How Reliable are Machine Averages???

skjansen · Post by **skjansen** » Fri May 25, 2007 7:40 am

I would like some feedback from some of you old timers on the accuracy of averages on the ResMed S7 Elite, or for that matter any machine. I have been looking at my daily results over the past week and my AHI is ranging between 4.8 and 7.8. My monthly, and yearly numbers show an average AHI of around 3.2, Don't know why these numbers have changed so dramatically. Keep in mind, I have never felt like I have had refreshed sleep since being on CPAP. Don't get me wrong, I am significantly better than I was before I started treatment, but I still do not have the spring in my step I used to.

Also, I had an AHI of 7.8 last night at a pressure of 13cm and I feel much better today than when I tried raising my pressure two nights ago to 14cm at an AHI of 4.8 (I was a walking zombie after I tried to raise the pressure). By the way, both days my leakage rate was 0.00L/S which is excellent for my machine so it is not a matter of leakage, and I use a full face mask so I am not breathing through my mouth. What do you all think of that. I did have alot of centrals and mixed apneas on my original diagnosis and I kind of think they are still there and that the high pressures are making them worse.

I am trying to make a case for my doctor to let me do another sleep study. I have an appointment on June 12. Your feedback would be sincerely appreciated.

JimInAL · Post by **JimInAL** » Fri May 25, 2007 7:54 am

I'm not an oldtimer, but I know that the leak rates reported on the LCD display by an M-Series Auto is unreliable if you leave the machine plugged in all the time. They might be better if you unplug it each day.

skjansen · Post by **skjansen** » Fri May 25, 2007 9:46 am

Thanks JimInAL. Anyone else have any thoughts????

JimW · Post by **JimW** » Fri May 25, 2007 5:04 pm

Guess it would partially depend on the makeup of your AHI numbers. It's possible that a lower AHI with a higher apnea component would leave you feeling worse than a higher AHI that was mostly (or all) hypopneas. The higher pressure could precipitate central apneas, according to what I've read here, if you're prone to them. Always possible as well that the higher pressure itself would disturb your sleep more.

I've found the machine-reported numbers to not tally precisely with the detailed numbers which can be exported from the software. I do think, though, that your lower 1 year AHI compared to the higher recent AHIs probably do reflect an actual increase in events recently.

Goofproof · Post by **Goofproof** » Fri May 25, 2007 5:52 pm

If you want control of your treatment, get the real software. It makes progress much easier. Jim