reset pressure of 4 to 20 cm?

[Mile High Sleeper]

This might relate to my posting on how does APAP work? I've never been titrated, just had one night in sleep lab for a PSG. My Respironics auto PAP w/ C flex is set to the default 4 to 20 cm and C flex on 3. With a leaky nasal mask and much better Aura, my pressures run from 4 cm to 17 cm. Since I don't yet have the software, I can't do much experimenting on my own until I get it. The problems I'm having are rainout (largely conquered), aerophagia (better but not solved), and leaky masks (Aura is helping greatly). My average mean pressure is 6.5 cm. Average device pressure 90% of the time is 11.1 cm. Which figure is more useful?

I still need to try my full face mask and don't know what pressures it may need. Is it better to leave some pressure in reserve in case you need it for some reason, like a different mask or cold or something? Or better to reduce your pressure to what you are actually using, and what are the advantages of that?

[Guest]

Here is a post relevant to your question:

I agree with Perry that 4 cm H2O is often too low for most people to be comfortable breathing through a mask. Most report feeling they have to work too hard to breathe down at 4. You're not going to suffocate, but it can sure feel like it.

It's also unnecessarily low for optimum operation of an autopap for most people. Especially for people who perhaps came away from the sleep study with a pressure they need only rarely during a night, or who have to deal with a high pressure in general. However, many posters have reported getting "smoother" sleep and feeling better when they put the low pressure of their autopaps right up on or just a cm or two below their titrated pressure.

I used to think the only reason really to have an autopap was to enjoy good treatment with pressures much lower than a titrated pressure most of the night. For some, that is the case. But for many of us, the autopap serves another purpose....letting us use titrated or just below titrated pressure most of the night, yet having a margin above that available for use when needed.

When might "more" than titrated be needed? There are lots of scenarios. Perhaps a change of meds, unusually stressful day, partying a little too much, illness, more congestion than usual, allergies acting up...the list can go on and on. And of course, there's always the chance the sleep study titration missed the mark in the first place.

I've experimented with a lot of different ranges with all three major manufacturers' autopaps, and had the software to download from each. For me (and it can be very different for others) a range starting with 8 or 9 as the low works best. I can set the upper pressure anywhere at all as the machines rarely ever need to use more than 14 for me, and then only briefly on random nights. Most of the time, my autopaps stay down on 9 or 10 all night.

Why did I decide to put my lower pressure up on 9? It was because experimentally I could test it while wide awake. Lying in bed, with machine going, while I was waiting to drift off to sleep, I could feel my throat close if I had set my autopap's low pressure at anything less than 8 or 9. I could very distinctly feel it shut off all air if I deliberately and consciously let my throat relax as much as possible. I knew if I could "make" that happen while I was awake, it was definitely happening in the more complete relaxation of sleep. So, there was no point in my setting the machine below the threshold that would keep my relaxed throat open to start with.

Hey, what can I say? I guess I'm a straight cpap'er at heart.

But I'll always use an autopap -- for the extra pressure it can provide when occasionally needed.

[Snoredog]

your bottom pressure is too low in my opinion, you should kick that up to 6cm or higher if you can tolerate it, if not leave at 6cm. The more you increase that bottom pressure the more flow limitations and hypoapneas you'll eliminate later on during sleep, the result would be lower AHI scores.

If your 90% pressure is 11.1, then that is the pressure that treats 90% of the events seen. It most likely would be the pressure found during any PSG titration. So a pressure of 12cm, would cover just about anything you should encounter.

If your seeing 17cm or higher than 12cm, that is probably due to mask leaks or mouth breathing, but you would have to study the reports to be sure.

you want to be careful when you start getting up in the high teens with pressure as that can be where pressure induced centrals are seen. Not so much a problem with the machine your using but it can be. If your going to set a high limit on the machine, I would go 1cm to 2cm above your 90% pressure, that will allow the machine to dabble with higher pressure if needed. The Remstar likes to dabble at higher pressures and if it doesn't see any improvement it settles back to the lower pressure and calls that your 90% pressure. If you see snores or hypoapnea events lower at the next pressure say 12cm, then you want to set any straight cpap to that pressure.

Lowering the Cflex setting from 3 to 2 might also result in a lower scoring. The bottom line is how you feel, if not feeling much better start increasing the bottom pressure 1cm each night, the closer you can get that to your 11/12cm the better you'll feel.

[Mile High Sleeper]

Thanks, Guest and snoredog.