What is AHI?

I am trying to learn, so please bear with me. I am very new to all of this. I tried the search function but found 35,292 hits on AHI.

I have been using a Resmed VPAP S for 33 days. I have logged 238 hours. My DME ( learned that acronym last night) showed me how to turn it on, change the filter, and hook up a humidifier that I did not purchase because I didn't know why I needed it!

I was reading in a different thread posting.php?mode=reply&f=1&t=63082 and folks were talking about their AHI like it was something everybody should know... I didn't want to hijack the thread so I started a new one here.

Since neither my doctor or my DME explained this to me, I was hoping somebody here could.

What is an AHI?
Why does it matter?
How do you find it on a VPAP S machine?

Any input will be appreciated- although it may be followed be a lot more questions!

Thanks in advance...

http://www.apneaboard.com/CPAP%20Adjustment.htm

Scroll down till you find your machine and it will tell you how to get to the clinician menu and find your AHI and other data that is available on screen.

wiki/index.php/Category:CPAP_Definitions

AHI and other definitions of acronyms at above link. You will need to understand apnea, hyponea also to get the basic understanding for AHI.

It is important because we use that number as a way of measuring therapy effectiveness and also is a number used in sleep study reports to differentiate the diagnosis.

Here is a video for the S8 II series which should be pretty similar to get to the AHI. basically AHI is how many events per hour that you stop breathing. it is more complicated than that but that is the basic idea.
http://vimeo.com/19565675

AHI is something that used to be used on the older era machines and actually meant something. The current machines are being engineered to give you a low AHI no matter how your machine is set up. I would not go by the current AHIs, Id go more by how you feel and how good your sleep is and how well OSA symptoms are being controlled if you are compliant.

that means: minimal to no EDS, hypertension under better control, blood sugar under better control if that is an issue, sleep is restorative, mood is better, more energy and less fatigue. If you are not experiencing this with CPAP compliance, you need a sleep doc who will go by your symptoms and not just computer downloads and AHI scores exclusively.

Disgusted

The goal is to have an AHI <5 which is considered effective treatment but many people feel more rested if there AHI is lower than that. Welcome and keep asking questions.

Thank you all so much for your responses. I have learned a lot today! With the info you all shared, I can now take a more active role in MY therapy which makes me very happy.

My AHI for the week was 7.7. For the month it is 8.4. (I hope that means it is trending down) either way- now that I know how to get the numbers- I can watch them AND most importantly influence them.
Thanks to all of you for taking the time to help me!

ps. not really sure what these numbers mean but my:
IPAP is 17.0
EPAP is 13.0
Rise time is 300ms
TI max 2.0
TI min .35

DoriC wrote:The goal is to have an AHI <5 which is considered effective treatment but many people feel more rested if there AHI is lower than that.

What can I do to lower my AHI number?

thanks!

F3adventure wrote:

DoriC wrote:The goal is to have an AHI <5 which is considered effective treatment but many people feel more rested if there AHI is lower than that.

What can I do to lower my AHI number?

thanks!

When using a "bilevel" machine (like the VPAP S machine you mention in your signature), raising the EPAP pressure another full cm or two can lower the AHI for many people. You'd want to be sure your leak rate is already nice and low before raising pressure or you might make the leaks worse since it can get more difficult for a mask to hold a good seal at higher pressures.

http://vimeo.com/19565675

WOW - thanks for that! 12 years in and I'm only starting to learn how to read my data and if necessary tweak things!!! The other videos in the series are EXCELLENT.

xPAP therapy is a continual learning process. Thank you all for making it easy and accessible for me.

rested gal wrote:

When using a "bilevel" machine (like the VPAP S machine you mention in your signature), raising the EPAP pressure another full cm or two can lower the AHI for many people. You'd want to be sure your leak rate is already nice and low before raising pressure or you might make the leaks worse since it can get more difficult for a mask to hold a good seal at higher pressures.[/quote]


Hi Rested Gal,

I gave this a try last night. Originally my IPAP was set to 17.0 and my EPAP was set at 13.0. Last night I raised the EPAP from 13.0 to 14.0.

My AHI for the week is 8.6. My AHI from the previous night was also 8.6. My AHI last night was 10.6- but I also slept in a different bed with my three year old daughter kicking me in the back all night.

I think I will try this setting for a week or so and see if the results change at all.

And to Disgusted- I appreciate your comments. I am feeling better. I used to always fall asleep right before supper, I couldn't help it. That has not happened since I began this treatment so that to me is a clear indication of improvement. I just find myself wondering, how much better can I feel? After all, if I have to be a slave to this machine I want to get the maximum benefit!

Thanks to all for your input!

an IPAP is an inspiratory pressure
an EPAP is an exhalation pressure

Well my AHI was 6.1 last night so we are moving in the right direction!


Happy Easter to all!

My AHI is trending up, not sure why...

I left me settings at IPAP 17 and EPAP 14 and my AHI is climbing. My weekly average is now 12.0 (last night it was 17) not sure what i ned to do. Should I raise the EPAP higher? My leak rate for the week is .34 (I don't understand the meaning of this number so I don't know if that is acceptable or not)

Any thoughts would be greatly appreciated!!!

F3adventure wrote:My leak rate for the week is .34 (I don't understand the meaning of this number so I don't know if that is acceptable or not)

It is getting pretty darn close to unacceptable and if it were my leak, would already be deemed unacceptable.

Your machine is based on the S8 series of machines and their leak rate is reported in L/sec. S9 machines (and other brands) report in L/min now. So to get your leak converted to L/min multiply by 60 sec. Gives us leak rate of 20.4 L/min.
Now ResMed has always said that leaks above 24 L/min are big enough to impair therapy and data scoring. You probably have some small leaks and some large leaks that last quite a while to end up with the leak shown. During those large leaks it is possible that some events were able to sneak past the defenses.

Remember that ResMed already subtracts the unintentional vent rate so what you see reported is excess leak.

I have no experience with your type of machine so I can't comment on your other question but I would say that some work needs to be done on the leak for sure. If it were me I would be working on trying to cut that leak number at least in half.

That sounds like solid advice. I'll try to work on the leaks to see if that helps lower the AHI. Hopefully I can solve the leaks without chewing my face up too badly. I Have had a real problem with red marks and sores from not fitting the mask correctly

Thanks for the information and suggestion!