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I got a new CPAP, and when I turned it on after my first night, it displayed this info. What does this refer to?

Thats the pressure at which your CPAP has been set to operate. Your CPAP supplier would have set that pressure based on your sleep study report.

Or their best guess, and he's not Mr. Spock. (Star Terk REF) Jim

It's the pressure required to push a 10cm of water up the inside of a tube.

CPAP pressure is measured in units called cmH2O. One cmH2O is the amount of (additional) air pressure needed to raise a column of water by one centimeter. The cmH2O unit is basically a metric version of "inches of mercury" that we use in the US to measure the barometric pressure for weather forecasting. And just how much additional pressure does 1 cmH2O represent in terms that are meaningful to an average American? Well, if we go to http://www.unitconverters.net/pressure-converter.html and scroll way far down the list, we can convert 1cm H2O into (about) 0.029 inches of mercury. Since standard CPAP pressures range from 4 cmH20 to 20 cmH2O, that means they range from 0.116 to 0.58 inches of mercury.

Standard atmospheric pressure varies from day to day, but typical values are in the 28 to 30 inches of mercury range. Right now (Aug 14, 2011 at 8:10am), wunderground is reporting the air pressure in Buffalo, NY as 29.76 inches. When a typical storm front comes through, the air pressure drops anywhere from 0.25 to 1.5 inches of mercury. Some people are really sensitive to these changes in atmospheric pressure and get "pressure" or "weather" headaches or lots of joint pain. But most people don't notice them very much. At the maximum CPAP pressure of 20cmH2O, the machine is ADDING about 6/10 of an "inch" of additional pressure on top of the current atmospheric pressure---about as great of a pressure difference between a typical raining day and a typical sunny day.

Ok, that's what i thought. The dme confused me because they said that it was set at 12. My sleep study rated me at 11. After the first night my AHI was 0.3, and 0% mask leak. Maybe, I should keep 10?

Dive Apnea wrote:Ok, that's what i thought. The dme confused me because they said that it was set at 12. My sleep study rated me at 11. After the first night my AHI was 0.3, and 0% mask leak. Maybe, I should keep 10?

I sure would leave it where it is. Those are great numbers. Get used to your unit. Get used to the therapy. If you remain tired during the day, then consider talking with your doctor about it. But at the moment, it is a GREAT start. Here's hoping you have many more good nights of sleep ahead.

I wonder if that model doesn't come out of the box set at 10 by default and the DME simply didn't set the pressure. Anyone gotten a virgin PRS1 Pro machine and seen what the default factory pressure is?

Dive, it's possible that it's set to "ramp" from a pressure of 10 then gradually increase to 12 over a few minutes, but that would be really odd.

Is 10cm H2O a lot? or is it the mean?

Default is 10 CM h2o

it isn't a lot. mean.

it isn't a lot. mean.