| Abstrakt: |
A deep vein thrombosis (DVT) is essentially the formation of a clot in the veins of the leg. This causes obstruction to the normal flow of blood in the limb which can result in pain and swelling of the leg. Occasionally, a fragment of the clot can break off and pass in the blood stream to the heart or major blood vessels leading into the lungs from the heart. This phenomenon is known as pulmonary embolism and has been estimated to occur in approximately 1% of cases of deep vein thrombosis. The long-term consequences of venous thromboembolism are not insignificant and include risk of recurrence and post-phlebitic syndrome. It is now generally accepted that there is an association between any form of long-distance travel and venous thromboembolism and therefore the alternative term of "travellers' thrombosis" has been suggested as an alternative to the term "economy class syndrome." Thromboembolism is rarely observed after flights of less than 5 h duration and, typically, the flights are of 12 h or more. Stasis in the venous circulation of the lower limbs is undoubtedly the major factor in promoting the development of venous thromboembolism associated with travel. Some individuals may be particularly predisposed to develop venous thrombosis because of congenital (inherited) deficiencies of natural anticoagulants, such as antithrombin, protein C or protein S. However, routine screening of passengers for these abnormalities is not justified or cost effective but may be of value in selected cases. It has also recently been suggested that exposure to mild hypobaric hypoxia in pressurized aircraft may also result in activation of the coagulation cascade but the data are conflicting. The risk of venous thromboembolism is largely confined to those with recognized additional risk factors for venous thromboembolism. Leg exercises whilst seated help to reduce the risk of DVT. There is also clear evidence from prospective and randomized clinical trials to support the use of compression hosiery as a preventative measure. By contrast, there is no firm evidence to support the indiscriminate use of aspirin as a routine prophylactic measure. Airlines have recently taken positive steps to address the issue of air travel and thrombosis. At the same time, the travelling public needs to be more aware of the issues and assume some responsibility for ensuring fitness to fly and the choice (and therefore cost) of their seats. [ABSTRACT FROM AUTHOR] |
