Respironics AutoSV Advanced acting up?

[ameriken]

I started using this machine about 2 weeks ago for OSA, CSA, and other SBD's. When I am falling asleep, I like how it responds to and assists my breathing. When I inhale, it increases pressure and when I exhale, it decreases pressure. However, I've recently noticed something that I don't know if is normal, or a possible problem with the machine.

It occurs after I've slept for a few hours. I'd wake up, look at the time (maybe 330 or 4 am) and then try to fall back asleep. That's when I notice the machine seems to be 'fighting' me a bit. Instead of responding to my breathing like it normally does, it seems to force an inspiration when I am not ready to inhale, and then it forces an expiration when I am not ready to exhale. When I am still exhaling it is pushing pressure for me to inhale, and then vice versa. It seems as if it has a pattern it is forcing me to follow, rather respond to and working with my own breathing pattern. In fact it almost felt like it was pulling air out of me when I was trying to inhale. It is just not responding to my breathing the same way it did when I first went to bed. It seems to want me to follow it's pattern rather than vice versa. This morning, after fighting with it a little while and trying to adjust to it, I finally fell back asleep and later when I woke up it was again performing normally and felt great.

I called the DME and they weren't sure what was going on and said to unplug it, plug it back in and see what it does the next nite. I did that yesterday and it did the same thing this morning.

Are there any users of this machine that may know what I'm talking about? Is this something normal, or does it sound like there could be a problem with the machine?

[BrianinTN]

Does it seem to "stop" fighting you after a few minutes? If so, you're probably in normal territory. Many of us have a faster breathing rate when we sleep than when we are awake. If your backup breathing rate is set to "Auto," you may be awakening to exactly what it's doing while you sleep -- which is what your body had been telling it to do for the past few minutes.

[Mr Bill]

Yes. Mine sometimes does the same thing. Awake I breath 8-12 times a minute. Asleep, we are zinging along at 18 BPM. My guess is that since we have centrals and are hypocapneic (low CO2 in our blood and lungs). Having a smaller tidal volume when sleeping allows more CO2 to remain in our lungs and help us trigger our own breaths. I think the closed loop logic of the ASV homes in on the tidal volume and corresponding BPM that optimizes our our percentage of initiating our own breaths.

[ameriken]

@ Brian and Mr Bill, thanks for answering. Brian, yes...either it seems to quit fighting me or I quit fighting the machine because after a while I fell alseep again with it. What bothered me was how abrupt the machine seemed to be after I woke up and wanted to go back to sleep. However from your answers and knowing that yours does the same exact thing Mr Bill, I guess it's doing exactly what it was designed to do. Thanks again.

[JohnBFisher]

Greetings! The Respironics ASV unit does seem to behave that way. I find I fight more with it than with the Resmed ASV unit. However, the same thing can happen with that unit.

Essentially, the unit remembers what your breathing pattern was for the past three minutes (or so). This informs the machine how quickly you should breathe. However, when you awaken your breathing pattern would normally change (we use different mechanisms to drive our breathing when awake and when asleep). Thus, once awake you breathe more slowly. As a result "it seems to force an inspiration when I am not ready to inhale". After a few minutes, it should adjust to your new breathing rate.

However, if you find it is a "struggle to the death", you can do what I do and cheat. Just turn off the unit and turn it back on. That resets what it remembers about your breathing pattern. It's a simple solution when you and your machine are not going to get along.

Here is a description of Resmed's ASV algorithm. Respironics has some differences, but they are fairly similar:

http://www.resmed.com/assets/documents/ ... ow_eng.pdf

[ozij]

Greetings! The Respironics ASV unit does seem to behave that way. I find I fight more with it than with the Resmed ASV unit. However, the same thing can happen with that unit.

I'm puzzled by something, John.

On another thread, you described the ResMed ASV as a harsh taskmaster.

And yet here you say you fight more with the Respironics machine.

Could you explain the difference to me - a person who has never experienced an ASV if any kind?

Thank you,
O.

[JohnBFisher]

Greetings! The Respironics ASV unit does seem to behave that way. I find I fight more with it than with the Resmed ASV unit. However, the same thing can happen with that unit.

I'm puzzled by something, John.

On another thread, you described the ResMed ASV as a harsh taskmaster.

And yet here you say you fight more with the Respironics machine.

Could you explain the difference to me - a person who has never experienced an ASV if any kind?

Thank you,
O.

No discrepancy. Let me use cars to build an analogy....

One car (let's say a luxury car) might have great, comfortable seats. But the steering is "loose". It takes a while for changes you make to the steering wheel to show up in the driving.

But another car (let's say a sports car) has okay, but not as comfortable seats. But the steering is very "tight" and responsive. You barely nudge the steering wheel and the car shoots off in that direction.

It's sort of like that. The Resmed unit IS a breathing task master. The steering is tight. If my breathing gets shallow, it immediately compensates. If I pause, it immediately reminds me by switching to inhalation pressure. Breathe - two - three - four - Breathe - two - three - four ...

So, in this case, with the tight steering, I turn the wheel a bit, and the car reacts. I turn it back, and it reacts. We tend to stay in synch.

But, if the steering is "loose" it is more likely that you will "fight" the car than if it is "tight". I turn the wheel. Nothing happens, so I turn the wheel more. Suddenly the car is turning too far. Now, I need to turn the wheel back. We are fighting one another. We are out of synch.

And that is exactly how the difference between the two ASV units "feels" to me. I tend to go out of synch more readily with the Respironics unit. I tend to stay in synch more with the Resmed unit. Though it is a breathing task master, the "tighter steering" works better for me. I tend to stay in synch when I use it.

Hope that makes sense.

[ozij]

Thank you, John, that explanation makes a lot of sense.

[ameriken]

Greetings! The Respironics ASV unit does seem to behave that way. I find I fight more with it than with the Resmed ASV unit. However, the same thing can happen with that unit.

Essentially, the unit remembers what your breathing pattern was for the past three minutes (or so). This informs the machine how quickly you should breathe. However, when you awaken your breathing pattern would normally change (we use different mechanisms to drive our breathing when awake and when asleep). Thus, once awake you breathe more slowly. As a result "it seems to force an inspiration when I am not ready to inhale". After a few minutes, it should adjust to your new breathing rate.

However, if you find it is a "struggle to the death", you can do what I do and cheat. Just turn off the unit and turn it back on. That resets what it remembers about your breathing pattern. It's a simple solution when you and your machine are not going to get along.

Here is a description of Resmed's ASV algorithm. Respironics has some differences, but they are fairly similar:

http://www.resmed.com/assets/documents/ ... ow_eng.pdf

Thanks for chiming in John and I appreciate the confirmation. I just wanted to be sure there wasn't something wrong with the machine. Outside of those wakeups, I tolerate the machine very well and sleep well with it. I plan on getting software so I can see if it's actually helping my breathing. I also do turn it off and back on now so I can start over if we're not in synch.

[archangle]

If you wake up and are "out of synch" with the machine, try turning it off and back on. Maybe it will start back into the "going to sleep" mode and be more in harmony with you.

[ameriken]

If you wake up and are "out of synch" with the machine, try turning it off and back on. Maybe it will start back into the "going to sleep" mode and be more in harmony with you.

Thanks, lol, you missed the last line of my previous post.

I appreciate it however, that's what I've started doing. What was wierd however, was the first time I restarted it, it continued in the same mode as before I turned it off. I unplugged the machine, plugged it back in, and it started up fine and has been fine since.

[Mr Bill]

Another trick, if your sinuses are a little plugged and you feel like you need more air. Just hold your breath a couple puffs and the ASV will kick the pressure up and you will get the flow you want. It will more gradually reduce that same pressure to whatever works as you fall asleep.

[Paper_Nanny]

What was wierd however, was the first time I restarted it, it continued in the same mode as before I turned it off. I unplugged the machine, plugged it back in, and it started up fine and has been fine since.

When the flex on my machine is off, I don't feel like we ever get in sync, no matter how many times I turn it off and then on again. With the flex set on 2, I usually only have to turn it off and on again once, but somtimes up to three or four times.

Deborah

[dsm]

It is interesting to read that so many of you are feeling this 'bump' when using the ASV. Reason it has caught my attention is that my original model Bipap AutoSV was (and still is) such a good machine in regard to its smoothness in transition from one breathing mode to the other.

Years back (approx 2006) when I obtained my 1st Respironics Bipap (the Pro II). I *did* have big issues with the transition and after a lot of experimenting & trialling three different types of Bipap (bilevel only) machines including a then (2007) current model Bipap S/T, came to the conclusion that people who had nasal congestion or who restricted breathing (like UARS) in their nasal area, would have trouble with those machines. The feature that I believe caused the issues was the Auto-Track algorithm. Self is on Nasonex daily to help with nasal congestion. That has been the case for 4 years now).

Just to illustrate how far I researched this issue, I even purchased the Original (1980s) very big square box Bipap plus a (1980s) Respironics multi-function clinical titration Cpap/Bipap machine plus a (late 1980s) healthdyne BiLevel & tried them. *Not one* of those very old Bipap machines exhibited the 'deficient' transition (Respironics took over Healthdyne as an out-of-court settlement over a bilevel patent infringement case). The only relevant difference between those older machines & the Bipap Pro II / Bipap S/T was the Auto-Track feature.

Then Respironics produced the Bipap Auto and there was a noteable improvement in that breathing mode transition. Then came the original Bipap AutoSV & it was to me faultless in this area.

I am thus rather surprised to hear that there may be a step backward re this issue. But if anyone can confirm that they also have nasal air flow issues, it will be helpful to try to figure out a probable cause (it may be back to Auto-Track changes impacting people with nasal airflow restrictions).

Cheers

DSM

[BrianinTN]

I think this is a pretty isolated issue we're all talking about here -- namely, waking up in the middle of the night. It isn't so much of a problem going to sleep as it is when the algorithms have had the 3ish minutes of data. My sleeping BPM is around 18; my awake BPM is under 10. That's a huge difference. Given the fairly particular nature of the issue we're discussing, it seems like an unintended side effect of improved and more precise algorithms more than a step backward.