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[CPAP] AHI = 1.0 – too good to be true?
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Mark Opti Offline

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Joined: May 2013

Machine: Resmed S9 Autoset
Mask Type: Nasal mask
Mask Make & Model: Resmed Mirage Swift II
Humidifier: H5i
CPAP Pressure: 9
CPAP Software: Not using software ResScan SleepyHead

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Sex: Male
Location:

Post: #1
Question AHI = 1.0 – too good to be true?
Hi,

I am a bit suspicious about unusually low AHI that my brand new ResMed S9 reports. Hope somebody can provide some advice.

I have been diagnosed in 2006 with OSA with AHI =10. I was titrated at the lab for CPAP pressure 9.

Since then I’ve been using APAP/CPAP machines every single night. I had 3 machines:
1. Respironics REMstar Auto 2006 to 2009
2. ResMed S8 AutoVantage 2009 to June 2013
3. I’ve just got a few days ago ResMed S9 Autoset

On #1 and #2 machines I really could not use APAP mode over long time. I was setting APAP pressure to min 6 and max 11.5. I was frequently awaken up by high pressure close to max blowing into my nose. So for the most of the 7 years I was using the machines in CPAP mode with pressure set to 9. And all these years my AHI index was around 5.


With the new ResMed S9 in auto mode, the machine shows AHI=1 or less. Can it really be that machine provides that level of improvement, or something is different in how S9 calculates and reports AHI? I.e. do I really get a better treatment or this is a gimmick from ResMed.
06-13-2013 09:32 PM
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zonk Offline

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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: #2
RE: AHI = 1.0 – too good to be true?
No its not a gimmick, for an apnea to get scored have to last 10 seconds or more, obstructions less than 10 seconds are not scored as an apnea. To get technical you need to look at waveform and flow limitations graphs

Prolong leaks above 24 L/min can affect the accuracy of data reporting
06-13-2013 10:44 PM
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PaulaO2 Offline
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Machine: S9 Autoset
Mask Type: Full face mask
Mask Make & Model: F&P Simplus
Humidifier: H5i
CPAP Pressure: 14-20
CPAP Software: SleepyHead

Other Comments: Ehlers-Danlos Syndrome, Hypermobility Type; chronic sarcasm

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Location: western NC, USA

Post: #3
RE: AHI = 1.0 – too good to be true?
It is very possible indeed!

The only time to be concerned that your machine is possessed by aliens is if the S9 shows zero AHI for more than a day. It is some kind of quirk (aliens!). To fix it, just unplug it for about 30 seconds and plug back in.

Your machine is data capable. All you need is a card reader. You can get a real cheap one for just a few bucks if your computer does not have one. Both ResScan and SleepyHead work with your machine. Try using both of them for a few weeks to decide which one you like.

Looking at the data would let you know how often you bump up against your upper limit, if you do at all.

PaulaO2
Apnea Board Moderator
www.ApneaBoard.com


Breathe deeply and count to zen.

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.
06-13-2013 10:49 PM
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Shastzi Offline

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Posts: 1,174
Joined: Dec 2012

Machine: ResMed S9 Autoset
Mask Type: Full face mask
Mask Make & Model: FitLife Total face mask
Humidifier: F&P HC150 with Hybernite heated hose.
CPAP Pressure: 15cm-20cm H2O (auto)
CPAP Software: SleepyHead Other Software

Other Comments: CMS50-F wearable Oximeter; Software: SPO2 Assistant

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Location: Florida, USA.

Post: #4
RE: AHI = 1.0 – too good to be true?
Hi Mark Opti!

Welcome

You are in the right place.

Since I got everything with my sleep tuned up I am doing about 0.4 to 1.5 with an occasional 0.0!

This is good for you, because it means your machine is kicking some OA butt!
You will need to be always vigilent though so get the SleepyHead going and you'll be monitoring
your own therapy so you can take corrective action when the time comes.

Good Luck, Cheers & Sleep-well

"With ordinary talent and extraordinary perseverance, all things are attainable." - Thomas Foxwell Buxton

Cool
06-14-2013 07:55 AM
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archangle Offline
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Machine: ResMed S9 AutoSet
Mask Type: Nasal pillows
Mask Make & Model: ResMed Swift FX
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CPAP Pressure: 16-20
CPAP Software: ResScan SleepyHead EncoreBasic

Other Comments: Happy PAPper

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Location: USA

Post: #5
RE: AHI = 1.0 – too good to be true?
I THINK:

1) The S9 AutoSet does a better job of finding the right pressure and treatment in general than the S8.

2) The S9 scores fewer apneas vs. the S8 for many people due to changes in the detection algorithms. There are some things that fall in the "gray area." I don't think this is "marketing," and that the newer algorithm is more in line with what the medical professionals think in terms of scoring apneas.

Even if everything is "right," there's still some "judgment" in apnea diagnosis and treatment. Sometimes, one thing works better than another, and you have no real explanation why.

If your AutoSet ever starts showing 0 AHI night after night, unplug the power for a few minutes. A number of people have reported their machines getting "confused" and needing a reboot. Unplug the power, don't just turn it off. It doesn't seem to affect treatment, just data recording. Also, it's a "stuck on 0.0" problem, not a "record low values" problem.

Get the free SleepyHead software here.
Useful links.
Click here for information on the main alternative to CPAP.
If it's midnight and a DME tells you it's dark outside, go and check it yourself.
06-14-2013 04:55 PM
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RonWessels Offline

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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: #6
RE: AHI = 1.0 – too good to be true?
Another point is to not be automatically afraid of what seem to be high AHI values. From personal experience, if I have my CPAP on but am futzing with my pillows or something, I will often end up periodically (consciously) holding my breath for long enough to register as an obstructive apnea. Look at your collected data. If all (most) of the apnea events are right at the start or end of a session, they will contribute to the overall AHI for the session, but aren't really "real". Look at what is happening while you are asleep to see if there really is a problem.

This is why most people tell you to run away from "brick" (non data-logging) machines. Just the summary can be misleading.
06-14-2013 06:00 PM
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zonk Offline

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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: #7
RE: AHI = 1.0 – too good to be true?
S9 AutoSet nuke apnea events before occurring as it respond to snoring and flow limitation which are precursors to apnea events. Also differentiate between obstructive and central apnea through FOT, take no action if open airways is detected but deal with it if closed airways is detected. For this reason the S9 enhanced algorithm is more efficient than its predecessors
06-14-2013 06:15 PM
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Mark Opti Offline

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Posts: 2
Joined: May 2013

Machine: Resmed S9 Autoset
Mask Type: Nasal mask
Mask Make & Model: Resmed Mirage Swift II
Humidifier: H5i
CPAP Pressure: 9
CPAP Software: Not using software ResScan SleepyHead

Other Comments:

Sex: Male
Location:

Post: #8
Thumbsup RE: AHI = 1.0 – too good to be true?
Thanks a lot to all for the input!

As I said, my main concern was that for 7 years on 3 other machines (REMstar Auto and two S8 Vantage) I was hovering around AHI 5. So I was looking for a possible explanation about why that much difference with S9.

I think, like Archangel pointed, S9 does both:
1. Does better job with different algorithm
2. Interprets data differently.


I did check SleepyHead reports – everything looks good. I do feel that S9 has better Auto mode. Other machines were going to Max pressure often and that woke me up. So I used most of the time CPAP mode.

S9 seems has very nice Auto algorithm and applying Max pressure more intelligently (not as often).
06-16-2013 09:14 PM
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SuperSleeper Offline

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Machine: PR System One REMstar Auto (DS560)
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CPAP Software: SleepyHead

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Post: #9
RE: AHI = 1.0 – too good to be true?
(06-16-2013 09:14 PM)Mark Opti Wrote:  I do feel that S9 has better Auto mode. Other machines were going to Max pressure often and that woke me up. So I used most of the time CPAP mode.

S9 seems has very nice Auto algorithm and applying Max pressure more intelligently (not as often).

This used to be common in older APAP machines. It's why even today, many sleep doctors are prejudiced against APAPs, thinking that the pressure can "run away" and go to the max too soon, as you described.

But with today's newer machines, this just doesn't happen much any more, making APAPs the machine of choice for many OSA patients.

SuperSleeper
Apnea Board Administrator
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.

06-17-2013 10:11 AM
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britincanada Offline

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Machine: Respironics BiBpapautoSV Advanced
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Sex: Male
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Post: #10
RE: AHI = 1.0 – too good to be true?
Congrats for the Low AHI

We all aim for below 5

But the Main thing is How are you Feeling if you Feel great with a AHI of Say 3
Does worrying about getting it any lower really help
If its not broke don't Fix it
(This post was last modified: 06-17-2013 12:50 PM by britincanada.)
06-17-2013 12:48 PM
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