How to interpret leak numbers on sleepyhead?

[Matty332]

Hey folks,

I am a bit confused about the leak data on sleepyhead. Can someone please take me to school on this issue? For example last nights leaks were:

MED: 4.8.
95%: 22.80
MAX: 45.6

How to I interpret each figure and is this a bad leak rate?

Thanks in advance!

[robysue]

Hey folks,

I am a bit confused about the leak data on sleepyhead. Can someone please take me to school on this issue? For example last nights leaks were:

MED: 4.8.
95%: 22.80
MAX: 45.6

How to I interpret each figure and is this a bad leak rate?

Thanks in advance!

First and foremost: You signature shows you are using a RESMED machine. That's imnportant because Resmed machines report only rthe excess leal---i.e. the leaking that is above and beyond the intentional leak rate that is built into the mask. Other machines, including the Respironics machines report total leaks, which include both the intentional leak and the excess leak. So don't go comparing your leak numbers with leak rates from people usinf Respironics equipment.

Next: The Resmed engineers define a large leak as a leak AT or ABOVE 24 L/min. Around here that figure is often referred to as the Red Line because the ResScan software draws a Red Line at that level on the leak graph. Note that a few short-lived "large leaks" are not necessarily a problem. For example, if you pull the mask away from your face to reseat it with a better seal or in a more comfortable position, you may see a short-lived large leak. And Mr. Red Frowny Face only shows up on the machine's LCD Sleep Quality report if you have been leaking AT or ABOVE 24 L/min for at least 30% of the night.

Now let's look at your numbers: MED: 4.8 is your median leak rate. You were leaking AT or BELOW 4.8 L/min for 50% of the night and you were leaking AT or ABOVE 4.8 L/min for 50% of the night.

95%: 22.80 is your 95th percentile leak rate. You were leaking AT or BELOW 22.80 L/min for 95% of the night and you were leaking AT or ABOVE 22.8 L/min. Technically, this is a low enough leak rate to satisfy the Resmed engineers, and hence Mr. Green Smiley Face showed up on the LCD.

MAX: 45.6 is your maximum leak rate. At some point during the night, the machine detected a laek rate of 45.6 L/min. The leak might have been very sort (a few seconds) or it could have lasted several minutes.

Now for your real question: Are these numbers acceptable?

In my humble opinion, that 95% leak rate is close enough to the Red Line to warrant some investigation. You need to look at the leak graph and not just the numbers. Given the numbers, it is possible that you might be having leaks near, but below the Red Line for extended periods of time (as in maybe 25% to 40% of the night. But it is also possible that you are leaking close to the Red Line for only a few short spells that add up to 5% of the night. And the only way to tell which scenario is closer to what's going onn is to look at the leak graph and not the numbers.

If you want a more detailed, but elementary, refresher on the statistical terms median, average, and 95th percentile, you might want to read my blog post at http://adventures-in-hosehead-land.blog ... de-to.html