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Big swings in AHI - sttebr - 03-30-2023
Hello and thanks for the help you offer here.
I have been on CPAP for only about 3 weeks so far, so I expect my body to take some time to adjust to it, but my AHI seems to be widely variable, with different events making up the score each night. I had an overnight sleep study done with a mild AHI of 14.5 and was prescribed a CPAP fixed at a pressure of 7. For the initial week or so of use, I was scoring AHI's in the 8-12 range. I changed to a Resmed F30i mask from a pillow and my scores dropped into the 4 range. From knowledge I gained here on the forum, I decided to turn ramp down to 5 minutes and turn EPR off to help with my CA events. The next night I scored a 1.55 AHI and felt good the next day.
Last night with all settings the same, I had a horrible night of fitful sleep, scored 15 AHI, (my highest yet) and feel exhausted today. All event types increased dramatically. Nothing about my daytime activity or environment was much different than any other day.
Any ideas on what might have caused this?
RE: Big swings in AHI - sttebr - 03-31-2023
Follow up - Next night
After previous bad night and report, last night was fine. Slept well, feel rested, AHI 2.5. ???
RE: Big swings in AHI - Sleeprider - 03-31-2023
The clusters of obstructive apnea are the result of your sleeping position, or more precisely sleeping positions that cause your airway to bend and obstruct such as chin-tucking. Your pressure is fixed at 7.0 with no EPR. You will be much more comfortable with EPR as it will reduce the relatively high flow limitations and respiratory effort related arousals. I do recommend you change to Autoset mode, with minimum pressure 8.0, maximum pressure 10.0 and EPR full-time at setting 3. This will actually reduce your pressure to a range between 8.0/.0 to 10.0/7.0 (inhale/exhale).
Read the wiki on positional apnea and the clusters of apnea, and consider if you are using multiple or tall pillows that might be contributing to the problem. http://www.apneaboard.com/wiki/index.php?title=Optimizing_therapy#Positional_Apnea
RE: Big swings in AHI - sttebr - 03-31-2023
Thank you for the response.
I have a soft collar coming from Amazon today, so I will try that tonight. I only use 1 pretty flat pillow, but I do have an adjustable bed that I raise the head a little most nights. I'll sleep flat with the collar for a few nights and see how that goes.
My reason for turning EPR off was to reduce my CA's which seemed to have worked well except for the one bad night. Will your suggested change to APAP 8/10, EPR 3 cause that to rise again?
RE: Big swings in AHI - Sleeprider - 03-31-2023
The disadvantage of EPR is that it can washout CO2 and increase the incidence of CA. Maybe try easing into it with EPR 1 and gradually increase EPR unless CA rises unaccepably.
RE: Big swings in AHI - sttebr - 03-31-2023
Thanks for your advice. I'll give that a try.
RE: Big swings in AHI - sttebr - 04-08-2023
I made your suggested changes to APAP 8-10 / EPR 1 and do feel somewhat better with AHI in the 2-4 range. I looks to me like I am staying in the upper end of the pressure range most of the night. OA's are gone, but still have several CA's. I'm using a soft collar and trying to stay on my side which I think has helped with the clusters of positional events. Do you think I need a little more pressure, or should I leave it alone for a while?
RE: Big swings in AHI - Sleeprider - 04-08-2023
You don't need more pressure, you need more EPR to cut back the flow limitations that are driving pressure to the top of your settings. You are using EPR 1, but I think 2 or 3 may be better.
RE: Big swings in AHI - sttebr - 04-08-2023
Thank you, I go to 2 EPR and see how that works.
RE: Big swings in AHI - sttebr - 04-09-2023
I know one day's result after a change doesn't mean much, but I went from EPR1 to EPR2 as suggested and woke up feeling tired, no energy and ready for a nap. AHI went up a little from the previous night, but more importantly was how tired I feel.
I have attached the Oscar report for the full night and a 3 minute zoom of the last hour where my pressure range dropped and my flow rate and flow limits smoothed out. What does the flow rate pattern on the zoomed view indicate and is this hours pattern what I want to achieve more of through the night? Should I go on to EPR 3?