CPAPtalk.com

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.

Your doctor has a reasonable rationale, but my doctor disagrees. Is it possible to have the same results every single night? This is unlikely, as sleep conditions change with positions, how big a meal one ate, how one is feeling (e.g. sinus congestion), etc. If you post your data, I am sure you have SOME events, but they may be variable from one night to another. My doctor says that this is why autopaps respond better to the changing needs of sleep from one night to another. In his opinion, and he's very experienced in sleep disorders, sleep is a fluid situation, which varies from night to night. Unless you build a wall around yourself in bed, eventually you will end up on your back sometime, and there goes a change in AHI right there, and in pressure needs. I bet that with your vigilance, you have a good titration, but it it perfect? No, as it is subject to change every night.

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.

There is a huge advantage, if an individual is subject to spikes in pressure that are intermittent, and variable. I am one such person, and occasionally, I will get a spike of a 11 or 12, even once a 13 on a 'bad night." If I were set at my 95% pressure (that is 9.5), those occasional spikes would not be treated, and I'd have apneas that are not being chased, but ignored completely. A lot of folks on this board seem to get variability and spikes on a given night,

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.

Your position is known and understood, and clearly, you're following your doctor's advice. My doctor gave me the opposite advice, as situationally, the structure of my sleep isn't so regular that one set pressure can prevent all apneas. Also, the comfort factor of having my pressure for 95% of the night at a lower number, and still achieve successful therapy is important to me. I do feel rested, and have a fairly low AHI (normally 1-2), and few apneas, with an occasional hypopnea that my machine successfully catches and treats. For you, obviously a fixed pressure seems to work better. For many of us, it doesn't, as our sleep isn't as uniform as yours seems to be. You're lucky that a fixed pressure catches all events, but I am skeptical about that---it would be logical that there would be some night to night variances.

drubin007 wrote: 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...

If the APAP "chased events" to that level, how can it be "overkill"? It's the level YOUR body needs to prevent YOUR events.

And, allowing that it may be higher than absolutely necessary, at some time during the night, so what? What's the harm?

(Not trying to be argumentative here...just stimulating logical thought. )

Thanks everyone. You have given me some ideas, and I appreciated hearing the different opinons, and especially the reasons you do what you do. I'm leaving on a trip this morning, so my experiments will be suspended for a week, but when I get home, I'll try a number of things. I haven't noticed that the pressure changes of APAP bother me, but it has been about 8 years since I tried straight CPAP. I will certainly give it a try, after I learn a few more things from my experiments. It sounds like it varies from person to person, so trying it seems like the best next step.

I won't be able to check my data while traveling, as I haven't been able to install Encore Pro onto my laptop, so I will just go with what has worked best so far. That is a pressure range of 6 to 8.5, no Flex, Humidifier at 1, and my full face mask. In general, my nose is much less congested when I travel, so I will take along my nasal mask and maybe try that on the trip. I have more problems with leaks with the full face mask, but it seems to help with nasal congestion, which is why I have been using the full face mask recently.

If anyone else wants to offer an opinion, I will be checking here while on my trip, so go to it. Now I am off to play airport games with my laptop and CPAP machine - I wonder what twists they will be offerring this week at the security check points.

Barry

I'm not familiar with the exact mechanisms that APAP machines use to determine if pressure needs to be increased, but I'm pretty sure it is not simply responding to apnea events. In fact, I thought I had read on some threads in this forum that it is specifically NOT responding to apnea events, but things like snoring and flow limitation--which occur prior to an apnea event. So, I don't think the logic that you will necessarily get apneas using APAP is correct. I also think it varies by machine manufacturer... my sleep tech said they believe the algorithm in the ResMed machine is generally more effective than that of other manufacturers they had experience with.

I switched to an APAP machine last June. I'm still trying to dial it in. In my case it turns out that I have good weeks and bad weeks and trying out settings for less than two weeks at a time isn't very productive. I am using a spreadsheet to track my settings and daily results.

I started with straight CPAP and tried to find the single pressure point that was most effective. After that I went to auto mode with a narrowly defined range. I ended up at 12.0 to 12.5 and stayed there for quite a long time. This helped me to see how much my therapy effectiveness is swinging.

Now I'm trying a wider range (11.5 to 14.5) to see if the extra range will have an impact. My results on average are about the same but I haven't had the really good nights or really bad nights either. I'm about to shift my range a little higher and see what happens.

The change in pressure doesn't seem to bother me so I'll probably stay with auto mode, just a matter of finding the proper range for me.

Bottom line is that you need to find what works for YOU. For me I think it's pretty clear that auto is best.

Autopapdude wrote: I am sure you have SOME events, but they may be variable from one night to another.

Well, of course I do. Every apneac does. The goal is to minimize them.

Autopapdude wrote: There is a huge advantage, if an individual is subject to spikes in pressure that are intermittent, and variable. I am one such person, and occasionally, I will get a spike of a 11 or 12, even once a 13 on a 'bad night." If I were set at my 95% pressure (that is 9.5), those occasional spikes would not be treated, and I'd have apneas that are not being chased, but ignored completely.

By the time your machine "chases" an event, it's already happened. Neither mode will eliminate all of those.

Autopapdude wrote: You're lucky that a fixed pressure catches all events, but I am skeptical about that---it would be logical that there would be some night to night variances.

It doesn't always get them all. And I have a fair amount of hypopneas. But I've had 3 nights of 0.0 AI in the past week. (Not that one person's results are indicative of anything!)

I may try a few nights of APAP @ low=90% pressure/hi=20cm just for kicks. What can it hurt if there are no "spikes" to drive it above my normal 90%??

It doesn't always get them all. And I have a fair amount of hypopneas. But I've had 3 nights of 0.0 AI in the past week. (Not that one person's results are indicative of anything!)

I may try a few nights of APAP @ low=90% pressure/hi=20cm just for kicks. What can it hurt if there are no "spikes" to drive it above my normal 90%??

That is great! Seriously, I am glad that your AI is 0.0. I have had similar results--an extremely low apnea rate, approaching zero. Once again, my hypopnea rate is what is most of my AHI--of the 1-2 average AHI, .8 to 1.8 is hypopneas. When I get the "spikes," it is usually a cluster of hypops during REM sleep. However, for the majority of the night, my pressure is 9-9.5 or below. That is why my 8.5-14 works nicely. I doubt that any machine would get all of the events, no matter how hard we tried, whether or not it is at fixed or variable pressure. I do feel that the advantage is that an autopap can deal with non-static conditions, and while not preventing them, it helps to curtail additional ones from happening.

Beats the heck out of the 96 AHI from my sleep study (and likely what I'd had for several years before diagnosis!)

Beats the heck out of the 96 AHI from my sleep study (and likely what I'd had for several years before diagnosis!)

That is for damn sure! My diagnostic AHI was 67, but I would not be surprised if it was even worse. Isn't it interesting that we've all come a long way, if you think about it. Even if we have disagreed on message before, we're all in the same place--getting treated successfully, being intelligently informed about our illness, and being responsive and proactive.

Autopapdude wrote:

I may try a few nights of APAP @ low=90% pressure/hi=20cm just for kicks. What can it hurt if there are no "spikes" to drive it above my normal 90%??

Link, if you do this, I'd be interested in your results, "just for kicks".