Auto vs. Constant CPAP- I am confused

Selena (but really Julie) wrote:Hi - I use a Resp. Auto without C-flex, and I do have a ramp feature and I can use it whenever I want (though it's extremely rare that I do except to reset my pressure occasionally, which is another story entirely). Maybe newer (or older) machines don't have a useful ramp feature, or maybe the C-flex ones don't, but mine does and it does work.

If you're talking about pressing the Ramp button to reduce the pressure instantly to your Minimum pressure setting when you say, "I can use it whenever I want to"...that's true. That's true of any Respironics Autopap. And that's probably what you mean is happening on the occasions you've hit the ramp button. Yes, it does drop back to your Minimum pressure then. But it will stay at the Minimum until it senses from your airflow a reason to raise the pressure. That might happen almost right away, or might not happen for quite some time...all depends on what it senses from you. It won't behave like a traditional ramp which would increase pressure gradually over a set period of time to get up to a certain pressure, regardless of what's happening in the breathing.

A true ramp feature doesn't exist in any of the Respironics autopaps when they are run in auto mode, as far as I know. I used a Respironics REMstar Auto without C-Flex (like your machine, Julie) for almost a year. Later I got a Respironics REMstar Auto after they added C-Flex to their autopap. Neither machine had a real ramp feature in auto mode.

When I say they didn't have a ramp feature, I'm talking about when they were run as an autopap -- in APAP mode (the older REMstar Auto without C-Flex) or in APAP or AFLE mode (the newer REMstar Auto with C-Flex. A traditional ramp feature could be enabled only if they were in cpap mode, or cpap with c-flex.

In both those REMstar machines in their auto modes, there is no true ramp. At least, not in the sense of being able to set a ramp timer for the pressure to gradually build up over time (5 - 45 minutes) which is what people usually mean when they talk about using "ramp".

With the REMstar Autos, old (with no C-Flex available) or new (with C-Flex available) the only thing the ramp button does is drop the pressure back to your minimum pressure setting -- if you are using the machine as an autopap.

Assuming your machine is set up the way it should be, I'm guessing the machine is detecting a flow limitation due to your congestion. You'd have to take a look at the software to know for sure. I don't know what you have C-flex set at, but if it's not at 3, give that a try. It'll give you greater expiratory pressure relief.

Once again RG comes to the rescue. Her explanation is exactly right on. The only thing the ramp button does in the auto mode is to immediately, upon pressing it, reduce the pressure to your lowest level set. I always have a small Maglite flashlite beside me so that I can see the display of the Respironics should something strange to me occur. If you have mask leakage beyond what the algorithm determines is appropriate the machine will increase in pressure until it hits the maximum pressure level you have set. You likely will not see the pressure increases on the LCD screen. At that point it will display dashes on the screen. Pressing the ramp button will lower the pressure down as RG has stated but if you adjust your mask to reduce the leakage, the pressure will also reduce down to your lowest level set or maybe to the last known level before the leak, I'm not sure which as mine has always gone back to the lowest.

Darth Vader Look wrote:If you have mask leakage beyond what the algorithm determines is appropriate the machine will increase in pressure until it hits the maximum pressure level you have set. You likely will not see the pressure increases on the LCD screen. At that point it will display dashes on the screen. Pressing the ramp button will lower the pressure down as RG has stated but if you adjust your mask to reduce the leakage, the pressure will also reduce down to your lowest level set or maybe to the last known level before the leak, I'm not sure which as mine has always gone back to the lowest.

Good point DVL, about adjusting the mask to see if that will settle things back down.

I'll have to experiment sometime with causing a massive leak, because I'm not sure if the machine will run all the way up to the maximum pressure we've set. Maybe it does. I never have a "Large Leak" (that dreaded solid black block on the graph...LOL!!) show up on my Encore Pro data, so I've not had occasion to notice what was going on in the LCD window on the machine.

I do know, from having looked at others' Encore Pro graphs that if a leak massive enough to get marked as an "LL" (Large Leak) occurs, the pressure graph line falls down to the minimum that was set, and stays down there for the duration of the Large Leak situation. I don't recall noticing if the pressure had risen all the way to their maximum setting just before the precipitous drop, though. I'd hope the graph would reflect exactly what the pressure has done during the Large Leak...that it's not going to stay up at the max...not gonna blow our brains out during a "Large Leak". Thank goodness!

The machine also stops recording or responding to events during a Large Leak.

Viva "tape".

Here's one test I do RG. I turn on the unit and let it work away into the air. I'm not sure if the pressure does go right up to my preset high pressure level of 12cms but it does feel like it. The only way to really check that is to read what is output by the processor to the motor using a scope or logic analyser. But even if the pressure does increase as many have posted, the higher the pressure the more leakage would take place and your brains would remain intact . In fact I would think that the treatment pressure with a large leak would be pretty much nil. Something to fiddle around with I guess.

The Ramp down button has always been used to reduce pressure even on the earliest Remstar Auto models, but there are different functions for that Ramp button, it all depends on the mode the machine is currently in, if it is blowing or not blowing on how it functions:

AUTO/AFLE modes: when the Remstar Auto is in one of the available auto modes with air blowing, hitting the Ramp DOWN button will reduce the current pressure where it will automatically increase the pressure during the night to meet your needs.

with airflow off, hitting the Ramp Down button accesses the Patient Menu to verify settings.

CPAP/CFLE modes: when the Remstar Auto is in one of the available cpap/cfle modes with air blowing, hitting the Ramp DOWN button will reduce the current pressure to the minimum or LOW pressure setting value where it will automatically increment back up to prescribed pressure based upon any timer value established.

As stated, there is NO RAMP (or Ramping UP of pressure) feature available in ANY of the auto modes. Hitting the Ramp Down button in those modes ONLY reduces the current pressure but it will automatically increase back up to meet your needs during the night.

As for Large Leak actions, instead of guessing I suggest one take out the User manual and read it. It does NOT increase pressure to the maximum level, after continuous leak for 45 seconds is detected it triggers the Patient alert circuit if enabled, with alarm beep and will shut off. With the Patient alert disabled it does not beep, it simply shuts off. Stupid feature I know, but you cannot have a machine that would increase pressure, if the patient developed a large leak, machine ramped up pressure and the patient rolled over essentially stopping the leak suddenly, it could blow a central apnea. As a result, the Remstar Auto does a very good job in all aspects of avoiding central apnea even with large leaks.

NightHawkeye wrote:

beneyw wrote:Why did the machine not re-adjust to my needs and yet remain at a pressure of 10.0 cm. when I was not asleep? Is that how the AUTO works, once it reaches the maximum pressure I need shouldn't it automatically re-adjust downward during a wakeful period of time?

Beneyw, I'll answer your question, but first I'll explain the likely sequence of events for this thread:
1) question involving Respironics algorithm is stated (i.e., your question)
2) a possible explanation is offered
3) numerous statements are made that Respironics algorithm is so close to perfect no one could notice any adverse effects
4) thread degenerates quickly into tangential issues, emotional harangues, and vicious personal attacks as vested interests attempt to diffuse any direct discussion of the issue

(Please understand that this discussion forum is open to all and that some posters here are seriously vested in white-washing certain topics.)

beneyw wrote:Could there have been leaking I was not aware of to cause the highest pressure yet recorded after 2 months of machine use or are there other things I should be considering? I know one thing, the 10.0 cm. of pressure was too much for me to nasal exhale.

Yes, and as a practical matter, I think you would be well advised to monitor your therapy and try to understand what happens to cause the pressure increases. What I observed WHEN I USED A REMSTAR-AUTO was that 1) nasal congestion caused uncontrolled pressure increases, and 2) leaks caused uncontrolled pressure increases.

Are other machines any better? Beats me. I've never used anything other than Respironics. What worked for me was nightly nasal irrigations and careful control of leaks. As near as I can tell, taking these actions works for others as well. Again, I'll say that monitoring therapy with software is likely to help you understand and deal with this. Also, you should probably also consider alternative machines, however painfully expensive that prospect might seem. The major manufacturers APAP algorithms are significantly different from each other so that even if one causes problems for you, the others might not.

Hope this helps.

Regards,
Bill (just telling it like it is)

Guest, here are the facts:

- 22 posts were made in this thread
- exactly one was mine
- I pointed out exactly four things for beneyw to look into; congestion, leaks, monitoring software, and other machines
- beneyw indicated that congestion was a problem, leaks were not, would rely on DME to read Smart Card, and chose not to investigate other machines
- numerous tangential issues have been discounted by beneyw

I don't know about you, Guest, but I shall be interested in seeing what beneyw finds helpful to his situation. It is, after all, his unique situation. The rest of us are merely speculating and trying to offer helpful suggestions. Naturally, with 22 posts, some are more useful than others. (I have no expectation that my post was more useful than others.) Sorry if this process offends you at times.

Good luck to you, beneyw.

Regards,
Bill