Help understanding last night's SH output

Why is my Resmed Airsense10 not upping the pressure more?
Does my respiration rate chart look reasonable?

zoom in on the 4:40 high RR, we'll count the breaths and see what the machine is counting. There may be a hiccup and counting twice. Sleeprider is very good at flow rates, I think he has a book on it or something.
Was that a typical night for your median and 95% pressures?. if so the min can be moved to 11, if it's an aberration stay where you are. If the machine is double counting, some times more pressure will take the hiccup out of the flow rate. when it's all sorted, you might want to tidy us some leaks, or is that odd too?

ajack wrote:zoom in on the 4:40 high RR, we'll count the breaths and see what the machine is counting.

I'm just going out the door right now (to see my DME) I'll display the chart you suggest later this afternoon.

Out of curiosity any idea why his respiratory rate spikes when leak rate is low and vice versa?

Leaks annoy the heck out of me, it's one of my peeves with cpap. It's the reason I have a draw full of masks that didn't work.
This is how it seems to me, The leak at the beginning of the night seems mask fit
The leak at 1:30+ follows the path and severity a of a pressure rise. seems mask fit,
The leak at 3:30+ starting again after waking up, seems the same as the beginning of the night. For some reason there is leaking when first falling asleep?

USMCVet wrote:Out of curiosity any idea why his respiratory rate spikes when leak rate is low and vice versa?

I think this apparent inverse correlation is a coincidence. I've looked at other of my SH reports that showed little correlation between those two variables. What my respiratory spikes seem to correlate with are blockage events.

Josiah wrote:Why is my Resmed Airsense10 not upping the pressure more?

When and why do you think it is not increasing the pressure adequately?

Your minimum pressure is the most critical setting in terms of holding the airway open in the first place and allowing the machine to get to where it needs to go quickly enough to better prevent the outliers that need more pressure for whatever reason.

These machines sit by and twiddle their little thumbs during the actual airway collapse..they won't increase at all during the apnea event.
They wait until it is over and they evaluate things (like past events and flow reduction, etc) and then decide if they want to increase the pressure and they don't do the increase in a blink of an eye type of thing. They take a few minutes to think about it and do it...and while all this is going on the airway can still collapse....the trick is a little more minimum so the time involved doesn't let the airway collapse as often.

These machines work best when just holding the airway open and preventing the collapse and increasing only when trying to address the outliers that might need more pressure (like supine sleeping or REM related stuff where we might need more pressure).

Your minimum pressure setting is your most critical setting in the majority of situations.

Pugsy wrote:They wait until it is over and they evaluate things (like past events and flow reduction, etc) and then decide if they want to increase the pressure and they don't do the increase in a blink of an eye type of thing. They take a few minutes to think about it and do it.

Thank you Pugsy for your descriptive analysis. What you said is pretty much the way I understood the auto cpap to work and I guess I would have expected my machine to gradually raise my pressure as long as the hypopnea events kept occurring. At about 1:20 the pressure went up seemingly for no reason from 10+ to 13+ which was then followed by an event after which the pressure gradually dropped. That's not how it's suppose to work.

My min pressure is now 9. How about raising it to 11?

Josiah wrote:At about 1:20 the pressure went up seemingly for no reason from 10+ to 13+

You don't show the Flow Limitation graph but I suspect if you look at the FL graph at that time it probably looks a bit more active.
Remember the FLs are part of what the auto algorithm will try to prevent..
Heck, might have even been some minor snoring going on too.
There's more to what the machine will respond to than the OAs and Hyponeas and we can't always easily see what it doesn't like and is trying to kill.

Josiah wrote: My min pressure is now 9. How about raising it to 11?

There will be those that advocate that 2 cm bump in minimum and it might be needed to better clean up the flagged events as well as the FLs but I tend to be conservative with increases because sometimes a little works just as well as a lot and I always try to keep the pressure minimums as low as possible for a number of reasons.

So I tend to do the suggested increases a bit slower/smaller when we are down to the tweaking stage like you are.. If your AHI was a lot higher consistently then yeah...bigger faster jump. Going up slowly is a bit easier of an adjustment sometimes and comfort plays a factor in sleep quality.
If a person isn't comfortable with a higher pressure they can't get to sleep and we have to get to sleep first. Going up slowly lets the body adapt/adjust easier for some people.

Up to you...but me...I would just do 1 cm increase for a few nights and then maybe do another 1 cm to make it to 11 cm.

There is some truth to the "give it time" thing when we are in the tweaking stage.
I experienced it first hand some years ago when I was where you are right now. I am not the most patient person in the world and my knee jerk reaction to a "bad" night is to fix it but I also learned that we don't sleep the same each night and my "bad" night could easily be just a fluke. Heck, I still have them from time to time after over 8 years. I came up with some pressure settings that would at least work well some of the time and decided to really give them a good fair time to see how much the "give it time" thing affected things.
So I picked something that worked sometimes (but not all the times) and I think my AHI was running in the 3 range like yours. I left it alone for 6 weeks and it was hard to do when I had those bad nights but over time I noticed the bad nights were coming around less and less and the good nights more and more.
At the end of the 6 weeks my AHI was averaging half of what it averaged at the beginning of the experiment with no changes other than "giving it time".
Now obviously we don't want to give it time when the therapy isn't close to optimal. No amount of time can fix that...but once we get close and we are getting some good nights (and a few bad nights) then we can afford to "give it time".

So your choice...try both even... but whatever you do give it a fair trial unless the results are horrible for some reason (aerophagia or comfort or whatever).

Your respiration rate thing. I don't know what to make of it. The max I always throw out...and the 95% number is till a 95% number with the AT OR BELOW definition and people forget the OR BELOW part of the definition.
I tend to rely mostly on the median average number for those type of statistics myself because the "or below" thing leaves us wide open for all sorts of stuff.
Now why we might have a max of 30 or 40...dunno...maybe an awake thing...maybe a bad dream...maybe a really good dream
If it is a huge concern then zooming in on the flow rate during the high rate time might be worth doing.

Thank you again Pugsy for going into so much detail about my situation. I will abide your caution and curb my enthusiasm about upping my minimum pressure precipitously and let some weeks go by to let things settle in.

Do you suppose ResMed would send me any technical literature about the algorithm their machine uses in calculating the pressure or have you ever encountered descriptive material on the Web?

Thanks also for your wishes that my visits to dreamland be about particularly pleasant encounters.

Josiah wrote: Do you suppose ResMed would send me any technical literature about the algorithm their machine uses in calculating the pressure or have you ever encountered descriptive material on the Web?

ResMed has never been particularly helpful when it comes to the technical stuff and the end user...us.
They tend to think of the DMEs and doctors as their customers. Point of major annoyance to me but nothing I can do about it.

The algorithm explanation of sorts is available though and maybe someone here has a saved link. We've talked about it in the past but I never really bothered to save it. I kinda always thought it is what it is and I might as well make do with what I have to use now. I understand the basics and for me it suits my needs.

Now the S8 auto algorithm...that's not the same algorithm because ResMed changed things with the S9 model...and I am pretty sure that the AirSense auto algorithm is the same as the S9.

If I have time later I will poke around in the archives and see if I can find something that might go into more detail in terms of how and why it does what it does in auto mode. I have seen more detailed information but didn't save it myself. Maybe one of the other forum members has some additional information handy and will chime in.

FWIW...I would increase the minimum to at least 10 cm right now....I wouldn't wait. You've been on this thing long enough and from what you have reported I would have no problem with being a bit more aggressive now.
I have been down this road too...early in my therapy with the minimum thing.
I settled on a 10 cm minimum and 20 max range...It consistently gave me decent results in terms of the software reports and how I slept and felt.
So then I decided to see if increasing the minimum changed anything...Went on an experiment where I increased that minimum 0.5 cm and used it 7 days...then another 0.5 cm for another 7 days...so a 6 week experiment and I ended up with a minimum of 13 cm.
The AHI never was really consistently any different from what I saw at 10 cm minimum...still was running around 2.0 on average.
My sleep quality never changed nor did how I might feel during the day. I aborted any further increases because it was getting uncomfortable and I wasn't seeing any change in anything anyway. Saw no sense in going higher.

Also remember when looking at your AHI...those centrals/CAs...you have to mentally remove them from the evaluation process in terms of pressure unless you start seeing an unusually large number or increase. More pressure won't fix or prevent centrals with your machine.
Also try to learn where SWJ might be clouding the numbers a bit by learning about flow rate evaluation. SWJ has to be ignored when evaluating pressure needs because they aren't real.

Josiah wrote:Do you suppose ResMed would send me any technical literature about the algorithm their machine uses in calculating the pressure or have you ever encountered descriptive material on the Web?

Like Pugsy says, it's doubtful ResMed will send you anything more than generic information you can already find on their website - ResMed.com, if that.

Here are a couple articles you might find interesting:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4629962/
https://www.resmed.com/us/en/healthcare ... Algorithms
http://openres.ersjournals.com/content/ ... 5.full.pdf

A Google patent search is another good source of information. Here's a start: https://www.google.com/search?tbm=pts&s ... 8oWGKwOT_U

For example, Pressure based on Flow Limitation https://www.google.com/patents/US5335654

Jay Aitchsee wrote:Here are a couple articles you might find interesting:

Thanks a lot Jay, I will look at them.

There is a reason labs recommend fixed pressure. For an experiment, you could try min 13 for one night, because breathing issues are often resolved by more pressure. It's not the max pressure the machine goes to, it's about what a fixed pressure could be and will show if it's because the machine isn't increasing up enough to prevent issues. I would actually use your 14cm pressure and see.