Yet another question?? Exhalation Relief / APAP / CPAP

[jillybean]

I have an Apap s8 re med, well if you have a cpap I take it the air pressure is continuous so you must have to exhale against the pressure whereas mine seems to `breathe` with me is that right??
Just a random wonder really, and is it not difficult to breathe against and also if the pressure is fixed it cant alter but I have noticed my pressure alters a lot I just dont really understand that.
I have obviuosly got too much time on my hands if these are the things I am thinking about LOL
So I am off to please my Husband.............

by doing housework!!!!

[James @ Intus]

There's two elements to it really.

There are indeed fixed pressure CPAP machines which blow *throughout the night* at say X cm H2O (officially HectoPascals these days).

Then there's Auto-CPAPs, or APAPs for short, which blow between Xlower and X higher cm H2o throughout the night.

The APAP will monitor for breathing events such as snoring, hyponpoeas and apnoeas. When it sees an event, it ramps up the pressure until the event is remedied. It then stays at this increased pressure for a certain number of minutes, after which, if no further events detected, it will slowly drop again, by something like 0.1 cm H2O per 1-5 minutes. This slow decline is a precautionary measure. This cycle then repeats. The exact algorithm varies per model.

That's the basic CPAP and APAP difference.

Now to complicate it, there are certain manufacturers who built in exhalation relief. This is a breath by breath thing. ResMed calls it EPR, Respironics C-Flex and A-Flex. Covidien have a related but not quite the same feature in Adaptive Pressure Stability. These are all designed to reduce the effort it takes to breathe. They can be features of CPAP as well as APAP and are distinctly different from an APAPs ability to monitor events and react to them with pressure changes.

Your ResMed S8 is probably doing both. It has EPR on to make breathing out that bit easier and it's also Auto-Adjusting when a respiratory event happens.

The EPR will be regular, the auto titration will only happen when required.

Your pressure latering a lot is because there's a fair few events still happening. This could be a sign that the lower pressure programmed into the APAP is too low and causing too many events. Up this a bit and it may prevent these events from happening, thus reducing the need to flare upwards as a reaction. That's a pro-active measure as oppose to waiting for the machine's reactive measure.

Hope that makes sense!

[leswaller]

I have a CPAP rather than an APAP and it is not as peculiar as it sounds. You are not breathing against the pressure, as when you exhale the air from your lungs goes out through the vents in the mask, the machine also compensates and the pressure remains the same. The machine builds up pressure to its preset value and maintains it at that level, so whilst you perceive a constant presssure the machine is varying it all the time to maintain that pressure. For example if you bung up the end of the hose the machine pressurises the hose to the preset pressure then effectively goes to sleep until the pressure falls. Likewise if you take the mask off your face or have a major seal leak then the machine goes into overdrive to try and maintain the pressure

[jillybean]

Thanks Ill let you know when I need to know something else.

[James @ Intus]

I like the avatar you added, very appropriate, or at least, that's what you're aiming for