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Guidelines dispute 'economy-class syndrome'

By Marnie Hunter, CNN
updated 5:31 PM EST, Tue February 7, 2012
New guidelines suggest that economy-class passengers are not at increased risk for blood clots.
New guidelines suggest that economy-class passengers are not at increased risk for blood clots.
  • Guidelines say there's "no definitive evidence" that traveling in coach increases clot risk
  • Most people with dangerous blockages have known risk factors, researchers say
  • They say window seating, especially for obese passengers, increases risk

(CNN) -- Good news for airline passengers sardined in coach: You're no more likely to develop dangerous blood clots than your first-class neighbors, according to medical guidance issued Tuesday for the treatment and prevention of life-threatening clots.

Drinking cocktails instead of water during your flight isn't likely to increase your risk either, according to guidelines from the American College of Chest Physicians that will appear this month in the journal Chest.

"There is no definitive evidence that dehydration, travel in economy class, and drinking alcoholic beverages on the flight are related" to the risk of pulmonary embolism or deep vein thrombosis, the guidelines say.

Most travelers who experience dangerous blockages have one or more known risk factors, including previous clotting, recent surgery, pregnancy, advanced age, active malignancy, estrogen use and limited mobility.

While the guidelines challenge the notion of "economy-class syndrome," certain space and mobility constraints do raise the risk of dangerous clots, the evidence suggests. Sitting in a window seat ups the risk, especially for obese travelers, according to the new guidelines. Also likely to be more vulnerable are very tall or short passengers and travelers who don't move during the flight.

The guidelines advise long-distance travelers against the use of aspirin or other blood-thinning medications to prevent clots.

Passengers with known risk factors are encouraged to book an aisle seat for long-distance travel, move around in the cabin and do calf muscle exercises. The guidelines recommend the use of compression stockings for long-distance travelers at increased risk. For other travelers, the guidelines recommend against using the stockings.

A panel of medical experts developed the new guidelines after reviewing the latest studies and evidence related to blockages of arteries in the lungs (pulmonary embolism) or blood clots in large veins, usually in the legs (deep vein thrombosis), addressing air travelers in addition to hospitalized medical patients and other nonsurgical patient groups.

Overall, the risk of a dangerous blockage for air travelers is very small. In the month following a flight, the likelihood of an incident is one in 4,600 flights, according to the report. The risk rises by 18% for each two-hour increase in the duration of travel, the guidelines said.

Travel by bus, car or train also appears to increase the risk of thrombosis, according to the guidelines.

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