help understanding leak data

[Terry67]

hi could anyone explain this in laymens terms.....sorry a bit of a noobie

[cflame1]

is it set to intentional or unintentional?

I'm asking because if it's intentional leak... then if the leak is close to the leakage chart for your mask it's ok. If it's unintentional then it's over and above what's acceptable for your mask.

So what's your software set to report?

[RandyJ]

is it set to intentional or unintentional?

I'm asking because if it's intentional leak... then if the leak is close to the leakage chart for your mask it's ok. If it's unintentional then it's over and above what's acceptable for your mask.

So what's your software set to report?

Don't S9 Autosets report unintentional leak only? In which case a 95th percentile number of 6 is very good. The maximum is not important, because this number could have registered while he was adjusting his mask.

For Resmed S9s any 95th percentile number less than 24L/min is considered acceptable. 6L/min is excellent.

In layman's terms, and I hope I say this correctly, the leak rate was at or below 6L/min for 95% of the time. Which is great!

[robysue]

Terry67's leak numbers are: Median: 0.0, 95th% 6.4 and Maximum 20.4.
What do these numbers mean?

Terry67,

Since you are using an S9 AutoSet, the numbers represent your UNINTENTIONAL leak rates.

In other words, ResMed and ResScan subtract off (an estimate for) the intentional leak rate for your mask at your pressure setting. So all the leak that is reported is UNINTENTIONAL or EXCESS leak---the kind you want to minimize.

Median: 0.0
This means that for 50% of the time the S9 was running, your unintentional leak rate was AT or BELOW 0.0 L/min. In other words, for at least 50% of the night, the S9 could detect no unintentional leaking. It also means that your unintentional leak rate was AT or ABOVE 0.0 L/min for 50% was running. If these are overnight figures, that's 50% of the night with leaks AT or BELOW 0.0 L/min and 50% of the night AT or ABOVE 0.0 L/min.

95%: 6.0
This means that for 95% of the time the S9 was running, your unintentional leak rate was AT or BELOW 6.0 L/min. It also means that your unintentional leak rate was AT or ABOVE 6.0 L/min for 5% was running. If these are overnight figures, that's 95% of the night with leaks AT or BELOW 6.0 L/min and 5% of the night AT or ABOVE 6.0 L/min. And how much is 5% of the night? Well, 5% of one hour is three minutes. So you can get an idea of an upper bound on how long your worst leaks (the ones above the 95% leak figure) lasted by multiplying the usage (in hours) by three minutes/hour. For example, if your machine was running for 7.3 hours and the 95% leak figure is 6.0, that means your leak rate was AT or ABOVE 6.0 L/min for a total of (7.3 hours)*(3 minutes/hour) = 21.9 minutes

Maximum: 20.4
This means that at some point when your S9 was sampling the leak rate it detected a leak of 20.4 L/in. We know you could not have been leaking at this rate for more than 5% of the night because your 95% is much lower than 20.4. When the max leak rate is this much higher than the 95% leak rate it could simply be that the S9 happened to sample the leak rate just as you were making a major adjustment to the mask and you knew the seal was broken because you'd pulled the mask away from your nose in order to reseat the mask. Or it could be that you had a 15 minute leak that was really, really bad. Only the leak line tells which case is more likely.


Are the leaks really a problem?

Leaks come in three basic varieties:

• Leaks that are LARGE enough and LONG enough to adversely affect your therapy. These obviously have to be dealt with. Are your leaks in this category? Well, the Resmed engineers believe the machine is capable of compensating for leaks up to 24 L/min as long as they're not too long lasting. The infamous Mr. Red Frowny Face shows up when the Resmed engineers believe your leaks are both LARGE enough and LONG enough to compromise both your therapy and the data the machine records. Mr. Red Frowny Face shows up when your 70% leak rate is AT or ABOVE 24 L/min. In other words, the Resmed engineers believe that if your leak rate is AT or ABOVE 24 L/min for 30% (or more) of the night, there's a real leak problem that the machine cannot cope with. And at that point, you really do need to do something to address the leaks.
• Leaks that are LARGE enough and/or LONG enough to adversely affect your comfort. These are leaks that are either not large enough or not long enough to clearly adversely affect your therapy and the data. But if a leak wakes you up, it's a problem. If you wake up with dry eyes from leaks causing air to blow in your eyes, that's a problem. If you wake up with a dry mouth, that's a problem. If you can't get to sleep in the first place because every time you move in bed the mask springs another leak that makes you more alert, that's a problem. And if you can't get to sleep because the leaks simply annoy you and keep you from drifting off into slumberland, that's a problem. In other words, if the leaks are causing you discomfort, they're a problem and they need to be dealt with so that you'll be more comfortable, and hence, sleep better.
• Leaks that are NOT large enough and/or long enough to adversely affect your therapy AND do NOT cause you any discomfort. My advice on these leaks is to not lose sleep over them. No one is going to have 95% leak rates equal to 0.0 L/min night after night after night. If that 95% leak rate is below 10 or 15 and you're sleeping through the leaks and not waking up with any problems caused by the leaks, then don't get too worried about working excessively hard to eliminate the last bit of leaking.

So Terrry67, you've got some really great leak figures here---particularly for a newbie!

[Terry67]

Thanks for the replies



My Inital overnight test data post S9 revealed a result of 59.1 AHI and 85% oxygen ave,at its worst I dropped to 61% with my lips actually turning blue !!
I have dont my follow up apointment until 25th Nov,although I can see using the S9 my AHI has reduced I want to make sure the wasnt anything else effecting my score.Thanks agian for putting my mind at rest.



Regards

Terry

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