Can someone explain how EPR reduces flow limitation?

[Sleeprider]

Thanks G. Good input! I suspect the extent to which positive pressure inhibits expiration varies by individual, as does the effect of pressure support. Your underlined sentence is why I suspect Vcom is inappropriate for many as well.

[G. Szabo]

Thank you, Sleeprider for the added thoughts.  

I also wish to clarify a part of the controversy that emerged on this forum during the last few weeks about the correct setting up of EPR. 

One argument emphasized that it is the expiratory pressure that keeps the airways open; hence, once some EPR is added to an already established constant-pressure CPAP therapy, the expiratory pressure should be increased by the same amount as the EPR drops the pressure during expiration. 

The other line of arguments, based on experience, emphasized that adding EPR in the above situation might benefit and reduce flow limitation even without increasing the expiratory pressure.

From the above two comments of this thread, it becomes clear that EPR can benefit even without a simultaneous increase of the exhalation pressure because "... a less efficient exhalation leads to limited inhalation or a particular inhalation flow limitation." 

However, it is always a good practice to adjust the EPR and pressure support in an APAP regime where the instrument can take care of the expiratory pressure  if and only if needed.

[Dormeo]

A simple statement that may help people understand: EPR reduces pressure when you exhale, but by the same token, it increases pressure when you inhale. It's the increased pressure for inhalation that helps reduce flow limitation.

[obstructedairway101]

Fantastic discussion my knowledge and the mechanisms of epr makes alot more sense. It's def a fascinating paradox and will guide me in my treatment.

[Sleeprider]

Dormeo, I really appreciate your simplified explanation. I tend to get mired in the details and simplicity often eludes me. I will add.

[JumpyBob]

Dormeo, I really appreciate your simplified explanation. I tend to get mired in the details and simplicity often eludes me. I will add.

FWIW: Your input is greatly appreciated. Please keep the details coming! While I realize simplicity has benefits, some of us—nerds—greatly appreciate in-depth information!

[Sleeprider]

I have made some changes to the wiki based on suggestions here. G Szabo, your comment raised an important aspect of bilevel therapy where low EPAP pressure is critical in individuals with COPD and other pulmonary conditions that restrict expiration. Getting into expiratory flow limitation was not the purpose of the article, or this conversation, but it is out there. https://www.apneaboard.com/wiki/index.ph...Limitation

[G. Szabo]

Everyone appreciates Sleeprider's long-time efforts to maintain and improve the Wiki, which is a wealth of essential information. 

THANK YOU!

[Dormeo]

Hear, hear!

[SeePak]

I would like to speak to the 'underlined comment' by Sleeprider that is in Szabo's post about exhalation.

I have been using the VCOM for a couple weeks and have had decent success so far.
What i have definitely noticed is that my EXHALATION times have INCREASED dramatically.

And at first i had excellent results in AHI and most importantly rest, sleep and not tired during the day!
However, CA events are returning, i suspect due to the increased exhalation time.
On this forum it has been suggested this is temporary and my body will adjust.
I trust this will be the case.

Also, i will gladly share my results should they be asked for and appropriate for this forum.

Sorry, forgot to mention, while getting advice from this forum , and using EPR 3, i had days of 100+ CA events !
This scared me to some extent, to where i no longer use EPR at all.

However, once i get my sleep and rest back, i would be willing to revisit this use of EPR.