Help with numbers please

[RipVanWinkle]

Can't seem to find exactly the right help in previous threads so can someone please help me with numbers?
Recent user, first 12 days fantastic and index came way down.
Every night since, I have woken up with a "bruise" on the bridge of my nose and have watery eyes. Sleep clinic checked mask and said it was the right size and wasn't too tight, so I've been putting a small piece of soft cloth under the bridge of the mask. Now I have more leaks.
However it's the numbers that confuse me: Last 3 nights are:
AI 2 Hy 1.3 AHI 3.3
AI 2.2 Hy 1.7 AHI 3.9
AI 1.7 Hy 0.4 AHI 2.1
BUT...over a 30 minute period last night I had 9 Obstructive, 1 Central and 6 Hypopnea events from 10 to 35 seconds, so how can the AHI be 3.3? The night before it was 11 events from 10 to 29 seconds and 7 hypopneas.

Hope to get some help?

[zonk]

AHI is average number of events per hour, you might have some events in some period (such as sleeping on your back, or/and during REM) and none in other periods. Below 5 is normal on PAP

As for mask bruises, try not over-tighten the straps, Resmed nose pads, Remzzz liners, pad a cheeks liners, also don,t hesitate ask your DME to trial a different mask

[PaulaO2]

The AHI goes by the number of events, not how long they lasted. That's where watching your data comes in handy.

With that many events in such a short time period, my guess would be you rolled over onto your back. As long as the leak rate was within normal ranges, you were either on your back or your neck was at an angle or something similar to help cause the obstruction.

The Quattro is a full face mask, right? Instead of putting it just under the part that is sore, cut out some cloth the fit under the entire seal. Something very thin like an old tshirt. There's products out there (zonk mentions them) that work, too, but until you get some, you can try this. But putting the cloth under just that part, you aren't getting a good, solid seal.

[PaulaO2]

And the further explain the AHI, the AHI is the total number of apneas (both central and obstructive) plus the hypopneas added together then divided by the number of hours slept.

AI is the Apnea Index which is the central and obstructive events divided by the hours
HI is the Hypopnea Index divided by the hours

If your AHI is 4, then you had an average of 4 events an hour that night. If you slept 8 hrs that means you had 32 events during the night. You could have had them all in one hour or maybe widely spread out over the entire night or, like that one night you mentioned, have 16 of them in one half hour and the rest scattered. Again, this is where watching your data and seeing what is your normal ranges is a good thing to do!

[RipVanWinkle]

Thanks everyone, I knew I would get help here....what would we do without the forum???

[Tez62]

Rip, also most people that use an Autoset would probably have a higher AHI than straight CPAP, because the pressures will only increase when apneas are detected, so we are going to get some apneas. The bit of material is the right way to go for the bruising as well as the mask liners as Zonk suggested. I can send you the instructions on how to make them fairly cheaply, Remzzzzs are fairly expensive here in Australia. As long as your leaks are below 24l you are ok. I also suggest to everyone to have the hose coming from above your head either over a bed head or you can buy a hose lift or make one yourself. It saves getting tangled and reduces leaks and pressure on the mask as it pulls up instead of down. Hope this helps.