long-time user experiencing trouble

[svhr67]

Background: I've been a CPAP user for maybe 20 -25 years--got lots of help here at the start. I have no problem using the macahine and use it religiously every night and for naps. My machine's AHI has always been low. I've been very tired for the best part of this year, but I've also had two shoulder surgeries, so I wasn't sure what was causing my trouble.

Finally, my sleep doctor asked to see my SD card (my machine wasn't transmitting data for some reason). I sent it to him and this was his response:
"SD card review shows nonstop unstable breathing. Sometimes it looks like PLMS, but more often just respiratory instability, arousals, post-arousal instability. This is concerning for high loop gain. The device algorithm misses all of it.
 Ideally, a lab titration should be considered, given persistent fatigue."

I responded in MyChart that I'll do whatever he thinks best, but I haven't heard back yet. (This was only today--I'm impatient...)

What do you all think is going on? I've had 2 previous in-lab sleep studies, but the last one was 15 years ago....

[mlmollenkamp]

I'm impressed that your doctor actually looked at the SD card, most don't look at the details.... The wireless connection only sends statistics, no real data. My pomologist has never looked past compliance, leakage and AHI.

I've been using CPAP for a long time, almost as long as you. Its not reasonable to expect that things will be the same as they were 15 years ago. My last lab was 10 years ago, if I didn't monitor and tune my settings I'd be in trouble, things just aren't the same.

By all means get the lab titration, its the quickest way to figure out what's going on.

[Nocibur]

got lots of help here at the start.

What was your user name back then?

You could post your data in a SleepHQ file to investigate this "high loop gain" thing, and if, in fact, "the device algorithm misses all of it".

[svhr67]

I was just “svh” back then. I should probably have found that old login and used it. I didn’t think.

I can’t upload my data because my doctor still has my SD card. I suppose I could get another and start gathering new data.

My machine always says my AHI is very low—below 1, but I’m still tired.

[LSAT]

I'm impressed that your doctor actually looked at the SD card, most don't look at the details.... The wireless connection only sends statistics, no real data. My pomologist has never looked past compliance, leakage and AHI.

I've been using CPAP for a long time, almost as long as you. Its not reasonable to expect that things will be the same as they were 15 years ago. My last lab was 10 years ago, if I didn't monitor and tune my settings I'd be in trouble, things just aren't the same.

By all means get the lab titration, its the quickest way to figure out what's going on.

ResMed Air View has a tremendous amount of information. It's there if the doctor downloads it. Should be the same data as the SD Card.

[svhr67]

Yes—my doctor had expected to be able to get my data from the machine remotely, but something went wrong. Sending the physical card was our best alternative.

[Nocibur]

I was just “svh” back then.

That's OK I found it.

I suppose I could get another and start gathering new data.

Not if it's a massive insurmountable problem.

My machine always says my AHI is very low—below 1, but I’m still tired.

You can't fix bad sleep with a CPAP machine.

The guy who said he's going to fiddle with CO2 and the guy talking "high loop gain" are both (or "is" if it's the same guy) MF idiots.

[svhr67]

I really, really don’t think my doctor (yes, those quotes are from the same person) is an idiot. He’s the guy who pioneered EERS, and he’s an expert in sleep disordered breathing, as well as the trouble I have sticking to a circadian rhythm.

He’s in China right now, but he’ll be back on the 20th and said he’d arrange my in-lab sleep study then. I really look forward to finding out if there’s a potential solution.

I put my doctor’s note into google’s AI, asking what it meant, and got the following:
1. Nonstop unstable breathing... respiratory instability, arousals, post-arousal instability: Your breathing pattern is fluctuating in a jagged wave rather than a smooth, steady line. You breathe heavily, then shallowly, which triggers a micro-arousal (your fragile sleep snapping awake). Once you wake up, your breathing becomes even more erratic ("post-arousal instability") before you slide back under, repeating the loop.

2. Concerning for high loop gain: High loop gain is the most critical phrase here. It means your brain’s internal "thermostat" for carbon dioxide is way too sensitive. When you sleep, tiny drop in your breathing causes your brain to panic and command a massive, exaggerated breath. That big breath blows off too much carbon dioxide, causing your brain to then tell you to stop breathing. Your respiratory system is drastically over-correcting all night, creating severe sleep fragmentation.

3. Sometimes it looks like PLMS: PLMS stands for Periodic Limb Movement Disorder (involuntary leg twitches). Unstable breathing and high loop gain can cause rhythmic body shifts that look identical to leg kicks on a basic data chart.

4. The device algorithm misses all of it: This is why checking your CPAP app (like MyAir) wouldn't show a problem. Standard auto-CPAP machines only count blatant, long pauses in breathing (apneas). They are completely blind to the subtle, chaotic wave patterns of high loop gain and rapid arousals. Your machine has been reporting that everything is fine, while your actual sleep architecture was in complete chaos.

[Nocibur]

He’s the guy who pioneered EERS...

If the only thing in your toolbox is a hammer then everything becomes a nail.

What do you all think is going on?

Hey, you asked. I don't believe anybody can offer thoughts until we (or at least, I) see what he sees, which means SleepHQ.

Meanwhile, put "Does high loop gain associated with sleep apnea resolve?" into Google AI and see what you come up with.

Then see if you can dig up some data files from back in ~2006.

[svhr67]

I understand that without the data, it’s impossible to know what’s going on. That said, your tone (“If the only thing in your toolbox is a hammer then everything becomes a nail,”seems unnecessarily dismissive, given how little you know about my doctor. This is not the only thing in his toolbox. I have a complicated combination of issues (fragile sleep, circadian rhythm trouble, hypervigilance, etc.), and he’s really a world-class expert at much of what ails me (my sleep, at least).

I’m happy to have your thoughts. I just think it’s better to assume the best about people, not the worst. At least until they show you otherwise. I was just looking to better understand the doctor’s somewhat cryptic message. I don’t doubt his understanding of my problem.

[Nocibur]

...your tone...

Easy fix.

Just add me to your list of "Foes" in "Friends and Foes" and Presto! problem solved.