ResMed 11 Autoset vs "Autoset for her"

Last night my pressure was a lot higher. I woke up with it at 14.2 after about 4 hours of sleep. My average pressure was 12, which is higher than the typical 8-10.

I first thought something was different since I cleaned the tube, or because I changed masks, but realized I had put it on "Autoset for her" instead of "Autoset" after using it in CPAP mode yesterday while awake, to try to adjust myself to higher pressure.

Does the "for her" mode typically produce higher pressure?

Does anyone else find that ironic in a meta way?

KittyMom22 wrote: ↑

Thu Nov 10, 2022 9:17 am

Does the "for her" mode typically produce higher pressure?

The "For Her" mode will reset the minimum pressure (higher) for the night under specific circumstances. I'd have to go back through the clinical manual to find a description of what the circumstances are that leads to the resetting of the minimum pressure for the night.

I believe the rationale is that if the machine believes a higher minimum pressure is needed, that will lead to fewer rapid spikes in pressure increases and the idea is that those spikes in the pressure increases may cause additional arousals. The "for her" algorithm also increases pressure more slowly (if I recall correctly) and after the pressure is at a certain point, it only increases pressure in response to flow limitations, not events. All of this means that having the min pressure set high enough becomes more important.

Does anyone else find that ironic in a meta way?

I believe the "for her" algorithm is supposed to be "gentler" in terms of how the pressure increases are done because there's an assumption (in the design of the program) that rapid pressure increases might lead to more spontaneous arousals. The "for her" algorithm is supposed to minimize spontaneous arousals while still giving plenty of pressure support to prevent obstructive events from happening as well as minimize flow limitations, RERAs, and snoring.

The S11 machine has the "for Her" setting. It can be set to CPAP for a Fixed Setting....AUTOSET for a variable setting or..."for Her".
Here is Nick's you tube explanation of that setting. https://www.youtube.com/watch?v=_RdD9WmSgA8

I actually used the for Her mode for quite some time a while back. It did NOT routinely give me higher pressures than I might see in the regular auto adjusting mode.

Yes...the for Her mode will establish a new minimum pressure when certain conditions are met. I think one of the conditions is 2 OAs within a rather short time frame. The new minimum is going to be limited to 2 cm above the original minimum though. So the new minimum it wants to set isn't going to be all that much higher than the original. I have seen this in action myself.
It won't go changing a 6 cm minimum to a 10 cm minimum though....the most it will create is a new minimum at 8 cm.

Above a certain pressure level it does get more picky about how it responds to anything and I think that is 12 cm. People who routinely see 12 or higher pressures for a good bit of the night or all night probably wouldn't do well with the for Her mode.

As for the difference .....remember that we don't sleep the same each night and there is no guarantee that the increase you saw was strictly the algorithm. There's chance you would have seen 14 anyway no matter the mode.

KittyMom22 wrote: ↑

Thu Nov 10, 2022 9:17 am

Does the "for her" mode typically produce higher pressure?

This can't be answered.

If you would take a few minutes to download OSCAR, in all likelihood, you could be told the exact reason(s) why the pressure was at its various levels.

• It could be setting changes since changing from CPAP
• It could be For Her Mode establishing a new minimum pressure
• It could higher pressures because of SWJ presenting as OAs or Hyponeas
• It could be Pugsy's aliens

All of which, except Pugsy's aliens, often present very obvious in ones charts.

The for Her algorithm is designed to respond even more directly to flow limitation and to snoring than to apnea, so the potential exists for a higher average pressure to result, but ResMed marketing copy nevertheless says:

"The AutoSet for Her contains features which are designed to keep the average CPAP pressure lower and make pressure changes more gentle, and therefore more comfortable, for you."--https://www.resmed.com/en-us/sleep-apne ... -in-women/

Personally, although I am an overweight male with a rather classic male form of OSA, I do get slightly better (maybe 0.5 better on average?) AHI using the for Her algorithm. I now use a machine without that algorithm, though, and the difference doesn't seem significant in practice for me as far as how I feel. I average well below 2.0 either way.

I find I can't judge differences well using short time-frame comparisons. I need to see what a change does over at least a few weeks of time before I can draw any meaningful conclusions.

Research has shown that female patients have greater flow limitation so the AutoSet for Her algorithm is designed to be more sensitive to flow limitation.--https://shop.resmed.com.au/resmed-airse ... r-machine/

what is specifically meant by "flow limitation?"

KittyMom22 wrote: ↑

Thu Nov 10, 2022 12:51 pm

what is specifically meant by "flow limitation?"

In general, in the context of treatment machines, an indication of less flow of air, often used, according to context, to refer to something less than a hypopnea or apnea.

Each algorithm defines it a bit differently in the specifics, based to some degree on breath "shape," and "flatness," according to ResMed's marketing copy. And each algorithm responds a bit differently.

This is an example in the context of a sleep study, just as an example of a reduction in flow, change of overall shape, and flattening of the breath:



In relation to the two algorithms you have used with a ResMed:

ResMed AutoSet evaluates flow every breath looking for apneas, snore, and flow limitation, but responds to flow limitation on a 3-breath average, has faster decreases in the absence of flow limitation and has a higher rate of pressure change to all responses (apnea, snore, and flow limitation) than AutoSet for Her.

In comparison, ResMed AutoSet for Her evaluates the flow for every breath looking for apneas, snore, and flow limitation, and delivers a proportional increase in pressure depending on the degree of deviation of the event from normal, modulated by the current pressure setting and leak rates. If pressure is >10, then the response to flow limitation reduces and a louder snore is required to produce a response. Both AutoSet for Her and AutoSet respond less as leak gets higher.--https://www.dovepress.com/treatment-of- ... ticle-MDER

I'm throwing you in the deep end with that quote and link. But you can handle it. It may spark more interest, fascination, and research on your own.

In your spare time, I mean.

Or you can simply go with the ResMed glossary definition:

Flow limitation
This refers to any event that limits the flow of air into your body, due to a blockage or collapse of your upper airway.--https://ap.resmed.com/knowledge/flow-limitation

By "collapse," I believe they mean to include partial collapse, as in any significant narrowing of the airway.

Like a stuffy nose that limits the flow of air or your airway collapsing.

Edit: funny cuz Joy just did this same thing switching settings.

Thanks, all!