Calculating Minimum Pressure Settings

Someone here once said how to calculate minimum pressure settings by using the Average reading and the 90% Pressure readings for a period of time.

I've been using this formula and its really making a huge difference in my sleep therapy, Im actually sleeping longer and not waking as much. When I started using the NEW ResMed S9 AutoSet (coming from ResMed S8 AutoSet Vantage) I was averaging 6.5 hours of sleep now 30 days later for the past 4 nights it's 8.3 hours and last night I actually slept 7.4 hours and NO wake ups.

So currently my 14 day average pressure is 11.91 and my 90% average pressure is 13.27, and my machine is set at minimum pressure 11.8 with EPR 1.

The way I calculate it my minimum pressure setting is really close....if I did my math correct I should eventually get to around 12.6 as a minimum, of course I know that will change if EPR or other factors change.

I don't recall who first brought this to my attention.......but thank you

Here's my latest graph:

fdw wrote:Someone here once said how to calculate minimum pressure settings by using the Average reading and the 90% Pressure readings for a period of time.

I've been using this formula and its really making a huge difference in my sleep therapy, Im actually sleeping longer and not waking as much. When I started using the NEW ResMed S9 AutoSet (coming from ResMed S8 AutoSet Vantage) I was averaging 6.5 hours of sleep now 30 days later for the past 4 nights it's 8.3 hours and last night I actually slept 7.4 hours and NO wake ups.

So currently my 14 day average pressure is 11.91 and my 90% average pressure is 13.27, and my machine is set at minimum pressure 11.8 with EPR 1.

The way I calculate it my minimum pressure setting is really close....if I did my math correct I should eventually get to around 12.6 as a minimum, of course I know that will change if EPR or other factors change.

I don't recall who first brought this to my attention.......but thank you

Here's my latest graph:

It might have been me. I usually advise picking a pressure somewhere between the "average" and "90%" (or 95%) for either a minimum pressure of fixed single (CPAP) pressure.
Sometimes, depending on how low the minimum pressure has been, it may become a moving target, but at some point, if the minimum is high enough, the selected pressure becomes more valid.


Den

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It might have been me. I usually advise picking a pressure somewhere between the "average" and "90%" (or 95%) for either a minimum pressure of fixed single (CPAP) pressure.
Sometimes, depending on how low the minimum pressure has been, it may become a moving target, but at some point, if the minimum is high enough, the selected pressure becomes more valid.

What do you think about my calculations?

What Im wondering is if my minimum pressure is set at 11.8 and I decide to raise EPR from 1 to 2 would I then need to increase the minimum pressure to 12.8?

fdw wrote:

It might have been me. I usually advise picking a pressure somewhere between the "average" and "90%" (or 95%) for either a minimum pressure of fixed single (CPAP) pressure.
Sometimes, depending on how low the minimum pressure has been, it may become a moving target, but at some point, if the minimum is high enough, the selected pressure becomes more valid.

What do you think about my calculations?

What I wondering is if my minimum pressure is set at 11.8 and I decide to raise EPR from 1 to 2 would I then need to increase the minimum pressure to 12.8?

epr reduces your pressure (except when inhaling) by however many you set it to.

so, effectively, yes.

fdw wrote:

It might have been me. I usually advise picking a pressure somewhere between the "average" and "90%" (or 95%) for either a minimum pressure of fixed single (CPAP) pressure.
Sometimes, depending on how low the minimum pressure has been, it may become a moving target, but at some point, if the minimum is high enough, the selected pressure becomes more valid.

What do you think about my calculations?

What Im wondering is if my minimum pressure is set at 11.8 and I decide to raise EPR from 1 to 2 would I then need to increase the minimum pressure to 12.8?

I guess you won't know till you try it. You're getting into the "fine tuning" territory. Your numbers and your report looks pretty good as is. But, yes, you may need to compensate for the EPR setting with increased minimum pressure.

I always try to mention to the users that they might want to try a week at a single pressure setting, too. Maybe around 13 cm. in your case. That way you can try to compare the results and see if your sleep quality is any different. Some people are sensitive to changing pressures and sleep better with a single pressure.


Den

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fdw wrote: What Im wondering is if my minimum pressure is set at 11.8 and I decide to raise EPR from 1 to 2 would I then need to increase the minimum pressure to 12.8?

Maybe.
It depends on how close you are to the line where apnea events happen if you go below so and so pressure.
Not everyone needs to compensate for that reduction during exhale...some do and some don't. My money is on you won't really see much of a difference if you increase EPR. I could be wrong but I think that you have tweaked things to the point that a little reduction of pressure during exhale isn't going to allow a truck load of anything to sneak past the defenses. I think that you are well above that fine line where just a little drop allows a truck load of apnea events to materialize.

I'm pretty much a contrarian so may not hold for all. My stomach valve (LES) is pretty much shot so I was literally pumped up until I fiddled with my low setting. By trying different low settings over time I learned anything over 7.5 was adding to my problem. I set my low at 6.0 for comfort and pressure mostly stayed below 7.5. My AHI went up a notch or two but remained below 5 and I felt better.

My advice is to set the low as you did unless it bloats you and if it does, lower it as needed. Below a point it doesn't matter much what your AHI is and chasing a Zero is just a game. Mine stayed around 3.5 for years and I only checked it occasionally after a bit. Recent med change upset my sleep and scores went bad. So just realize sometimes meds, etc can affect sleep regardless what you do to your machine.