Unreliable sleep study?

[lukazi]

Hi guys,

I have been constantly tired over the last 20 years or so. I'm 40, male, healthy and fit. About a year ago I did a level 3 home sleep study with the machine ApneaLink Air by Resmed. It showed that I had no apnea, AHI was 1.1.

A year later (about a month ago) I decided to do level 2 home sleep study, with a number of sensors all over my body. It showed moderate sleep apnea, AHI was 16.2.

Could you please explain how it is possible that the 2 studies showed vastly different results? Is one of the incorrect, or did I develop apnea only recently (and have been tired over the last 20 years for some other reason)?

Finally, is my AHI serious enough that I have to use CPAP?

Thanks a lot ?

[staceyburke]

Just for information, there are 3 types of apnea.

first is central apnea - it is when there is no obstruction but you are basically holding you breath - Main reason is not having CO2 in the amount to have your body to breath. It is not because of lack of oxygen. If this is bad enough a special pap machine is needed to help you breath.

2nd is Obstructive apnea - it is when your airway shuts down and a pap machine is used to apply pressure to keep it open. (most common)

3rd is positional apnea - it is when you sleep in a position where your airway is kinked and air can not get through, think of it as a kink in a water hose. No pressure from any machine will clear that position. The only way to stop it is not to get into that position. Many people have found that a collar will keep them from getting into that position. That position is called chin tucking where your chin drops down to your sternum cutting off your airway.

Out of those 3 the most likely is the 3rd one positional apnea. The first night you did not get into a position that cut off your air. The next test you had a higher pillow - allowing your chin to drop or maybe you slept on your back and your chin tucked. The difference of the two nights would be huge. Take a look at the link I have in my signature on collars and you can see the difference of people without collars and the same people with collars...

[lukazi]

Just for information, there are 3 types of apnea.

first is central apnea - it is when there is no obstruction but you are basically holding you breath - Main reason is not having CO2 in the amount to have your body to breath.  It is not because of lack of oxygen. If this is bad enough a special pap machine is needed to help you breath.

2nd is Obstructive apnea - it is when your airway shuts down and a pap machine is used to apply pressure to keep it open.  (most common)

3rd is positional apnea - it is when you sleep in a position where your airway is kinked and air can not get through, think of it as a kink in a water hose.  No pressure from any machine will clear that position.  The only way to stop it is not to  get into that position.  Many people have found that a collar will keep them from getting into that position.  That position is called chin tucking where your chin drops down to your sternum cutting off your airway.

Out of those 3 the most likely is the 3rd one positional apnea.  The first night you did not get into a position that cut off your air.  The next test you had a higher pillow - allowing your chin to drop or maybe you slept on your back and your chin tucked.  The difference of the two nights would be huge.  Take a look at the link I have in my signature on collars and you can see the difference of people without collars and the same people with collars...

Thanks so much! Over the 3 nights I have been using CPAP (and 3 nights about 2 weeks ago) I have been getting consistently AHI of around 1. Would that indicate that my problem is not related to chin tucking?

Also, with the chin tucking test, when in seated position, am I supposed to drop just the chin or do I lower the whole head? 

The level 2 sleep study showed that I had hypopneas. My partner says that I snore very loudly when on my back. I also snore when on my side most of the time but not as loudly.

[SarcasticDave94]

It also depends on how many sensors were involved in these tests. Home sleep tests will likely not have the same amount of sensors. And that lack of monitoring might be the difference between the 2 test results.

Given you say you're in a fatigued state, I'd be inclined to believe the result that showed higher AHI is more correct. You mention more sensors on the newer test, which likely affected accuracy. Of course it could just be some other factor that your AHI is up and down, but without the test results it's hard to tell.

[Sleeprider]

The problem with the home studies and many clinical studies is that they are designed to qualify you for reimbursement by insurance for CPAP. These studies do not adequately measure respiratory effort related arousal or flow limitation that falls short of scoring apnea., but respiratory effort related arousals can cause all the symptoms you describe. At best a sleep study is a snapshot of a few hours of your sleep disordered breathing, and the home studies are significantly limited without EEG. This sleep study cannot distinguish sleep from wake and will under-estimate AHI and cannot identify sleep stage which is important to determine quality of sleep.

Sleep studies can be very inconsistent, especially with upper airway resistance syndrome (UARS) and central apnea. You sound a bit like a UARS candidate to me.

Regarding chin-tucking, just relax and let your head drop so your chin drops towards your chest. I literally wrote the wiki on this. http://www.apneaboard.com/wiki/index.php...onal_Apnea

[lukazi]

   
    SleepriderThe problem with the home studies and many clinical studies is that they are designed to qualify you for reimbursement by insurance for CPAP. These studies do not adequately measure respiratory effort related arousal or flow limitation that falls short of scoring apnea., but respiratory effort related arousals can cause all the symptoms you describe.  At best a sleep study is a snapshot of a few hours of your sleep disordered breathing, and the home studies are significantly limited without EEG.  This sleep study cannot distinguish sleep from wake and will under-estimate AHI and cannot identify sleep stage which is important to determine quality of sleep.  

Sleep studies can be very inconsistent, especially with upper airway resistance syndrome (UARS) and central apnea.  You sound a bit like a UARS candidate to me.

Regarding chin-tucking, just relax and let your head drop so your chin drops towards your chest.  I literally wrote the wiki on this. http://www.apneaboard.com/wiki/index.php...onal_Apnea

Thanks so much! I just tried the chin tuck test and I didn't notice flow restriction.

Please see below my level 2 sleep results. Would you kindly let me know your thoughts?

[StratCat48]

If your home sleep studies included SPO2 monitoring as part of the tests, what kind of numbers did you get?
Back when I suspected an apnea problem I got an O2Ring which recorded O2 saturation levels while sleeping. Like yourself I was feeling like crap during the day. My O2 Sat readings appeared to indicate a problem. I took several nights of data from the O2Ring to my doctor and with no hesitation he agreed to a in hospital sleep study which showed a significant number of hypopnea occurrences. I got a CPAP shortly after the sleep test.

The chart below represents what I might average in a night pre-CPAP and some nights were much worse as well as some that were better. Since I've been on CPAP the O2 scoring is typically in the high 9's with O2 drops in the low numbers and I do feel better during the day.

[Sleeprider]

Your last sleep study confirms that while apnea index is low, you have a lot of hypopnea and arousal from respiratory effort, or flow limitation or UARS. Assuming you get CPAP be sure to get one that provides some bilevel pressure with a difference between inhale and exhale pressure like the Resmed Airsense 10 Autoset. You don't need high CPAP pressure, but you will benefit a lot from pressure support (the increase in pressure during inhale) to prevent the flow limits and hypopnea. How far down the rabbit hole do you want to go? Bilevel pressure is going to change your life. http://www.apneaboard.com/wiki/index.php..._and_BiPAP

[lukazi]

   

Sleeprider pid='436919' dateline='1645928915']Your last sleep study confirms that while apnea index is low, you have a lot of hypopnea and arousal from respiratory effort, or flow limitation or UARS.  Assuming you get CPAP be sure to get one that provides some bilevel pressure with a difference between inhale and exhale pressure like the Resmed Airsense 10 Autoset.  You don't need high CPAP pressure, but you will benefit a lot from pressure support (the increase in pressure during inhale) to prevent the flow limits and hypopnea.  How far down the rabbit hole do you want to go?  Bilevel pressure is going to change your life. http://www.apneaboard.com/wiki/index.php..._and_BiPAP

Thanks so much, really appreciate your help!

Is AHI of 16 serious enough for me to buy CPAP? I just don't want to waste money if this is not a big deal.

Also, do you think this last study (showing AHI 16) is reliable enough for me to go and buy CPAP? Or should I do a second test to confirm that I really need CPAP. I am just confused that the 1st study showed no issues, make me think the last one may be questionable.

Please see attached the 1st study results. Any thoughts would be much appreciated. 
   

[lukazi]

If your home sleep studies included SPO2 monitoring as part of the tests, what kind of numbers did you get?
Back when I suspected an apnea problem I got an O2Ring which recorded O2 saturation levels while sleeping. Like yourself I was feeling like crap during the day. My O2 Sat readings appeared to indicate a problem. I took several nights of data from the O2Ring to my doctor and with no hesitation he agreed to a in hospital sleep study which showed a significant number of hypopnea occurrences. I got a CPAP shortly after the sleep test.

The chart below represents what I might average in a night pre-CPAP and some nights were much worse as well as some that were better. Since I've been on CPAP the O2 scoring is typically in the high 9's with O2 drops in the low numbers and I do feel better during the day.

Thanks for your comment!

Please see my study results in one of the above posts. The lowest O2 level was 90% which doesn't seem too bad?

---

Your last sleep study confirms that while apnea index is low, you have a lot of hypopnea and arousal from respiratory effort, or flow limitation or UARS.  Assuming you get CPAP be sure to get one that provides some bilevel pressure with a difference between inhale and exhale pressure like the Resmed Airsense 10 Autoset.  You don't need high CPAP pressure, but you will benefit a lot from pressure support (the increase in pressure during inhale) to prevent the flow limits and hypopnea.  How far down the rabbit hole do you want to go?  Bilevel pressure is going to change your life. http://www.apneaboard.com/wiki/index.php..._and_BiPAP

Any chance you would kindly be able to comment on my first few nights of experience with CPAP? The thread is here (last post).

http://www.apneaboard.com/forums/Thread-...dy-results