Can someone please explain pressure?

mth712 wrote:What I changed to red text above is why I started a post saying we are all too darn concerned about leaks that don't show as large leaks unless the leak is disturbing your sleep causing an arousal by blowing on you somewhere or creating noises that arouse you. Don't sweat the small stuff so to say! I don't want to see a bunch of posts of look at my perfect flat leak line after I post this especially if you have a puny pressure under 12 or especially under 10.

If someone could DEFINITIVELY tell me that my M-series autopap with a-flex will deliver 12cm of pressure no matter what I do to the circuit, that'd be fine. I want something to back it up though.

While flow and pressure are different, how can a mask with a leak rate of 20 and a mask with a leak rate of 40 still give the same pressure to the airways? Something would have to compensate for that, right?

I KNEW I shouldn't have slept through Chemistry so I could have actually taken physics.

ractar28 wrote: If someone could DEFINITIVELY tell me that my M-series autopap with a-flex will deliver 12cm of pressure no matter what I do to the circuit, that'd be fine. I want something to back it up though.

While flow and pressure are different, how can a mask with a leak rate of 20 and a mask with a leak rate of 40 still give the same pressure to the airways? Something would have to compensate for that, right?

I KNEW I shouldn't have slept through Chemistry so I could have actually taken physics.

OK, I well tell you, if your M-series autopap with a-flex, is set to CPAP @ 12 CM, it will deliver 12 CM +/- .5 CM, as long as the leak rate is between 20 LPM & 35 LPM MAYBE EVEN HIGHER to even 40 LPM?

What compensates for that, is the M-series autopap with a-flex, it's designed to do that.

For something to back it up, How about a Old Remstar Classic, that's my back-up, and my other one is my other new Remstar APAP Classic! Jim

ractar28 wrote:If someone could DEFINITIVELY tell me that my M-series autopap with a-flex will deliver 12cm of pressure no matter what I do to the circuit, that'd be fine. I want something to back it up though.

While flow and pressure are different, how can a mask with a leak rate of 20 and a mask with a leak rate of 40 still give the same pressure to the airways? Something would have to compensate for that, right?

I KNEW I shouldn't have slept through Chemistry so I could have actually taken physics.

Again ... pressure and flow rate are two differnt things. That is why you can have two different masks with different leak rates and still theoretically maintain the same pressure.

HOWEVER, leak rates will affect pressure for APAP machines because the APAP machines are NOT "constant" pressure (ie. CPAP). An APAP uses a computer algorithm to adjust the pressure up and down ... and to do that it also uses a "flow sensor" as input into the computer algorithm. Therefore, leaks WILL affect pressure levels when using an APAP in "auto" mode.

For CPAP mode, leaks are generally compensated for so long as they are not too large (ie. beyond what the flow generator can compensate for).