Tips for Preventing Blood Clots while Traveling

Safe Travels: How to Prevent Blood Clots during Long-Haul Trips

Thanksgiving has traditionally been the busiest travel holiday in the U.S., and this year is no different, with nearly 51 million Americans expected to be on the move via car, plane or train - the most in more than a decade.

Blood clots can be a serious threat to the body while traveling, especially on flights. University of Maryland Vascular Surgeon, Dr. Tanya Flohr, provides her top tips for preventing this potential medical emergency. 

Q: What are the health risks associated with long-haul flights?
Dr. Flohr: The most common risk associated with flights lasting more than four hours is venous thromboembolism. The most common forms of venous thromboembolism include deep venous thromboses (DVTs), pulmonary embolisms, and superficial thrombophlebitis.

Deep venous thromboses are blood clots that occur in the deep veins (the veins that travel along the bones) of the legs or arms. Sometimes pieces of DVTs can break off and travel to other veins. Sometimes DVTs can grow or lengthen in size and prevent the blood in the venous circulation from draining properly. 

Pulmonary embolisms occur when a blood clot from a vein travels to the pulmonary arteries (the blood vessels between the right side of the heart and the lungs). If a pulmonary embolism is large enough, it can prevent blood from being oxygenated by the lungs.

Superficial thrombophlebitis is a blood clot in the superficial venous system of the upper or lower extremities. Very infrequently do these blood clots travel to other locations.
Q: Who is at greater risk of developing those risks?
Dr. Flohr: People who have a history of thrombophilia (known increased risk of forming blood clots), obese individuals, smokers and those taking oral contraceptives are at increased risk for developing venous thromboembolism. People with thrombophilia are 16 times more likely to develop DVTs with long-haul flights. People taking oral contraceptives are 14 times more likely to develop deep venous thromboses.

Other passenger-related risk factors predisposing people to venous thromboembolisms include chronic heart disease, cancer, recent surgery or trauma, pregnancy or recent pregnancy, history of venous disease, and being of age 40 or older.
Q: Why is it that air travel can cause these conditions?
Dr. Flohr: Passengers of long-haul flights often experienceprolonged immobility, cramped sitting position, low air pressure, decreased percentage of oxygen in the blood, low humidity and dehydration. Cramped positioning and sitting for prolonged periods of time can lead to the sluggishness or compression of venous blood flow particularly through the lower leg. 

Q: Can short flights cause blood clots, too?
Dr. Flohr: Travelers exposed to prolonged seated immobility are at risk of developing venous thromboembolism. The risk increases with the increased number of flights in a short period of time, and absolute increased risk for flights of 12 hours or more.

Q: What can travelers do to help prevent DVTs?
Dr. Flohr: Leg exercise during long travel is the best way to prevent DVTs.  If you can, walk around the cabin.  Exercise prior to boarding the plane by walking for 30 minutes.  Drink plenty of fluids to hydrate yourself, and avoid beverages such as tea, coffee and alcohol which are likely to dehydrate. Keep your legs elevated as much as possible on the foot rest or above your carry-on luggage. 
Q: What are the symptoms of blood clots/DVTs?
Dr. Flohr: For DVTs of the legs, tenderness and swelling of the affected leg typically are the symptoms experienced. Symptoms can be similar if the arm is affected. DVTs occur most commonly below the knee in the deep veins of the calf. Fever is also a very common symptom of DVTs and any venous thromboembolism. If the blood clot travels to the lung circulation (pulmonary embolism), symptoms experienced might include shortness of breath, chest pain, anxiety and elevated heart rate.
Not uncommonly, DVTs are completely asymptomatic (no symptoms).  In a prospective study by Schwarz and colleagues comparing the occurrence of blood clots in people that recently had a long-haul flight vs. people that had not traveled, 70% of the group that had taken a long-haul flight and were diagnosed with a DVT were asymptomatic.

Q: What should someone do if they suspect they have a blood clot?
Dr. Flohr: For a suspected DVT, contact your primary care physician to be seen within 24 hours. If this is not possible, go to a local urgent care center or emergency room for evaluation. There, a trained physician can evaluate your vital signs, assess your physical findings and have an ultrasound performed to look at the deep veins of the extremity of concern. When a person is short of breath and a pulmonary embolism is suspected, go to your local emergency room for evaluation.

Dr. Flohr is an assistant professor of surgery at the University of Maryland School of Medicine, and a vascular surgeon at the University of Maryland Vascular Center. She sees patients in Baltimore City and Waldorf. Meet our vascular team.

For more information about our services or to schedule an appointment, call 443-552-2900.