Speaking of Dr. Krakow's possible view regarding flow limitations and UARS:
-SWS wrote: . . . I see his view as almost universally correlating FL with UARS. . . .
I also think he (Dr. K) sees flow limitations that way.
jnk wrote:I would not disagree with that view of his views, as I read them. If a tired/sleepy person with flow limitations improves, subjectively, with PAP therapy, I am guessing he would call that UARS.
As would most doctors who subscribe to the idea that there
is such a thing as a
SYNDROME called UARS (Upper Airway Resistance Syndrome), described by Dr. Guilleminault.
But here's where I think Dr. K goes too far -- in his thinking that
every last flow limited breath needs to be rounded out before a person is getting
optimum treatment.
I have no problem with his promoting bilevel machines as being more comfortable for most people to use...feeling more like natural breathing. I also think his work in cognitive behavior therapy to help people with sleep disorders or difficulty adapting to "cpap" is wonderful.
What I
do question is Dr. Krakow's idea that if, during PSG titration, some flow limitations still appear, pressure should be raised and raised and raised until EVERY inspiratory/expiratory phase of the breath is rounded.
Even if they are not causing any arousals whatsoever on the EEG channel.
Even if that means going to an IPAP pressure of 20 or more.
Even if all apneas, hypopneas AND RERAs (Respiratory Effort Related Arousals) disappeared long ago at a much lower pressure.
The list -SWS gave of Dr. Krakow's remarks just on this message board alone, sure lead me to believe that Dr. K does, indeed, equate flow limited breaths --
even ones that do not cause an EEG measurable arousal -- with a thing that needs to be treated. I think Dr. K actually does equate flow limitations that don't cause arousals with UARS as a syndrome, no matter how Dr. K waffled with the words "probably", "close", and "pragmatically", when answering a question -SWS asked him:
In his first post on page 1 of a topic Dr. Krakow started (BILEVEL PAP Therapy Pearls: Clearing the First Hurdle)
viewtopic.php?p=243359#p243359
Dr. Krakow wrote:
A reminder that for all practical purposes, the following three terms are interchangeable:
· UARS (upper airway resistance)
· Flow limitation
· RERAs (respiratory effort-related arousals)
On page 6 of the same topic (BILEVEL PAP Therapy Pearls: Clearing the First Hurdle)
-SWS asked:
I have a question for Dr. Krakow. My question regards Dr. Krakow's repeated verbal equation between the phrase "flow limitations" and the acronym representing the syndrome referred to as UARS. Dr. Krakow, do you consciously intend to equate "flow limitations" and "UARS" as implied equivalents?
Dr. Krakow replied:
My point is that flow limitations probably do not equate to UARS but they come close, meaning that if you look hard and long for people who think they are normal sleepers, I think you will discover that many of them are not.
-- snipped --
So, pragmatically, it's generally useful to equate flow limitation with UARS, but I concur that technically, there may be patients who suffer flow limitations for other reasons for which PAP therapy may not be the answer. Although I don't know what causes this problem, I think it is important to note that some of these cases show flow limitation ending not in an EEG arousal but in a new normal breath. I suspect these FLEs are clinically relevant.
Note especially Dr. K's last sentence -- talking about flow limitations that do not cause an EEG arousal:
I suspect these FLEs are clinically relevant.
Dr. K would aggressively titrate even the most harmless (imho) flow limited breaths away in the cause of "optimum" (in his view) PAP treatment. Because he views them as "clinically relevant." I think a titration that aggressive, that results in very high pressures could easily cause many other problems...mask leak problems primarily...that could
greatly interfere with getting "optimum" treatment.
If it
really took rounding out every last flow limitation to say a person was getting optimum treatment, that would be one thing. I'd jump right on Dr. K's "round 'em ALL out" bandwagon. I just don't think that's the case...not when talking about flow limited breaths that do NOT cause EEG measurable arousals.