S9 Settings

It's a tradeoff.

If you set your maximum pressure to something "low," be sure to check if you're hitting the maximum pressure very often. If so, evaluate whether the pressure needs to be raised.

If you leave it wide open, you need to watch to see if your pressure is getting to high, if you're having problems like central apneas, etc. If your pressure increases a lot, you should consider if there's some particular reason.

I leave mine wide open, but I watch it, and it doesn't tend to run away on me.

Thanks you guys, excellent feedback, But i am still somewhat confused about the meaning of auto on the S9, i thought that i could leave the machine on its default settings of 4-20. If not what does the auto refer to. forgive my ignorance, and also if this topic has been discussed previously

Slight simplification:

The machine will start at a pressure of 4, adjusting upwards to 20 as it thinks you need it.

One problem is that you may spend part of the night at a too low pressure until you have enough apneas to make it adjust up to the right pressure. It only adjusts slowly, perhaps one pressure unit per minute. You may suffer and find it hard to sleep while it ramps up.

It also starts back at 4 every time you turn the machine off.

If you only have apnea during part of the night, such as during REM sleep, it may drop the pressure to a lower pressure and you may suffer again until it ramps up again.

They will also sometimes set too high a pressure. Sometimes they don't get the pressure high enough to work right.

Some people are bothered by the pressure changes.

If you start at a low pressure, get your mask to fit right when you're at 4 cmH2O, your mask may leak when the pressure goes up during the middle of the night.

For these reasons, a lot of people think it's good to choose a narrower pressure range, especially the minimum pressure, and monitor the results.

Thank you archangel, I think I fully understand now about the S9 Auto. I think I'll put in, as you suggest, a minimum and a maximum pressure and see how I get on for a week. Will let you know more as and when I get results. Thanks again.