From: ed@titipu.resun.com (Edward Reid)
Newsgroups: rec.backcountry
Subject: Re: [l/m 9/2/92] Snake bite: Distilled Wisdom
Date: Sun, 13 Dec 92 11:24:59 EST(-0500)
Organization: Accuracy, Ltd.
Reply-To: ed@titipu.resun.com (Edward Reid)
Distribution: world
X-Mailer: uAccess - Macintosh Release: 1.6v0

greg@antizen.EBay.Sun.COM writes:
> 1. The concept of 'constricting bands below and above the bite'
>     is very vague and misleading. Santa Clara Country EMT protocols
>     call for a 'venous tourniquet' below and above (this is the same
>     concept as the constricting band) ...... in order to decrease venous
>     flow without compromising arterial circulation.

A TOURNIQUET IS NOT THE SAME AS A CONSTRICTING BAND.

I know that you are describing something different from a normal tourniquet
(a "venous" tourniquet).  I start with the above warning nonetheless, because
of the importance of avoiding misunderstanding which leads to mistreatment,
circulatory impairment, and amputation.

I don't understand the idea of a tourniquet that slows venous flow without
affecting arterial flow -- not over a period of more than a few seconds. 
What blood goes into a limb must come out, so if you impede venous flow, you
slow arterial flow as well.  Either you can trap some blood in the limb and
make it swell up, which will increase pressure in the limb and restore venous
flow, or you decrease circulation in the limb.  I suspect that the statement
about venous vs. arterial flow is inaccurate and misleading and that (as you
say) the purpose of the "venous tourniquet" is the same as that of a
constricting band -- but much more accurately applied.  Applied at a specific
quoted pressure which has a limited and safe effect on circulation.  In fact,
trained and equipped EMTs can safely do many things that others cannot -- in
this case they can monitor circulation and measure pressure, and as a result
can be more aggressive about applying pressure.

The panel written by Hal Lillywhite describes constricting bands rather
clearly, I believe:

: Try to slow the spread of the venom.  Use constricting bands above
: and below the site of the bite.  These should *not* be tight enough
: to cut off circulation, all you want to do is slow down the movement
: of the fluids under the skin.   Keep watching these bands, they should 
: not be on a swollen area and you may have to move them as swelling 
: increases.  To re-iterate:  *Do*not*cut*off*circulation*.  

However, I agree that clarity on this point is critical, and if you can come
up with clearer wording, I'm sure that Hal will welcome it.

Greg writes:
> 2.  The use of a 6 inch ace bandage wrapped firmly first on the bite than
>     distal (away from the heart) and then back again is the current recommended
>     treatment.

This is described in the panel in the paragraph following the one quoted
above:

: A more recent development for immobilizing the venom is to wrap the
: area snugly with fabric and immobilize the limb with a splint.  Any
: type of fabric, including elastic bandages, works well.  Just be
: sure it is not tight enough to cut off blood circulation and watch
: for swelling which might make it too tight.

Greg continues:
>     This has been in use in Australia with great success against
>     the venomous snakes. Even this technique is under investigation however
>     since snakes in Australia do not have the necrotoxic componant in the 

The panel applies to North America only, for reasons of space, time, and
available expertise.  This is stated but perhaps not emphasized clearly
enough.  Anyone reading the panel outside North America, or planning to
travel outside North America, should augment his knowledge with sources
specific to his geographical region.  I imagine that a world-wide extension
to the panel would be welcome, but the time to gather the expertise and write
the article is considerable, especially to match the depth and quality of Hal
Lillywhite's article.

> 3.  Your article does not mention the Sawyer Extractor ... The
>     Extractor, a syringe-like pump device, is powerful enough to extract
>     30% of the venom ... (or so Sawyer's research claims). This device is
>     essentially 'non-invasive' in that it can't make matters much worse

This is described in the panel, though not by name.  There seems to be a
difference between the advertised claim and independent judgements, perhaps
because the manufacturer's assumption of application within 3 minutes is
considered unrealistic.

: 2.  You have appropriate suction devices to remove it.  This means a
: syringe style suction device ...  Removal of 5 to 15% 
: would be about all you can expect. ...

Edward Reid  (8*}>
  eel:   ed@titipu.resun.com  or  nosc.mil!titipu.resun.com!ed
  snail: PO Box 378/Greensboro FL 32330
Newsgroups: rec.backcountry