range is too wide, the machine will tend to "chase" the apneas, making it go higher than it would really need to be.

After a year of using APAP I finally turned off my flex (EPR) and was amazed at how much quieter it was! I am well used to breathing at high pressures, so I didn't have any difficulty adjusting to the absence of exhalation pressure relief. My range is nicely dialed in, and it's rare that I wake with the machine blasting at full pressure.

[robysue]

It's almost impossible to duplicate high quality sleep breathing when we are awake.

The wave form the machine is looking for is:

• Extremely regular---i.e. it looks like a periodic function. All the inhalations are the same in both length and size. And all the exhalations are the same in both length and size.
• The tidal volume is constant or close to constant.
• The shape of the inhalations is nice and smooth. No sharp jaggies anywhere. No flat tops.
• The quality wave form is sustained over many minutes and has no substantial changes when the pressure is decreased on those tests of decreased pressure.

By contrast, when we are breathing while awake, our breaths are seldom exactly the same, breath after breath after breath, for several minutes in a row. And we typically breath much more deeply when we are awake than when we are asleep---even if we are at rest. And both of these things still are present even when we are consciously paying close attention to our breathing. Indeed, when we are paying very close attention to our breathing, we often breath more deeply than normal and at a slower respiration rate for several breaths or several minutes. But then, as we lose our focus or as our O2 saturation has hit 100% and our CO2 levels have dropped, we naturally start breathing more shallowly so that we don't hyperventilate. And perhaps a bit less regularly. And if we've been lucky enough to convince the machine that our focused wake breathing was high quality "sleep" breathing for a long enough time, that wake breathing pattern is now part of the baseline the machine uses to detect hypopneas, apneas, flow limitations, and snoring. So as we relax our focus on breathing and our breathing starts to become a bit more shallow and a bit more irregular, the machine can very well think we just might be in the middle of a hypopnea or we're starting to have some flow limitations. And so the pressure goes back up at the end of the pressure test, if not before.

[chunkyfrog]

The machine is designed to work when you are unconscious--asleep.
Hit the ramp and catch a few more zzz's.
Make friends with your machine.
After a while, you will barely notice it's there--may even have to check if it's running.

[BasementDwellingGeek]

Compare your wave forms at the beginning or end of the sleep session to those in the middle of night, absent events, to illustrate the issues that robysue has pointed out. After a while it is easy to see where you are awake and not.