Do mask leaks cause false readings?

I have a Swift fx mask and I am still working out occasional leaks which vary from night to night. The highest AHI I've had with the mask is 3.0 but usually in the 1.3 range, last night was .8. TAI and CAI are in the . 5 range. I am now wondering if the leaks cause a false reading and I'm actually having more apneas than indicated. The leak readings as I said vary but range from a high of 22.8 to 6.8, a couple nights I had 0 leaks. What is puzzling is that there doesn't seem to be a correlation between increased leaks and increase AHI, TAI and CAI. I don't have software, yet. This is my log from what I read on the S9 LCD. Any thoughts?

Thanks,

Bob

bob007 wrote:I have a Swift fx mask and I am still working out occasional leaks which vary from night to night. The highest AHI I've had with the mask is 3.0 but usually in the 1.3 range, last night was .8. TAI and CAI are in the . 5 range. I am now wondering if the leaks cause a false reading and I'm actually having more apneas than indicated. The leak readings as I said vary but range from a high of 22.8 to 6.8, a couple nights I had 0 leaks. What is puzzling is that there doesn't seem to be a correlation between increased leaks and increase AHI, TAI and CAI. I don't have software, yet. This is my log from what I read on the S9 LCD. Any thoughts?

I have wondered the same thing myself in trying to interpret my FIL's data. His leak is too high but his AHI is OK. I'm not sure if the AHI index is valid and interpretable in the presence of leaks. I would guess it depends in part on how big the leaks are. But either way, you're not getting the pressure you're set up to get... whether it's still enough, who knows? Probably also depends on whether the leak rate shown is due to an episode or two of large leaks, or whether it's constant leaking all night long. You'd know that from graphs of the leak line. Sorry, I'm no help.

I had a S8, before my S9. In the Clinical Guide for the S8, it said that leak rate of 24 liter/minute affects both therapy and the accuracy of the data. It doesn't say this in the Clinical Guide for the S9, but I would assume that this is also the case.

Is that 24l/m rate after adjustment for mask venting?

magicland-- I would assume so. ResMeds report leaks "after adjustment". It would be confusing to refer to any other leak rate in the manual.

Also, most masks have vent rates higher than that at some pressures....AND all vent rates vary with pressure. That would be a VERY low "combination rate" to begin affecting therapy/accuracy.

To the original question-- Virtually ALL data/events are sensed by pressure and airflow changes and their timing, it's only logical that significant leaks would greatly affect the accuracy of the data. And the quality of the therapy, as well.

magicland wrote:Is that 24l/m rate after adjustment for mask venting?

For ResMed, yes. Based on your mask setting, the data calculates your mask venting, and gives you the actual leak rate.

No so, for other brands.

I would say for my machine definitely.