Trying cpap mode on apap, what pressure?

[RogerSC]

I'd like to try CPAP mode on my Autoset. The pressure range that I'm currently using is 10 - 14, and the pressures for the last week or so have averaged:

Median: 11.3
95%: 13.3
Max: 13.8

For the more experienced of you out there, if you had those pressures, where would you set a constant CPAP-mode pressure?

Thanks very much.

[khauser]

I vote you try your 95% value. The range you have is pretty small, so that 95% value is probably accurate UNLESS your machine is bumping up against 14 a lot. If that's the case, I would take a different approach (and remember I don't have your data at hand as I say this) ... that different approach would be to increase the minimum to the 95% value and increase the maximum (all the way to 20 would be one approach, or bump it to keep a 4 point range for comfort). But don't do this if you're seeing CAs.

[caffeinatedcfo]

Roger -

I would try gradually increasing your min pressure first to tighten up the range. I have found that as I moved my minimum pressure up my S9 auto doesn't have to chase events and therefore my maximum pressure has decreased. After a short time you will get to that pressure where it doesn't change much at all and you'll have your answer.

[StuUnderPressure]

Roger -

I would try gradually increasing your min pressure first to tighten up the range. I have found that as I moved my minimum pressure up my S9 auto doesn't have to chase events and therefore my maximum pressure has decreased. After a short time you will get to that pressure where it doesn't change much at all and you'll have your answer.

I would do as caffeinatedcfo says above.
But, along with raising your minimum pressure, I would also initially raise the maximum pressure to at least 16.

Run it at the same pressure range for a week & then tweak some more by gradually increasing your minimum pressure (assuming the 1st increase accomplished something).

[Pugsy]

If you never hit the max of 14...there's no need to think about the max or do anything with it. It becomes just a number.

Without seeing the reports to get a feeling for the overall trend...If I was choosing a CPAP pressure from this tight of a range of AAP pressures I would consider the median pressure as primary guide line to start with.

95% pressure just means that for 95% of the time you were at OR below that number...people tend to forget the "or below" part of the definition and think that is where they spend 95% of the time. For all we know we might be spending 90% of the time below 12 and even maybe closer to the median with only 5 % of the time up by 13 or so.

Here's why I suggest start at the median...
1. I have always felt it is an easier adjustment to go up gradually...simply from comfort side of things if no other reason.
I have changed from 8 to 9 to 10 up to even 13 in stages. Going from 8 to 9 isn't difficult really but going up by 0.5 (my Respironics machine only offered 0.5 increments) for 3 or 4 nights was an easier adjustment. When I tried going from 10 to 12..that 2 cm difference was noticeable. Not horrible but it was a bit more effort. Why not take it slow and easy and be more comfortable in the process? Discomfort for any reason can mess with our sleep and the data. No sense in adding another variable to the experiment.

2. We might get lucky and find out that we can get by with a lower pressure than we were thinking we would might need.
Duh...this one is a no brainer unless someone just wants to use more pressure than might be needed for some reason or other.

[avi123]

Roger, before going into it you need to answer:

1) What's your purpose for doing it.
2) How would you decide if a certain pressure in CPAP mode is the most optimal for you?

The pressures set- up on my APAP are very close to your. But I could not guess from my present nightly data what would be the optimal pressure for
setting the S9 Autoset in CPAP mode. However, I do know that the optimal pressure from my 8 months ago sleep titration study was 13 cm IN CPAP.

This is the present set-up on my S9 Autoset in APAP mode:



Could you tell from it that my optimal pressure in CPAP mode should be 13 cm? What graph would you be interested to see to give you a clue? Or may be that your criteria is the daytime sleepiness level?

[RogerSC]

If you never hit the max of 14...there's no need to think about the max or do anything with it. It becomes just a number.

Without seeing the reports to get a feeling for the overall trend...If I was choosing a CPAP pressure from this tight of a range of AAP pressures I would consider the median pressure as primary guide line to start with.

95% pressure just means that for 95% of the time you were at OR below that number...people tend to forget the "or below" part of the definition and think that is where they spend 95% of the time. For all we know we might be spending 90% of the time below 12 and even maybe closer to the median with only 5 % of the time up by 13 or so.

Here's why I suggest start at the median...
1. I have always felt it is an easier adjustment to go up gradually...simply from comfort side of things if no other reason.
I have changed from 8 to 9 to 10 up to even 13 in stages. Going from 8 to 9 isn't difficult really but going up by 0.5 (my Respironics machine only offered 0.5 increments) for 3 or 4 nights was an easier adjustment. When I tried going from 10 to 12..that 2 cm difference was noticeable. Not horrible but it was a bit more effort. Why not take it slow and easy and be more comfortable in the process? Discomfort for any reason can mess with our sleep and the data. No sense in adding another variable to the experiment.

2. We might get lucky and find out that we can get by with a lower pressure than we were thinking we would might need.
Duh...this one is a no brainer unless someone just wants to use more pressure than might be needed for some reason or other.

Good points, thanks. I've never seen it hit 14, although it may hit 13.9 a couple of times a night, about half the nights it makes it there. And it doesn't stay at the maximum, it goes up and then drops. Starting from the area of the median and going up from there makes sense to me. There's no sense in using more pressure than I need, just more leaks, etc.

Since I'm trying this to see if I can't get more solid sleep, I like this approach, starting from the middle pressure and seeing how that works. I might have to go up to the 95% pressure, but you're right, it makes more sense to get there incrementally, if need be.

[Pugsy]

Here's a good example of how getting a good solid minimum apap pressure (or even a good solid cpap pressure) does a better job of holding the airway open and thus the need for pressure changes is greatly reduced.
This person would likely do very well with 10 to 11 cpap pressure.
But at first glance it looks like they would need a lot more. Notice how the pressure needs stabilize and there isn't nearly as much movement once the minimum pressure was optimized.
Now you already had you minimum up to where it was doing a good job so yours might not be so dramatic but I think you can see what I mean that sometimes if the minimum is optimal...there is no need for that 95% number that you might have thought was needed.
viewtopic.php?f=1&t=39869&st=0&sk=t&sd=a

I see where you are coming from about trying cpap to see if you sleep better. Some people are indeed sensitive to pressure changes even if they don't realize it. They changes may cause little mini arousals which kick us out of a sleep cycle and thus interrupts the cycle sequence that is needed to feel optimal and have sleep work its restorative powers.
It's a good solid thought and experiment to try.

[RogerSC]

Roger, before going into it you need to answer:

1) What's your purpose for doing it.
2) How would you decide if a certain pressure in CPAP mode is the most optimal for you?

The pressures set- up on my APAP are very close to your. But I could not guess from my present nightly data what would be the optimal pressure for
setting the S9 Autoset in CPAP mode. However, I do know that the optimal pressure from my 8 months ago sleep titration study was 13 cm IN CPAP.

This is the present set-up on my S9 Autoset in APAP mode:

[ graphic deleted...]

Could you tell from it that my optimal pressure in CPAP mode should be 13 cm? What graph would you be interested to see to give you a clue? Or may be that your criteria is the daytime sleepiness level?

That's a good point. I tend to check in with how I'm feeling first, and then look at my sleep data to see what it's doing. I'm not experiencing daytime sleepiness, since that's pretty much of a constant, I'm not sleepy during the day, unless I shortchange myself on hours in bed *smile*. I wasn't sleepy during the day before I went on cpap either, but I had other symptoms. Now, I feel that I wake up more than I'd like in the morning after 5 or 6 hours sleep, and would like to have more solid sleep from that 5 or 6 hour mark when I start waking up to the 8 hour mark when I'd like to be asleep until *smile*. If you know what I mean. I'm trying straight cpap to see if removing the pressure changes helps with this. And watching my sleep data to be sure that I'm not going off the deep end, as well.

I'm assuming that you were titrated in a sleep lab, at the 13 cm mark for straight CPAP? I wonder what they would have ended up with if they had titrated you to a variable pressure at the lab? From what I've been reading, while there's a rough correlation between lab titration and what people experience at home, there seems to be a difference in a lot of cases. It is interesting that you needed 13 cm in the lab, yet when using an apap the range where you do well at home is lower than that. I don't know how to account for that, but there are a LOT of variables, and what matters is how things look at home in the end. And things can change over time, also...

[avi123]

Roger, as I remember, a lot of posters on this board have realized reduction in pressure after switching from CPAP to APAP mode. Which is the reverse way from your intention. But go a head and try it out!

When I have checked switching to CPAP mode for three nights, recently, but leaving all the rest CONSTANT, including the mask, I saw in SleepyHead that the AHI (if you believe in this measure) was higher in CPAP mode. See it here on 3/16 and 3/19, 2012:



I don't know how to remove the green highlight color.

You asked: I'm assuming that you were titrated in a sleep lab, at the 13 cm mark for straight CPAP? I wonder what they would have ended up with if they had titrated you to a variable pressure at the lab? As I understand it, Sleep Lab Clinics don't titrate APAPs. Usually, they do what the Sleep Docs ask them to do and mostly it is to find the minimal pressure at which the CPAP got rid of all "events".

About the length of sleep, during the last year I have slept 7 to 7:30 hours a night. But I have been getting up to urinate from 3 to zero times a night. I could minimize it by taking FlowMax Rx, but I hate to add more medications. Before going to sleep I take a couple of Rxs: Xanax 0.5 tablet ER and Gabapentin two capsules of 300 mg each. I am checking now if it's the Gabapentin which causes me sleepiness after breakfast, by reducing the dose. On those nights in which I don't fall asleep within one hour after masking or if I can't fall back asleep before 7 hours sleep, I take 5 mg tablet of Zolpidem, which always worked for me.

[Wulfman...]

I'd like to try CPAP mode on my Autoset. The pressure range that I'm currently using is 10 - 14, and the pressures for the last week or so have averaged:

Median: 11.3
95%: 13.3
Max: 13.8

For the more experienced of you out there, if you had those pressures, where would you set a constant CPAP-mode pressure?

Thanks very much.

Based on the numbers you posted, I'd suggest going with 12 cm. for a bit and see what the data shows. My "rule of thumb" is to split the difference between the "average" (or Median in your case) and the 90% or 95% (depending on which manufacturer is being used).


Den

.

[RogerSC]

Roger, as I remember, a lot of posters on this board have realized reduction in pressure after switching from CPAP to APAP mode. Which is the reverse way from your intention. But go a head and try it out!

When I have checked switching to CPAP mode for three nights, recently, but leaving all the rest CONSTANT, including the mask, I saw in SleepyHead that the AHI (if you believe in this measure) was higher in CPAP mode. See it here on 3/16 and 3/19, 2012:

[graphic deleted, see above...]

You asked: I'm assuming that you were titrated in a sleep lab, at the 13 cm mark for straight CPAP? I wonder what they would have ended up with if they had titrated you to a variable pressure at the lab? As I understand it, Sleep Lab Clinics don't titrate APAPs. Usually, they do what the Sleep Docs ask them to do and mostly it is to find the minimal pressure at which the CPAP got rid of all "events".

About the length of sleep, during the last year I have slept 7 to 7:30 hours a night. But I have been getting up to urinate from 3 to zero times a night. I could minimize it by taking FlowMax Rx, but I hate to add more medications. Before going to sleep I take a couple of Rxs: Xanax 0.5 tablet ER and Gabapentin two capsules of 300 mg each. I am checking now if it's the Gabapentin which causes me sleepiness after breakfast, by reducing the dose. On those nights in which I don't fall asleep within one hour after masking or if I can't fall back asleep before 7 hours sleep, I take 5 mg tablet of Zolpidem, which always worked for me.

That is pretty interesting that your AHI went up so high in CPAP mode. I'll be watching for that, didn't occur to me that might happen. Any chance that the added events were centrals from the consistently higher pressure? I am aware that one can get more centrals as the pressure goes up. Another reason for me to start CPAP mode at a lower pressure, maybe.

Anyways, thanks for passing that on, interesting.

[RogerSC]

Based on the numbers you posted, I'd suggest going with 12 cm. for a bit and see what the data shows. My "rule of thumb" is to split the difference between the "average" (or Median in your case) and the 90% or 95% (depending on which manufacturer is being used).

Den

Good suggestion, I may well be there pretty soon. Thought I'd start at about 11.5, and 12 would be my next step *smile*.

[sleepstar]

At our clinic we go with the 95% percentile
Good luck

[Pugsy]

Here's why I don't jump right on the 90/95% number unless I see the reports and do long term averages.
Which one to choose?
Long term...over 6 months the 90% number is 12 cm. Even using weekly averages for % numbers there was a very wide variation. I have seen 90% numbers hit 18 cm and couldn't blame it on massive large leaks. I sure wouldn't want to use 15 to 18 cm on cpap mode all night long.