CPAP versus Auto PAP

[barry15]

I used a Resmed Autoset T machine for 8 years, and I recently got a Respironics System One Auto machine. I had always assumed that using an Auto machine was “better” than using a constant pressure CPAP machine, because the Auto one could provide different pressures at different times and for different conditions (like sleeping position, degree of congestion, etc).

I have seen comments here on the forum that some people prefer to use constant pressure (CPAP) rather than Auto Mode (APAP), but I haven’t seen any explanations of why they have that preference. Is it because they think they get better therapy with CPAP? Is it more comfortable for them? Do they feel like they sleep better? Does it help with mask leaks? I would be very interested in any comments anyone would like to make on the subject of CPAP versus Auto PAP.

One reason I am asking the question (or questions) is that I have been looking at my recent data closely, and I see things I don’t understand. Looking at the detailed breathing waveforms for particualr nights, I often can’t see why my pressure was increased at any particular time (sometimes there have been no “events” or anomalies in the breathing waveform). I also notice that I tend to have more events when the pressure is at the high end of my range, as opposed to the lower end. At first, I thought that was because the pressure had been raised in response to those events, but when I look closely, it seems like just as often, there had been no events, the pressure went up, and then the events (hypopneas especially) would start. I plan to do a whole lot more experimentation with pressure ranges, but in the meantime, I thought I would try to learn what I could from other people’s experiences, to help guide my experimentation.

One last subject. When switching from Auto mode to CPAP mode, what pressure would be a good place to start? My minimum set pressure, and see what happens? I spend well over half the night at that pressure now. The maximum set pressure? The average pressure (averaged over a number of nights, of course)? The 90% pressure? Is there any accepted protocol for determining one’s CPAP pressure, based on the history of Auto results? Normally, one might just use the pressure one was titrated at, but my only titration sleep study was done over ten years ago, and I slept so little that the information it provided was almost useless. It is my intention to do my own experimenting, to find what works best for me. Any advice?

My current pressure range is 6.0 to 8.5. My average pressure for the last week has been about 6.5. The 90% pressure has been about 7.5. Some nights it goes to the maximum of 8.5 for short times, and some nights it never does. I have slept pretty well and my event scores are pretty good (AHI has been about 5 on average, but many or most of my events have been while I was awake; that is, falling asleep or about to get up.)

Thanks for any advice.

Barry

[BleepingBeauty]

I used a Resmed Autoset T machine for 8 years, and I recently got a Respironics System One Auto machine. I had always assumed that using an Auto machine was “better” than using a constant pressure CPAP machine, because the Auto one could provide different pressures at different times and for different conditions (like sleeping position, degree of congestion, etc).

That's true, and many share that POV.

I have seen comments here on the forum that some people prefer to use constant pressure (CPAP) rather than Auto Mode (APAP), but I haven’t seen any explanations of why they have that preference. Is it because they think they get better therapy with CPAP? Is it more comfortable for them? Do they feel like they sleep better? Does it help with mask leaks? I would be very interested in any comments anyone would like to make on the subject of CPAP versus Auto PAP.

Any or all of the above. For many of us, auto-titrating pressure can be disruptive to good sleep. Some people wake every time the pressure changes. For others, increased pressure means increased leak, increased discomfort, and/or less effective therapy.

One reason I am asking the question (or questions) is that I have been looking at my recent data closely, and I see things I don’t understand. Looking at the detailed breathing waveforms for particualr nights, I often can’t see why my pressure was increased at any particular time (sometimes there have been no “events” or anomalies in the breathing waveform). I also notice that I tend to have more events when the pressure is at the high end of my range, as opposed to the lower end. At first, I thought that was because the pressure had been raised in response to those events, but when I look closely, it seems like just as often, there had been no events, the pressure went up, and then the events (hypopneas especially) would start. I plan to do a whole lot more experimentation with pressure ranges, but in the meantime, I thought I would try to learn what I could from other people’s experiences, to help guide my experimentation.

Can't help you there, as I'm unfamiliar with the new PR1 machines and the data they produce.

One last subject. When switching from Auto mode to CPAP mode, what pressure would be a good place to start? My minimum set pressure, and see what happens? I spend well over half the night at that pressure now. The maximum set pressure? The average pressure (averaged over a number of nights, of course)? The 90% pressure? Is there any accepted protocol for determining one’s CPAP pressure, based on the history of Auto results? Normally, one might just use the pressure one was titrated at, but my only titration sleep study was done over ten years ago, and I slept so little that the information it provided was almost useless. It is my intention to do my own experimenting, to find what works best for me. Any advice?

I'll leave this one to the more experienced members, like Wulfman.

My current pressure range is 6.0 to 8.5. My average pressure for the last week has been about 6.5. The 90% pressure has been about 7.5. Some nights it goes to the maximum of 8.5 for short times, and some nights it never does. I have slept pretty well and my event scores are pretty good (AHI has been about 5 on average, but many or most of my events have been while I was awake; that is, falling asleep or about to get up.)

Thanks for any advice.

Barry

Just so you know, the 90% pressure figure is misleading. Most think it means they spent 90% of the night AT that pressure; what it really means is they spent 90% of the night AT OR BELOW that pressure.

Your pressure range is very tight (6.5-8cms), and you say you're spending well over half the night at the low setting. You could certainly start your CPAP experiment there and see how it goes for a week. If you're still having too many events, then try 7cms, and so on.

I'm sure other (more experienced members) will chime in with their advice. Good luck, Barry.

[bdp522]

I use one set pressure because my sleep was being disrupted everytime there was a pressure change. I also found that with a range of pressures, the machine was chasing snores-I'd snore the pressure would increase, I'd snore again, the pressure would increase again. I find that I sleep very well (and snore less) at one set pressure.

Brenda

[barry15]

Thanks for your comments, BleepingBeauty. You mentioned that my range is narrow, and I hadn't thought of it in that way. One of the things I am considering is to just continue to narrow it, approaching a CPAP situation, if the results stay good.

Brenda, thanks for sharing your personal experience. That is exactly the kind of thing I wondered about. I guess I won't know unless I try it, and I plan to do just that. Sometimes I wonder if my machine is "chasing hypopneas", to put it in the term you used, and I wonder what would happen if the pressure wasn't raised at that point.

I would love to hear the experiences of anyone else who has compared CPAP with Auto PAP.

Barry

[Wulfman]

If you're still getting AHIs of around "5", it sounds to me like your pressure is too low.
Personally, I don't know if I could handle pressures that low.


Den

[jmelby]

I recently had some experience with trying CPAP instead of APAP... see this thread:

viewtopic.php?f=1&t=48099&st=0&sk=t&sd=a

Basically, the sleep technician used my 95% pressure and rounded it to determine my CPAP pressure. However, this didn't work out all that well for me. My AHI increased, and I didn't feel I got very good sleep the nights I was on CPAP instead of APAP. I still don't know if was because the pressure bothered me, or if it was that the machine would have adjusted over my fixed pressure at some points in the night. I doubt it was due to central apneas being caused by the higher pressure all night since the AHI was made up of mostly hypopneas. Since I did well on APAP, with an average AHI just under 5, I switched back to APAP.

[ozij]

If you're still getting AHIs of around "5", it sounds to me like your pressure is too low.
Personally, I don't know if I could handle pressures that low.


Den

I can't handle pressure higher than 8.5 on exhalation.... it really is something personal.

Since the "The 90% pressure has been about 7.5" I'd start with that for fixed.
Does the PR1 give you a "time at pressure" chart?

I doubt it was due to central apneas being caused by the higher pressure all night since the AHI was made up of mostly hypopneas.

That can also be a response to too much pressure.
O.

[barry15]

If you're still getting AHIs of around "5", it sounds to me like your pressure is too low.
Personally, I don't know if I could handle pressures that low.


Den

Well, most of my "events" happen when I am awake, trying to fall asleep. Those dont' really bother me at all, although maybe I should be concerned about them. If I took out the ones that occur when I am awake, my number would be more like 2. Also, the vast majority only last for 15 to 20 seconds, with a very few up to 30 seconds, and I think that is favorable, too, although I don't know how long apneas and hypopneas last in other people, so I would be happy to get feedback on that. I also have more hyponeas than apneas, and I think that matters, too.

As for the pressure being too low, I have some data from many years ago that I have more "events" at higher pressures than at lower ones - that could be because the machine I was using then (Resmed Autoset T) didn't distinguish between Central Apneas and Obstructive Apneas, and I have read a number of times that higher pressures can bring on Central Apneas. I am only guessing there, though. What I do know is that I used to have worse AHI's at higher pressures.

There was a time when I couldn't fall asleep at a pressure of 6, as it seemed like I just needed more air than that or something, but that has changed in the last year. I had my old machine set to a range of 8 to 10 for a number of years. I have lost 70 pounds in the last 8 months, and I have found that the pressure I need has dropped. Now my pressure stays at 6 for most of the night, sometimes, and I sleep pretty well (when nasal congestion doesn't get me too much). I plan to try even lower pressures, to see what happens, and I also plan to narrow my range of pressure and probably try a continuous pressure eventually. I don't know where I will end up, though, and I will certainly try higher pressures as well, to see if my AHI drops. I prefer lower pressures if they are effective, though, because of mask leaks and because I think that less pressure is better, in general.

As far as the actual number, "5", it is hard for me to understand how significant the actual number is, based on what I have read here. Others have asked that question recently, and I have read all the answers carefully, and I just don't know how important a particular number is. I am certainly interested in any feedback I can get, though, and I thank you for your comments, Den.

Barry

[ozij]

Well, most of my "events" happen when I am awake, trying to fall asleep. Those dont' really bother me at all, although maybe I should be concerned about them. If I took out the ones that occur when I am awake, my number would be more like 2. Also, the vast majority only last for 15 to 20 seconds, with a very few up to 30 seconds, and I think that is favorable, too, although I don't know how long apneas and hypopneas last in other people, so I would be happy to get feedback on that. I also have more hyponeas than apneas, and I think that matters, too.

My apneas, on a ResMed, are frequently 10 secs long. I think shorter event are better.
And do I understand correctly from your post that the PR1 reports length of time in hypopnea?

[barry15]

And do I understand correctly from your post that the PR1 reports length of time in hypopnea?

With the Encore Pro 2.2 software, there is a "Waveform report" available. It only seems to keep the waveform infromation on the card for the last night, or maybe two nights, but I have been saving them as pdf files, so I can refer back to them. That means I have to download the card every day. It also appears to save them in the database on my computer, after I download them.

This Waveform Report shows your breathing "waveform", by which I mean it shows each breath and its magnitude, like a chart recorder, if you know what that looks like. Today I discoverd that it actually only keeps the last 8 hours of sleep time and dumps the beginning, if you sleep longer than 8 hours. The report has 9 pages - a cover sheet and a page for each hour, broken down into 6 minute segments per line. Each "event" is indicated, as are Periodic Breathing and High Leaks. It also shows where the pressure went up or down, although you can't really read the numbers for the pressure off that particular chart. So, a hypopnea shows the magnitudes of the inhale and exhale decreasing and then returning to normal. In an apnea, the breathing pretty much damps down to nothing. Across the long way of an 8.5 by 10 piece of paper (or your screen), there are six minutes shown, so it is like an inch and a half a minute. You can determine the length of the events by scaling them to the minute marks shown on the chart. It is approximate, and you have to decide when you want to count the beginning and the end of the event. If I knew how to post pictures here, I would post a page of one of the reports. I find them fascinating, and I am still learning more about them. There is an incredible amount of data there, which is right up my alley. I look at them in concert with the "Detailed Report" for that night. I can tell when I fall asleep and when I wake up, because the amplitude of my breathing is higher when I am awake than when I am asleep. It is easy to see times of "disturbed sleep" from time to time, and long periods where is is just as regular as anything, chugging right along.

It is probably too much data, actually, and I am probably trying to read too much into it, but it sure is fascinating to be able to look at each breath I take for 8 hours. The various events are identified in different colors and with labels, CA, OA, H, RERA, etc. One of the things I don't understand is why the machine raises the pressure sometimes when there have been no events for several minutes, at least. It also makes it obvious when the events occur at a time when I am awake, because the waveform tells me I am awake, from its amplitude.

I am still discovering things about this report, and I expect to learn a lot more in the future, as I correlate things to changes that I plan to make (pressure, Flex settings, Humidifier settings, etc).

Barry

[KatieW]

Welcome to the forum, Barry. My experience is that I do better on CPAP.

I was titrated at 7, so set my APAP at a minimum of 5, maximum of 8 with exhale relief of 3. I gradually raised the range to 8.4/10 over a period of 7 weeks. At that point I was responding well to therapy, but 1 out of 4 nights, was still "hitting my maximum" and having clusters of apnea which woke me up. When I raised my maximum to 11, I had severe pain from aerophagia (gas), so I was reluctant to go above a maximum of 10.

As an experiment I tried straight CPAP, starting at 10, which I knew I could tolerate, with exhale relief of 2. After 2 weeks, I bumped it up to 10.2, which felt comfortable, and no aerophagia problems.

Before and after numbers:

On APAP, Nov 5 to Dec 5: AI .6, HI 4.5, AHI 5.1

On CPAP, Dec 6 to Jan 11: AI .2, HI 3.1, AHI 3.3

I don't know if these numbers are statistically significant. But I know I sleep more soundly, and feel better rested.

[barry15]

Welcome to the forum, Barry. My experience is that I do better on CPAP.

I was titrated at 7, so set my APAP at a minimum of 5, maximum of 8 with exhale relief of 3. I gradually raised the range to 8.4/10 over a period of 7 weeks. At that point I was responding well to therapy, but 1 out of 4 nights, was still "hitting my maximum" and having clusters of apnea which woke me up. When I raised my maximum to 11, I had severe pain from aerophagia (gas), so I was reluctant to go above a maximum of 10.

As an experiment I tried straight CPAP, starting at 10, which I knew I could tolerate, with exhale relief of 2. After 2 weeks, I bumped it up to 10.2, which felt comfortable, and no aerophagia problems.

Before and after numbers:

On CPAP, Nov 5 to Dec 5: AI .6, HI 4.5, AHI 5.1

On APAP, Dec 6 to Jan 11: AI .2, HI 3.1, AHI 3.3

I don't know if these numbers are statistically significant. But I know I sleep more soundly, and feel better rested.

Hello Katie,

Thanks for sharing your experience. That will help me decide what I should try. I am a little confused, though, as you say that you do better on CPAP at the beginning, but at the end, it appears that your numbers are better on APAP, although not necessarily statistically significant, as you point out. Is there any chance that you have reversed the labels "CPAP and APAP" at the end of the post? That would make more sense to me, based on what you wrote. Are you currently using CPAP or APAP, and which did you use from Dec 6 to Jan 11?

Barry

[KatieW]

Is there any chance that you have reversed the labels "CPAP and APAP" at the end of the post? That would make more sense to me, based on what you wrote. Are you currently using CPAP or APAP, and which did you use from Dec 6 to Jan 11? Barry

Sorry for the confusion Barry. I wrote my post, when it was past my bedtime. Yes, I am currently using CPAP, from Dec 6 to Jan 11. I edited my original post.

[LinkC]

My sleep doc explained to me that she didn't like APAP because it REQUIRES apnea events to work. It starts out at a level known to be too low to catch all events, then bumps up as events occur to an effective level. Once no events are occurring, it backs off until they do. And the cycle repeats throughout the night, allowing totally unnecessary events to occur.

I understand the argument that it changes pressure in response to needs, thereby providing a lower average pressure. But, unless you are subject to pressure-indued centrals, I don't see any real advantage there. And, as has been said, some people are bothered by the constant pressure changes.

With the concurrence of my doc, I normally use CPAP at my 90% pressure. Every 6 months or so (sooner if I feel any change), I do a week on APAP to confirm my 90% hasn't changed. I rarely have an AHI higher than 1.0...and my AI is 0 about 30% of the time (meaning my AHI is mostly hypopneas). I have far more apneas during my "self-titration" week on APAP than I normally have on CPAP, which is why I do that so rarely. It just seems to me that any apnea I prevent is a good thing, as the results are cumulative.

I also understand some get better numbers on APAP. I've never heard any explanation how that could happen, but I'll take their word for it.

[drubin007]

I started on a cpap and at my 3 month follow up I requested to be changed to an apap to try and improve upon my therapy.

I still feel the same, but then again never knew I had an issue. It took a hard copy of my sleep studies to convince me that I do need to be on a cpap...

I think you are getting a lot of good opinions on here, and not much I could really contribute.

To me, personally, I think apap is better as it will chase events. with a cpap it is a constant pressure, may be overkill if your body does not need it...When I started with the cpap I would record my info the following morning and every week make adjustments in pressure to try and acieve the best results.

now with the apap machine, I review my information once a month and determine if any changes are warranted based on that. I think the apap would be more effective though because it will increase/decrease as needed, but as some others in here have said, it wakes them up. I guess im spoiled with my F&P as it makes breathing easier!