My First CPAP and ASV Experience

[Rundgren]

I had a sleep study done a few weeks ago at Washington University's (St. Louis) sleep center. I didn't sleep very well, but the doctor said I had both obstructive and central apneas. I don't know the numbers, but apparantly they weren't severe enough to start me using a mask during my first study, which they do in some cases. I went back yesterday for a titration study. According to the technician, first they used a regular CPAP and then they used an ASV. I seemed to sleep pretty well with the CPAP but not the ASV. At first I used a nasal pillow mask, but it seems like after I woke up the first time, it would cause me to open my mouth every few minutes and gasp for air and get this weird unpleasant rush of air from the mask and it kept me from sleeping. So they switched me to a full mask, which was not very comfortable (they tried two different ones). What I'm not clear on (I had taken zaleplon and was sort of groggy) is that I think the mouth gasping thing with the nasal pillow may have started when they switched me over the the ASV. Which brings me to the ASV. I didn't like it at all. I would start to doze off and it would wake me right back up. It seemed like the pressure was very strong. It seems like it would do about roughly five respirations and then give me one big one that felt like too much air, almost like I was suffocating or something. The thing is, if I need a machine to breathe for me in and out like that while I sleep, I don't want it beforehand when I'm trying to fall asleep. It's not comfortable at all, especially the big burst of air every minute or two. I don't know how this stuff works, I'm kinda flying blind, but I'm supposed to hear from the doctor later today about the results of the study. Maybe I can just use the regular CPAP with the nasal pillows for a while and see what happens. Anyway, I don't really have any specific questions yet, other than does that sound normal for an ASV?

[Rundgren]

Actually I just read something in another thread (linked below) that is similar to what I'm talking about with the ASV, it seems "violent and unnatural" and "feels like someone jammed one of those old fashioned bellows into my mouth and started rhythmically pumping".

viewtopic/t108920/Anyone-use-ST-or-ASV- ... e-wST.html

[Julie]

Don't judge what your Cpap/ASV experience might be like at home by the study, because they purposely try you out at extremes then to get 'baseline' figures for future records. What happened there is not what will happen at home, but unless they test for limits of your OSA they won't know how to prescribe what pressures you need for the machine.

[metsfan302]

Last night I started ASV. I too have obstructive apnea and alot of central apnea.... This IS the machine I NEED. Yes its a weird feeling I do understand what your saying, but pressures can prob be adjusted and the machine will get a feel for how you breath is how I understand it.....

I went from 50+ahi's on my cpap to I think a 7.1ahi last night on my ASV.

Hope it works out for you and that you get the theropy you need. Welcome to the forum, its a great place! I would not of known what Central Apnea was, ASV, lmnop or anything till I found this place.

Eric

[JDS74]

Rundgren:

Could you post your equipment in text mode using the User Control Panel entry?
If you select your model of ASV machine and it doesn't show up on the Preview screen, you will need to make a text entry in the signature line - some of the machines don't show up and that's the way to do it. Mine is that way for example.

If you don't already have copies of your sleep study report as well as the scrips for your machine and your mask to have so you can refer to them as necessary.

Next, because ASV machines react much more quickly than other types of CPAP machines, they sometimes will switch into ventilator mode (that's the high pressure you are feeling) at the slightest hint that you are experiencing a central event.
That can be caused in different ways:
During sleep transition similar to what you are reporting, sometimes a pseudo-central will occur as your body is switching between blood CO2 level controlled breathing to blood O2 level controlled breathing. That can cause a short but temporary cessation of breathing while your body adjusts.
Sometimes the patient is "observing" their own breathing patterns and this causes an irregularity in breath duration and interval.
Sometimes when rolling over in bed, the patient voluntarily stops breathing until the movement is over.

For any of these, the ASV can react and begin treating the perceived central event and to stop the initiation of a cluster of events.

You can try a couple of things to ameliorate this happening to you. Check and see if your machine is set to some fixed back-up rate and re-set it to auto if that is the case. If, on the other hand, it is already set to auto, then try setting it to a low number like 6 or 8 to reduce the ASV's algorithm kicking in quite so fast.
Or, you can try setting the ramp time to a number that is a little longer than the reported sleep onset time reported in your sleep study (another reason to get a copy of your sleep study if you don't already have one.)

Over time, you will get used to the way the machine behaves and this kind of event won't be much of a bother if you notice it at all.

[klv329]

What machine did they test you on? the s9 asvauto mode can be a bear if the settings are wide open. i suppose the respironics can be too if wide open.

i tried asvauto once on the S9, and it gave me a good epap setting estimate that is close to what i still use in straight asv mode, but i lowered the top end a bit.

yeah, that asvauto mode, I woke up in the morning when i get more CAs and it was like a freight train of air going up my nose -- quite an eye opener I'll never forget. I suppose i could limit the settings to a nice range and the asvauto would be fine and perhaps quite beneficial. But I tried asv mode (fixed epap, variable ipap) with a min PS under 1 which seems pretty gentle to me and works well for me, and of course your mileage may vary.

[Rundgren]

Thanks guys. I did talk to the doctor today and I will be a getting an ASV machine sometime in the next week. She said I did sleep two hours with it and had 20 minutes of dream sleep. She said when they tried the CPAP first, I slept but was still having centrals which woke me up, even though I don't remember waking up. I guess I will know more when I get the machine and can figure out the settings. Also, I will call them to request a copy of my study.