RE: Help in understanding AHI & Leak Rates.
(10-22-2013, 05:05 PM)bwexler Wrote: I have found with some full face masks when I open my mouth ( yawn) I move the mask enough to cause leaks and may need to adjust the mask after I close my mouth. The bottom of one mask would wind up in my mouth, like a bit in a houses mouth.
I am also a side sleeper and do not like most FFMs I have tried.
but, if you have 0% median, 0 to low % 95 % and 75% or higher sometimes for the maximum, how important is the maximum % (I agree that is due to a short time leak). Is that something the doctor will try to say why your pressure is off?
I had a sleep study where for 29 minutes at pressure 16, they felt it was sufficient when 95% of the time, daily, with low leaks, I am at 19.9%. Even at 16, my machine only goes to 20 and I feel that this machine is not sufficient based on ResScan AND Sleepy Head reports.
RE: Help in understanding AHI & Leak Rates.
You are right that the maximum value should be taken with a grain of salt. If you lift the mask for a few seconds to scratch your nose, that will count as a new maximum leak rate (and a high one at that), but will not affect the 95% value. Even briefly dislodging the mask as you turn over could register as a new maximum leak value without affecting the 95% value.
10-22-2013, 05:36 PM
(This post was last modified: 10-22-2013, 07:29 PM by me50.)
RE: Help in understanding AHI & Leak Rates.
(10-22-2013, 05:29 PM)RonWessels Wrote: You are right that the maximum value should be taken with a grain of salt. If you lift the mask for a few seconds to scratch your nose, that will count as a new maximum leak rate (and a high one at that), but will not affect the 95% value. Even briefly dislodging the mask as you turn over could register as a new maximum leak value without affecting the 95% value.
got it. that is exactly what I thought. thank you very much to everyone that responded to my post
RE: Help in understanding AHI & Leak Rates.
(10-22-2013, 04:53 PM)me50 Wrote: how important is the maximum if your median and 95% is within normal range? That's a great question.
Here's my opinion. The max leak rate is totally unimportant if the 95% leak rate is within the normal range. Why? Well, if your 95% leak rate is well below the "Large Leak" territory for your machine, then you know that your large leaks are lasting less than 5% of the night. And how much is 5% of the night?
Well, 5% of one hour is three minutes. So if you sleep for 8 hours and your 95% leak rate is well below the Large Leak boundary for your machine, then you know that any Large Leaks lasted for less than 24 minutes out of the entire night. And that's not really enough to get worried about: Any large leaks most likely did not last long enough to really adversely affect the quality and efficacy of your therapy or severely affect the overall accuracy of your data. Hence, unless a leak woke you up, if that 95% leak rate is within the normal limits, it's safe to assume you don't have a serious leak problem.
RE: Help in understanding AHI & Leak Rates.
(10-23-2013, 12:55 AM)robysue Wrote: (10-22-2013, 04:53 PM)me50 Wrote: how important is the maximum if your median and 95% is within normal range? That's a great question.
Here's my opinion. The max leak rate is totally unimportant if the 95% leak rate is within the normal range. Why? Well, if your 95% leak rate is well below the "Large Leak" territory for your machine, then you know that your large leaks are lasting less than 5% of the night. And how much is 5% of the night?
Well, 5% of one hour is three minutes. So if you sleep for 8 hours and your 95% leak rate is well below the Large Leak boundary for your machine, then you know that any Large Leaks lasted for less than 24 minutes out of the entire night. And that's not really enough to get worried about: Any large leaks most likely did not last long enough to really adversely affect the quality and efficacy of your therapy or severely affect the overall accuracy of your data. Hence, unless a leak woke you up, if that 95% leak rate is within the normal limits, it's safe to assume you don't have a serious leak problem.
agree. and the sleep doc thought that is why my pressure is so high. I am going to change it from 12 to 20 to 15 to 20 and see how I do tonight. Thanks again for your help
RE: Help in understanding AHI & Leak Rates.
(10-23-2013, 12:55 AM)robysue Wrote: Hence, unless a leak woke you up, if that 95% leak rate is within the normal limits, it's safe to assume you don't have a serious leak problem.
That's the part that concerns me. When a leak is too high it means the CPAP machine may no longer be able to maintain the pressure splint in your airway. In simple terms, your airway collapses, you stop breathing, and you wake up.
Using SleepyHead you can see when the large leaks are occurring, but you can't tell if you had an apnea because the machine can't reliably determine apneas during large leaks.
I would say that large leaks for a small percentage of time are less of a concern, but they still are a concern for me. They signal to me that my chinstrap is not tight enough, or it's time to replace it with a new one. Chinstraps, like all straps, stretch out and need to be tightened. If you're like me you use them way past their useful life until they no longer have enough stretch even when tightened all the way.
Sleepster
INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
RE: Help in understanding AHI & Leak Rates.
(10-23-2013, 11:06 AM)Sleepster Wrote: I would say that large leaks for a small percentage of time are less of a concern, but they still are a concern for me. Concern me too. I like to see the numbers close to each others, huge variations in leak rates disturb my sleep ... disturb sleep makes me grumpy
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