AHI - what's the magic number?

[Babette]

Oh blazes, I can't find the link to the "magic number" for AHI. How low is the magic bar?

I've got 3.1 from two nights on the new machine. Is it "Below 5" or "Below .5" I'm looking for? Or am I completely way off base on that magic number?

Thanks!!!!!!!!!!!!!!!!!!!
B.

[Bookbear]

Below 5 (whole number 5).

[Babette]

Oh thank you!!!!!!!!!!!

Well, THAT'S GOOD NEWS! I'm below 5!

I always new I was MENTALLY below 5, and definitely am not smarter than a 5th grader...

Many thanks!
B.

[bdp522]

Congrats on being below 5! Hopefully now you have everything working for you and you will see almost constant improvements.


Brenda

[split_city]

Depends on where you live. In Australia, anything <15 is considered 'normal'

[robbieh]

I swear mine is 666. My AHI graph looks like a big earthquake with all the ups and downs. I'm above 5 as much as under. My best number was 1.5 and my worst is 7.2. At least my machine is not full of water currently...

[Babette]

I suppose this means I have to start exercising and lose weight... I've elminated all the excuses for doing same.

Australia, why <15? Seems high to me. Is it geographical? Like elevation?

Cheers,
B.

[rested gal]

Australia, why <15? Seems high to me. Is it geographical? Like elevation?

It would be way too high to me, too, Babette.

Kinda' depends on which doctor one talks to. In any country, I suppose.

http://www.pulmonaryreviews.com/sep02/p ... Index.html

[Nev]

In Australia, anything <15 is considered 'normal'

I'm a bit surprised at this. Do you have a source?
Anything I've seen in Aus goes with <5 = within normal limits; 5-15 = mild; 16-30 = moderate; 30+ = severe.

[StillAnotherGuest]

Depends on where you live. In Australia, anything <15 is considered 'normal'

OK, are you talking about AHI or RDI? From your other post, and my question:

This is what is at the bottom of all our sleep reports:

Current versus historical RDI values. In accordance with recent internationally agreed recommendations2, the AISH laboratories transferred in 2002 from using oronasal thermistors to using nasal pressure transducers to measure airflow and at the same time adopted a new standard for scoring apneas and hypopnoeas2. Nasal pressure is a more sensitive measure of airflow and as a consequence, average AISH reported RDI values are now higher for the same severity sleep disordered breathing. The best estimate is that RDI has increased by approximately 40.%. This is relevant when interpreting current patient results with respect to our earlier studies of normal subjects1 and other previous epidemiological studies, which relied on thermistors to measure airflow.

Severity of sleep disordered breathing. Bearing in mind the above, AISH consultants have adopted the following consensus classification of severity of sleep disordered breathing

RDI: <15 Normal (see above caveats)
>15 - <30 Mild
>30 - <45 Moderate
>45 Severe

Hmmm, now SAG is greatly confused. Regardless of the diagnostic airflow methodology used, during intervention the waveform from the PAP machine is used to score events, and that is a pressure transducer. Are you then saying that RDI during titration and APAP is normal as long as it is <15?

Also, what are your components of RDI? Are they apneas, hypopneas and RERAs? RERAs and hypopneas need to have an associated event, be it an arousal and/or a desaturation. And >5 events per hour of those events are abnormal.

Or put another way, the diagnostic device selected is really academic. Either device (thermistor or pressure transducer) will identify an apnea, but beyond that, a respiratory event without an associated desaturation or at least an arousal is nothing.
SAG

Or put another, another way, let's say a patient has 14 respiratory events, all of which cause desaturations. Under the thermistor rule, that would be a problem. Are you saying that under pressure transducer, that's no longer a problem?

OK, let's say instead, there were 14 arousals that were associated with thermistor-defined events. Are you saying that with pressure transducer technology, they are no longer considered to be respiratory-associated events? Especially if the waveforms have a flattened appearance? And if not, then what do you call them?

The whole idea behind pressure transducer is that it picks up events that thermistor may miss. And it's not the respiratory event per se that's the issue, it's the associated desaturation, arousal and/or increased effort (i.e., the flattened waveform seen in UARS). And that number is almost universally accepted as being 5.
SAG

[oceanpearl]

My cumlative is just over 3.0. Some nights it gets below 2 and I am very happy with that.

_________________

CPAPopedia Keywords Contained In This Post (Click For Definition): cpap machine

[Snoredog]

DEFINITIONS:
APNEA = cessation of airflow for 10 seconds or greater.
HYPOPNEA =>50% decrease in airflow for 10 seconds or greater with a decrease in oxygen saturation of >3%.
APNEA/HYPOPNEA INDEX (AHI) = apnea plus (+) HYPOPNEA/hour of sleep.
RESPIRATORY AROUSAL INDEX (RAI) = AHI +snoring related EEG arousals/hour of sleep.
AHI/RAI** Scale =<5 events /hour = (none); 5-15 events/hour = (mild); 15-30 events/hour = (moderate); >30 events/hour = (severe).
Respiratory related sleep fragmentation: Sleep arousals due to respiratory events or snoring.
Desaturation = Drop in O2 oximetry distribution saturation by 3% below average saturation.
SaO2 scale: >89%=(none); 85-89%=(mild);80-84%=(moderate); <80% (severe).
EPWORTH SLEEPINESS SCALE =<10=(does not indicate EDS (Excessive Daytime Somnolence));10-15=(indicates daytime somnolence-not excessive);>16 (indicates EDS).
RESPIRATORY EFFORT RELATED AROUSALS (RERAs)=Sleep Arousals due to respiratory events characterized by pressure flow limitations in the airflow indicator channel without significant O2 desaturations.
StageIII and StageIV are combined and referred to as Deep Sleep.
Sleep Efficiency = Normal is >80%
As established by AASM/ABSM 1999.

Normal Sleep Architecture:
Stage1: 5%
Stage2: 50%
Stage3: 10%
Stage4: 10%
Stage REM: 25%

[Guest]

I'm going to try and find out why we Australians classify an RDI <15 as normal. I'll get back to you when I find out.

[Guest]

In Australia, anything <15 is considered 'normal'

I'm a bit surprised at this. Do you have a source?
Anything I've seen in Aus goes with <5 = within normal limits; 5-15 = mild; 16-30 = moderate; 30+ = severe.

I guess it all depends on whether the labs use either pressure transducers or thermistors

[lindychris]

DEFINITIONS:
APNEA = cessation of airflow for 10 seconds or greater.
HYPOPNEA =>50% decrease in airflow for 10 seconds or greater with a decrease in oxygen saturation of >3%.
APNEA/HYPOPNEA INDEX (AHI) = apnea plus (+) HYPOPNEA/hour of sleep.
RESPIRATORY AROUSAL INDEX (RAI) = AHI +snoring related EEG arousals/hour of sleep.
AHI/RAI** Scale =<5 events /hour = (none); 5-15 events/hour = (mild); 15-30 events/hour = (moderate); >30 events/hour = (severe).
Respiratory related sleep fragmentation: Sleep arousals due to respiratory events or snoring.
Desaturation = Drop in O2 oximetry distribution saturation by 3% below average saturation.
SaO2 scale: >89%=(none); 85-89%=(mild);80-84%=(moderate); <80% (severe).
EPWORTH SLEEPINESS SCALE =<10=(does not indicate EDS (Excessive Daytime Somnolence));10-15=(indicates daytime somnolence-not excessive);>16 (indicates EDS).
RESPIRATORY EFFORT RELATED AROUSALS (RERAs)=Sleep Arousals due to respiratory events characterized by pressure flow limitations in the airflow indicator channel without significant O2 desaturations.
StageIII and StageIV are combined and referred to as Deep Sleep.
Sleep Efficiency = Normal is >80%
As established by AASM/ABSM 1999.

Normal Sleep Architecture:
Stage1: 5%
Stage2: 50%
Stage3: 10%
Stage4: 10%
Stage REM: 25%

This all needs to get nto the Cpapopedia. Thanks Snoredog for a comprehensive list of definitions. I'm still not fully clear as to what a flow limitation is, but the rest is great!