Facing lawsuits, Australia's two biggest airlines and British Airways are warning customers about the danger of potentially deadly blood clots for passengers on long, cramped flights.
Australia's two biggest airlines, Ansett and Quantas, said Wednesday they will print health warnings onto their tickets, and British Airways has started giving out brochures on how to prevent the condition.
The health warnings will advise long-haul passengers to wear loose clothing, eat light meals and avoid drinking too much alcohol to lessen the risk of potentially fatal blood clots.
The moves comes as a Melbourne law firm prepares to file compensation claims against 20 airlines for about 800 people who say they have suffered deep vein thrombosis while on flights.
Up to 400 people may be arriving at Sydney airport every year suffering from "economy class syndrome," or potentially deadly blood clots, an Australian surgeon said on Wednesday.
Reginald Lord, a surgeon at Sydney's St. Vincent hospital, says his hospital alone had investigated 122 cases of deep vein thrombosis in the past three years -- "a little less than one a week."
"Now we think, and this is just an estimate, that...there may be say 400 of similar types of patients arriving at Sydney airport annually," said Lord.
Lord, who is also a professor of surgery at the University of New South Wales, has been urging airlines for years to allow doctors to carry out proper studies of the condition, which occurs when blood clots form because of immobility. If the clots reach the heart or lungs, instant death is likely.
CBS News Correspondent Kimberly Dozier reports the emergency department that treats passengers arriving at London's Heathrow airport has dealt with 30 passenger deaths from the condition in the last three years.
Dr. John Belstead of Ashford Hospital says, "Remind people to exercise their legs -- if people can take aspirin, probably an aspirin is helpful, and support stockings or support socks are helpful."
Economy class syndrome can occur any time a person is immobilized for a long period. But the condition has recently been linked to air travel after several people on long-haul flights died.
While Dutch investigators have ruled out any link between blood clots and air travel, some airlines have begun to produce inflight videos showing passengers how to take mild exercises that would minimize the risk.
Melbourne law firm Slater & Gordon says it has 800 Australians on its books who want to sue 20 global airlines over economy class syndrome, and many more were likely to sign up as the condition receives greater publicity.
Lord said the number of people affected in Australia was small in proportion to the 14 million passengers who pass through Sydney airport every year. But at one in 100,000 as a "minimal estimate," the condition was common enough to have to be taken seriously.
"Some of us are persuaded that thee is a genuine link between travel and this condition," he said.
He cited as risk factors the pressurized cabins on aircraft, which slightly reduce oxygen in the blood, the constricted space and the fact that airline passengers frequently suffer dehydration.
"We are in a broad state of ignorance. We need to fill that in," he said.
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