general CPAP musings

Is there a chance that CPAP doesn't work to get rid of the apneas in every case? That NO pressure would keep the airway open? No matter what setting I use, I still have apneas and hypopneas. I was given advice to leave the auto at one pressure for a while. Why? How would this be different than the auto changing it all night long? Just a couple questions

Seems one has to go through a process of elimination. Set one pressure say around my 12 which i understand is a lower pressure then go to bed and see the results........ next night step it up and so on until you have postive experience.

I am not a doctor ............just an opinion on your question of of why one pressure.

One thing I learned from experience is, don't change things nightly. Your variables change from day to day, night to night. So in order to get an accurate trend, at least one week of any setting should be a rule of thumb. You could keep the same exactly setting for two nights and get two entirely different results. So at least a week, in my experience and from recommendations of others who know far more than I, would be a good idea.

I did an experiment and tried auto a few weeks back and thought auto was no good for me. Was on CPAP, on which I was getting great results, but wanted to see what auto would do. I had worse results on auto for the first three nights and went running back to CPAP. When the CPAP gave me the same results that the auto was giving me, I decided to try auto again and now I'm on it nightly. I get great results, even had two nights in one week with zero AHI's.

So don't make the same mistake I did. Give yourself at least a week on any given adjustment to see if it works or not and for a real trend to develop on which you can base that determination.

Be sure to remember that you can be having some events, and that these are considered normal for most people. Sometimes when we are being treated, we forget what is normal and strive for perfection.

True, but those "normal" people they talk about aren't on CPAP, right? During my sleep study, pressure 8 was shown to stop the apneas. Why, now that I'm home on a machine, isn't it stopping them? I truly don't understand. And, I just don't get why night to night things would be THAT different. I go to bed at almost the same time every night, and can't think of any variables that would make any difference *shrug*

Your variables change from day to day, night to night. So in order to get an accurate trend, at least one week of any setting should be a rule of thumb. You could keep the same exactly setting for two nights and get two entirely different results. So at least a week, in my experience and from recommendations of others who know far more than I, would be a good idea

uhhmm..isn't this what the AUTOpap is doing though? Changing it from minute to minute sometimes..I'm just not getting the logic of keeping the pressure the same...

Barb,
One reason for keeping you pressure absolutely stable for a while is to see how you body handles that pressure after it gets used to it. Bodies are living things, and they take time getting used to changes in their environment, including pressure while they sleep. Think for instance of the time people need to get acclimated to hight altitude, or of the time people need to get used to lifting heavy wieghts. For many people xPAP therapy is similar.

A second reason not to make many changes at once it part of the basic logic of research. You make only one change at a time, otherwise you don't know which of the changes you made effected the results. It's difficult when we start CPAP because we do have many changed things at once - pressure level, pressure variability (if on auto), mask, noise for some of us - but in order to tease out what works, or doesn't we have to try to make changes one by one.

A third reason is that some peoples bodies simply don't take well to the variability caused by the auto machine, they simply do better on a stable pressure, no matter what their breathing problem is.

A fourth reason is that some kinds of hypopneas - those that are not concurrent with flow limitations - are not responded to by most auto algorithms. If you have than kind of breathing disturbance, you are simply better off with a stable pressure that will eliminate them. An auto, once it senses you breathing is OK will lower the pressure gradually - and then not raise it when those hypops appear. Which means an auto might leave you beneath the optimal pressure for treating you hypopneas. Autopap is not necessarily the best mode for some people.

O.

thank you for your thoughtful explanation..that last one really does make sense about the stable pressure *nods*

the first part though still puzzles me. An auto is constantly adjusting the pressure during the night..still wondering how that's different than me changing it only every few days...

If the auto's algorithm is good for you, it's pressure changing are a reaction to what it senses at that moment in your breathing pattern. It's reactive change to something identified. The changed are in tune with your needs

If the algorithm is not good for you, the changes aren't either.

The changes you make are not based on sensing subtle changes in your breathing, which is why you can't really compare them to what a well tuned auto does.

O.

That makes sense

What's an algorithim? *scratching head*

Hi Barb
An algorithm is (more or less) a set of rules for doing something. Different autopaps have different sets of "if this happens then do that". Those are their algorithms.

O.