The following text taken from internet is quite illuminating.
It explains how Aspirin and related drugs affect blood chemistry and the
possible effects on divers.
DIVING and ASPIRIN USE
for ibuprofen while diving, 800 mg every 4 hours or even as a
ritual seems excessive, as you probably only need one 200 mg
in a 24-hour period. God almighty you guys must bleed like
if you ever cut yourself (ibuprofen prolongs bleeding time just
aspirin, not to mention the effects it has on your stomach).
impossible to give any hard line "best effect dose" which attains the
of ibuprofins benefits with the least amount of side affects. I
submit that it's part science, and part 'art' on behalf of the
High doses are definitely required to gain benefit mind you, and
would appear that at least a few others on this list are unaware of
use and benefit. For the moment, I wish to address aspirin
and not ibuprofen. Although both are used for the same
aspirin's use has been widely documented with respect to
diving. I submit the following to whomever for the sake
further discussion and intelligent hypothesis.
is a powerful medication and is actually an analgesic and
anti-inflammatory drug. Aspirin is a brand name in Canada;
acid is the generic name. ASA, a commonly used
for aspirin (or acetylsalicylic acid) in both the U.S. and
is the term used in Canadian product labeling. Aspirin is an
(OTC) medicine, and because it is so common and so
available, many people do not consider it a "real medication."
is a common misconception and aspirin is a very "real drug." Its
in staged decompression diving has been extrapolated from other
that aspirin has been prescribed for (1).
main use in diving is to prevent blood clotting and
aggregation. Although aspirin is referred to as a "blood
it does not actually "thin" the blood. Instead,
alter proteins in the blood that are responsible for
while antiplatelet drugs prevent platelets from clumping and
clots. Aspirin functions to make the platelets less 'sticky',
acting as an anti-coagulant. Aspirin is an aid; not a
for proper hydration, even though its main benefit to the
is to allow improved blood flow and gas transport by increasing
vitro and in vivo studies have shown that hyperbaric pressure
red blood cell (RBC) aggregation (2). Enhanced RBC
in pathologic states can cause increased clotting. Both
and clotting hamper the transport of gas which may lead to
number of hyperbaric related injuries.
It is known that the
of platelets is remarkably important in the
of decompression sickness (3).
investigation (2) examined the effects of pressure on RBC
in human volunteers. The hypothesis tested was that RBC
is increased during hyperbaric exposure. Subjects
in dives to 300 fsw in a chamber. Blood samples were taken
the surface, at 66 fsw, and at 300 fsw. The median aggregate size
of RBC/aggregate) of RBCs was significantly increased at depth.
deeper one goes, the greater the aggregate size. These results show
even mild pressure increases RBC aggregation in the human
Therefore, aspirin is used as a preventive measure to a
prohibitor of gas transport, which may lead to symptomatic DCS.
are some controversial lines within the diving community
the use of aspirin. All groups are aware of the later; the
comes from discussion of aspirins effect on blood
There are some who contend that aspirin will reduce blood
and therefore do more harm than good. Reduced blood viscosity
reduce gas tensions and therefore contribute to micro bubble
is unproven however, that aspirin will decrease the viscosity of
and contribute to micro bubble formation.
Decreases in systemic
(blood count of red cells) tend to decrease blood viscosity
promote microvascular vasomotion and tissue perfusion (4,5), whereas
abnormally high hematocrit increases blood viscosity and results in
and aggregation of the erythrocytes, capillary occlusion and
redistribution of the circulation.
study (6) examined the effects of aspirin and dipyridamole
dye-peer-id-a-mole -- its a powerful platelet aggregation
antithrombotic adjunct) on platelet function, hematology, and
chemistry of saturation divers. 24 divers were assigned randomly
4 treatment groups. Group I received aspirin (325
t.i.d. (ter in die, Latin meaning 3 times a day); Group II received
(75 mg) t.i.d.; and Group III received both drug regimens;
group IV received matching placebo.
procedures were followed. Treatment began 24-h prior
a 48-h saturation dive (inclusive of 17 hour decompression) and
throughout and for 3 days after the dive. A post-dive
in circulating platelet count was observed in all groups,
the group that received aspirin only. Platelet survival was
in all treatment groups. Five cases of Type I DCS occurred
were treated by recompression, two in the aspirin plus dipyridamole
two in the dipyridamole group, and one in the placebo group; none
the aspirin only group.
Blood chemistry and hematology profiles
that divers with decompression sickness had elevated GOT
oxaloacetic transaminase), GPT (glutamic pyruvic
and CPK (creatinine phosphokinase is one of several
usually released in the blood after a heart attack, an
of this form of isoenzyme in the blood is a diagnostic clue to
damage). Divers with DCS had more elevated cholesterol and
levels, and greater reductions in platelet count, platelet
4 and thrombin (an enzyme formed in the clotting) clotting time
most other subjects. Subjects receiving either aspirin or aspirin
dipyridamole had fewer changes in these parameters. Failure of
to potentiate, or add to, dipyridamole may be due to other
of aspirin such as inhibition of prostacyclin (PGI2 )
, a prostaglandin, is formed mainly in the blood vessel walls and
blood platelet clumping. Aspirin, in doses as little as 4 mg/kg
body weight, inhibits prostacyclin as well as thromboxane formation.
may induce or inhibit platelet aggregation and constrict
dilate blood vessels. For an in-depth overview on prostaglandin and
biosynthesis; the role of steroidal and non- steroidal
drugs; the reader is referred to an excellent review
Smith et al (7) )
particular study (6) seems to favour the use of aspirin in a
environment, however further studies of the role of
drugs such as dipyridamole in decompression sickness may be
These results indicate that the combination of aspirin and
offers no measurable advantage over aspirin alone. This
also suggests that antiplatelet drugs such as dipyridamole may
be a contra-indication for a hyperbaric environment.
another study examined the hematology and blood chemistry in
diving using antiplatelet drugs, aspirin, and VK744. Blood
and cellular parameters were studied before, during, and after
dives in a habitat, on two separate occasions. The results
previous observations and indicate that
loss of platelets may be related to sequestering of
platelets, possibly by microbubbles, and that the phenomenon
be inhibited by some antiplatelet drugs.
it should be stated that in vitro and in vivo research
demonstrates the influence of nutrition on platelet aggregation
clumping ie. eating fatty foods compounds the problematic blood
is effectively used by many staged decompression divers who
tolerate the drugs side effects. In general, sustained release
by divers, range from 325 mg to 600 mg, (single one time dose)
60 to 120 minutes before a dive. There does not appear to be a
or "magic" dose to provide for the best protection with the
amount of side effects. The anti-aggregating therapy usually
with hyperbaric treatment involves administration of
acid in low doses; 3.5 ~ 5 mg/kg of body weight (3).
one study (12), platelet functions were studied after
single doses of aspirin (75 mg, 150 mg, 300 mg, and 600 mg) in
males. Clotting time and platelet counts remained unchanged.
de-aggregation of platelets occurred only with 600 mg of
Another study (13) by Heavey et al, reports that an oral dose
aspirin (600 mg) causes rapid and substantial inhibition of
PGI2 production, but recovery occurs within 6
this implies that endothelial PGI2 synthesis would be spared most
the time during dosing once daily with even this relatively large
of aspirin (13).
another study (14), examined the effect of chronic
of variable low doses of aspirin on platelet
platelet count, bleeding time and clotting time to find
as to how low the dose of aspirin needs to be in order to have an
antiplatelet effect in individuals who require such therapy
over a longer period of time).
A statistically significant
in the platelet adhesiveness was observed in all the groups,
the best effect was exhibited by 50 mg of aspirin dose. Bleeding
was also increased in all the groups but statistically significant
were observed with 50, 75 and 100 mg doses.
far we have doses somewhere between 50 mg/day, minium for long
chronic dosing; 325 mg t.i.d. for up to 5 days dosing (15); to 600
one time minimum effective dosage. If one cares to search, they
find a myriad of studies for aspirin and effective dosages.
it is next to impossible to give any hard line "best effect
which attains the best of aspirins benefits with the least amount
aspirin's side affects. There are several brands of coated aspirin
as 'Entrophen 10', an enteric coated tablet of ASA, which are
in the gut instead of the stomach (650 mg effective for up to
hours or so). What is known however, is that antacids can decrease
effectiveness of aspirin.
aspirin is an analgesic and an anti-inflammatory, where high
are used, it may mask mild symptoms of DCS. Many antihystamines
corticosteriods used by divers for certain conditions, to aid in
of equalization, can have the same effect. Excessive bleeding may
be a concern from an acquired injury such as cuts, bruises, broken
etc. Bleeding into the middle ear or sinus from a squeeze may
special precaution as well. Every diver has minor trauma that
usually of little consequence. This can become a major problem if
diver is on perscription anticoagulants, however most authorities
Davis, DAN, etc.) agree that divers taking coumadin or other
is either a relative contra-indication or an absolute
to diving and therefore not an issue (16).
may have more benefits to the decompression diver, with less
effects than those of anticoagulant drugs such as coumadin,
added side bonus of aspirin in deep diving is of course, that
helps prevent pain associated with CO2 headaches commonly attributed
hard work and/or improper breathing techniques underwater. In short,
is a sign that something is not right, however it's
a sure sign of CO2 buildup. The need for proper, slow,
deep breathing technique during extreme depth diving
be overstated mind you.
Popovic P, et al. Levodopa and aspirin pretreatment beneficial in
decompression sickness. Proc Soc Exp Biol Med. 1982
Taylor WF., Chen S, Barshtein G, Hyde DE, Yedgar S. Enhanced
of human red blood cells by diving. Undersea Hyper Med
Reggiani E, et al. Blood coagulation processes in decompression
and hyperbaric therapy. Minerva Med. 1981 May
Messmer K. Blood rheology factors and capillary blood flow, in
G, Vincent JL (eds). Update in Intensive Care and Emergency
Vol 12, Tissue Oxygen Utilization. New York, Springer-Verlag,
Restorff WV, Hofling B, Holtz J, et al. Effect of increased blood
through hemodilution on general circulation at rest and during
in dogs. Pflugers Arch 1975; 357: 25-34.
Philp RB, Bennett PB, Andersen JC, Fields GN, McIntyre BA, Francey
Briner W. Effects of aspirin and dipyridamole on platelet function,
and blood chemistry of saturation divers. Undersea Biomed
Smith WL, et al. Prostaglandin and thromboxane biosynthesis.
Ther. 1991;49(3):153-79. Review.
Adam O, et al. Platelet aggregation and prostaglandin turnover in
during defined linoleic acid supply with formula diets. Res Exp Med
Temme EH, et al. Individual saturated fatty acids and effects on
blood aggregation in vitro. Eur J Clin Nutr. 1998 Oct; 52