Long distance air travel can be dangerous for patients who have a blood clot or who are at a high risk of developing blood clots, reports the Centers for Disease Control and Prevention. However, patients can take certain precautionary steps to reduce the risk of complications due to blood clots when flying.
Traveling by air for more than four hours can increase the risk of blood clots forming in the deep veins, according to the Centers for Disease Control and Prevention. This is especially the case if the patient sits still in confined spaces for a long time. Some evidence suggests that low air pressure in planes affects the blood's coagulation system, increasing the risk of blood clots, suggests The New York Times. The dryness of air in the planes may lead to dehydration, which causes blood to become more concentrated and increases the risk of blood clots, notes the Hospital for Special Surgery.
Precautionary measures such as walking the aisle whenever its safe and doing toe-to-heel exercises while seated can reduce the risk of complications due to blood clots while traveling, according to the National Blood Clot Alliance. The patient should also wear compression stockings, loose-fitting clothes and drink enough water. Doctors may prescribe low-molecular-weight heparin before a long distance flight to reduce the risk of complications due to blood clots.