As mentioned in the "Attn: Please Read" sticky post at the top of this forum, board members need to exercise a degree of caution when they read "medical" posts on these forums from non-medically trained or informed folk. Pescador775 (who calls himself Pesky) is a case in point. I have gotten the impression that Pesky tries to read some about diving medicine, but truly
understands very little of what he reads. Unfortunately, this little bit of half-understood knowledge seems to have led him to believe that he is a medical expert qualified to give medical advice on this board. In my experience, he lacks even the most basic knowledge of anatomy, physiology, and pharmacology and is frequently, shall we say, off-target.
For example in his first post above, I suppose Pesky might have been trying to change the subject from CNS O2 toxicity to an unrelated subject (the "bends"), but as has been so politely pointed out, Pesky seems to have missed the point of the discussion (again). I think it may be quite possible that Pesky doesn't even really understand the difference between CNS oxygen toxicity causing a "hit" (seizure) and neurological decompression sickness. Dr. Deco also pointed out Pesky's incorrect understanding about the basic physiological effects of hydration on surface tension.
Pesky also likes to promote the use of aspirin on this board periodically. While he is correct that aspirin reduces platelet adherence, which is involved in blood clotting and it reduces inflammation, which is involved in decompression illness, aspirin has not been found to improve the outcome in decompression illness, and it can have negative effects (which Pesky always fails to mention when hes promoting aspirin).
From Bove and Davis' Diving Medicine, 3rd edition:
Because of evidence that bubble-blood interaction may cause platelet deposition and vascular occlusion that are refractory to recompression, there is reason to believe that agents that inhibit the functions of platelets (like aspirin) and soluble clotting factors might be beneficial in decompression sickness. Aspirin and other antiplatelet drugs inhibit the mild drop in platelets observed after dives. A single case report indicated neither benefit nor harm from heparin administration to a patient with neurological decompression sickness. Animal studies in which single agents were administered have shown no benefit from anticoagulation; however in a canine model of arterial gas embolism, a triple combination of indomethacin (an aspirin relative), prostaglandin I2, and heparin resulted in a beneficial short-term effect.
Furthermore, there is histologic (microscopic tissue examination) evidence of hemorrhage (bleeding) in arterial gas embolism, inner ear decompression sickness, and spinal cord decompression sickness. Thus, there is little evidence that antiplatelet agents (e.g. aspirin) or other anticoagulants alter the neurological outcome in decompression sickness, whereas there is reason to believe that some lesions actually may be made worse. However, in individuals with severe neurological deompression sickness and leg weakness, deep vein thrombosis and pulmonary embolism (blood clots) have been described. In these patients, therefore, some form of prophylaxis against deep vein thrombosis, which might include low-dose heparin, is recommended. (When prescribed by a doctor!)
Regardless of their effects on platelet function, nonsteroidal anti-inflammatory drugs (like aspirin) are commonly prescribed (by a doctor, not a fisherman) for the discomfort of pain-only decompression sickness because of their analgesic (pain relieving) and anti-inflammatory properties. If the clinical response to recompression is to be observed, these agents should not be administered until after hyperbaric treatment.
From Edmonds, Lowry, & Pennefathers Diving and Subaquatic Medicine, 3rd edition:
There are more arguments against the use of aspirin than for it, in that the effects on an already haemorrhagic (bleeding) disease could be catastrophic- and haemorrhage in the gastrointestinal tract and brain have been the cause of some decompression deaths. Also, the likelihood of aggravating inner-ear or spinal cord haemorrhagic pathology is increased. It has a variety of other negative influences on susceptible individuals, such as bronchospasm and metabolic changes.
From Bennett and Elliotts The Physiology and Medicine of Diving, 4th edition:
Bubbles do induce platelet accumulation, adherence, and thrombus (clot) formation. Consequently a variety of antiplatelet agents, and especially aspirin, have been extensively tried- prophylactically and therapeutically- but without success. This failure is probably because bubble-induced platelet accumulation is not as rheologically (the study of flow) important as the concurrent accumulation of polymorhonuclear leukocytes (white blood cells).
The only non-steroidal anti-inflammatory drug (the family of medicines that aspirin is in) for which there is a supportable role in the decompression illnesses is indomethacin, but then only in combination with prostaglandin PgI2 and heparin.
As noted above, anticoagulation with aspirin can be associated with an increased risk of bleeding. Bleeding often occurs with barotrauma. Barotrauma is the single most frequent diving injury- particularly in new divers. If you suffer a barotrauma injury to your ears, sinuses, lungs, etc., taking aspirin could potentially turn a minor event into a significant problem. Pesky knows this (because he's been told before) but he always chooses to leave this tidbit out when he's promoting his personal agenda for aspirin. Aspirin has its potential benefits, but it also has potential risk, (the risk is low, so it really is
unlikely to hurt if you take aspirin and dive, but its even
less likely that it will help), but as Peskys been told before, to fail to even mention potential negative effects of a course of action when you're dispensing medical advice is irresponsible.
Bottom line? Pescador775 has a lot to offer when discussing dive technique, equipment, etc. Ive learned from his posts in other sections on the board. But when reading medical "information" from ole Pesky on this board, proceed with caution. Even though he has apparently done a little reading on dive medicine issues and has learned a few big words and catch phrases, I don't believe that he truly understands just how much he really doesn't understand- yet he dispenses medical "knowledge" and advice freely and without qualification. I can only hope that one day he will come to a self-realization of his own limits and stop dispensing incomplete, incorrect, and even just downright BAD medical information and advice on this board. In the meantime, if
you have the training and knowledge to follow what he says and pick out the inaccuracies, then of course feel free to read his "medical" posts with amusement. But if you don't already know the answers, I'd recommend waiting for the "corrective" posts from more knowledgeable people (that will almost surely follow) before you quote anything that he says about dive medicine.
Just my 2¢,
Bill
By the way, Pesky, aspirin and heparin work by
entirely different mechanisms to affect blood clotting- a fact you seem to have completely failed to notice. And its coumadin (warfarin), yet another totally different type of anticoaglulant (about which Ill bet you know as little as you do aspirin and heparin) that is sometimes used in rat poison, not heparin.