AHI and what it means

[keroseneburner]

I guess I'm the new guy here. I have been on cpap since 08. Started with a remstar m series at 11.0 cm. which was a life saver. About 6months ago I started feeling tired a lot. Through diet and exercise I had lost 35lbs and I purchased a remstar auto (older model that uses proprietary card). I don't have the card reader so no sleepyhead. The auto model is set 9-13 cm and 2 cflex. The AHI average is 2.1 with an average of 10.5 cm. is the AHI so low because od cpap or do I not need it anymore? I don't feel well rested anymore. I have crap insurance so another sleep study is out. Just trying to learn what I can.

Thanks in advance
Burner

[Pugsy]

The AHI is low because the machine is doing its job. The AHI you see is made up of the apnea events that the machine couldn't prevent. We have no way to know how many events it prevented from happening without a sleep study without cpap.
Now you could maybe get an idea of how many it is preventing by reducing the pressure and seeing if the AHI increases if you wanted to do that but even with pressures as low as 4 cm there is therapy value at 4 cm.
So not much AHI at 4 cm doesn't necessarily mean no more need for the machine.

[keroseneburner]

I did use a pulse ox meter for a couple of week and there is no desat. 93% is the lowest it dropped and that was momentary. I had thought of lowering pressure range from 6-10 and see what happens. I am ready to wake up refreshed again. Would too high pressure cause tiredness also?

[chunkyfrog]

Have you had a medical check-up lately?
Fatigue may be related to a variety of conditions, OSA being only ONE.

[Pugsy]

There's more to OSA than just desats so going by the pulse ox report alone doesn't mean nothing is happening.
Not everyone with OSA will have significant desats.
Using more pressure than what might be needed isn't known to cause fatigue unless the pressure changes or the higher pressures are causing sleep disturbances.
You could try lowering the pressure and/or using apap mode with a tight, tight range and see what happens.

The fact that you lost a significant amount of weight may or may not affect the pressure needs.
Worth trying though just in case. Maybe something really tight like 6 to 7 range...see what happens.

Is the newer machine one that still uses the smart card? Or did you get one of the older System One machines that uses the SD card?

Oh...when evaluating fatigue...in terms of sleep you need to evaluate the hours of sleep and are those hours fragmented with a lot of wake ups? If so that alone could be a potential culprit. Fragmented sleep will make us feel like crap during the day.
And of course there are other potential causes for fatigue that are unrelated to sleep apnea or sleep in general that need to be looked at.

First thing I would look at though is hours of sleep...how many hours of sleep and how many wake ups during the night for whatever reason.

And meds...any new meds?

[keroseneburner]

Full medical work up shows no significant problems other than hiatal hernia and reflux. Only med I take is zantac for this. Will be getting surgury to correct this next week. The machine uses the proprietary cards that look like a credit card and requires a special reader. I'm pretty sure wake up a lot, momentary turn over and back to sleep type of thing.

Burner

[Pugsy]

Some wake ups during the night are normal...maybe count them on one hand and usually don't present a problem when it is "wake up, turn over, go right back to sleep". It's very rare that I don't wake up a handful of times for no specific reason or maybe some back pain.

If you are waking up frequently...double digits and having trouble getting back to sleep then it might be worthwhile to investigate why and try to fix it.

Otherwise I would suggest trying a lower pressure and in a very tight range and see what happens.
If you see a truck load of apnea events show up on that AHI then you at least have an answer about needing the machine.

Those Respironics machines with the smart card requiring the special reader...the data on the LCD display is 7 and 30 day averages so you need to make a change and leave it for 7 days to get a true picture of what happened or didn't happen.
Unless you wanted to rest the therapy hours every night to zero and then the 7 day average would really be a 1 day average.
Do you want to do that...change the therapy hours nightly? If so let me know and I will go dig out the instructions on how to do it...and tell me exactly which machine you are using...is it another M series machine or older than M series?

[keroseneburner]

It is an m series auto. I have the clinician manual and will reset it to zero tonight. Since the 90% average is 10.5 I guess it would not be good to set much under that like 7-10?

[tiredandscared]

Desats or rather (hypoxemia) as measured by SPO2 are the single most important factor in OSA. AHI is just a measurement of how well your throat muscles are working, it's more significant in measuring total arousals and sleep fragmentation. Only the length of an obstruction or the time inbetween are clinically significant.

[Pugsy]

The 90% number just means that you were at OR BELOW that number for 90% of the night...doesn't mean you were at that number pretty much all night.
We don't know (without the software reports) how long you might have been at the lower pressure.
Sometimes that 90% number is easily elevated by just a relatively short period of time at the higher pressure.
So...if it were me I would probably limit the max and see what happens...and yeah..I would likely try 7 min and 10 max and see what the AHI did...or try 8 min and 10 max...or really get gutsy and try 7 min and 9 max.

2 goals...see if the AHI increases and see if the limited pressure movement affect sleep quality any.

[Pugsy]

Desats or rather (hypoxemia) as measured by SPO2 are the single most important factor in OSA. AHI is just a measurement of how well your throat muscles are working, it's more significant in measuring total arousals and sleep fragmentation. Only the length of an obstruction or the time inbetween are clinically significant.

Going to respectfully disagree with you on this one. While desats can be important they aren't always that big of a deal and sleep quality and OSA could still be really bad.
I have a friend who has OSA in the severe category with 60 plus events per hour and her oxygen levels never dropped below 95% ( I saw the sleep study report)...you wake up or arouse 60 times an hour for any reason and you are going to feel like crap...

You are making an absolute statement about something related to OSA and there are no absolutes when it comes to OSA.

Let me come over to your house and stick you with a pin once a minute all night long and your O2 won't drop because you would wake up 60 times an hour and the O2 never has a chance to drop...and let's see just how good you feel.

[tiredandscared]

Desats or rather (hypoxemia) as measured by SPO2 are the single most important factor in OSA. AHI is just a measurement of how well your throat muscles are working, it's more significant in measuring total arousals and sleep fragmentation. Only the length of an obstruction or the time inbetween are clinically significant.

Going to respectfully disagree with you on this one. While desats can be important they aren't always that big of a deal and sleep quality and OSA could still be really bad.
I have a friend who has OSA in the severe category with 60 plus events per hour and her oxygen levels never dropped below 95% ( I saw the sleep study report)...you wake up or arouse 60 times an hour for any reason and you are going to feel like crap...

You are making an absolute statement about something related to OSA and there are no absolutes when it comes to OSA.

Let me come over to your house and stick you with a pin once a minute all night long and your O2 won't drop because you would wake up 60 times an hour and the O2 never has a chance to drop...and let's see just how good you feel.

Listen... i'm not saying AHIs don't disturb sleep or cause poor sleep quality. But the effects of sleep fragmentation are largely reversible, the loss of cells is not. I'd rather be your friend than have 6 AHIS and drop into the 60s and 70s. The times my oxygen drops notably during days where my sleep is bad( to 86%, and I haven't even been able to gauge my extent of oxygen desaturations, because of how finger measurement affects sleep position) I feel like I wake up a retard. And I have relatively mild issues(I'll sleep as car passenger or on computer while relaxing).

If it comes down to disturbed sleep or progressive brain/physical damage. I'm pretty sure i'd pick the first over the other.

[nanwilson]

I still have my old card reader and 3 cards for the M series, if you want it just pm me. Pugsy if you want it for your "stash" you know how to find me .
Nan

[Wulfman...]

I guess I'm the new guy here. I have been on cpap since 08. Started with a remstar m series at 11.0 cm. which was a life saver. About 6months ago I started feeling tired a lot. Through diet and exercise I had lost 35lbs and I purchased a remstar auto (older model that uses proprietary card). I don't have the card reader so no sleepyhead. The auto model is set 9-13 cm and 2 cflex. The AHI average is 2.1 with an average of 10.5 cm. is the AHI so low because od cpap or do I not need it anymore? I don't feel well rested anymore. I have crap insurance so another sleep study is out. Just trying to learn what I can.

Thanks in advance
Burner

Maybe the "don't feel well rested anymore" condition is caused by the constant pressure changes all night long. As you enter different sleep stages, your breathing changes and that may trigger the machine to make pressure increases......which MAY bump you out of your needed sleep stages and into lighter ones........and will leave you feeling unrested.
I'd suggest setting your machine for a fixed pressure of 11 or 12 centimeters and see how that works.

An AHI "average" of 2.1 still means there are lots of events taking place during the night......and you STILL DO NEED IT.

Get the software (you'll need a version of Encore as Sleepyhead won't work with those machines) and card reader and see what's happening.


Den

.

[Pugsy]

But the effects of sleep fragmentation are largely reversible, the loss of cells is not. I'd rather be your friend than have 6 AHIS and drop into the 60s and 70s. The times my oxygen drops notably during days where my sleep is bad( to 86%, and I haven't even been able to gauge my extent of oxygen desaturations, because of how finger measurement affects sleep position) I feel like I wake up a retard. And I have relatively mild issues(I'll sleep as car passenger or on computer while relaxing).

I am having a really hard time following your logic here and I am NOT saying that drops in oxygen are unimportant...I am just saying that this statement

Desats or rather (hypoxemia) as measured by SPO2 are the single most important factor in OSA.

simply isn't necessarily true for the bulk of OSA patients.

It might be the single most important thing for you but it isn't for everyone....and that statement gives the impression that if someone doesn't have desats then they don't have a problem and that simply isn't true.
I didn't want a newbie reading it and thinking that "my O2 doesn't drop so I don't have OSA" and not follow up getting appropriate therapy. There's a whole lot more to Sleep Disordered Breathing than just O2 levels...maybe not in your eyes but for the bulk of the population there's so much more to getting good sleep.

Oh...btw....you don't want to wish significant desats on anyone no matter how infrequent...My AHI during non REM sleep was only 12 but my O2 levels went to 73%. Didn't even have enough REM sleep to measure it during first sleep study because every time I went into REM I would desat and wake up.
In REM sleep my AHI was over 50...wonder what my Oxygen levels would go to then if I stayed in REM.
I woke up every day with a killer headache from the low O2....cpap fixed that issue for me immediately.