AHI with CPAP never < 5

[jdm2857]

I have been using CPAP for a bit over a year. I had one sleep study during which OSA was diagnosed (AHI mid-forties, no centrals, worse when supine), but for monetary reasons never had a titration study. Instead, I acquired an APAP (S8 AutoSet II) in the hopes that I could use it to help determine the best pressure settings. For several months I examined ResScan reports, slowly raising the minimum pressure from 10 to 13, but never reduced my AHI to acceptable levels (<5).

I got discouraged and stopped tracking data but continued to use the machine. Then I slowly started to become less than fully compliant. About 2 months ago I got more serious about my therapy and began using it every night again. I got a Swift FX mask (to replace my LT and Opus 360) in part because it looked comfy, and in part because I knew that a new toy would increase my interest in my therapy, at least in the short term. I also resumed uploading and examining my data daily.

At this point I have increased my minimum pressure to 15 (I've always used APAP with the max at 20). And still I have never had a single night with a AHI less than or even close to 5. I've not tried straight CPAP (as some here recommend) because APAP mode has always been well behaved. Pressure increases follow events (usually snores) and the pressure slowly decays over time. No runaway pressure, and pressure increases do not appear to trigger events. I have never tried EPR. I have tried some homemade devices to keep me off of my back, but I do not believe that they worked. I'm also thinking about rigging up an infrared webcam to record my nights and possibly get some additional clues.

Here is last night's data, which is pretty typical:






Any suggestions?

[sleepmba]

From my experience from the sleep lab performing titrations....

From the shape and timing of the graphs, it looks like your events are leak related. Where the leak spikes are is where your events are concentrated roughly. Again, from the time frame, I bet this is happening when you are going into REM. When in REM, you lose muscle tone. This lets your mouth drop open in your case. I would recommend a chin strap or some people tape their mouth closed. Personally, I have a pillow on my chest that I hug that pushes my jaw up too. If you control that leak in REM, you will be golden.

Good Luck!

[-SWS]

Your flattening index line shows that just about every breath you take has residual flow limitations---some fairly severe. That hints that your pressure might not be high enough to completely address your obstructive component.

I'd suggest a PSG, if possible, to get the correct pressure titrated. A PSG will also tell you if there are central apneas or if you need BiLevel/ASV modality instead of APAP.

[jdm2857]

Where is the normal flattening index line? All the way at the top of the graph?

As you know, the ResLink modules are pretty rare, so I have little to compare my graphs with. And I have not found much info online about the flattening index. I do understand the basic idea of flattening, which I gleaned from ResMed videos on OSA.

[Wulfman]

If you haven't........try straight CPAP (fixed) pressure.


Den

[kteague]

What would be the suggested fixed pressure to start?

[Wulfman]

What would be the suggested fixed pressure to start?

Since he's set his minimum to 15, that might be one trial setting......or 13......something he's become used to.

And, Jeff, if you're sleeping on or rolling over onto your back, you might try to avoid that.


Den

[jdm2857]

I start out on my side, but I know that I switch positions a bit. If I modify a webcam (remove IR filter) and rig up an IR LED light source, I will know more.

I've been considering scrounging up a backpack and filling it with packing peanuts, but it seems like it would be pretty uncomfortable. Anyone have a fleece backpack?

[jdm2857]

Google is fast

I just searched for "flattening index" and my initial post in this thread was the first item returned. 40 minutes after posting. Wow.

[-SWS]

Where is the normal flattening index line? All the way at the top of the graph?

As you know, the ResLink modules are pretty rare, so I have little to compare my graphs with. And I have not found much info online about the flattening index. I do understand the basic idea of flattening, which I gleaned from ResMed videos on OSA.

Right... any Resmed flattening graph "all the way at the top" represents perfect breathing without flow limitation. The wave-shape tops of those perfect breaths would appear as rounded sinusoidal flow patterns---hence that nice rounded/sinusoidal key in the legend to the left at the very top. Notice on that same legend---visually working our way down---that the icons become more and more flattened/distorted as flow limited breathing becomes progressively more severe.




In summary, the further away from the top your flattening graph travels, the more distorted your flow wave shapes measured because of corresponding flow limitations. And according to that graph, boy do you have a LOT of residual or under-addressed flow limitations. That, in turn, hints at an under-addressed obstructive component---whether you happen to have centrals or not.

[jdm2857]

I will continue to increase my minimum pressure and see what happens..

I am wondering why the AutoSet algorithm is not responding with more pressure increases than it does. I believe that at pressures over 10, AutoSet stops responding to apneas (to avoid increasing pressure in response to centrals, but does respond to snores, hypopneas and flow limitation. It's quite obvious that my machine is responding aggressively to snores, but hypopneas and flow limitation appear to be ignored.

[DoriC]

What would be the suggested fixed pressure to start?

Since he's set his minimum to 15, that might be one trial setting......or 13......something he's become used to.

And, Jeff, if you're sleeping on or rolling over onto your back, you might try to avoid that.


Den

Yes, I'd really be interested in seeing a fixed pressure for a few nights. Keep us posted on that.

[Jason1975]

I don't mean to barge in but I am kind of in the same boat. I can't get below and AHI of 10. Usually between 13 and 20. I, too have a autoset II with Resscan 3.10 and noticed that you have snore index, flattening index, and minute ventilation. I can only get AHI, Pressure, Leak, and usage. Is it because you have version 3.7 and I have 3.10 or is there something I have to do to get those?

[Wulfman]

I don't mean to barge in but I am kind of in the same boat. I can't get below and AHI of 10. Usually between 13 and 20. I, too have a autoset II with Resscan 3.10 and noticed that you have snore index, flattening index, and minute ventilation. I can only get AHI, Pressure, Leak, and usage. Is it because you have version 3.7 and I have 3.10 or is there something I have to do to get those?

What are all of your machine settings? (Pressure, Ramp, EPR, etc.)


Den

[jdm2857]

Jason:

ResMed made an expensive data collection add-on for the S7 and S8 machines. Called ResLink, it was meant for clinicians to lend to patients for a few nights to collect more data (it uses a SmartMedia card instead of the usual S8 card). But it never caught on and was discontinued. I happened to find one on cpapauction.com for a reasonable price.

The ResLink is responsible for the additional data. ResScan can display this additional data.