Understanding pressure.

I can't find this anywhere, but I'd like to get some information about pressure in general.

Obviously there is a large range of maximum pressure settings. Obviously you have to get it right for each individual.

Masks - Am I correct in ASSuming that part of the pressure setting is to inflate the soft silicone of the nasal masks? i.e. There's an absolute minimum that the pressure has to be set at?

Even though my machine is set at 10.5, the 90% record keeps showing that my machine is running at less than 8 all the time. My logic (good luck there) tells me that setting the machine anything over 8.5 would be useless since at higher settings I would still max out at less than 8. Or does it work where when you set the maximum pressure higher, you can then max out at a higher number.

Leaks and pressure settings. I seem to feel that I can feel (leak) some air coming into the mask when I inhale. Except for when I move in such a way as to move my mask (I'm a side sleeper), I don't get leaks from the pressure in the mask. Should I still be concerned about leaks when I inhale?

Finally. Vibration snoring. From what I've read here, the machine is very sensitive to vibrations of any sort. Right now, that appears to be one of my biggest issues about getting restful sleep. Increasing the pressure is supposed to minimize that to some degree, correct.

Totally different subject. Although I am waking up 3, or so, times per night, for the first time in over a year, I'm actually dreaming. That seems to correlate with feeling somewhat better. I'd still like to get 7 hours of uninterrupted sleep.

Again, thanks for all of the experienced information I keep getting here.

Interesting questions, and you seem to have a pretty good grasp of things. You don't mention any AHI or data results, but it sounds like you're aware of your pressure range. Monitoring your data on Sleepyhead would also tell you if leaks are an issue for you. Are you using a software program to look at your sleep results?

The machine minimum pressure is 4.0 cmH2O and that is sufficient to cause air to exhaust through the mask, but it may not be sufficient for therapy. Do you know what your therapeutic minimum pressure is? It would be good to increase the minimum pressure to near that threshold, especially if you feel you're not getting enough air at times, or if AHI events are clustered at lower pressures. Again, software is the only way to know this.

Leakage cannot occur inwards. If you're feeling a draft on inhale, it is from the machine or leakage outward. It can be hard to perceive airflow direction in a nasal mask, and since you can tolerate nasal therapy, the nasal pillows might be good for you to minimize that sensation of air moving on your skin.

Dogjudge wrote: i.e. There's an absolute minimum that the pressure has to be set at?

there may be, which would possibly vary from mask to mask... however, I imagine it's below the lowest pressure the commercial machines can be set to, and the lowest pressure I know of is 3cm in the case of the devilbiss intellipap and 4cm for most others.

Dogjudge wrote:Even though my machine is set at 10.5, the 90% record keeps showing that my machine is running at less than 8 all the time. My logic (good luck there) tells me that setting the machine anything over 8.5 would be useless since at higher settings I would still max out at less than 8. Or does it work where when you set the maximum pressure higher, you can then max out at a higher number.

if you increase the maximum, you can indeed max out at higher numbers, IF the machine decides you need it to prevent events. if the machine decides you don't need more than 9cm, for example, then it doesn't matter if you have the max set to 9, or 20... the max ONLY affects how high it CAN go, it has nothing to do with the calculation of how high it WANTS to go.

Dogjudge wrote:Leaks and pressure settings. I seem to feel that I can feel (leak) some air coming into the mask when I inhale. Except for when I move in such a way as to move my mask (I'm a side sleeper), I don't get leaks from the pressure in the mask. Should I still be concerned about leaks when I inhale?

I'm not clear on what you're asking. leaks are air exiting the mask, typically where it shouldn't, (ie, around the seal) as opposed to the "intended leak" which I like to refer to as 'vent' air, coming from the vent holes.

of course, more air is going to enter the mask from the hose when you inhale, at 8cm around 29 liters per minute are flowing into the mask and out the vent, constantly. with variation as you breath in and out.

Dogjudge wrote:Finally. Vibration snoring. From what I've read here, the machine is very sensitive to vibrations of any sort. Right now, that appears to be one of my biggest issues about getting restful sleep. Increasing the pressure is supposed to minimize that to some degree, correct.

increased inspiratory pressure helps to keep the airway open and reduce snores and flow limitations. if you haven't yet, watch this: https://www.youtube.com/watch?v=-gie2dhqP2c

Dogjudge wrote:Totally different subject. Although I am waking up 3, or so, times per night, for the first time in over a year, I'm actually dreaming. That seems to correlate with feeling somewhat better. I'd still like to get 7 hours of uninterrupted sleep.

there have been threads recently about dreams... the prevailing wisdom is that you dream every night, your mind forces it on you, however, as soon as a dream is over, it starts to fade rapidly, if you don't wake up (at least some) at the end, you won't remember you dreamed. so, it's likely that your arousals are what is causing you to remember the dreams.

Thanks for the replies.

I increased the pressure from 10.5 to 11.5.

The first night was horrible. AHI over 5, 90% pressure was 9.5, periodic breathing was 17 etc., etc. etc.

Last night was one of the most refreshing sleeps I've had in maybe 9 months. I might have awaken once during the night.

AHI this morning (2nd night) was 1.4, 90% pressure was 7.5 (where it had been), periodic breathing was ZERO.

I know 2 days does not make a pattern, but even one night of feeling that you have 90% of your old energy was spectacular.

Thanks again.

I seem to follow the top number whatever it is. I was hovering near 16 but my ears were blowing out. I am now at 12 and AHI is under 1. Ears settling down so will stay at lower pressure.

I had to limit my pressure due to aerophagia.
There may be a few reasons why you limit the top pressure