Questions about flow limitation
I've read the various descriptions of flow limitation, and I think I understand it at a high level.
More specifically:
- Last night I had the following readings for flow limit: 0.06 95%, and 0.22 max.
Is that good, bad, average? Is there such a thing a benchmark for what is acceptable, similar to AHI
- In my previous post, people said I should pay attention to my flow limitation, and recommendations were made to increase EPR to 2 or 3.
I did that and saw no results. In fact, flow limitation might have been worse. But, in general, why does making it easier to exhale improve flow limitation?
Thanks as always.
RE: Questions about flow limitation
Several things. Making it easier to exhale does nothing for flow. Limitations. That is actually a side effect of managing flow limits.
Flow limitations that we are talking about are inspiratory flow limitations.
First realize that exhale pressure is what treats obstructive apnea, not peak or inhale pressure. This is the case on all CPAPs or bilevels.
Pressure Support, pressure above the exhale pressure or EPAP is what treats hypopneas, flow limits, RERAs, UARS, and even snoring.
With CPAP you increase pressure to treat everything. EPR is officially nothing more than a comfort feature, to make it easier to breathe, to tolerate.
One goal of treatment is to use the lowest effective and tolerable pressure.
When we suggest a increase in EPR we are evaluating if a drop in exhale will cause an issue. This is done by evaluation of the obstructive apnea that is present and the amount of drop that an EPR increase will cause, expecting the increase in EPR will improve flow limits. Not all individuals are adequately resolved with EPR or PS of 3, I needed PS of 5 and thus my VAuto. It is the higher pressure of the inhale that treats the flow limits, not the lower pressure of the exhale.
RE: Questions about flow limitation
There is no standard for treatment of flow limits, it depends on the user. Some are highly sensitive to pressure changes but are more than adequately treated for events other than flow limits. Since flow limits are with ResMed a major driver of pressure increases so in these individual you want to set the max either at or slightly above the min pressure and often with reduced or no epr
RE: Questions about flow limitation
Honestly, I'm still confused.
But thank you for the explanations.
The confusion is on my end.
Is '0.06' 95% good, back, or irrelevant?
It seems like the answer is the latter, with individual responses the key factor.
RE: Questions about flow limitation
In general it is good. There are rare individuals where it is not.
RE: Questions about flow limitation
Grazie!