Result of lowering pressure

[zbaba4]

I have been using my S9 Autoset with a pressure range of 9-13.6 for over a year (my sleep study result is 12). The mean pressure usually winds up very close to the max, like 13.4, and my AHI was usually 4-5, sometimes up to 8.

I have been losing weight so I thought I would try adjust the range down a little to see what happens. Somewhat surprising results. I have slowly reduced the pressure range down to 8-10.8. I still wind up with a mean pressure very close to the max (10.6) whatever it is set to, BUT my AHI is now typically 1-3 !

Something is going on here. Seems like the higher pressures are inducing apnea events and/or hypopneas are causing the pressure to stay high or ???. My general impression is my sleep quality has improved as the pressure and AHI get lower.

I was expecting that if a lower pressure was sufficient the S9 pressure result would automatically adjust lower along with my AHI becoming lower.

I am losing confidence in the S9 algorithms.

[STL Mark]

Too high of pressure on a machine will induce central Apnea. The Autoset can not effectively deal with centrals. What type of events exist when you look back at your higher pressure nights with 4 and above AHI?

[Sleepster]

I have been losing weight so I thought I would try adjust the range down a little to see what happens. Somewhat surprising results. I have slowly reduced the pressure range down to 8-10.8. I still wind up with a mean pressure very close to the max (10.6) whatever it is set to, BUT my AHI is now typically 1-3 !

You need to look at the three separate indices that are added together to give you the AHI. I suspect the CA index is dropping as you lower the pressure.

You could also put the machine in straight CPAP mode and see what happens.

Also keep in mind that the AHI can drop like that for no reason at all. I'm at the point now where I look at month-long averages to make my pressure adjustment decisions.

[trish6hundred]

Hi zbaba4,
WELCOME! to the forum.!
Hang in there for more suggestions.

[zbaba4]

In general, when I get a higher AHI, I can see large clusters of events, central and not, occurring a few time a night right at the time I wake up. I cannot tell if they occurred before or after, Rescan time and clocks not accurate enough. I have a hard time falling back to sleep and I know awake breathing does not fit into the algorithms. I might awake 2 or 3 times night. These event clusters account for the AHI being high. With the lower AHIs I sleep right through. So, I don't know cause and effect of waking up.

I have read that losing weight only rarely improves sleep apnea. However, I can't think of any reason not to try reducing the pressure slowly, as long as
I monitor the AHI and can look at detailed data. IF this is successful down to around 6 (?), I would get another sleep study before turning it off.

[Sleepster]

However, I can't think of any reason not to try reducing the pressure slowly, as long as
I monitor the AHI and can look at detailed data. IF this is successful down to around 6 (?), I would get another sleep study before turning it off.

Reducing the pressure will have a negative side effect. Your body and brain are now trying to adjust to a new set of circumstances. It used to be that your brain had to keep waking your body up to breathe. Now that you have CPAP therapy it has to adjust to that change. This is why you are seeing these clusters of events.

Leave the settings alone and give yourself time to adapt.