Any idea what could be going on here?

[old dude]

I've only been using my BiPap machine for about 4 months now and most of that time has been spent with a Mirage Quattro mask. Although my AHI was 131 at diagnosis, within 60 days it had come down to the 1.7-2.1 range. Having said that, I've been unsuccessfully experimenting with other FF masks recently because of the facial trauma caused by the Quattro. So reluctantly I've gone back to the Quattro, but this time I've tried to keep the mask much looser than the extremely tight adjustment I previously used hoping for less facial damage. I read somewhere that this is preferred anyway because it allows the seal to inflate and do it's job.

So, last night I had the mask on fairly loose (not tight anyway) and boy it was getting a really good seal-no obvious leaks and lots of perceived pressure. (I should say my prescription is 17/13).The seal incidentally was new, only 2 days old. I wound up sleeping nearly 5 hours which was pretty much a record for me. So since I've just learned to read the info on my machine I thought I'd check and see how I did. I was shocked to find an AHI number of 10.2 and large leaks of 82%!

Given that the mask felt so efficient compared to the past usage I just can't make this compute. Would anyone have any thoughts?

[jgjones1972]

You might have pried, twisted or pulled the mask against the pillow in your sleep or something like that - after a while the leaking may have awaken you just enough to shift position and stop the leak. If so, then the machine was probably logging a boat load of false apnea readings during the large leak. I'm not familiar with your machine, but my AutoSet will start marking down tons of "Unspecified" Apneas if I have a big leak. I accidentally pried my hose crooked on the mask connector one night and the machine recorded over 100 false "unspecified" events in the hour before the noise woke me up.

With software you can look at the event chart and leak chart - see what happened when and can tell what is likely accurate and what isn't. ResMed says their machines can't detect apneas reliably when unintentional leak (leak rate minus mask venting) is over 24Lm, so events or lack of events in data should be taken with a grain of salt when the unintentional leak exceeds 24LM. I'm not sure what level of leak the sensors on your machine can overcome; but, at some point, large leaks will keep the machine from reporting properly.

[old dude]

You might have pried, twisted or pulled the mask against the pillow in your sleep or something like that - after a while the leaking may have awaken you just enough to shift position and stop the leak. If so, then the machine was probably logging a boat load of false apnea readings during the large leak. I'm not familiar with your machine, but my AutoSet will start marking down tons of "Unspecified" Apneas if I have a big leak. I accidentally pried my hose crooked on the mask connector one night and the machine recorded over 100 false "unspecified" events in the hour before the noise woke me up.

With software you can look at the event chart and leak chart - see what happened when and can tell what is likely accurate and what isn't. ResMed says their machines can't detect apneas reliably when unintentional leak (leak rate minus mask venting) is over 24Lm, so events or lack of events in data should be taken with a grain of salt when the unintentional leak exceeds 24LM. I'm not sure what level of leak the sensors on your machine can overcome; but, at some point, large leaks will keep the machine from reporting properly.

OK, well, that makes sense. I had no idea that large leaks could encourage the machine to record false apneas, but in any event I presume 82% is a large number for leaks.

I certainly wasn't aware of major leaking, and I'm sleeping in a recliner these days so bumping the mask while rolling over likely wasn't an issue.

I think I'm going to need to go ahead and download some software and learn a bit about it to be able to tell much more. I've held off on the SleepyHead since evidently it isn't optimized for Mac, but I'm guessing it might be my best bet nevertheless.

Thanks for your thoughts!

[RonWessels]

A large leak may make the flow variations due to breathing next to impossible to determine because they are so comparatively small. Hence, the machine may think you have stopped breathing, even when you haven't, because it thinks the variations caused by your breathing are simply the variations in the specifics of the leak.

It does sound like you had over-tightened your mask. Given you felt you had a good seal in your initial fitting, one of three things might have happened. As has been suggested, you may have accidentally dislodged the mask to cause the leak. It may be that your head position changes when you sleep from when you fit your mask straps. I do find that if I bend my head down, the lower straps are no longer as tight and leaks develop. And it may be that, as you fall asleep, your facial muscles relax enough that your face "shape" changes and the seal is simply no longer as good.

[Mark Risley]

The responses you got here are great. I will just add this comment. You stated you achieved a record 5 hours sleep. Great. Don't worry and build on that. I am sure you had a major leakage of 100% but got it fixed and then got some great sleep. Focus on how you felt, the improvement and keep up the good work. Don't get hung up on the numbers if you body is telling you that improvement is taking place.

[courtney123]

Don't get hung up on the numbers if you body is telling you that improvement is taking place.

+1

[old dude]

The responses you got here are great. I will just add this comment. You stated you achieved a record 5 hours sleep. Great. Don't worry and build on that. I am sure you had a major leakage of 100% but got it fixed and then got some great sleep. Focus on how you felt, the improvement and keep up the good work. Don't get hung up on the numbers if you body is telling you that improvement is taking place.

Don't get hung up on the numbers if you body is telling you that improvement is taking place.

+1

Excellent suggestions folks and I appreciate them. It's just that knowing my earlier AHI numbers had been averaging 1.7-2.1 I was a little shocked at the one night 10.2. For the record, last night was a 4.2. At least headed in the right direction I suppose, I just hate to lose ground. Had to tighten the mask down pretty good to get there though.

[SuperSleeper]

Excellent suggestions folks and I appreciate them. It's just that knowing my earlier AHI numbers had been averaging 1.7-2.1 I was a little shocked at the one night 10.2. For the record, last night was a 4.2. At least headed in the right direction I suppose, I just hate to lose ground. Had to tighten the mask down pretty good to get there though.

The data is only one thing to consider - As other have said, how you feel is important as well.

Should you completely ignore data that seems to contradict the "how you feel" method? No, you should not. But that said, keep in mind that one or two nights of data does not a trend make. When looking at data, especially after making pressure changes, it's important to realize that you'll need several nights worth of data before that data sample is large enough to use for actual conclusions.

You want to look at your averages, primarily. Individual nightly spikes in AHI can be caused by many things - leaks, what you ate the day before, medicines you took, how much water you drank, the amount of exercise you got, the climate and humidity of your bedroom, a mask that was moved out of place during the night, etc. Too many variables to consider one or two night's data as having any significance.

You may be interested in this article on how to properly adjust pressures:

http://www.apneaboard.com/adjust-cpap-pr...re-on-cpap

Also, on your mask, be sure to not tighten it too tight - it's designed to work with a lose seal, not tightened down a lot. Another article on How to Obtain the Best Mask Fit is here:

http://www.apneaboard.com/forums/Thread-...GUARANTEED