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>> >> I was expecting to ear from the experts on this topic. I'm just back from >> a trip to France and over there, Aspirin seems to be a standard part of >> the treatment of DCS, as standard in fact as pure O2. >> >> I was reading a new French magazine (Octopus No2, juin-juillet 1996 >> p14, Jacques Migueres) and the recommended dose seems to be 500 mg (as >> long as you don't suffer from allergies). It seems that it can be taken >> at the treatment phase but there's no word on a the usefullness of a >> preventive dose. It's no good if the your ASA brand contains >> "paracetamol" apparently. >> >> So let me ask the experts again what is the status of aspirin use in the >> treatment of DCS in America? Time to phone up DAN? > >Until one year ago (more or less), aspirin was also with O2 the standard >treatment of DCS as recommended by the FEBRAS (belgian part of CMAS). The >intended effect of aspirin was prevention of blood coagulation (one effect >of acid acetylsalicilique and not of paracetamol). > >It has been supressed because of studies who have shown that aspirin has >little >or no currative effect (it is too late to get the intended effect). Some >studies >showed a preventive effect but at the dosis needed to achieve the result, the >problems of aspirin outweighted the advantage. The use of aspirin would seem to have at least "theoretical" advantages (there's much in medicine that unfortunately looks good on paper but has little effect on the body in practical terms). Hold onto your socks....<Physiopharmacology Warning!> Doc-Speak about to be committed in full public view!! We know that micro bubbles (certainly macro bubbles) damages the endothelial lining of blood vessels. This physical damage (much like the initiating damage of atherosclerotic plaques in hardening of the arteries) activates cell membrane phospholipids which form arachidonic acid. The arachidonic acid is acted on by cyclooxygenase to form amoungst other metabolites, Thromboxane A2 which is a potent vasoconstrictor and PLATELET AGGREGATOR. Aspirin blocks the reaction of cyclooxygenase on arachidonic acid, therefore lowering the amount of Thromboxane A2 produced. The body thus tends to limit these small "micro white clots" of platelets. This is the whole reason for taking aspirin *prophylactically* to reduce the risk of heart attacks. By taking the aspirin AHEAD of time, you've already jumped on blocking the cycloxygenase pathway. Once you've triggered the clotting mechanism, and the cat's out of the bag so to speak, aspirin has been shown not to be as effective.(though not necessarily zero) Now, with DCI, (by definition the patient is already symptomatic or you wouldn't be treating would you?) you already have bubbles, so you are already in process damaging the blood vessel linings. It would seem unlikely that you would get a sufficiently high blood level of aspirin at this point, fast enough, in the pathology to do much good. But that is SPECULATION ON MY PART and speculation rather than experimental/clinical evidence makes for bad science. So, I'd not dismiss any of this out of hand. For the antithrombotic effects of heart attack prevention, very little aspirin is needed (something like one tab every other day) so taking a tab the morning of a dive at first blush doesn't seem unreasonable. But, aspirin does have neurotoxic effects. Take it in sufficiently high enough doses (like some arthritics do for it's antinflammatory effect) and you get ringing in your ears (tinnitus). Now, supposedly divers wouldn't be taking aspirin in such high doses that it would have a synergistic effect with their O2 deco gases, but theoretically they are both hammering on the same system. Just something else to keep in mind. I wish I read French to see the data. It sounds "interesting" at least. Robb Wolov ==================================== CDR Robert B. Wolov, MC, (FS), USNR Department of Orthopedic Pathology Armed Forces Institute of Pathology Washington, DC 20306-6000 wolov@hi*.co* (preferred) wolov@em*.af*.os*.mi*
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