FL? RERA? Should I be concerned?

As I'm starting to learn more about my therapy, and in trying to get ready to actually meet with a sleep doctor, I'm trying to understand more of what my EncoreView reports really mean. I understand the obstructive apnea, the clear apnea, and the hypopneas. From what I've read, the vibratory snore on the System One can be pretty useless, as simple things like movement on blankets can set that off. What I'm wondering is if I should be concerned about my numbers for flow limitaion and for RERAs? Could someone explain just what flow limitation is (since it is not apnea or hypopnea), and just what RERAs are, or how they effect you? I guess I'm just having a hard time how a machine that can only monitor (and assist) my breathing can detect so many different issues (oa, ca, h, fl, rs, and rera). I'm feeling like a total newbie again!

Thanks for your help!

Flow Limitation
My understanding of "Flow Limitation" is based on my experience with the ResMed S9, not the PR S1 you're using. But some of the things should still be relevant from what I've read on the Resprionics web pages in preparation for my switching to a PR S1 BiPAP Auto.

Both the Resmed S9 and the PR S1 track the "shape" of your flow wave with every breath and measures several things about the shape of the inspiration part of the wave. [Note, you don't get to see the wave form data in Encore Viewer, as I recall.] At any rate, these different measures are then fed into a propriatory algorighm developed by the manufacterer of the machine to compute something called the "roundness/flatness" index/score, which is just a way of saying whether the wave flow form is associated with shapes that are known to be tied to airways that are starting to collapse or are slightly collapsed, but are not yet severe enough to trigger a hypopnea or an apnea. But basically, ROUND = GOOD open airway and FLAT = BAD collapsed/closed airway. I know he Resmed S9 AutoSet responds to flow limitations by increasing pressure since flow limitations can be precursors to apneas. I believe the PR S1 Auto also responds to flow limitations by increasing pressure as well.

Now, I really don't understand how the PR S1 scores a "flow limitation event" in terms of how bad the "roundness" index has to be or how long the flow limitation has to last before you get a tick mark on the Flow Limitations line. But somewhere there must be some data on how the PR S1 decides that a Flow Limitation event has occured. In ResScan, there's no flow limitation index---the flow limitation data is shown as a continuous curve potted against time. Sometimes I have flow limitations that last several minutes (5 minutes or more) when the S9 is running at it's max allowed pressure and have no apneas during the flow limitation. And sometimes I have small clusters of obstructive apneas even though the flow limitation graph is at the highest ROUND value through the whole cluster.

RERAs
The acronym RERA stands for Respiratory Effort Related Arousal. In a sleep study done in a sleep lab with all the equipment and wires, scoring a RERA relies on data collected from the belts (to measure respiratory effort); the nasal monitors or CPAP flow wave data (to measure air flow into your body); and the EEG (to determine if you've had an arousal). I've not found a definitive definition of a RERA on-line, but maybe I haven't looked hard enough. Most of the definitions I've read, however, tend to describe a RERA as an arousal triggered by increased respiratory effort that does NOT (quite) satisfy (all) the requirements of a hypopnea. So a RERA might not last the 10 seconds required for a hypopnea. Or it might not involve a (sufficiently large) desaturation. Or it might barely miss on the required reduction of airflow for a hypopnea. And so on. The critical idea in a sleep lab is that a RERA is an arousal that can be linked to a specific respiratory event, but that the event itself cannot be scored as a hypopnea for some reason. In sleep labs that score RERAs, they are frequently added into the RDI (Respiratory DISTRUBANCE Index) and the diagnosis of moderate sleep apnea is done on the RDI being above 15 (if I recall correctly). The idea is that for folks with lots of RERAs (and very few or no desats), the arousals themselves are enough to distrub the sleep cycle and the quality of sleep.

Now the ResMed S9 makers do not claim it scores, counts, or records RERAs. The PR S1 makers, however, do claim that they've developed an algorithm for scoring likely RERAs that the PR S1 uses. Since the PR S1 has no EEG to actually determine whether a genuine, bonafid arousal has taken place, their algorithm has to be based in some kind statistical study of what recovery breaths look like. The recovery breaths occur during the arousal, if I recall correctly, and my guess is that Resprionics has analyzed recovery breaths from full PSGs very, very carefully to come up with statistical data that says if the breath in the wave flow data has the following criteria (whatever they are), then there is a high probability that the breath is a recovery breath. And if the recovery breath does not follow a scored hypopnea or apnea, then it more than likely gets labeled as a RERA. But that's just speculation on my part. I'd love for someone who has located some real information on Resprionics's algorithms to post some links to how the PR S1 scores both flow limitations and RERAs, as well as their seemingly somewhat flawed VS algorithm that appears to have many false negatives from what I've seen posted here.

And a search of the forum turned up this thread from when the System One was first released concerning its detection of RERAs: viewtopic/t44463/viewtopic.php?f=1&t=44 ... cting+RERA

Thanks, RobySue! I can always count on you to give an informed and understandable explanation.

I'm really beginning to think my head just may explode! There is just SO much information to try to absorb, and doing so is so difficult when I do not feel rested.

Now, if only I could figure out what information to take with me, and what questions to ask, when I finally get to see a real sleep doctor......

How are you doing on the machine? Are you having any concerns?

If there's nothing specific, print out the last week's worth of data from EV to take to the doctor. He/She can easily see your compliance and pressures and overall AHI's.

If you have specific issues and concerns that are indicated by the data, then print out that data so it can be a point of discussion.

Hopefully you have a doctor that cares and will sit down with you and discuss this. Too many doctors just want to get this follow-up appointment over with. They need to document your compliance so the DME gets paid, this "face to face" visit is mandated by Medicare and many insurers, but--in too many cases--the doctor isn't too interested because he is not getting paid much for this visit.

So I wouldn't stress and obsess too much over it. IF you are having a problem and need your doctor's input, then you may need to pin him or her down. But if all is well, don't be surprised if the appointment is short and not too involved.

All is definitely NOT well! lol

I have been completely compliant, have no problems wearing my masks, am handling the transition to xpap rather well, but I still don't feel ANY better. The only positive result of my therapy is that my husband is sleeping better (me not snoring). My AHI is still high (average around 7-8, sometimes higher). I am having centrals, obstructives, and hypopneas. I have been playing around with pressure settings (System One Auto), and can not seem to find anything that works for me.

I have never seen a sleep doctor. The only person I have seen is the tech who did the sleep study, and my pcp, who admits that I know more about OSA than he does. The first time I told him the therapy was not working, he suggested I go back to the DME and have then help me. (Yeah, the company that set my auto with a wide open range, and told me there was no software available--don't think that's going to be much help.) After a repeat visit, in which I specifically asked for a referral, he gave me one. Unfortunately, I can't get in until after the first of the year ($$$).

What I'd really like to do is just send the new doctor all my graphs and say "Here, Fix this!" But I know that's not realistic. I'm just so tired, and my brain is not functioning as it should (duh, I have sleep apnea!) that I can't even come up with the questions that I should ask, or the information that I should bring along. I almost feel like I need a "caretaker", who would help me figure all this out, and do the talking for me. (Nope, hubby would never do that.)

I apologize if this comes off as a nasty attitude. I'm really a pretty laid back person. I'm just really frustrated with not feeling better, and feeling all alone in this. At least I can come here and try to get some answers.

jbn3boyz - A sleep physician is definitely the main person you should talk to regarding your concerns. A lot of DME companies are notorious for working like xPAP machine and supply shipment centers, though some are really good at setting up and following up with their patients to make sure they're compliant.

You'd be surprised at how many physicians there are that don't understand much about sleep disorders and how to treat them. Sleep's a rapidly growing health field that's still has an upward climb in gaining respect in not only the professional medical field, but society as well.

In general I'd say:

Sleep Physician - Sleep related inquiries
DME Company - Machine related inquiries and troubleshooting
PHC - General health inquiries, but you should keep him/her abreast of the info your sleep physician tells you.

As good as it is to understand what's on your report, I wouldn't overwhelm yourself with every detail. During your visit with your sleep physician be sure to bring all of your relevant reports from the machine and card (if you have one installed). Your sleep physician should go over them with you thoroughly, but don't be afraid to ask questions. It's much easier to learn how everything works when someone can explain it in laymen's terms.

As for the technology of how your machine analyzes and reports all of your info, that's something even your doctor might not understand fully (though I'd guess it involves an algorithm based on temperature, pressure, and position).

Good luck!

jbn3boys wrote: I'm really beginning to think my head just may explode! There is just SO much information to try to absorb, and doing so is so difficult when I do not feel rested.

Now, if only I could figure out what information to take with me, and what questions to ask, when I finally get to see a real sleep doctor......

Been there, done that so to speak.

My advice is that since you don't feel rested and you do feel like your head's going to explode is to write down all your concerns on paper, make a copy to leave with the doctor (for your medical files) and keep a copy for your personal files. After you have every concern and any information about side affects etc. written down and you have made printouts of your Encore Viewer reports, then sit down and organize a shorter list of talking points that you feel you absolutely must talk about with the doctor. Bring that list of talking points with you too.

You also say:

All is definitely NOT well! lol

I have been completely compliant, have no problems wearing my masks, am handling the transition to xpap rather well, but I still don't feel ANY better. The only positive result of my therapy is that my husband is sleeping better (me not snoring). My AHI is still high (average around 7-8, sometimes higher). I am having centrals, obstructives, and hypopneas. I have been playing around with pressure settings (System One Auto), and can not seem to find anything that works for me.

You want to mention that you're not feeling any better inspite of being compliant and having no mask problems. Be prepared to hear "It takes time for some people to start feeling better." Ask about a time frame and point out how long you've been using CPAP.

Tell the doctor that you are concerned that your AHI is still too high (and provide him with the appropriate data from Encore Viewer) and that you're worried about the centrals, obstructives, and hypopneas (in what order?)

If you are having any side affects such as aerophagia, let the doctor know both about what's happening and whether you've been able to do anything to address it and how successful (or unsuccessful) it's worked.

And if you're waking up at night for some (possibly unknown) reason, let the sleep doctor know that too.

What you don't want to do is have the conversation side-tracked into how to manage a leak problem or whether your current mask is working out for you. Those are DME-type issues.

And you write:

What I'd really like to do is just send the new doctor all my graphs and say "Here, Fix this!" But I know that's not realistic. I'm just so tired, and my brain is not functioning as it should (duh, I have sleep apnea!) that I can't even come up with the questions that I should ask, or the information that I should bring along. I almost feel like I need a "caretaker", who would help me figure all this out, and do the talking for me. (Nope, hubby would never do that.)

You could ask the sleep doctor's receptionist if it would be ok to drop off some of your Encore Viewer printouts ahead of time: Nothing ventured, nothing gained.

Start writing down questions as they come to you since your appointment is not until after the New Year, if I read your posts correctly. When a question pops into your head, write it down. You can evaluate whether the question is really important or not later on---in the context of other questions that have also arisen. Sort out which are the most important a few days before you actually see the doctor. Pare the list down and bring in the REVISED list of questions with you. Bring something to write on and something to write with if you think you won't be able to remember what the doctor tells you.

And I strongly suggest that you bring your hubby with you to your appointment. And add your hubby's name to the HIPPA release as someone who they can release information to. And tell your hubby you need him with you to describe what he's seen during the night when you are asleep. And that you'd appreciate it if he'd try to remind you of the most important things to ask about. Be honest with your hubby and tell him you are worried that you are not up to the task all by yourself.

Thanks for the advise, SleepsWell, and welcome to the boards!

RobySue, I'm going to mark this and come back to it. Once again you are a wealth of information, and my brain is just not into it today. I will look at all the things you have suggested, and start making my lists.

Thank you!
jbn

I have the same question. My AHI's are now down to about a median of 0.50 after 2 years of CPAP therapy, mostly H , occasionally OAS events. This is good, but I am starting to see RERA's every other day. They keep at about 0.15. I don't know if I should worry about. I seldom if ever had RERA's with the original pressure settings prescribed by my doctor, ( 10cmH2O-15cmH2O) but I have subsequently adjusted them upward to 13cmH2O-18cmH2O to see if there is an optimal level in terms pf AHI's. The RERA's seem to have increased with the increased pressure range . I don't know if it is a coincidence or if there is a connection with the pressure settings. I also feel more sleepy and sluggish at wake-up than before, until late morning. I don't know what I should make of these RERA's, given the sleepiness I have reported above. I attach a screenshot
Any comments?



Thanks
Ittiandro

ittiandro wrote: ↑

Sun Apr 03, 2022 4:27 pm

Any comments?

It would be better if you made your own thread in the future, instead of gloming on to something 12 years old. (Maybe the moderator will split this off).

Anyway, your minimum pressure is too low, causes the machine to spend the night raising then lowering the the pressure and constantly reacting to breathing issues.