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Meaning and relevance of AHI, AI, and HI readings
#1
Greetings!

First:
My thanks to everyone here who has posted, both questions and answers. This is a totally awesome resource, and I am glad I found it.
Thanks

Second:
Accept my apologies for a potential re-post of this question, however the search function will not accept a search with terms like "AHI", "AI", or "HI" in it as they are "too short"
Huhsign (there should be a "Doh!" smiley)

Question:
Looking at my efficacy data, I see, (among other things), readings for AHI, AI, and HI. (the rest are things like pressure, how often I use it and for how long, leak rate, etc.)

So far, I have not found anyone who discusses what these readings actually mean, (i.e. their definition), and their relevance, (i.e. what do these readings actually tell me.)

I know that an AHI of less than five is boss, (mine is currently 3.2), and the sub-readings are AI = 0, HI= 3.2.

An explanation of these readings, their meaning, and their relevance would be gratefully appreciated!

What say ye?

Jim (JR)
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#2
jharris1993,

You might find my blog entry, Understanding the data in your sleep test report useful in learning what things like AHI, AI, and HI mean and why they are important. A lot of this information is also this site's wiki as well.
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#3
Hi jharris1993,
WELCOME! to the forum.!
Hang in there for more responses to your post and best of luck to you with your CPAP therapy.
trish6hundred
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#4
(06-15-2014, 02:30 PM)jharris1993 Wrote: I know that an AHI of less than five is boss, (mine is currently 3.2), and the sub-readings are AI = 0, HI= 3.2.

An explanation of these readings, their meaning, and their relevance would be gratefully appreciated!

What say ye?

Jim (JR)
Which machine are you using
[Image: which-remstar.jpg]

Events definition from the clinical manual, available via Email from here:
http://www.apneaboard.com/adjust-cpap-pr...tup-manual

An apnea is detected when there is an 80% reduction in airflow from baseline for at least 10 seconds or if there is no airflow detected for 10 seconds

A hypopnea is detected when there is an approximately 40% reduction in airflow from baseline for at least 10 seconds

User profile - CPAP Pressure: 8-???
Is machine set on fixed pressure 8 or on auto range - if on auto whats the range (minimum and maximum pressures), 90% pressure and leak





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#5
Acronyms/abbreviations
http://www.apneaboard.com/wiki/index.php?title=Acronyms

From there, you can click the links and start bringing up more info. Read up a little on that and if you have any questions, feel free to ask!

Doing a forum search for any of those terms would just overload your computer as it comes up an awful lot!
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.




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#6
Just adding my Hello and welcome to the board Smile

As you learn, 'AHI' and 'Leak rate' are two biggies to watch - bad/uncontrolled leak rates can/will skew all other readings depending on how bad the leak(s) are. In other words, an 'AHI' of 3.5 may well be meaningless if you 95% leak rate is 30 - just an example.
*I* am not a DOCTOR or any type of Health Care Professional. My thoughts/suggestions/ideas are strictly only my opinions.

"Only two defining forces have ever offered to die for you. Jesus Christ and the American Soldier. One died for your Soul, the other for your Freedom."
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#7
(06-16-2014, 11:32 AM)Peter_C Wrote: Just adding my Hello and welcome to the board Smile

As you learn, 'AHI' and 'Leak rate' are two biggies to watch - bad/uncontrolled leak rates can/will skew all other readings depending on how bad the leak(s) are. In other words, an 'AHI' of 3.5 may well be meaningless if you 95% leak rate is 30 - just an example.
Peter_C, you can't just tell someone that a 95% leak rate of 30 L/min is "bad" just because it is "bad" on the Resmed machine that you use.

The OP is using a Resprionics machine and Respironics machines report the Total Leak rate instead of excess leak rate. Total Leak rate includes both the intentional vent rate for the mask and any excessive leaks beyond intentional leak rate for the mask. The intentional leak rate for a mask depends on both the mask and the pressure used.

Most masks have an intentional leak rate of 30 L/min for pressures of around 7-8cm. And the intentional leak rate for the mask increases as the pressure goes up. When you are using a Resprionics machine, you want your (total) leak rate to stay close to the intentional leak rate for your mask. And that means that the total leak numbers as reported in software (either Encore or SleepyHead) will USUALLY be over 30 L/min, and may be well over 30 L/min if you are using a full face mask at at high pressure setting

While Respironics does not publish an official line for "Large Leaks", the Encore software typically starts to score Large Leaks when the TOTAL leak rate is somewhere up around 80-90 L/min. The Respironics line for Large Leaks does seem to be related to the pressure setting used.

Points to remember about interpreting leak data

Respironics users need to know the intentional leak rate for their mask at their pressure in order to interpret the leak data. The intentional leak rates for the mask can be found in the user manual for the mask. A great leak line is one where the (total) leaks are usually within a few L/min of the intentional leak rate. But if the (total) leaks are well under 80 or 90 L/min, then the machine can and will compensate for the leaking. If the leaks are often above 80-90 L/min, then the leaks are large enough to adversely affect therapy.

Resmed users need to know their machine reports ONLY the excess leak rate and that Resmed defines anything over 24 L/min as an official Large Leak. A great leak line is one where the leaks are usually less than 5 L/min and often reported as 0 L/min. But if the leaks are well under 24 L/min, then the machine can and will compensate for the leaking. If the leaks are often above 24 L/min, then the leaks are large enough to adversely affect therapy.

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#8
Yup - /my bad.

Thank you for correcting me. My only (feeble) defence was pointing it out as an example.
*I* am not a DOCTOR or any type of Health Care Professional. My thoughts/suggestions/ideas are strictly only my opinions.

"Only two defining forces have ever offered to die for you. Jesus Christ and the American Soldier. One died for your Soul, the other for your Freedom."
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#9
On the ResMed S9 units, we all don't have to worry about all the technical details of leak rates and all that sort of egg-head type stuff....

ResMed conveniently lets us know whether our mask leak rate is "good" or "bad" by putting a green smiley face or a red frown face on our machines.

For many of us, that's as technical as we want to get. Bigwink Too-funny

Eat-popcorn
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.



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#10
(06-16-2014, 02:10 PM)SuperSleeper Wrote: ResMed conveniently lets us know whether our mask leak rate is "good" or "bad" by putting a green smiley face or a red frown face on our machines.
A picture is worth a thousand words
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