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How Leaks impact AHI
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Dawei Offline

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Posts: 342
Joined: Feb 2012

Machine: ResMed S9 AutoSet
Mask Type: Other
Mask Make & Model: Respironics "FitLife"
Humidifier: H5i
CPAP Pressure: 10-20
CPAP Software: ResScan SleepyHead

Other Comments: Began CPAP in 2006; spent the first 6 years with a "brick"

Sex: Male
Location: Western North Carolina

Post: #1
How Leaks impact AHI
Recent experience has demonstrated to me just how mask leakage affects AHI numbers reported by ResScan software, and perhaps this example may be of interest to others.
During a four night period (June 3-6), my 95% Leakage rate was 50.4 and the AHI for that same period was 12.5. During the next four-night period, the 95% leak rate dropped to 7.8 and the AHI was 2.6! A leak-elimination tip from a fellow board member is responsible for this dramatic change, but the numbers clearly show how excessive leakage skews AHI reports.
06-11-2012 07:19 AM
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Sleepster Offline
Wiki Editor
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Posts: 4,995
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: #2
RE: How Leaks impact AHI
(06-11-2012 07:19 AM)Dawei Wrote:  but the numbers clearly show how excessive leakage skews AHI reports.

If the leak is large, the machine can't measure AHI in any meaningful way. If you dig a little deeper, and look at the components of he AHI, they become even less meaningful. The machine cannot, for example, distinguish between a CA and a OA when there's a large leak.

The bottom line is this. If you have large leaks, regardless of the reported AHI, your therapy is ineffective.

Sleepster
Apnea Board Moderator
www.ApneaBoard.com


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06-11-2012 03:42 PM
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Dawei Offline

Preferred Members-2

Posts: 342
Joined: Feb 2012

Machine: ResMed S9 AutoSet
Mask Type: Other
Mask Make & Model: Respironics "FitLife"
Humidifier: H5i
CPAP Pressure: 10-20
CPAP Software: ResScan SleepyHead

Other Comments: Began CPAP in 2006; spent the first 6 years with a "brick"

Sex: Male
Location: Western North Carolina

Post: #3
RE: How Leaks impact AHI
Along the line of what you suggested, Sleepster, I noticed that when significant leaking is present, I see lots of yellow (unknown) event markers mixed in with the red markers on the ResScan events graph. I don't see much in the way of CSA markers, but the software actually announces with those yellow markers that it doesn't recognize the leak events.
06-11-2012 04:17 PM
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