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Essay on "'Economy-Class Syndrome':
Blood Clots and Air Travel"
by Aubrey Weese
A discussion of the article 'Economy-Class Syndrome': Blood Clots and Air Travel by Sally Squires, which was published in The Washington Post.
Introduction
The article "Economy Class Syndrome" by Sally Squires begins with the story of a woman who recently died from a blood clot forming in her legs during air travel. This incident has awakened airlines to the seriousness of economy class syndrome, or deep vein thrombosis, the formation of blood clots in the deep veins of the legs which can happen during long periods of inactivity such as on cramped airline flights. Symptoms usually don't appear until about 13 days after the clot forms, and can include swelling, tenderness, or a dull ache in the leg. It's also possible for there to be no symptoms. Deep vein thrombosis is especially dangerous, and can be fatal, if a clot later breaks off and travels to the lungs.
People who are obese, smokers, take oral contraceptives, or live sedentary lives are at the highest risk for deep vein thrombosis. Those who are at high risk may be able to reduce their risk by taking blood-thinning medications such as heparin, warfarin or aspirin. It is also a good idea to try to move around as much as possible during an airline flight. The article recommends getting up and walking around at least once every hour, and if you can't do that, to do leg exercises in your seat such as flexing and pointing your toes, and rolling your ankles.
Library Research
| For my library research I will discuss what causes a clot to form, and
how they form. A clot forms in response to damaged tissue. The particles
in the blood that form clots are called platelets. We have about 250,000
platelets in each cubic centimeter of blood, although they account for less
than one percent of our total blood volume (Vogel, 1992). These platelets
normally flow through the veins inhibited without sticking to anything. But
if the wall of the vein is damaged, the underlying tissue is exposed, and
in this tissue is a protein called collagen. The presence of collagen causes
platelets to become sticky, and they stick to the damaged vein wall. The
presence of sticky platelets causes other platelets which are floating by
to also become sticky, and add on to the clot (which is an example
of a positive feedback loop). These platelets eventually coagulate into an
insoluble, fibrous protein called fibrin.
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The body has a mechanism to prevent the clot from getting too big. As it grows, it extends into the middle of the vein, where blood flow is faster. The fast flow provides a shearing force which offsets the accumulation of platelets. It also helps to move away the chemicals in the blood that cause clot formation to begin, and well as bring our natural anti-coagulant chemicals onto the scene, which are normally found in the highest density in our capillaries (Hirsh and Hoak, 1996).
Well, blood moves more slowly in the veins of the legs when people are sedentary for a long period of time. This is because the blood has to move upwards, back towards the heart, against in the force of gravity. The veins in the legs are designed in such a way that muscle contraction, such as walking around, will increase the pressure in the veins, propelling the blood upwards (Vogel, 1992). This is why if you sit with your legs dangling, it actually takes concentration to get them to stay still. The legs want to move because this movement helps keep the blood flowing.
This slow movement of blood can cause clots to grow larger than they normally would or form where they normally wouldn't. As the American Heart Association says, "The thrombogenic effects of activation of blood coagulation are amplified by stasis and counteracted by rapid flow" (Hirsh and Hoak, 1996). And that is why people who ride on airplanes for a long period of time tend to get deep vein thrombosis.
Conclusions and Impact
I chose this article while I was looking through the Washington Post looking for biology articles because it looked interesting. I take long trips on airplanes sometimes to visit my parents who live in California so it is also something that is applicable to me. The article I did last semester was on a subject that was hard to research, and this one looked like it would be easy and straightforward to find sources for.
I learned a lot more about what causes clots to form and what I can do to prevent it. It is important to know this information because of the risk of Pulmonary Embolism, a blood clot dislodging from the vein and getting caught in an artery in the lung, which can be fatal. It is also good information to know because the risk for deep vein thrombosis increases during pregnancy and pulmonary embolism is the number one cause of death during childbirth (Hirsh and Hoak, 1996).
Taking Biology 104 has increased my understanding of the circulatory system, which gave me a better frame of reference to understand this article.
Literature Cited
BUPA. (2000). Deep vein thrombosis. Mosby Fact Sheets. [On-line], 14 paragraphs. Available: http://hcd2.bupa.co.uk/fact_sheets/mosby_factsheets/Deep_Vein_Thrombosis.html [Accessed 2000, Apr 1].
Hirsh, J., and J. Hoak. (1996). Management of Deep Vein Thrombosis and Pulmonary Embolism. American Heart Association.
Squires, Sally. (2000). 'Economy-Class Syndrome': Blood Clots and Air Travel. Washington Post.
Vogel, S. (1992). Vital Circuits. Oxford University Press, New York.