Drink May Prevent
In-Flight Blood Clots
NEW YORK (Reuters Health) - Drinking a beverage containing electrolytes
and carbohydrates during long airplane flights may be superior
to water in preventing the development of potentially dangerous
blood clots, Japanese researchers report.
"Consuming (electrolyte and carbohydrate beverage) during flight
resulted in lower urine volume and increased fluid retention, when
compared to water," lead author Dr. Hirofumi Okoshi, a physician
at Japan Airline's Medical Services in Tokyo, Japan, told Reuters
Dehydration is a concern on long airplane flights because it
may increase the risk of deep vein thrombosis (DVT), in which
blood clots form in the legs. DVT in turn increases the risk of
pulmonary embolism, a potentially deadly condition that occurs
when a blood clot lodges in the lungs.
The researchers conducted a test of 40 healthy men on a 9-hour
overseas flight. The passengers were randomly assigned to drink
either the fortified beverage or plain water immediately before
takeoff and four times during the flight. In total, the study
participants consumed about 1.3 liters of their assigned beverage.
Urine samples were collected every two hours during the flight
and blood samples were drawn upon landing. The passengers' body
weights were measured before boarding and again after landing.The
drink, called Pocari, contains sodium, potassium and carbohydrate,
and is manufactured by Otsuka Pharmaceutical Company in Tokyo,
Japan, the funders of the study. The findings were published in
a research letter in the February 20th issue of the Journal of
the American Medical Association.
The researchers reported that those who drank the fortified
drink had a significantly greater net fluid balance at the end
of the flight. In addition, those who had the electrolyte- and
carbohydrate-containing drink were less likely to have an increase
in the thickness of the blood in their legs, which may contribute
to blood clots.
"Supplying fluid in this situation is to prevent hypovolemia
(reduced plasma volume), a factor of blood clotting, and to prevent
concomitant elevation of blood viscosity," Okoshi explained.
The researchers conclude that the beverage may be a better method
of maintaining hydration than plain water during long airplane
Even if patients can't stay awake in order to consume the beverage
every two hours, he noted, a smaller amount may still have some
However, Okoshi pointed out that an increase in blood viscosity
and a reduction in plasma volume are only one of many clotting
factors involved in DVT, and preventing them will not guarantee
that clots don't form in the legs.
In all situations requiring people to sit for long periods of
time, he noted, "it is important for the passengers to be aware
of the risk factors, to periodically drink adequate amounts of
fluid and to exercise (their) lower extremities as a preventive
"I certainly believe dehydration as a cause of the thickening
of the blood is one of the contributing factors (to DVT)," noted
Dr. Bo Eklof, clinical professor of surgery at the University
of Hawaii, who recently attended a World Health Organization conference
in Geneva on the issue. "Theoretically, to add electrolytes to
the fluid is a positive idea. I think we need more research, but
the principal is correct."
SOURCE: Journal of the American Medical Association 2002;287:844-845.
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