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From: screwloo@is*.ne* (John Dunk)
To: Joel Markwell <joeldm@mi*.co*>
Cc: Geoff Kelafant <kelafant@we*.co*>, Techdiver <techdiver@aquanaut.com>,
     Cavers
Subject: Re: General DCS Information
Date: Thu, 15 Jun 2000 19:07:58 +0000
On Thu, 15 Jun 2000 15:59:44 +0000, you wrote:

>on 6/15/00 7:56 PM, Geoff Kelafant at kelafant@we*.co* wrote:
>
>> Medications per se are not necessarily disqualifying but often the =
condition
>> they are prescribed for may be a contraindication to a number of =
activities,
>> scuba diving included.
>
>Geoff,
>
>My question is specifically related to prophylactic use of ibuprofen and
>aspirin to prevent or help to prevent DCS. Is it effective? Where can I =
see
>research on this specific question?
>
>Most of what I've read indicates that aspirin MAY have some use in this
>area, but one study (below) seemed to indicate that it doesn't seem to =
do
>what it ought to do and its use may be very limited and that other drugs
>(VK744) are more useful but carry with them more side-effects. It =
finally
>draws no absolute conclusions.
>
>That study I include below:
>
>SNIP>>>
>Hematology and blood chemistry in saturation diving: I. Antiplatelet
>                              drugs, aspirin, and VK744.
>
>                              Philp RB, Freeman D, Francey I, Bishop B
>
> Blood chemistry and cellular parameters were studied before, during, =
and
>after saturation (2.4 ATA) dives in the HYDRO-LAB habitat on two =
separate
>occasions. In both, platelet count fell greater than 20% 12-24 hours =
after
>surfacing and moderate (5%) reductions in hemoglobin, red-cell count, =
and
>packed-cell volume were observed. Plasma cholesterol and triglyceride =
levels
>were depressed postdive as were most plasma enzymes (GOT, GPT, CPK, LDH,
>ALP). The latter changes were very slight. In the first study, the
>incidental ingestion of aspirin by some divers did not prevent the loss =
of
>platelets even though the platelet-release reaction in response to ADP =
was
>inhibited. In the second study the platelet-suppressive drug VK744 was
>administered, on a double-blind randomized basis, to six divers, six =
others
>taking a placebo capsule. Dosage of VK744 was 300 mg TID for 2 days =
before,
>5 days during, 3 days after saturation dive. The drug inhibited the =
postdive
>loss of circulatory platelets and in fact the treated group showed a =
rebound
>in platelet count above control values, 48-72 hours postdive.
>Megathrombocyte counts indicated the production of new platelets in both
>groups at this point. The treated group also showed a marked and =
significant
>reduction in plasma cholesterol and triglycerides, suggesting an
>antilipidemic effect of the drug. Theses results confirm previous
>observations and indicate that postdecompression loss of platelets may =
be
>related to sequestering of reactive platelets, possibly by microbubbles,=
 and
>that the phenomenon can be inhibited by some antiplatelet drugs.
><<<SNIP
>
>I'm not trying to rain on anyone's parade here, I'm just trying to find =
out
>what is actually KNOWN and not what is BELIEVED.
>
>Later,
>
>JoeL


   As I read this Joel, it doesn't make any claims one way or the
other about DCS prevention and aspirin. It notes that aspirin
inhibited a loss of platelets that normally occurs after a
decompression (in this case saturation) dive. The suggestion is that
the loss occurs because the platelets attach to microbubbles, which
may or may not be true, but even if it is, it doesn't tell us whether
they don't bind because the bubbles are no longer there, or whether
the platelets are just desensitized to their presence.
   So, I don't think this piece helps.. but I don't have a better one.
Any body out there that does?
 =20
--
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