My Therapy Thread: [reports+updates]

[Sleeprider]

Resmed graphs flow limitations and uses them in its auto-pressure algorithm. It also uses EPR which is an effective way to treat flow limitation. If you really want to focus on flow limits it is a much better device. I'm not sure, but you may have User Defined Flags in Oscar. These can show flow reductions of 20% and 50%. Maybe that will help.

[MADAwake]

 I'm not sure, but you may have User Defined Flags in Oscar. These can show flow reductions of 20% and 50%.  Maybe that will help.

Fantastic idea. I'll prepare the charts with User Def Flags and report back shortly. If this helps identify flow limits reliably then....

Resmed graphs flow limitations and uses them in its auto-pressure algorithm. It also uses EPR which is an effective way to treat flow limitation.  If you really want to focus on flow limits it is a much better device.

I'd get this machine if I indeed have a FL problem. Let me get back with the User Defined flags charts and take it from there.

[MADAwake]

OK, charts attached. I defined:

UF1 (50for5) as flow restriction down to 50% for 5 seconds
UF2 (60for5) as flow restriction down to 60% for 5 seconds

50for5 was 9.77 per hour
60for5 was 5.25 per hour

Also attached is the Resp. Rate, Tidal Volume, Minute Vent and Insp Time for the same 11-minutes sample.

Looks like I have so many mini events that don't match the definition. I'm not sure what to make of that. These don't seem (to my uneducated eyes) to be flow limitations but rather semi-events. Is there anything I could conclude from this info?

[Sleeprider]

That seems to identify the periods of lower respiratory volume. On the detail graphs for minute vent, tidal volume I think you should customize the Y-axis scale. Just right click next to the label and use the context menu for y-axis/override, and put in a more appropriate scale, i.e. tidal volume 0 to 1500, minute vent 0 to 20.

[MADAwake]

Y-axis fixed

   

[Sleeprider]

As you can see, the tidal volume and minute vent are actually higher where your UF flags occur. This seems to show a longer inspirolatory time rather than strictly a restricted flow. The start of inspiration appears to be a relatively low flow rate, but it amounts to a larger volume breath. I don't get this extent of variation in Vt or Vm when I compare.yours to mine. I think this is one of the benefits of pressure support on my bilevel machine, that each inspiration receives pressure support that seems to even out the volume. The missing graph in your chart is respiration rate.

[MADAwake]

Here it is with resp rate included.
   

So if this is not flow limitation, what is it? And could it be why my cpap therapy hasn't given me better results than I'm experiencing? Or, is it just something normal and I'm lost in the details? I'm seriously confused.

[Sleeprider]

Well it's not what I would define as normal, if such a thing even exists. You have flow limitation to some degree, but I can't interpret why the flow reductions are occurring, only that they are present. My best guess is that you have partial apnea or flow restriction from time to time just as you transition from exhale to inhale. This is why some breaths have an inspiration time of up to 6 seconds, and results in a hypopnea or flagged UF. Your typical respiration rate is somewhere around 15 bpm or about 4 seconds per cycle. Obviously if you are spending that much time in inspiration, you are losing breath cycles that are just short of the definition of apnea. Whether that arises from a lack of pressure support, pressure or other therapy parameter is very difficult to know.

[Sleeprider]

MADAwake, take a look at this from a recent post on the forum http://www.apneaboard.com/forums/Thread-...epy?page=3 The O.P. took our advise and got a Resmed. Compare his graphs in post 29 to those earlier in the thread that look a LOT like yours.

[MADAwake]

Thanks for the pointer, Sleeprider, that's really interesting. Maybe a VAuto is what eventually would help, but before paying for it I wanted to look at different things in an effort to try and verify my issue is just FL and not something else. So last night I upped the APAP to 11-12 and surely AHI went down even further. However my custom flags are still high. But I noticed something very interesting!

What's interesting: The "events" (whether official or user defined), consistently, everyday, gather at periods of reduced respiratory rate. This is cyclic! Last night's chart is a good example that shows the cycles and correlation.

Every night while asleep, when I'm breathing near & above my median rate I get little or no events or flags. Rate slowly goes down to a point when stuff starts happening. Then slowly goes up and no events or flags. Then slowly goes down and the cycles continue.

I'm a noob looking at these charts, so maybe it's the other way around, maybe events are causing the lower resp rate?

Isn't this indicative of events happening at a certain sleep stage? Or maybe chin tucking or something similar?

Oximeter & pulse are on the charts too for last night.