Accuracy of CPAP AHI scores?

[schnarchen]

I have a Resmed S8 Elite II CPAP that I have been using for a month at 7 cm. My AHI values from the machine range from 4 to 8. While that doesn't sound too bad, I am one who has nearly all my apneas/hypopneas when I try to enter REM sleep. (REM AHI of 30-40 from my sleep studies).

Is this value trustworthy? If so, I probably need to take further action to get better results.

[schnarchen]

Last night's score was 10.4. It's getting worse. Is that typical?

[dtsm]

Are your leaks under control?

I'm not familiar with Resmed S8 Elite II - does it have full data capability? If show, post some images....

[Pugsy]

The S8 Elite is fully data capable. What does your nightly leak rate show?

Do you have the software for more detailed reports? It can be priceless for clearing up questions.

I too am one of those with many more events in REM sleep. I ended up increasing my minimum pressure a little to give me a better fight against them. Not saying that you need to do that though. Only saying that sometimes we do.

First thing to check would be leaks. If leaks are too much then we lose effective therapy.
Also, are you using EPR on the Elite? EPR drops the pressure by a cm for each number you choose. Setting of 1 is a 1 cm drop and 2 is a 2 cm drop and so on. 7 cm overall straight cpap pressure isn't a lot of pressure and then if you are routinely dropping pressure with the use of EPR, it is possible that some events will sleep through.

So check the leaks. What is the leak report showing? Remember ResMed machines already factor in for mask intentional vent rate that what you see being reported is excess leak above the normal vent or intentional leak. Do you use EPR?
With answers to those questions someone can give you a more informed idea.

[Samba]

So it's straight CPAP at 7 ? That's not very high, i'd try 8 & see.

[jbn3boys]

So it's straight CPAP at 7 ? That's not very high, i'd try 8 & see.

I would NOT change your setting until you have looked at the data and addressed any leak issues.

[schnarchen]

I do not have the software or USB adapter to read the data. I am getting it all from the display on the machine. Sounds like it would be worthwhile to invest in it. Will it give a plot of when the apneas/hypopneas occurred like I got from my sleep studies?

My leak rates also seem to have gotten worse. Early on they were typically less than 0.1, but lately the numbers are in the range of 0.4. Maybe that's part of the problem. What is normal?

[rested gal]

I have a Resmed S8 Elite II CPAP that I have been using for a month at 7 cm. My AHI values from the machine range from 4 to 8.

While using a ResMed S8 machine and seeing an overnight AHI of " 8 " , the first question I'd ask is...what is the AI (apnea index) and what is the HI (hypopnea index) ?

schnarchen, is your AI usually very low ( 1.0 or less ) and the HI usually considerably higher when you look at your overnight data in the display window?

ResMed S8 machines use a different definition for "hypopnea" than the newer ResMed S9 machines use.

ResMed changed its definition of "hypopnea" in the newer ResMed S9 machines.

Changing the definition for "hypopnea" means the designers of the S9 have changed their definition for how bad a "flow limitation" has to be before the machine labels it a hypopnea instead of still just a "flow limitation."

ResMed S8 machines usually report a higher number of "hypopneas" than the ResMed S9 machines (and other brands of machines) report. Doesn't mean one way is right and the other is wrong. It's purely a matter of "definition" -- an arbitrary line drawn in the sand.

All the manufacturers use their own definition of "hypopnea." And sometimes a manufacturer will change their definitions when they come out with a newer model. As ResMed did when they changed the definition for "hypopnea" in their S9 models.
viewtopic.php?p=488559#p488559

If it were me, and I were using an S8 machine, and the bulk of my AHI was made up of hypopneas rather than apneas, I'd mentally cut the HI (hypopnea index) in half before adding the HI to the AI to get an idea of what my S8-machine-treated AHI possibly really is.

Leak rate with a S8 should be less than 0.4 liters per second. I'd personally strive for a leak rate that was no greater than 0.2 L/s when using a ResMed S8. A high leak rate ( 0.4 or more with that machine) can interfere with how the machine interprets what's happening with the person's breathing and how the machine decides what to do.

You have a very good machine in the S8, schnarchen. I personally don't think the software is necessary for a person to tweak their treatment well with ResMed machines. There is plenty of informative data in ResMed's display window since it breaks down the AI and HI and it can show overnight data in addition to just the weekly, monthly, etc. averages that, say, the Respironics and Philips Respironics machines show in the window. Several nights of "daily" data is what I like to look at, rather than weekly/monthly averages.

Bottom line -- I'd just not be concerned about the AHI reported from an S8... if the AI was nice and low and the HI was the biggest reason the total AHI was greater than " 5.0 . "

[Slinky]

Right on, RG!!! You explain things so well.

[Pugsy]

My leak rates also seem to have gotten worse. Early on they were typically less than 0.1, but lately the numbers are in the range of 0.4. Maybe that's part of the problem. What is normal?

There is no real "normal". There is acceptable. Your reported leak is certainly acceptable and well within what the machine can deal with. It is doubtful that this leak is causing the therapy to be ineffective. Many people would be very happy with a leak rate that low. Some people do get a "zero" leak but most will have some leak.

You are only 30 days into treatment. Have you discussed your concerns with your doctor? They may not listen but again they might.

RG makes some excellent points. I was just trying to compose something along those same lines.

If the software were available to you there is a report generated that shows the events spread out over the hours of sleep. Sometimes this is helpful, sometimes it doesn't give any clear answers.

[schnarchen]

I have discussed with the sleep lab, and I have a followup appointment with the ENT coming up. Over the phone, they suggested trying some different masks to get a lower leak rate.

As for the software and data card cable, where do you find it? Everywhere I look says it is not available.

[Pugsy]

As for the software and data card cable, where do you find it? Everywhere I look says it is not available.

The software can be easily found. Look at member Uncle Bob's posts and check his signature.

Data card cable could be more difficult since suppliers no longer carry the S8 series machine they don't carry the other stuff that works with it.

[schnarchen]

As for the software and data card cable, where do you find it? Everywhere I look says it is not available.

The software can be easily found. Look at member Uncle Bob's posts and check his signature.

Data card cable could be more difficult since suppliers no longer carry the S8 series machine they don't carry the other stuff that works with it.

OK, got the software and installed it on my PC. That's fine, but the only card readers I can find are on ebay for $70-100. Ouch. I have SmartMedia reader on my PC, will that work? Any other ideas?

[Pugsy]

OK, got the software and installed it on my PC. That's fine, but the only card readers I can find are on ebay for $70-100. Ouch. I have SmartMedia reader on my PC, will that work? Any other ideas?

With the S8 you will likely need the special card reader. If you had a S9 machine that data card would likely work on your computer.

There were some S8 users here that were able to modify a less expensive card reader and get it to work. I forget which one it was and what they had to do. I don't have a ResMed machine so no experience to draw from.
Lots of discussion here on the boards about it but will have to wait till I either remember what it was or someone comes along to explain it or point you to those threads.

Your S8 and my M series machines have a different type of data card and even I needed a high dollar card reader.
Mine won't work on your machine either.

[robysue]

I do not have the software or USB adapter to read the data. I am getting it all from the display on the machine. Sounds like it would be worthwhile to invest in it. Will it give a plot of when the apneas/hypopneas occurred like I got from my sleep studies?

Yes, ResScan will give you a plot of when the apneas and hypopneas occurred. It will even tell you how long each apnea lasted.

My leak rates also seem to have gotten worse. Early on they were typically less than 0.1, but lately the numbers are in the range of 0.4. Maybe that's part of the problem. What is normal?

When was the last time you replaced the mask, the mask cushion (the part that seals the mask) or the pillows if you're using a nasal pillows mask? Sometimes an increasing leak rate is a good signal that the mask---or at least the cushion/pillows need to be replaced.