AHI and flow limitation about the same for 5–7 and 6–20

alexander · Post by **alexander** » Tue Aug 27, 2019 4:15 am

I’ve been trying changing the maximum pressure from 7 to 20 for the past couple of nights. It’s too early to tell if I feel better with the new maximum pressure. I probably feel a bit worse, but I understand that it can take time to adjust to a different one. In general I feel fine with 5–7 or 6–7. (I have very recently increased the minimum to 6 as I find it easier to breathe at that pressure.)

What I don’t understand is why the machine with maximum at 20 increases the pressure to 11.56 when I get about the same AHI and the flow limitation numbers are so similar when using maximum pressure of 7. Should I consider going back to 6–7, or maybe a fixed pressure somewhere around 6 and 7?

5–7: https://i.imgur.com/7W9qEEh.png

6–20: https://i.imgur.com/bnJTI7R.png

Pugsy · Post by **Pugsy** » Tue Aug 27, 2019 6:53 am

Because similar isn't necessarily the same.
We don't sleep the same each night for one thing.
The increases in your pressure line correspond to increased activity in the FL line and there is a pattern. My best guess is that is a REM stage sleep pattern and your OSA worsens a bit during REM which is quite common. Both supine sleeping and REM sleep stages can cause OSA to worsen and cause the machine to work harder trying to hold the airway open.

Your machine wants to fight the FLs it senses. Simple as that.
You get to decide if you want to allow it to do what it is designed to do or not. Simple as that.
If allowing it to do what it is designed to do causes problems...you don't have to allow it...you can limit it....Simple as that.

alexander · Post by **alexander** » Tue Aug 27, 2019 7:09 am

Pugsy, thanks for your explanation!

I’ll give it some more time with maximum pressure set to 20.

Pugsy · Post by **Pugsy** » Tue Aug 27, 2019 7:49 am

The maximum number is irrelevant unless it is limiting the machine from going to where it wants to go.
The machine will only go to where if feels the need for whatever reason. Having it set to 20 or even 100 if it could be done would have zero effect on the actual response or results.

I don't see an urgent need in your case to let the machine go higher if the going higher seems to cause a problem.
Your AHI is low...you reported feeling fine so I assume happy with how you feel and sleep..and while the FL graph is a bit active it is far from really ugly and if that were my FL graph and I was sleeping and feeling fine with no complaints I would have shrugged my shoulders and moved on. Your original settings were working well enough.
There's no urgent reason to go on a hunting trip to try to kill those FLs unless you aren't feeling the good numbers like you expect to feel and there's no guarantee that killing those FLs would make someone feel better anyway.

Your choice as to how much time and effort you want to put into this experiment.

Now if your FL graph looked like this one below...we might be having a different discussion.

Your FL graph is far from ugly....now this one is really ugly.

alexander · Post by **alexander** » Tue Aug 27, 2019 8:33 am

Pugsy wrote: ↑
Tue Aug 27, 2019 7:49 am
The maximum number is irrelevant unless it is limiting the machine from going to where it wants to go.
The machine will only go to where if feels the need for whatever reason. Having it set to 20 or even 100 if it could be done would have zero effect on the actual response or results.

I don't see an urgent need in your case to let the machine go higher if the going higher seems to cause a problem.
Your AHI is low...you reported feeling fine so I assume happy with how you feel and sleep..and while the FL graph is a bit active it is far from really ugly and if that were my FL graph and I was sleeping and feeling fine with no complaints I would have shrugged my shoulders and moved on. Your original settings were working well enough.
There's no urgent reason to go on a hunting trip to try to kill those FLs unless you aren't feeling the good numbers like you expect to feel and there's no guarantee that killing those FLs would make someone feel better anyway.

Your choice as to how much time and effort you want to put into this experiment.

Now if your FL graph looked like this one below...we might be having a different discussion. Your FL graph is far from ugly....now this one is really ugly.

That doesn’t look too well.

I guess my therapy is optimized either way. When I look at the past few weeks of data I feel that my flow limitation graph looks similar across different pressure settings. It doesn’t really matter (and I’m not going to spend any effort finding out), but it makes me wonder if other algorithms would react (very) differently.

Pugsy · Post by **Pugsy** » Tue Aug 27, 2019 8:46 am

Other algorithms would likely react differently.
Does it matter? Dunno.
There are multiple ways to skin a cat as that old saying goes. You can go about it differently but the end result still is a skinned cat.
What are your goals? What do you wish to accomplish? Anything? Or just curious?
Scratching that curiosity itch can be done but it ain't cheap to do it.
I don't know where you live or how easily or you can try other brands of machines...but here in the US it's not easy to simply try different brands and certainly isn't cheap.

If you have the money to spend on different machines and try them out....and want to...go for it.
You have likely seen the discussion in your other thread about Respironics vs ResMed's auto adjusting algorithms...did you go look at the study that Capn Loki posted?

alexander · Post by **alexander** » Tue Aug 27, 2019 9:04 am

Well, I’m mostly curious, but not to the extent that I will buy a different machine. When ResMed releases a new AirSense (or whatever they will name it), I will probably buy it. Both because it most likely has a refreshed design, but also because it might come with new and improved algorithms.

I was thinking about AutoSet for Her algorithm and DreamStation. I’m not too familiar with other manufacturers.

Edit: Yes, I’ve been following that discussion. I feel like I’m constantly learning something new.

AHI and flow limitation about the same for 5–7 and 6–20

AHI and flow limitation about the same for 5–7 and 6–20

Re: AHI and flow limitation about the same for 5–7 and 6–20

Re: AHI and flow limitation about the same for 5–7 and 6–20

Re: AHI and flow limitation about the same for 5–7 and 6–20

Re: AHI and flow limitation about the same for 5–7 and 6–20

Re: AHI and flow limitation about the same for 5–7 and 6–20

Re: AHI and flow limitation about the same for 5–7 and 6–20