Leak rate numbers.

[RoseWeissman]

Hi all,
Just a quick question on leak rate- I know this gets asked a lot but I just want to be sure I have this correct. I have a Resmed Airsense Autoset 10. I’ve read a lot of the explanations here so have attached last night’s OSCAR data to see if I have the correct understanding.  
 
The minimum rate at 0%- I’m a bit confused about this and will get back to it later.
 
Medium 0.0%- for up to 50% of the time the machine was being used there was no unintentional leak. This is good news? Correct?  
 
95% rate = 13.20. This means for 95% of the time the machine was running there was an unintentional leak of up to 13.20 l/min. Is this correct? This is not good surely? I know it is well under the Resmed 24 l/min but the closer to 0 the better?
 
Maximum leak = 19.20. This means the highest one off leak was 19.20 l/min. Correct? And because my 95% leak was 13.20 it means my maximum leak of 19.20 l/min could not have been for more than 5% of the time??
 
So why then is the minimum leak 0%? Or is this an OSCAR and Redmed thing that is always 0%?
 
Looking back over the last few months my medium leak is 0%- I presume this is a good figure to have?

I have had a lot of mask problems and have tried numerous different types and have settled with the Airfit FF 20. Also started using the Dr Dakota neck support and have found that makes a huge difference with leaks and it seems to have stopped me taking off the mask in my sleep with no recollection of it the next day. Tried different hose positions so am just trying to maximise by therapy.

Edit: mimimum leak at 0% means exactly that. The lowest rate was 0 and that's the ideal figure isn't it?

[Crimson Nape]

You are confusing "percent" with "percentile".  The "Med" stands for Median, or 50%-tile.  Median is defined as a value that is at the center of all recorded values that have been arranged by order of ascending value.  It is not the average value. Your average can be seen by hovering over the parameter name with your mouse pointer.  

An Example:
Values as recorded: 7, 9, 3, 7, 9, 2, 1, 4, 6, 4, 8.  
Sorted by value: 1, 2, 3, 4, 4, 6, 7, 7, 8, 9, 9
Average: 5.454545
Median or 50%-tile: 6 (since "6" is exactly in the middle of all the values)

The 95%-tile means that you were experiencing a leak at 13.20L/min or less for 95% of the time.  The maximum is actually a 99%-tile report.  This is to remove those little erroneous spikes in the data.  This means your leak was 19.2L/min or less for the night.

A lot of the parameter's minimum data will be always be reported as "0" (zero).  This is due to certain parameters not reporting a value until 1 minute after startup. So the initial value is reported as 0.

EDIT: Looking at your screenshot again and seeing the 4 major leak blips, I bet that is when you were changing sleeping positions.


I hope this made sense.

[RoseWeissman]

Thanks Crimson Nape and yes that does make sense to me. Based on what you saw from one screenshot would you be reasonably happy with the results so should I try more to reduce leaks further? T

[mesenteria]

If your treatment pressures are met consistently, and there are no major leaks, and your nightly AHI are under 5.0, you are being well treated. Most of us fret more over the AHI if it’s higher than about 2 or so, and worry about leakage if they are both “large” and if they persist.

Watch for your pressures chart to show maximum pressure often (those on simple CPAP with fixed pressure needn’t concern themselves with this). If your machine is almost constantly running at your max setting, and you’re not on a fixed pressure, leakage may be an issue, but not necessarily. It could mean you actually might benefit from more pressure or from a different way of sleeping, including starting to use a soft cervical collar to keep your chin from falling toward your chest during sleep and pinching your airway.

[Crimson Nape]

I'd keep your settings where they are. One night's data doesn't make a trend. If you have found your "sweet spot", I expect the AHI number to bounce around but not by much, if. The most important thing now is, "How do you feel?"