Flex and Outbreath resistance with Respironics AutoCPAP

Hi,

I was recently diagnosed with sleep apnea, and got a Respironics AutoCPAP machine. Some nights, I
struggle to get to sleep because it seems to resist my out breath long enough to bother me.

Because it is a continuous PAP, I use the Flex setting of 3 ( max ) to reduce the exhalation pressure.
However, this feature does not seem to kick in easily.

I find that :
When lying my side, the machine learns and after 10 min is able to allow me to exhale with little or no resistance.
When lying my back, the machine seems to NOT learn and there is always resistance to my outtbreath.

I believe Flex is working because when I do get to sleep, I find that as I'm waking up, the device offers almost
no resistance to my outbreath.


Q1) Does anyone have any info regarding Flex? I can only find the sales or marketing type info so far.
Q2) Is this how Flex works? and how do I trigger it?

Thanks,

InOut wrote:Hi,

I was recently diagnosed with sleep apnea, and got a Respironics AutoCPAP machine. Some nights, I
struggle to get to sleep because it seems to resist my out breath long enough to bother me.

Because it is a continuous PAP, I use the Flex setting of 3 ( max ) to reduce the exhalation pressure.
However, this feature does not seem to kick in easily.

I find that :
When lying my side, the machine learns and after 10 min is able to allow me to exhale with little or no resistance.
When lying my back, the machine seems to NOT learn and there is always resistance to my outtbreath.

I believe Flex is working because when I do get to sleep, I find that as I'm waking up, the device offers almost
no resistance to my outbreath.


Q1) Does anyone have any info regarding Flex? I can only find the sales or marketing type info so far.
Q2) Is this how Flex works? and how do I trigger it?

Thanks,

The "Flex" (exhale relief) is proportionate to the user's exhalation breathing force.


Den

.

Cpap and Apap machine that I a familiar with do not "learn" ... it is you that is learning .

InOut wrote: find that :
When lying my side, the machine learns and after 10 min is able to allow me to exhale with little or no resistance.
When lying my back, the machine seems to NOT learn and there is always resistance to my outtbreath.

I believe Flex is working because when I do get to sleep, I find that as I'm waking up, the device offers almost
no resistance to my outbreath.


Q1) Does anyone have any info regarding Flex? I can only find the sales or marketing type info so far.
Q2) Is this how Flex works? and how do I trigger it

the machine does not *learn* anything, at all, what you are doing is becoming acclimatised to the pressure, so that you don't notice it.

respironics has always been very vague about exactly what flex does, much to the annoyance of it's users, but basically, aflex provides a small reduction in pressure when you start to exhale. the more forcefully you're breathing, the more relief it gives.... here's a diagram:

I found exhaling the hardest thing to get used to, if I focus on my breathing at all I start to get anxious. Maybe it is similar for you? I have to stop myself whenever I find my mind wandering to thoughts of breathing, but it's getting easier all the time. Just takes time to adjust imo.

InOut

As others have explained, Flex provides a small amount of exhalation pressure relief, but the amount of relief depends on the forcefulness of the exhalation. My guess is that by morning you've become accustomed to exhaling against the positive pressure of the CPAP. At the beginning of the night, you're not used to it and that's why you notice it.

It may be hard (or impossible) to do, but you might see if the DME would be willing to switch you from a PR APAP to a Resmed APAP. The Resmed APAP uses a different form of exhalation relief called EPR. EPR reduces the pressure on exhalation by a fixed amount that can be set for 1, 2, or 3 cmH2O. The amount of exhalation relief on a Resmed machine does not depend on the forcefulness of the exhalation.

If you can't swap the machine out, don't despair. Many new CPAPers find it difficult to exhale against the pressure at the start of the night regardless of what form of exhalation relief their machine provides. However after a few weeks, most new CPAPers no longer find that they have any problems exhaling against the pressure at the beginning of the night.

[quote="robysue"]InOut

As others have explained, Flex provides a small amount of exhalation pressure relief, but the amount of relief depends on the forcefulness of the exhalation. My guess is that by morning you've become accustomed to exhaling against the positive pressure of the CPAP. At the beginning of the night, you're not used to it and that's why you notice it.

It may be hard (or impossible) to do, but you might see if the DME would be willing to switch you from a PR APAP to a Resmed APAP. The Resmed APAP uses a different form of exhalation relief called EPR. EPR reduces the pressure on exhalation by a fixed amount that can be set for 1, 2, or 3 cmH2O. The amount of exhalation relief on a Resmed machine does not depend on the forcefulness of the exhalation.

If you can't swap the machine out, don't despair. Many new CPAPers find it difficult to exhale against the pressure at the start of the night regardless of what form of exhalation relief their machine provides. However after a few weeks, most new CPAPers no longer find that they have any problems exhaling against the pressure at the beginning of the night.[/quote
My understanding is that the PR AFLEX isn't any different then ResMed EPR so don't think one would need to go the extreme measures of changing machines.

Hi everyone,

Sorry for my late reply. Thanks for the info and relating your experience with Flex.

Wulfman, grayhost4, palerider, robysue and tonyg :
Thanks for pointing out there the machine is not learning. Somewhere I got the impression that Auto in AutoCPAP means the machine will monitor
and follow my breath.

Michelle, you hit it on the head when you pointed out that when I am the last one to sleep, it is all quiet and my mind focuses on the breathing,
giving rise to my anxiety. I find that if I sleep before others, there is enough distractions that I don't focus too much on the breath and am able to fall asleep,
sometimes.

In talking to SleepMetrics, the vendor I am working with, the device that allows separate adjustments to inbreath and outbreath is the Respironics AutoBiPAP.
not the AutoCPAP.

The sales brochure says
> Bi-Flex makes the breathing cycle feel natural and comfortable. Flex Technology allows the System One 60 Series BiPAP Auto to track each breath
> and provide pressure relief during three critical points in the breathing cycle.
> Pressure is reduced by .5 increments during the transition from exhalation to inhalation, inhalation to exhalation and during exhalation.
> The Bi-Flex setting can be adjusted up to 1.5 H20 for maximum comfort.

I'll keep working on getting used to the AutoCPAP. It's good to know there is an alternative BiAutoCPAP that I can turn to if all else fails.

TonyG wrote: My understanding is that the PR AFLEX isn't any different then ResMed EPR so don't think one would need to go the extreme measures of changing machines.

Actually A-Flex and EPR work in quite different ways. Most people are not sensitive enough to tell the difference or develop a real preference, but some people are sensitive enough to tell the difference.

Here's a quick look at both systems of exhalation relief:

Resmed EPR reduces the pressure by a fixed amount at the beginning of every exhalation. The fixed amount can be set to 1, 2, or 3cm. The EPR works with "Easy Breath" and the pressure does not increase back up to the therapeutic setting until the beginning of the inhalation or the very end of the exhalation. The drop in pressure is constant regardless of how forceful the exhalation is.

PR A-Flex reduces the pressure by a variable amount at the beginning of every exhalation. The drop in pressure is proportional to the force of the exhalation: If you exhale very strongly, the drop in pressure is more than if you exhale very gently. The machine uses a "two step" increase in the pressure to get the pressure all the way back to the therapeutic setting: The pressure increases about half way back to the therapeutic setting as soon as the force of the exhalation starts to decrease. The machine finishes increasing the pressure all the way back to the therapeutic setting once the inhalation begins. The A-Flex setting controls two things: (1) the maximum possible drop in pressure on a very strong exhalation and (2) the "rounding" of the pressure decrease/increase---in other words how fast the pressure is dropped and then increased after the exhalation or inhalation is detected by the machine. Buried deeply somewhere in the PR web pages either I or pugsy once upon a time found a page that indicated that the maximum decrease in pressure was 2 cm. In other words, if you forcefully exhale with A-Flex set to 3, the pressure will drop by about 2cm. A more typical drop for a typical exhalation is in the 0.5-1.5cm range regardless of the Flex setting.


To summarize the two biggest differences between A-Flex and EPR:

Timing of the pressure increase
The PR with A-Flex starts to increase the pressure during the second half of the exhalation. The Resmed with EPR starts to increase the pressure at the point where the exhalation is ending and the inhalation is beginning.

Size of the pressure decrease
The Resmed with EPR reduces the pressure by a fixed amount on every exhalation; the EPR setting determines the fixed reduction in pressure. The PR with A-Flex reduces the pressure somewhere between 0.5 and 2.0 cm based on the combination of the A-Flex and the force of the exhalation; the amount of pressure relief varies from one breath to the next based on how forceful the exhalations actually are.

InOut wrote:Somewhere I got the impression that Auto in AutoCPAP means the machine will monitor and follow my breath.

it monitors apnea events, and adjusts the pressure, over a period of many minutes, to account for varying conditions. but it does nothing breath by breath. machines that do are rather more expensive.

InOut wrote:In talking to SleepMetrics, the vendor I am working with, the device that allows separate adjustments to inbreath and outbreath is the Respironics AutoBiPAP.not the AutoCPAP.

The sales brochure says
> Bi-Flex makes the breathing cycle feel natural and comfortable. Flex Technology allows the System One 60 Series BiPAP Auto to track each breath
> and provide pressure relief during three critical points in the breathing cycle.
> Pressure is reduced by .5 increments during the transition from exhalation to inhalation, inhalation to exhalation and during exhalation.
> The Bi-Flex setting can be adjusted up to 1.5 H20 for maximum comfort.

I'll keep working on getting used to the AutoCPAP. It's good to know there is an alternative BiAutoCPAP that I can turn to if all else fails.

biflex is just a version of the aflex that your machine has, adapted for the different inhale/exhale pressure, it behaves almost exactly the same as what your machine does as far as breathing, sorry.