Does this make sense?

Hello ALL,

Trying to understand last nights sleep? The question I have is, I had lot of fireworks early last night...Snoring, OAs etc but rest of night was pretty calm. I have not had a night with an AHI rate over 5 in over a month. Normally my AHI is 3 or less?

The part I don't get is sleepy head shows a massive decrease in leak rate increase in snore rate lots of events OAs, etc. Is this a mask leak? Is seems it would be the opposite indication to me? Or is this indication of something else?

Sure would appreciate any thoughts?

Thanks,
John

http://s1217.photobucket.com/albums/dd395/rottyjohn19/

Aliens.. They are usually the cause of whacko data.

Looks to me that something weirded out the sensors. I can't think of any logical explanation for that hour. The leak line shouldn't drop like that. It goes below the vent rate and that shouldn't happen. Something messed with the sensors.
In cases like this where there may not be any clear cut explanation I think aliens works about as good as any.

Thanks Pugsy,

At least I believe I now understand this intentional leak rate. If I am hearing you at a machine rate of 13cm my leak rate in sleepyhead shouldn't go below 42? Providing I dont change the intentional leak rate preference in the software? I do believe I had events last night as woke a bit foggyheaded with a headache and sore throat. Old familiar symptoms prior to cpap.

Is it possible to completely block vent? Wonder what happens if that occurs?

Thaks,
John

rottyjohn wrote: Is it possible to completely block vent? Wonder what happens if that occurs?

Yes, it is possible. Think an arm laying across the vent. That possibility might explain the leak line thing. I did think of that but with the snores and events also going wild....I just don't know how much one might impact the other in this situation. If you did have your arm across the vent for an hour and it didn't cause you any distress..at least we would know you won't suffocate.

And Yes....your leak rate baseline should be close to the vent rate at your pressure. May not be exact because there is always a little plus and minus factor as standard deviation. At least using SleepyHead and the Respironics machines which report Total leak.

I got to thinking. Dangerous I know.

Suppose the arm was over the vent. Don't know where the Asphyxia valve is on your mask...maybe it was also blocked or maybe not...but if the arm covered the vent and thus not nearly as much air movement...perhaps all those events weren't real "sleep" events but your body moving or fussing about the less than optimal air movement.

Just a far out there thought. I guess you could test it sometime...see what happens if you block the vent for 10 minutes or so. If you are really curious.

Thanks Pugsy...Oh yes strange minds think alike? I taped vent and turned machine just to see how it would react... it still operates pretty much same. The asphyxia valve opens and closes when I inhale/exhale. Guess machine regulator would lower volume of air as the demand would be much less with vent closed but still maintaining same pressure? Not sure how sophisicated the blower control is? I can't imagine both valves blocked at same time anyway? But we are dealing with aliens here! As an aircraft mechanic I can wrap my mind around most of this as aircraft air conditioning systems work similarly.

I have definitely woke up in the past with an elbow over mask like a vampire! but that hasn't occurred not for a long time. I force myself to side sleep now figured not possible to cover it. The vent valve on my mask is on top just under bridge of nose and and the asphyxia valve is underneath the elbow of mask connection. I guess it's also possible to block vent rolling over even further on side with a pillow.

John

Would be interesting to see how the leak line looked when you taped the vent. Takes a while to show up on the reports though. I have found this out when I tried experimenting to see if I could make hose noise fool the machine into thinking it was snores. I get bored real quick and 5 minutes won't even show on the graphs. One of these days maybe I can get enough time experimenting to give me a few minutes of graphs.

Yes... I am thinking about sitting in front of the TV with my mask connected for an hour with taped vent to see what data looks like?

I have been told that if the hose rubs against something just right it can confuse the sensors into seeing snores.

pickuptruck wrote:I have been told that if the hose rubs against something just right it can confuse the sensors into seeing snores.

Yep, I have been told that too... I am trying to duplicate it to see just how much rubbing it takes to fool the sensors into thinking it is snores. I am trying to prove what I have heard. So far even with using my finger nails rubbing against the hose..I can't get the machine to record some snores. I need a much longer length of time trying to create hose noise. In John's case here..even if those snores weren't real, that would not explain the dip in leak line.
I will try harder on the snore experiment. I need to prove it to myself.

Hello Pugsy,

I slept over 8 hrs last night... new record... go figure? Leak line stayed flat at 40ish for duration.

Here's the data from my vent test... hooked machine up and watched tv for almost an hour this morning...I was sitting up...

Started at 920 I had some trouble getting a complete seal over the vent so for the first 10 min partly sealed but after that and all the way to 10am 100% sealed close to 30 min. Actually used special tape that's used to seal cargo compartment lining panels very heavy stuff made to stop pressure leaks. Did have some concern it might not come off but it did. Then ran last 15 mins with tape off.

My analysis: not sure how good screen shots are?

Sensors picked up the following events: 1CA,1 OA, i H, 2 RERA, 3 small snores <1
Breathing was different but not completely uncomfortable and by end I was getting used to it?
Pressure line never wavered 13cm throughout
Leak line definitely moved around and dropped off for most part


http://s1217.photobucket.com/albums/dd3 ... nttest.jpg
http://s1217.photobucket.com/albums/dd3 ... =snore.jpg

Looks to me like the test showed that covering the vent will cause a marked reduction in the leak line itself well below the expected vent rate. More variation than I would have thought but part of that could be just the scale shown since it was such a brief time. If this had been one hour out of 8...that distance to travel on the graph would be much shorter and the variations wouldn't be so noticeable. Does this make sense to you? The larger the scale the more pronounced difference we see. Cram that hour into an 8 hour night and it might look more along the lines on what you saw the other night.

I would call this experiment a success. Gives a very plausible explanation as to what happened the other night.

Do you want to do hose noise experiment next? I can just rub/stroke that hose for so long and I go crazy with boredom. Yeah....it feels just like it sounds...dirty. For those of us with our minds in the gutter.

Yes Pugsy I agree...interesting that pressure stayed stable or report shows it that way. Seems to me there was just not enough of a volume of air output to keep my airway open? Even though the pressure was reported as correct.

The leak line is really a outflow measure... the newer sleepyhead allow me to adjust graph to ignore the intentional leak rate... that would show flow rates above the intentional rate but would negate what happened to me as it wouldn't show values below intentional rate. I suspect a much more logical number for most people because a true leak would result in a higher flow rate. My blocked vent forces machine to compensate by lowering the flow rate while holding pressure steady. I wonder how this would work with an APAP? As pressure setting is variable. Amazing to me that any of this can be done mathamaticaly with just a couple of sensors.

You're funny

So your asking me to do a hose rubbing or stroking test until I see vibrations on snore meter...cause you get too bored doing it? the hose rubbing that is? Oh my mind is never far from gutter

Thanks for a laugh!