Klarinet Archive - Posting 000670.txt from 2000/09

From: "dikarius" <dikarius@-----.com>
Subj: Re: [kl] Uh?????
Date: Fri, 22 Sep 2000 01:29:40 -0400

Warning: a disgusting amount of science and medical terminology is spoken
below. Sorry!

The short version: Regarding the intrathoracic pressures and the risk of
cerebrovascular accident (=event=CVA): To put this in perspective: there
are several reports of similar events associated with coughing and sneezing.
It's not going to stop me from playing, unless I were to find out that I had
a condition that increased significantly the probability of one of these
events happening.

The long version:
A correction and some clarification:

dissection (a clarification): The layers of the blood vessel split apart,
eventually allowing blood to leak out (either slowly or rapidly) - its not
that the vessel was torn in two, but that a "hole" (bad terminology - sorry
medical folks) develops.

The foramen ovale is an opening that connects the right and left atria. It
is normally open in fetuses and closes after birth. It is a relatively
common event for that to fail to close. Then it is called a patent foramen
ovale and it is often asymptomatic (the medical students find a few
undiagnosed every year in the anatomy labs here). One potential
complication of it remaining open is that blood clots can form within the
foramen, then break free and travel where ever the blood takes them (in this
case the brain). Presumeably, the high intrathoracic pressure developed by
the instrumentalist is being blamed for the blood clot breaking free.

Paradoxical cerebral embolism: This occurred in the person with the patent
foramen ovale - they are postulating that what happened here is that a blood
clot formed in the foramen ovale, broke free into the right atrium and was
forced backwards into the veins of the head (hence the paradoxical).
Blocking a vein stops circulation just as effectively as blocking an
artery - blood is a non-compressible liquid so if it has no where to go, it
stops moving.

spinal epidural hematoma: Not the brain, but the spinal cord was affected.
They are implying that the high intrathoracic pressure caused a blood vessel
located in the epidural space to rupture, causing the hematoma.

However, your definition of brass is right on! :-)

The intrapleural (intrathoracic) pressures go quite a bit higher in the
brass players than they do in woodwind players. There is risk associated
with that, particularly if you already have some predisposing factors (i.e.
the patent foramen ovale, defects in the blood vessels, etc...). In anyone,
you can make the veins in the neck distend pretty easily in the short term.
The pressure in the jugular veins is on the order of ~10 cm H20, while an
intrathoracic pressure in excess of 100 cm H20 can be recorded pretty
easily - it happens everytime you cough or sneeze. Since pressure in the
thorax is greater than in the veins, blood stops moving from the head back
to the heart - it collects in the veins, producing that distension. The
back pressure can cause a weakened vessel wall to rupture or a clot to break
free. This is why we can cite those reports of CVA's associated with
coughing and sneezing in the literature.

Hope this makes things somewhat clearer than mud...

Diane R. Karius, Ph.D.
Department of Physiology
University of Health Sciences

----- Original Message -----
From: "William Wright" <Bilwright@-----.net>
Subject: Re: [kl] Uh?????

> <><> translate this into some normal human language?
>
>
> I'm not a physician -- don't take this as medical advice or as
> authoritative -- but from what I remember of dissecting that 'ole cat
> with latex in its blood vessels (sorry, Shadow, they made me do it).....
>
> Two cases of ischemic [INTERRUPTED BLOOD SUPPLY] stroke due to
> carotid artery [THE TWO PRIMARY ARTERIES IN THE NECK] dissection
> [BEING TORN APART] occurring during wind instrument playing, probably
> caused by increased intrathoracic pressure [INSIDE THE CHEST] and
> subsequent intrapharyngeal pressure [FROM NOSE TO LARYNX], are
> presented. A review of the literature revealed three similar patients
> with other types of cerebrovascular events [BRAIN DAMAGE INVOLVING
> DISRUPTED BLOOD SUPPLY TO THE BRAIN], such as paradoxical cerebral
> embolism [OBSTRUCTION OF BLOOD SUPPLY, PERHAPS BY BLOOD THAT STOPPED
> MOVING AND THEREBY CLOTTED] due to a patent [OBVIOUS] foramen
> ovale [ONE OF THE OPENINGS IN THE BASE OF THE SKULL] hematoma
> [SWELLING IN THE FLESH FILLED WITH BLOOD] and spinal epidural [IN
> BETWEEN THE MEMBRANE THAT ENCLOSES THE BRAIN AND THE SKULL ITSELF]
> hematoma during trumpet [THE BRASS INSTRUMENT THAT USUALLY PLAYS TOO
> LOUD RIGHT BEHIND YOUR EAR, BUT IT SOUNDS SWEET WHEN MAURICE ANDRE IS
> PLAYING] playing.
>
>
> Anecdote: on the very first day that I began my clarinet lessons,
> the clerk at the music store mentioned to my instructor that <so-and-so>
> had suffered a stroke, and since <so-and-so> played a wind instrument (I
> never learned which one), should I and my instructor be worried?
> I decided on the spot not to worry; but it did take a few weeks for
> me to dismiss the conversation from my mind completely. And I haven't
> thought about it since. (That's why I'm mentioning it now?)
>
>
> Cheers,
> Bill
>
>
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