Sometimes CA's occurr during CPAP while you are still awake, before falling asleep or after you awaken. These recorded CA's are of no significance when they only occur at those times. I believe it has to do with our being awake and being conscious of that we are breathing in an unnatural way, as we breath out with more effor againsta pressure. As a result, we then tend to hyperventillate for a while, and then follow that with rest by pausing our breathing. If the pause is for 10 second, the machine records a CA. In most cases, it isn't a true CA, since it is doubtful there would be a drop in your oxygen saturation of any significance during wakefullness during those few seconds that you choose not to breath.
So if you are having a lot of CA's, try to remember if you struggled to fall asleep and whether the CA's occurred early during the time before sleep. Look for CA's in the morning, too, when you know you are just laying in bed hoping you might fall back asleep again. If those are the only times you have these CA's, you can subtract these machine events from the more real OS and hypopneic events to figure out a more meaningful AHI.
09-03-2012, 06:38 AM
[quote='Sleepster' pid='17711' dateline='1346345643']
The AHI is the sum of the OA, CA, and hypopnea indices. Were you diagnosed with simple OSA, or do you also have central apnea? For how long have you been collecting data? If you have simple OSA and you've been collecting for at least two or three weeks and your AHI is dominated by CA's then you might want to try lowering the pressure a bit to see if it lowers your AHI.quote]
Thanks to everyone for the information. I did extensive research on the Respironics website this weekend and used a combination of lowering my minimum Auto pressure from 12 to 10 and changing my white fine air filter and black sponge filters. Respironics recommends changing the white filters every 2 weeks to 30 days max. The result, my AHI dropped from an average of 11 down to 3.26 last night. Granted, that is just one night but it looks promising.
Respironics System One Remstar Auto with A-flex.
Resmed Activa Lt nasal mask with Softgel cushion.
Pressure settings Min=10 Max=17
Mode APAP A-Flex setting-3 Resistance=0
Heated Humidification setting 4
AHI: 3.26 RERA: 3.00
Hypoapnea: 0.52 Flow Limit: 0.26
Obst. Apnea 0.91 Vsnore: 0.39
Clear Airway 1.83 PB/CSR: 0.00%
"AHI dropped from an average of 11 down to 3.26 last night"
That sounds great & I hope it stays that way for you.
There is so much to learn & I have found that we aren't going to learn much from the sleep Doctor's or DME's because they would have a lot less revenue if we were not in the dark.
I have found much more help here but
My sleep Doctor does not say much & only gives 1 word answers mostly No! but he hast left so hopefully the new one is better.