Lab chases REM instead of AHI? Can we really self-manage?

[MikeSleeper]

I just had my second sleep study last night, with a full night titration. I talked a long time with the tech before the study. I asked him what AHI they looked for before they called the pressure "good" and stopped going higher. He said they did not chase AHI or apnea or Hypopnea events. He said they chased a good sleep architecture, looking especially for lots of REM. Once they got and maintained that they leveled off the pressure.

This is interesting to me. One reason is because the pressure they found for me was 14. On my machine at home I still show an AHI of 5 to 8 at that pressure. Not till I get up to about 18 cm H2O do I get the AHI down to 1, and I really dislike a pressure that high (gas in stomach, tight painful mask trying to prevent leaks). (Note, they used a machine similar to mine: Respironics, CPAP setting, C-flex).

I guess the real test is how I feel during day after nights at the various pressures, and I think I feel the same either way (14 cm or 18 cm, both I wake up feeling good and feel pretty good during day; maybe even worse at 18 due to the gas), but I am still new to this and have not tested it a long time yet at any one pressure. But I sure hate seeing all those apnea events on my graph at the lower pressure of 14; makes me wonder what I am doing to my body by allowing them to occur.

This lab is a really good one, accredited and associated with Stanford Univ. Their director is well known in the field. So I don't think this guy was just uninformed.

The key question to me is this makes me wonder about all the posts here where people primarily chase their AHI reading (as I have been doing). It makes me wonder about our ability to self-manage our treatment accurately, since we have no tools to self examine our REM.

Thoughts?

[mindy]

I wasn't having much REM at all before CPAP and I can tell from graphs that I am now having much better sleep cycles. I can see my apneas and hypopneas grouped at certain intervals. For example, the first 1 1/2 to 2 hours of sleep I have no apneas or hypopneas, then I have some for awhile, then none and then another batch, etc. I can also see my leaks go up with REM (since I'm more restless then).

I can only make inferences about my REM sleep but it has significantly improved since I've been on CPAP - I'm even dreaming again. My first sleep study I had only stage 1 and stage 2 sleep with about 2% REM.

I, too, have heard that Stanford is really good and would seriously consider what they say, IMHO.

Mindy

[Slinky]

To my way of thinking, it is how I FEEL that is the key. I could give a rat's rear about the device data if it doesn't jive w/how I feel. I could give a rat's rear about whether the sleep labs "chase" AHI or REM or anything else. Its how I feel and all that data does is give me something to HELP me feel rested on waking. When how I feel and the data don't jive on a consistent basis (one night doesn't count, I'm talking over a least a week's time span) I trust how I feel rather than the data. JMO.

[mindy]

I agree with most of what you said, Slinky. The issue for me in the first few months was that I had no idea how much better I could feel. So initially it really helped me to watch the data and adjust. Now that I'm feeling *much* better, I typically download once a week and didn't even get around to downloading last weekend and so lost some data and didn't think twice about it

Mindy

[NightHawkeye]

The key question to me is this makes me wonder about all the posts here where people primarily chase their AHI reading (as I have been doing). It makes me wonder about our ability to self-manage our treatment accurately, since we have no tools to self examine our REM.

Allow me to challenge your underlying assumption, Mike. Is it really true that we have no tools with which to monitor REM? Ever had a bad night's sleep? Ever felt really, really good in the morning? Both reflect on the quality and quantity of your REM sleep.

Question: What is the sleep lab really trying to accomplish by chasing REM sleep?
Answer: A good night's sleep!

Hmm ..., maybe I actually measure REM pretty good on my own.

Regards,
Bill

[MikeSleeper]

Thanks all for your excellent replies. Yes, I notice it when I wake up from a really good night’s sleep. Certainly that is my goal and I appreciate it when I do. But to use feelings alone as the sole measure of treatment success I feel takes us down a very slippery slope. Here is why:

Before I had my first sleep study, I actually thought I was sleeping great. I remembered dreams too. Then my orthodontist tells me I have a very small airway and I should be checked for OSA. I do and I discover I have severe sleep apnea. I sleep better now that I am on treatment, and dream more, and more energy during day. But could I now state based on feelings only that “I am having the proper amount of dreams, so I now know I am on the right treatment for sleep apnea and need to no longer worry about strokes and heart attack” No, I could not, and I doubt you could responsibly do that either without some backup from test results.

And isn’t the point of a scientific medical approach to separate our subjective feelings and use instead some repeatable objective analysis? Are we not throwing the scientific method of medical science out the window when we say to not worry about home AHI or the lab REM study, just trust how we feel? Again, I thought I was sleeping fine before and only lab tests told be otherwise.

For those that perhaps agree (if any), let me again ask my original question: can even the best of us use our home machine’s detailed readings (graphs etc) to self-manage our treatments? Or are we lacking some key measurement tools we need and should we instead rely on trusted lab results more than what our home machine tells us? Food for thought.

[mindy]

Mike,

In my case, "trusted lab results" are problematical because I don't sleep at all well anywhere except at home. My sleep doc has seen my results, including those where I modifed the pressures. She then suggested a much higher pressure based on those graphs, in spite of what the sleep study showed.

IMHO, it's not an exact science even using sleep lab equipment and having an MD degree. That said, I *do* listen to my sleep doc and keep her informed of what I do.

Mindy

[NightHawkeye]

1) If you're asking whether a sleep lab PSG provides more useful information than an APAP, then the answer is yes, of course.

2) Are you suggesting that we should get a new PSG every few months rather than assessing data from an APAP? Just try to find an insurance company that's gonna agree to that.

3) Or, are you possibly simply suggesting that we should accept the prescription values provided by the sleep lab without question and for all time, because all the folks who were involved in that process and all the excellent data which resulted could not possibly be improved upon by the ignorant creatures that we are who dare to access the information ourselves and make our own informed decisions regarding our own health care.

I'm not sure how many other possibilities there are, Mike. I believe the general consensus here is that using all the resources available to us individually results in better treatment.

[travismcgee]

It's an interesting question. When I went to see my sleep doc for the first time after starting treatment [I was on APAP for 6 wks. prior]. I had the data printouts from Encore and he lightly perused them and basically told me that his criterion for making a decision about whether or not PAP therapy was working was mostly based on how I was feeling and sleeping.
He is not uninformed about sleep disorders, he is a neurologist with classical physiology training and specializes in sleep problems.

I think you can be caught up in "chasing numbers" if you let the numbers dictate the way you are feeling. I also believe they are a valuable tool to help manage your therapy. In addition to AHI, mask leakage data is very useful. As far as your query about "our ability to self-manage our treatment accurately", I would say that given the tools we have we can manage our therapy more accurately than if we didn't have a data capable machine but less accurate than a sleep lab. Nevertheless the ability to get real-time feedback from your therapy, in an objective way, even without REM data is still a pretty powerful tool. That is why I view every night as one more trial in an ongoing experiment.

[dsm]

Chasing AHI is one of the few mechanisms we mere mortals have at home. I also agree that "a good night's sleep" is also an effective measure but I can show a chart where my AHI was 42 & I was sure I had had a good night's sleep that night.

The REM sleep target is IMHO a very effective one esp if it allows the lab to run the machine at a lower pressure that avoids the dreaded aerophagia & squeaking/leaking mask issues. They are worse than having an AI over 5 - mask leaks & squeaks wake partners plus ourselves & when your partner can't get a good nights sleep then your AHI scores start to take on new meaning.

REM is the goal but at home we have limited realistic mechanisms for measuring it.

DSM

[Slinky]

Okay, my understanding is that IF we remember dreaming it is because we woke up during REM sleep. So, if you're aware you are dreaming and remember your dreams you are NOT getting good REM as it is being interrupted.

My understanding of the reason for the inclination to having more apneas during REM than the lighter stages of sleep is the muscle "paralysis". Breathing is also slowed and more shallow altho the necessary muscles (such as the breathing muscles, i.e. diaphragm, etc.) continue to work, just at a slower pace.

REM (rapid eye movement) is associated w/the "processing" of our "memories" encountered and temporarily stored during the day and the "sorting" and "filing" of the "memories". There is a related field of psychotherapy for PTSD utilizing this eye movement and memory processing called, if I remember the sequence of letters correctly, EMDR, which has had quite some success. It doesn't lend itself well to structured sessions as the entire memory must be "processed" before ending the session.

From Wikipedia:

A second hypothesis suggests that eye movements facilitate processing of trauma memories by activating a neurobiological state similar to REM sleep wherein associative links to episodic memories are formed and these memories are then integrated into general semantic networks. Stickgold proposed that PTSD occurs when an event is sufficiently arousing to prevent its transfer from encoding from an episodic memory to a semantic memory.[48] As a result of high arousal levels, associations between the traumatic event and other related events fail to develop. He argues that the attentional redirecting in EMDR induces a neurobiological state similar to REM sleep. He then reviews the research that suggests that REM sleep enhances processing of episodic memory through the preferential activation of weak associative and semantic links. Thus in EMDR trauma-related information that is closely associated with a target event is weakened and ancillary information loosely related to the event is strengthened, allowing the integration of trauma-related material with other loosely associated events in the person’s life. Support for this argument comes from a study that found that, compared to eye fixation, eye movement promoted attentional flexibility and increased preparedness to process metaphorical material.[50]

[Guest]

My machine doesn't "read" my events because I have UARS rather than apnea proper. I only go by how I feel, and have simply made small changes in my pressure, stuck with them for a week or two, assesed how I felt overall during that time, repeat. Somewhere on medline I found a study where they tested patient titration against lab titration and the pressures were very close to identical.

I had less than 2 minutes REM in my original sleep study, and almost no stage 3 or 4 sleep. I have no idea what pressure they would have titrated me at, I was just given an apap and sent home with pressure set at 4-20.

But the point about thinking you feel fine than starting therapy and realizing how not fine you really were is valid.

I do worry that cpap therapy may not be entirely benign, and I would hesitate to reccomend that someone who feels fine and doesn't have significant day time sleepiness start cpap. But, I haven't seen any research about that at all. Then again, it's easy for me to say, I had no oxygen desaturation.

[MikeSleeper]

The way the lab guy explained it to me, it was the sleep disturbance they were mostly worried about, not AHI. So if they reached full sleep cycles, including full REM cycles, they were thinking they reached the right pressure level, one that cleared enough disturbances. And those full cycles could occur apparently with a fair number of OAs still in there.

If I were more alert at the time I was talking to him, I would have come back with, "Yeah, but what about oxygen blood level deprivation the OAs cause?", and I can only assume they check that too and dismiss it if it doesn't reach a certain average level.

Anyway, it was an eye opener, given how much focus I had been putting on trying to get my AHI down. Again, at the 14 cm they recommend, my AHI on my home machine in recent days has routinely been between 5 and 8.9, which if you use AHI guides alone, would say I was still in OSA territory. I guess I can be happy with those levels after all.

Or is there anyone out there that thinks I should keep chasing it and try to get it down lower? Again, I feel about the same at either level, so that info is not helping me.

Thanks all.

[Claire]

According to my respiratory therapist, the sleep docs here in Ottawa consider an AHI under 10 has a good outcome.

I think how you feel is critical. I went into cpap treatment very sick with what my GP thought was fibromyalgia. The pain turned out to be the result of moderate-severe apnea.

Since I have been on cpap the pain has virtually disappeared, except when I get very tired, and I no longer nap during the day. My AHI varies between 2.0 and 4.6. I consider this a success.

[Country4ever]

Hi Mike,
You mentioned that before your sleep study, you thought you were sleeping great. What symptoms were you having that lead you to believe that you might have a sleep problem? Did you have alot of fatigue?
Did you have a sleep study based solely on your dentist telling you you had a small airway??
What improvements have you had since starting CPAP, that make you think you needed it?
I have fibromyalgia, and still have lots of my old symptoms. But I can go a whole day without collapsing, so that's telling me that its at least helping in that area. I try to keep my AHI below 5. I seem to feel the best when its below 5 and my leak rate is down. I feel the worst if my leak rate is up, regardless of my AHI........but that may be because you can't trust your AHI, if you're leaking alot.
In my sleep study, I had no REM sleep, and very little sleep past stage 2. But I refuse to have another study, so I guess I'm just hoping I'm getting some REM sleep now!