Aircurve Vauto vs Fixed

Hi All,

I have a question on how to configure my new bipap machine. I used to use a Autoset s10, now an Aircurve Vauto. In my first machine I found comfort in autoset mode, median inhale of 10cm, median exhale of 7cm (lab titrated me to fixed 8cm/8cm). I wanted to switch to Bipap because I'd read it was more effective for UARS, specifically with regards to flow limitations. And in my observation the algorithm certainly is more sensitive to flow limitations than was the Apap algorithms. The lab prescribed me 10cm/6cm on the BiPap, but on their prescription they strangely fixed the inspiration time to 2 seconds, which felt SUPER weird, so I changed it.... For the last month I've been experimenting with different settings on the Bipap but haven't found something that works well.

1. After a lot of messing with the TI settings (max/min/sensivity), I finally settled on a TI-min of .8seconds, TI-max of 2seconds, and a Cycle Sensitivity of LOW, and a Trigger Sensitivity of MEDIUM. I keep coming back to these settings, so I believe they're good.

2. If I set the machine to Vauto (auto titration), inhale pressure rises to as high as 13cm. Do you guys recommend doing vAUTO or just fixed? or vauto in a really tight range? I heard that Vauto wasn't recommended since it jumps around so much....anyone have experience with the vauto vs fixed debate?

3. I'm quite confident my exhale pressure doesn't need to be higher than 8cm (was titrated for cpap as well for 8cm) and it in fact becomes intolerable much beyond that. I've most recently tried to set the machine to fixed at 11.4cm/7cm, but still having AHI/RDI readings consistently higher than they were with the Autoset machine, even though I use higher pressures...why would that be the case? Perhaps I will give vAUTO a try a gain, maxing out my inhale pressure around 12.6

Would appreciate any perspective...thanks

Hello, Apneak. It'd help a lot if you could post an Oscar daily chart from a recent night with the VAuto. Are you using Oscar? If not, just download it to your laptop or desktop: https://www.sleepfiles.com/OSCAR/ and then import the data from the SD card in your machine. No SD card? Get one, plus an SD card reader if your computer doesn't have one.

In the meantime, could you give the breakdown of the kinds of events you were having with the Airsense 10 Autoset and a breakdown for the VAuto?

Hi THanks! I am using sleepyhead, that's the same thing right? Here is a screenshot.....I can post more detail views too...It definitely is more clear airway events, HOWEVER, i'd attribute some of those with some mask difficulties I've been having recently, which I'll fix, resulting in my moving around a lot at night...


Fixed Pressure 11.4cm/7cm:


Fixed Pressure 11.2cm/6.8cm:


Fixed Pressure 11cm/7cm:

Apneak wrote: ↑

Sun May 17, 2020 1:08 pm

2. If I set the machine to Vauto (auto titration), inhale pressure rises to as high as 13cm. Do you guys recommend doing vAUTO or just fixed? or vauto in a really tight range? I heard that Vauto wasn't recommended since it jumps around so much....anyone have experience with the vauto vs fixed debate?

I think:

1. you should always use VAuto, in part because FL tracking is not available in S mode; VAuto with min EPAP of 6, PS of 4, and max IPAP of 10 = S with EPAP of 6 and IPAP of 10
2. but you should start with letting it do it's work, and if you have a problem with changing pressure, then you can constrain the range

3. I'm quite confident my exhale pressure doesn't need to be higher than 8cm (was titrated for cpap as well for 8cm) and it in fact becomes intolerable much beyond that. I've most recently tried to set the machine to fixed at 11.4cm/7cm, but still having AHI/RDI readings consistently higher than they were with the Autoset machine, even though I use higher pressures...why would that be the case?

The PS is leading to CAs.

With UARS, you have to balance the benefits of using PS to alleviate RERAs against the potential for it to cause CAs.

But this is often temporary, as your body adjusts.

Thanks Slowriter,

What are your settings? Do you think I should set the machine for a narrow range vAUTO, (not static so narrow that it's static)?

Apneak wrote: ↑

Sun May 17, 2020 1:08 pm

Hi All,

I have a question on how to configure my new bipap machine. I used to use a Autoset s10, now an Aircurve Vauto. In my first machine I found comfort in autoset mode, median inhale of 10cm, median exhale of 7cm (lab titrated me to fixed 8cm/8cm). I wanted to switch to Bipap because I'd read it was more effective for UARS, specifically with regards to flow limitations. And in my observation the algorithm certainly is more sensitive to flow limitations than was the Apap algorithms. The lab prescribed me 10cm/6cm on the BiPap, but on their prescription they strangely fixed the inspiration time to 2 seconds, which felt SUPER weird, so I changed it.... For the last month I've been experimenting with different settings on the Bipap but haven't found something that works well.

1. After a lot of messing with the TI settings (max/min/sensivity), I finally settled on a TI-min of .8seconds, TI-max of 2seconds, and a Cycle Sensitivity of LOW, and a Trigger Sensitivity of MEDIUM. I keep coming back to these settings, so I believe they're good.

2. If I set the machine to Vauto (auto titration), inhale pressure rises to as high as 13cm. Do you guys recommend doing vAUTO or just fixed? or vauto in a really tight range? I heard that Vauto wasn't recommended since it jumps around so much....anyone have experience with the vauto vs fixed debate?

3. I'm quite confident my exhale pressure doesn't need to be higher than 8cm (was titrated for cpap as well for 8cm) and it in fact becomes intolerable much beyond that. I've most recently tried to set the machine to fixed at 11.4cm/7cm, but still having AHI/RDI readings consistently higher than they were with the Autoset machine, even though I use higher pressures...why would that be the case? Perhaps I will give vAUTO a try a gain, maxing out my inhale pressure around 12.6

Would appreciate any perspective...thanks

1) TiMin should almost never be changed from the default by people with normal lungs, TiMax often is fine, and might as well be raised to 4 for most people, since it is only applicable to people that have lung problems that make it hard for them to exhale. Adjust trigger and cycle to whatever you feel you like.

2) I recommend setting MaxIPAP to 25, because for most people the maxipap is irrelevant. "tight range"is something promoted by people that don't know what they're doing, what is *important* for 90% of the people is the EPAP, because that is what holds the airway open. As to 'auto vs fixed', your sleep varies from hour to hour throughout the night. The only way to have adequate treatment with fixed pressure is to crank it up so that the pressure is high enough to prevent all your events, no matter what sleep cycle you're in, or what position you're in.

3) titrations are very often wrong, so I wouldn't put much stock in that. The primary difference between the Autoset and the VAuto is that the VAuto can provide more Pressure Support than the Autoset. The autoset maxes out at 3, and you're using 4.4 What were your settings on the autoset?

Apneak wrote: ↑

Sun May 17, 2020 2:26 pm

Hi THanks! I am using sleepyhead, that's the same thing right?

No, sleepyhead is older, has more bugs, and is no longer being developed, get Oscar.

Apneak wrote: ↑

Sun May 17, 2020 2:26 pm

Here is a screenshot.....I can post more detail views too...It definitely is more clear airway events,

Please review the directions below on how to set up your charts (yours aren't arranged to show us what we need to see), and how to post images. download links are not images, so don't use the img tag on them. It is greatly preferable to use either the built in forum's image facilities, or to use imgur so that your images display inline.

Hi, thanks palerider....

1. I believe .8 is the default TI min right? Mine was set to 2s when I got it, which was super uncomfortable, but I do not believe that that would the default...

2/3. I had a median pressure of 10cm/7cm on my autoset airsense. I understand that epap is what holds the airway up...but in this case you can only set the minimum epap and maximum ipap, so in setting the max ipap you are also setting the max epap....And I'd think that a max would be beneficial since the algorithm is sensitive to flow limitations, and it spikes the pressure quite bit when you change positions or something, since it thinks you stopped breathing....and I fear pressure could really escalate too much and wake me.

Will get Oscar, thanks!

Can you not see my images inline? I'm confused since I am able to see them inline...Let me know. thanks

Apneak wrote: ↑

Sun May 17, 2020 10:26 pm

Hi, thanks palerider....

1. I believe .8 is the default TI min right? Mine was set to 2s when I got it, which was super uncomfortable, but I do not believe that that would the default...

Default TiMin is 0.3, default TiMax is 2.0, I raised my TiMax to 3.5, because I noticed a lot of my slower breaths were having the inspiratory time cut off.

Apneak wrote: ↑

Sun May 17, 2020 10:26 pm

2/3. I had a median pressure of 10cm/7cm on my autoset airsense. I understand that epap is what holds the airway up...but in this case you can only set the minimum epap and maximum ipap, so in setting the max ipap you are also setting the max epap....And I'd think that a max would be beneficial since the algorithm is sensitive to flow limitations, and it spikes the pressure quite bit when you change positions or something, since it thinks you stopped breathing....and I fear pressure could really escalate too much and wake me.

What were the actual settings on the autoset? "median pressure of 10cm/7cm" isn't a *setting*.

On an autoset, you set a min pressure, and a max pressure, with optional EPR. so you only have one pressure.

On the VAuto, you set your minEPAP, and PS, and then let the pressure wander until the IPAP (EPAP+PS) gets to it's limit. Absent a couple of unusual situations, mainly aerophagia, there is no good reason to reduce the MaxIPAP from the factory default of 25, just like there's no good reason to reduce the max pressure on an autoset from the factory default of 20.
median pressure of 10cm/7cm
The auto machines raise pressure when they detect flow limitations, snores, hypopneas and obstructive apneas, they raise it for FL and snores because those increase the work of breathing, and disturb sleep in and of themselves, and if your airway narrows further, you get hypos and obstructive apneas, so, the fact that the machines raise pressure is *good*.

The machines *do not* raise pressure when you change positions or something, because while you may pause breathing, often long enough to cause an apnea, the apnea is usually central in nature, and no modern auto machine changes pressure in response to a central apnea.

What wakes you is not the pressure increase, what wakes you are the breathing issues you're having, that the machine is trying to get pressure high enough to prevent more of, then you wake up *because of the breathing events* and blame the pressure.

All those breathing events disturb sleep, that's the main reason we have cpaps in the first place, all you're doing by reducing the max pressure, or MaxIPAP is preventing the machine from being able to do it's job.

Apneak wrote: ↑

Sun May 17, 2020 10:26 pm

Can you not see my images inline? I'm confused since I am able to see them inline...Let me know. thanks

Nope, the link you pasted is to a dropbox *download*, not to the image itself.

all I see is "image image image".

Might also be worth mentioning that Resmed's standard bilevel titration protocol starts at PS 4.

At min EPAP of 7, you have no reported OAs, so you don't need more than that.

Maybe you should start again at the defaults all around, including turning off ramp?

• min EPAP = 7 (depending on what you found on the autoset; it might be that 6 is fine)
• max IPAP = 25
• PS = 4
• Ti Min = 0.3
• Ti Max = 2.0
• Trigger and Cycle = Medium (though many have found a trigger of high or very high can lower CAs)

Question for you guys on the inspiration time....are slower breaths necessarily a bad thing? Like should inspiration time stay relatively steady throughout the night? I always found that on my best nights of sleep with the autoset, my inspiration time was generally lowers and steadier....

Apneak wrote: ↑

Mon May 18, 2020 9:00 am

Question for you guys on the inspiration time....are slower breaths necessarily a bad thing? Like should inspiration time stay relatively steady throughout the night? I always found that on my best nights of sleep with the autoset, my inspiration time was generally lowers and steadier....

*everything* varies throughout the night, including RR, and no, long inspiration times are not an issue at all.

Apneak wrote: ↑

Sun May 17, 2020 10:26 pm

Can you not see my images inline? I'm confused since I am able to see them inline...Let me know. thanks

images can be posted right here to the forum, in this thread, using the attachment feature.

I can see 3 images. The detailed reports aren't quite optimal in terms of graph formatting though.

What do you guys make of really gnarly sections like this? does it have anything to do with treatment?

Looks like arousal/awake breathing to me.
Now as to why you weren't asleep. Have no idea. Could have been anything. Not everything is related to the airway...good or bad.