Pugsy wrote: ↑Sat Apr 21, 2018 8:05 am
It's not so much the machine couldn't determine OA or central but the fact that this particular model of machine simply doesn't distinguish between central vs obstructive apnea. One of the things I don't like about these high end ResMed machines.
We assume obstructive but can't prove it. Even in cpap mode it doesn't use FOT to decide open vs closed airway. You get UA flags.
I know because I had this machine to try and tried cpap mode.
Central apneas and obstructive apneas all get tossed in the generic "Apnea Basket"...so you get AI without any sub categories.
AHI is composed of AI plus the hyponea index and not the usual 3 categories.
If using ResScan it would be called "unclassified".
The hyponeas...most likely obstructive but would not be totally impossible for them to be central in nature.
And if obstructive most usually IPAP is what we look at but there's more than one way to obtain more IPAP than just increasing IPAP all by itself.
If we increase IPAP alone that increases PS and more PS might cause too much carbon dioxide blow off which could potentially make centrals worse.
If it were my report I would be increasing IPAP but I would do it by increasing EPAP so that it pushes IPAP up and not mess with PS.
All this after I zoomed in on the hyponeas to try to make sure they looked obstructive in nature and not central.
If new to therapy...and I assume has a follow up visit with the sleep doctor scheduled sometime soon...I would make sure that these results are brought to the attention of the sleep doctor.
If no follow up appointment is on the books for anytime soon...I would call them up and make one.
These settings aren't optimal and some adjustment is necessary. Ideally the sleep doctor should have his thumb on things and not let this slide.
Thank You for this answer. It answers my primary question, central or obstructive, my understanding of the machines capability, and for the purposes of this machine what the AHI can be composed of.
I’ve had sleep apnea for 15 years. I’ve lost count of the number of sleep studies I’ve had (very fortunate to have great health insurance). Sleep Apnea started out mild and continued to get worse. I’ve never been able to comply with insurance company requirements in the past. I have no choice now, I have to make it work!
After 2 consecutive sleep studies, and a thorough consultation with a respected neurologist and sleep specialist, he prescribed the Bipap at a pressure of 10-16. Very effective pressure for almost 2 months usually reducing AHI to 5 or less. The issue though was I couldn’t keep the mask on, and asleep for 4 hours. I have a whole box of full face masks, and the one I’m using now works great for about 3 hours, and then its blast off. I had a follow up appointment about 2 weeks ago and the doctor reduced the ipap to 14. Much more comfortable, sleeping a little bit longer, but at the expense of much higher AHI. After 2 incremental increases, the current pressure is 15.2 resulting in an average of about 10 AHI. Looks like I’m heading back to 16. My doctor has been very accessible and is considering some other things on a one at a time basis.
The answers and explanations from you and the other forum members will be very helpful. I suspected more obstructive than central, and yes Julie, sleeping on my side has been somewhat helpful in the past, and along with my dealing with congestion due to allergies, I now have an additional approach to work on. One last thing, what does the abbreviation FOT represent?
Thanks again!
