Post Reply 
Help in understanding AHI & Leak Rates.
Author Message
me50 Offline

Advisory Members

Posts: 2,559
Joined: Aug 2013

Machine: resmed S9 VPAP Auto
Mask Type: Nasal mask
Mask Make & Model: Wisp and Silicone Head gear
Humidifier: resmed H5i
CPAP Pressure: 18/8
CPAP Software: SleepyHead

Other Comments:

Sex: Undisclosed
Location: USA

Post: #11
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.
10-22-2013 05:18 PM
Find all posts by this user Post Reply Quote this message in a reply

Donate to Apnea Board
RonWessels Offline

Preferred Members-2

Posts: 465
Joined: Jun 2013

Machine: REMstar Auto AFlex DS560TS
Mask Type: Nasal mask
Mask Make & Model: ComfortGel Blue
Humidifier: REMstar Heated Tube DS6T
CPAP Pressure: 11 - 20
CPAP Software: SleepyHead

Other Comments: CMS50F Pulse Oximeter

Sex: Male
Location: Ontario, Canada

Post: #12
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 05:29 PM
Find all posts by this user Post Reply Quote this message in a reply
me50 Offline

Advisory Members

Posts: 2,559
Joined: Aug 2013

Machine: resmed S9 VPAP Auto
Mask Type: Nasal mask
Mask Make & Model: Wisp and Silicone Head gear
Humidifier: resmed H5i
CPAP Pressure: 18/8
CPAP Software: SleepyHead

Other Comments:

Sex: Undisclosed
Location: USA

Post: #13
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
(This post was last modified: 10-22-2013 07:29 PM by me50.)
10-22-2013 05:36 PM
Find all posts by this user Post Reply Quote this message in a reply

Donate to Apnea Board
robysue Online
Wiki Editor
Advisory Members

Posts: 1,230
Joined: Oct 2013

Machine: PR Dreamstation BiPAP Auto
Mask Type: Nasal pillows
Mask Make & Model: Swift FX
Humidifier: PR Dreamstation humidfier
CPAP Pressure: min EPAP = 4; max IPAP = 9;
CPAP Software: SleepyHead EncoreBasic EncorePro

Other Comments: Papping since September 2010

Sex: Female
Location: Buffalo, NY

Post: #14
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.
10-23-2013 12:55 AM
Find all posts by this user Post Reply Quote this message in a reply
me50 Offline

Advisory Members

Posts: 2,559
Joined: Aug 2013

Machine: resmed S9 VPAP Auto
Mask Type: Nasal mask
Mask Make & Model: Wisp and Silicone Head gear
Humidifier: resmed H5i
CPAP Pressure: 18/8
CPAP Software: SleepyHead

Other Comments:

Sex: Undisclosed
Location: USA

Post: #15
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
10-23-2013 01:14 AM
Find all posts by this user Post Reply Quote this message in a reply

Donate to Apnea Board
Sleepster Offline
Wiki Editor
Moderators

Posts: 4,993
Joined: Feb 2012

Machine: ResMed AirCurve10 VAuto
Mask Type: Full face mask
Mask Make & Model: F&P Simplus
Humidifier: HumidAir and SlimLine Hose
CPAP Pressure: MaxI 13.6 | MinE 5.2 | PS 4.4
CPAP Software: ResScan SleepyHead

Other Comments: Diagnosed Nov 2011. Conquered aerophagia.

Sex: Male
Location: Houston, Texas

Post: #16
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
Apnea Board Moderator
www.ApneaBoard.com


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.
10-23-2013 11:06 AM
Find all posts by this user Post Reply Quote this message in a reply
zonk Offline

Advisory Members

Posts: 7,908
Joined: Feb 2012

Machine: A10 AutoSet
Mask Type: Nasal mask
Mask Make & Model: Activa LT
Humidifier: Integrated /ClimateLineAir
CPAP Pressure: 9/13
CPAP Software: ResScan

Other Comments: CPAP since Nov 2010

Sex: Male
Location: Australia

Post: #17
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
10-23-2013 03:35 PM
Find all posts by this user Post Reply Quote this message in a reply

Donate to Apnea Board
Post Reply 


Possibly Related Threads...
Thread: Author Replies: Views: Last Post
  One good night, now leak issues? sleepyguy99 8 353 12-03-2016 02:17 PM
Last Post: sleepyguy99
  [Pressure] Another New Player with Some Leak Issues Platypus 6 230 11-28-2016 06:17 PM
Last Post: Sleeprider
  swift mask 'leak' noise--but not leaking... hegel 11 749 11-27-2016 09:53 PM
Last Post: Dangerous Dave
  Not so new member having mask leak issues erikk 9 359 11-26-2016 02:15 PM
Last Post: erikk
  Leak rate abrun7 8 441 11-22-2016 09:02 PM
Last Post: Sleepster
  My Leak Issue! harmon k 5 292 11-14-2016 05:22 PM
Last Post: edfreeman
Thumbsup [CPAP] Mouth Leak? Saskie 5 333 11-13-2016 07:01 PM
Last Post: Saskie

Forum Jump:

Who's Online (Complete List)