Auto-M Aflex with ramp...how does the algorithm handle it??

I'd like to introduce myself first...new poster here but by no means new as far as lurking. Best source I've found on the subject of CPAP/APNEA to include both the DME and Sleep Doctor...no real offense to either but when it comes to engineering or software details they tend to be out of their league. Some extremely knowlegable people her...kudos to CPAP and the members for a well run and informative board.

Although new as a registered member, I'm not new to an apnea diagnosis or CPAP...that extends back two years. I've been through five face masks before settling on the current one...spent over a year on a Remstar plus before getting and M-series auto a-flex a couple of months ago. Went down the route of a nasal mask to discover i had mouth leakage...then to a chin strap...then full face mask. Seems to be a continuing educational and esxperimental process on my part to cope with this issue.

I'm a shallow breather and according to the sleep lab...almost entirely suffer from hypopnia as opposed to apnea. Although that keeps my oxygen saturations higher than many apnea sufferers...it still puts me into the severe category with an AHI of 46 and my sleep is still severely interupted. The whole issue is compounded by long term persistent insomnia which makes sleep onset and maintence difficult and use of an XPAP with mask aggravates that issue. Problem is in attempting to deal with one sleep disorder, I can aggravate the other. Sleeping meds can increase the apnea...mask and pressure issues adversely impact the insomnia.


The APAP has given me much more flexibility in dealing with these issues. However, it has become obvious to me that my shallow breathing while awake contributes to false events and associated needless pressure runups...many significant enough to cause mask leaks and begin a vicisous runup cycle...and adversely affected my onset insomnia in the process. These false events while awake are the norm after going to bed. What I'd like to do is prevent the APAP from responding to those false events during the first half hour or so.

I researched the forum...and I believe it was Snoredog that indicated that by using the ramp and the old tank auto, one could reduce that response by simply setting the ramp start setting as the same as the minimum setting then selecting 30 minutes to prevent the machine from responding...or using a ramp below the minimum setting to keep the pressure below that pressure for that selected period.

My machine was set at 8-15...8 being my original titrated pressure but later APAP data puts the 90% at 11. Ramp setting was 8 and 30 minutes. In checking Encore Pro it showed the auto-M still provided a muted response to these events during the ramp period. Data shows though the machine read both aneas and hypopnias... the pressure rose to 10 in less than 15 minutes...very shortly after a hypopnia was signaled.

So, I thought, perhaps it doesn't ramp to the minimum pressure but to some average between the minimum and maximum. I changed the APAP pressure to 8-11 and lowered the ramp pressure to 6. In 15 minutes the pressure had ramped to 9...at the end of 30 minutes it was at 10.

It would appear to me that adjusting the time or initial pressure of the ramp on the autopap will indeed hold down the pressure runup. However, it does appear that it will still have some response to a registered event...perhaps holding that response to a limited pressure (10?), Lowering the intial pressure or increasing the time on the machine serves mainly to have a delaying effect on this response.

It's not a major issue here. By adjusting the time and pressure I can still pretty much accomplish what I want in preventing those machine runups on false events while falling asleep. My question is more a point of curiosity.

Obviously, my data on this is limited and I intend to do more checking. Hoever, my initial guess that it used the minium pressure as the end pressure of the ramp was obviously false...either that or I have a defective machine.

Any of you software/engineering experts have knowledge of how the M-series actually handles the ramp while on auto?

Classic:
The Class does NOT have any RAMP in Auto mode. Ramp button may function to override current pressure delivery and take it back to set Minimum.

M series Auto:Ramp:
The M series has Auto:Ramp, functions the same as Ramp in CPAP modes but also works in Auto mode(s). The Algorithm does not respond during periods of Ramp to SDB events, in essence also functioning as a "Settling" feature.

Beginning with the M series, you can enable Auto:Ramp and use it in the Auto mode. This is helpful if your auto begins to ramp up pressure before you fall asleep such from insomnia or sleep onset events.

Example of Auto:Ramp:

You can set a autopap range of 8 cm to 15 cm. Then you can have a even lower beginning pressure such as 6.5cm. You then assign a timer value to the Auto:Ramp feature from 5 to 45 minutes. I suggest using 30 minutes depending on pressures used. This timer also functions as a Settling feature to ignore sleep onset events.

With the Auto:Ramp enabled with the above settings, it would function as follows:

Turn on machine,
pressure starts at Auto:Min=8,
press the Ramp button, pressure drops from 8 cm to 6.5 cm.
timer begins at 6.5, then increments pressure up by .5cm every 5 minutes from 6.5 to 7.0, after 10 minutes 7.0 to 7.5, after 15 minutes to 8.0 which is the Auto:Min pressure setting. When setting Auto:Ramp, you should play or map it out so you know the timer/pressure settings used don't conflict.

Once Auto:Min pressure is reached (or timer expires) machine begins normal auto therapy mode. During period where Ramp is enabled the machine will ignore any events it encounters. It may log the event on the report but it will not respond with pressure to those events.

Many people have sleep onset events, these can be artifacts resembling central apnea, this can confuse the machine and cause pressure to ramp up prematurely and not represent your sleep into deeper states. Use of the Auto:Ramp functions as a settling feature and can get you passed these sleep onset periods so machine doesn't respond and cause more of them to appear.

You can also set the Auto:Min and Auto:Ramp pressures to the same value, then the Ramp timer only becomes a Settling feature (i.e. machine won't respond to events seen during that period).

For example, if you set Auto:Min=8 and Auto:Ramp=8 and Auto:Ramp timer=30 minutes, then that features becomes a 30 minute settling feature, during that period pressure will remain the same but the machine will NOT respond to any SDB event seen. This may be helpful with sleep onset events when the Ramp button is depressed.

The 420e also has a Auto:Ramp and functions in a similar fashion as the M series, it also works in the Auto mode.

If you have sleep onset events they will show up usually within the first 20 minutes of sleep. Use of Auto:Ramp may result in a lower AHI. Ramp pressures should show up on the reports as stair-stepping.

Thanks for the quick reply Snoredog...you're one of those experts I was referring to.

My machine is not functioning as advertised. It is indeed ramping up...but appears to be doing it twice as fast as the set time. I've used the software to set the ramp time...but based on your response...I'll use the clinician's menu to verify the settings to make sure the machine is operating with them. Note, I do use APAP not CPAP.

Here's what happened...only had two nights to check it so will have to explore this one futher. Used the 8-15 setting earlier last night with ramp at 8 and time at 30 to allow settling for 30 min. Turned machine and ramp on and was wide awake for over 1/2 hour. Woke up about 3:30 this morning and lay awake for over 1 hour so got up and downloaded the information. Machine had scored false hypopnias about 10 minutes into therapy and responded by immediately raising the pressure to 9 then to 10 at about 15 minutes and held that pressure for the remainder of the 30 minute time period. Note...under normal circumstances I have at least a runup to 12 while trying to fall asleep.

Changed the pressure to 8-11 with a ramp set at 6 and 30 minutes and went back to bed at 6a.m. Took about 45 minutes to fall asleep and once again awake for the entire ramp time and usual false hypopneas within 10 minutes...this time apneas also. From the Daily events per hour log it shows pressure at 6 for 7.0 minutes and at 7 for 6.5 minutes. Presssure trace shows it raised the pressure to 8 after about another 7 min then to 9 at 15 minutes (thought it was 10 earlier but reread the trace) where it held for most of the remainder of the 30 minutes. Pressure then immediately dropped back to 8 and stepped back up to 10. I hit the ramp again shortly thereafter as I could tell pressure was up...it indeed dropped back to 6 once again.

In both cases, it responded to the hypopneas/apneas but not as strongly as I usually see. There's obviously not enough examples to conclude that a restricted response results. However, it does seem to have limited the pressure while more closely followed the pressure rise curve I would have expected with a 15 minute ramp time.

In both cases it raised the pressure to above the minimum setting by 15 minutes with a 30 minute ramp time. My planned solution was to raise the ramp time to 45 minutes or lower the ramp setting further or use a combination to increase the settling period.

Any theories on what the issue could be...machine settings or potentially an algorithm bug with the ramping? (If its the latter I'll likely live with it and just use a workaround)

Thank your for your time and expertise Snoredog...also the initial suggestion. Even if I use a workaround to make it work...it still will solve a lot of these issues with runups associated with false events before sleep onset. You are a real asset to this board. I can say that even as a new member because I've been a lurker for some time.

Put the AutoDaily report up so we can see it.

Only thing I can suggest is you increase the Auto:Min=10 cm, then put the Auto:Ramp =8 cm (or lower), leave the timer at 30-minutes.

Theory of operation:

1. Turn on machine, it will go to 10 cm,
2. Press Ramp button it should drop to 8.0 cm,
3. Machine will increase pressure by .5 cm every 5 minutes, at 10 minutes you will be at 9.0 cm, at 20 minutes you will be at 10 cm (or Auto:Min) so Ramp is disabled after 20 minutes unless you set the Auto:Ramp pressure lower or Auto:Min pressure higher.

Hitting the Ramp button a 2nd time should reset both pressure and timer as many times as you press it.

What is your 90% pressure?

Am I understanding this correctly? If you set the ramp timer for 30 minutes, that only means that events will not be responded to for 30 minutes. It doesn't mean that the machine will take 30 minutes to come up to minimum pressures. The machine increases pressure at .5 cm each 5 minutes (or 10 minutes for each centimeter) independent of this setting. If you want a settling period of 30 minutes and a pressure no greater than your minimum during that time period, your ramp pressure must be at least 3 cm below your minimum with a 30 minute setting?

If so, I've misunderstood the concept. I thought that no matter your setting, the APAP would take 30 minutes to come up to minimum pressure (or CPAP fixed pressure). If you set it two cm below that pressure, the machine would only raise it one cm each 15 minutes. If that is not the way it works, it sheds new light on my approach. In particular, it would seem that the logical approach would be for me to lower the ramp setting to 5 with the 8 cm minimum and 30 minutes of time to gain the 30 minutes of settling. I'm hardly ever asleep in 15 minutes anyhow so that 5 cm setting will not have much affect on the therapy regardless.

I would happily provide those daily reports...had them set up as JPGs to do so. However, can find no way to attach them other than a link to a host which I'm not set up to do.. Appreciate someone filling me in on how to do it. Can't easily provide the one from after 6AM this morning as I used a separate card and deleted it from Encore in order prevent it from impacting the Encore Pro Analyzer. However, if important, did make a hard copy so can scan it if necessary.

I started using the ramp three days ago. The two weeks prior (had the APAP longer than Encord Pro as it wasn't easy to get 1.8 for the M Aflex)...it wasn't used. Prior to using the ramp, my 90% was 11 or 12. Since using it, it has fallen to 10.
Since I'm sensitive to pressure, that fall is important to me, hence my interest. I'm suspicous of that 10 also as I will wake up during the night and toss and turn for 15 minutes or so so suspect that I'm getting false readings during that time period to raise my AHI and that 90%. Two year old polysomnogram titrated 8 but, granted, it could have changed. That sensitivity to pressure is the reason I'm still using 8 as the miniumum. In spite of A-Flex, the associated noise and pressure of a higher setting affects my ability to fall asleep. I adapted to the 8 setting after nearly two years on CPAP. My plan and hope on APAP is to gradually raise the setting to 10. I've raised it to 9 but can tell the difference in how long I'm able to tolerate the machine...wouldn't think one cm would do so, but it does.

Life would be easier with just the apnea (or just insomnia). I certainly can't say I was blessed to be given both but, unfortunately, didn't have any choice in the the cards I was dealt. Talk to a sleep doctor about insomnia and one of the first rules is to have a quiet, dark sleeping environment. Putting a mask on your face and sleeping next to a blower which changes pitch with each breath does not qualify. As I said, what I do to improve one usually adversely impacts the other. Its frustrating but I haven't given up yet...nor do I intend to do so.

Just downloaded last nights data. On Aflex with setting 8-11. Ramp setting now lowed to 5 with 30 minute timer.

1st observation is I need to bump that 11 setting back up...machine topped out 3 times and failed to address at least one apnea as result. 90% pressure was at 11...same as the max setting.

However, the pressure trace is very instructive on how the ramp performed. When first going to bed I used the ramp and had the usual false apneas with onset. I got up shortly after 4a.m. and used the ramp again upon returning to bed. No events scored during ramp time on this one. So, the trace shows how the ramp behaved both with events and without them.

When the false hypopneas were detected 5 to 10 minutes into the first ramp, the machine immediately responded and raised the pressure from 6 to 9 in less than 10 minutes...holding that pressure from about 15 minutes into the ramp until the end of it at 30 minutes. It scored the events in the daily events per hour...giving a hypopnia index of 10 at a 6 pressure.

When no hypopneas were detected on the second ramp, it performed as expected with a stepped ramp-up from 5 to 8 over the 30 minute period.

It's obvious that this machine responds to events during the ramp period... in an apparently restricted manner. Same as before, the pressure goes 1 cm above the minimum machine setting to a 9 on an 8-11 setting. It would appear that the allowable maximum pressure during ramp is related to the actual settings as two nights ago with an 8-15 setting and the ramp set to 8...it allowed the pressure to rise to 10.

My machine is a relatively new one. Is it possible that Respironics has modified the algorithm since the initial release of the machine? Perhaps due to liability issues to demonstrate some response to events during the ramp-up. Just a thought.