M Pro Calulating Leak Rate

[DoninOrlando]

I have what sounds like a dumb question... but here it goes.... How does the machine (M series Pro) distinguish between breathing and leaks ? If it has an average calculated for leaks for a particular mask, and then an average for your actual breathing, does it assume anything above is leaks ? Or does it measure breath on every inhale and/or exhale ?
The reason I am asking is this morning I woke up, but stayed in bed with mask on for about 20 minutes. I turned from my side to my back, felt around the mask for leaks, and even pressed it to my face to see if it got quieter indicating it was leaking. I did not feel or hear any leaks at all. I laid there 20 min thinking it would show up as perfect for leaks. It showed up as the worst for the night, about 10 LPM above expected ! I do frequently breath deep when I first wake up with mask on. I also believe I breath deeper when awake than asleep as I am more concious of breathing and like to breath deeper. Could the extra air I am inhaling somehow be calculated as leakage ? How does the machine know the difference in me taking a deep breath, or pulling my mask up to scratch my nose ? Does it use an average from your normal sleep breathing to calculate leakage, (after expected mask leakage for exhaust) ?
Don

[Wulfman]

I have what sounds like a dumb question... but here it goes.... How does the machine (M series Pro) distinguish between breathing and leaks ? If it has an average calculated for leaks for a particular mask, and then an average for your actual breathing, does it assume anything above is leaks ? Or does it measure breath on every inhale and/or exhale ?
The reason I am asking is this morning I woke up, but stayed in bed with mask on for about 20 minutes. I turned from my side to my back, felt around the mask for leaks, and even pressed it to my face to see if it got quieter indicating it was leaking. I did not feel or hear any leaks at all. I laid there 20 min thinking it would show up as perfect for leaks. It showed up as the worst for the night, about 10 LPM above expected ! I do frequently breath deep when I first wake up with mask on. I also believe I breath deeper when awake than asleep as I am more concious of breathing and like to breath deeper. Could the extra air I am inhaling somehow be calculated as leakage ? How does the machine know the difference in me taking a deep breath, or pulling my mask up to scratch my nose ? Does it use an average from your normal sleep breathing to calculate leakage, (after expected mask leakage for exhaust) ?
Don

My take on this.......

With your single-pressure, data-capable M Series Pro CPAP, it puts out a fixed pressure. It has sensors inside it that monitor and maintain the output pressure. If it senses the pressure drop (due to leakage or loss of air in the circuit), it then increases the airflow to try to compensate and maintain the pressure level. In its advanced sensors, circuitry and programming, it calculates/determines the additional amount of air it's putting out as "leakage". There is going to be "some" amount of "Vent Flow" based on the stated, deliberate flow rate of the mask (so you don't re-breathe too much CO2) but the machine compensates for that......and the difference between that stated Vent Flow Rate and the total leak number is essentially "leakage". The machine programming takes its measurements at certain intervals, so there may be some variations in what it reports in the data.

I doubt that your deep breathing would be calculated as leaks, because you eventually exhale.
It doesn't know what type of mask you wear or when you lift your mask to scratch an itch.......it just calculates the airflow and pressure and makes overall recordings based on that information.


Den

[desert rider]

There isn't anyplace on the M Series to configure the leak rate for your mask, is there?

[Wulfman]

There isn't anyplace on the M Series to configure the leak rate for your mask, is there?

Nope. They're not like the ResMeds.


Den

[DoninOrlando]

Oh well, I guess it will remain a mystery. It just seems weird that the leak rate was lower when I was asleep than laying there awake, perfectly still, after checking and with no noticeable leaks. With Swift my best leak rates were always when awake.