published Thursday, July 17th, 2014

Cleaveland: Air travel can cause blood clots

By Dr. Clif Cleaveland

Commercial airlines continue to pack more people into economy-class cabins without regard to comfort or safety. I took two recent, long-distance flights that highlighted this issue.

Space is inadequate for leg and foot movement, especially if items are stored beneath the seat in front of you. Seat width has been diminished. An overweight seatmate immediately spills into your limited space. Rows of seats are situated so closely together that reclining one's seat is all but impossible. And if the person seated ahead of you vigorously tilts the seat backward, you are kneecapped.

Aisles are so narrow that, during serving of food and beverages, there is no prospect for moving about the cabin. Narrow aisles would seem to pose a significant problem should emergency evacuation be required. Seat-belt signs are illuminated for inordinate periods of time to keep passengers in their seats.

Acquisition of two or three additional inches of space between rows of seats requires payment of a premium. In effect, this is a payment for safety as much as an increase in comfort. Of course, relocation to a higher class of travel is always available for a hefty increase in ticket price.

I am unaware of any organized support on behalf of patient safety and comfort on passenger jets. In our anti-regulation environment, the likelihood of any government intervention on behalf of passengers seems remote.

The most common risk to passengers of cramped seating is thrombophlebitis -- or blood clots -- in deep veins of the legs. Lack of leg movement combined with steady pressure on the backs of thighs from firm seat edges impairs drainage of blood through veins. Sluggish blood flow promotes clotting. Acutely, these clots cause local swelling and tenderness. Swelling of the feet and legs follows due to impaired drainage of blood from the affected extremity.

Blood clots in deep veins are fragile and may break loose, traveling into the vena cava, the main vein that drains the lower half of the body. From there, the clot can pass through the right side of the heart and embed in the lungs, causing a pulmonary embolus. A small embolus may cause breathlessness, a rapid or irregular pulse, and sharp chest pain; a large clot may prove fatal. An embolus may not occur until days after the development of a clot in the leg.

Because airline passengers immediately disperse widely upon landing, there is no accurate data on the incidence or severity of thrombophlebitis and pulmonary emboli related to air travel, but such travel is one of the first things a doctor will ask about if you have a blood clot in your leg. Ultrasound studies of leg veins in passengers flying nonstop for 12 hours showed an incidence of blood clots in up to 4 percent of travelers.

Risk factors for clots include flights longer than four hours, age over 40, a prior or family history of blood clots, obesity, varicose (dilated) veins, recent surgery or injury, leg cast or brace, pregnancy or up to six weeks post-delivery, and cancer with or without chemotherapy.

Frequent leg movement is the most important preventive measure. Avoid crossing legs. Avoid prolonged sleep during which veins may be compressed for long intervals. Move around whenever possible. Non-alcoholic fluid intake should be increased. If you have risk factors for clotting, discuss with your physician the use during flight of pressure-gradient, below-the-knee stockings. Daily aspirin or other clot-preventers may be considered.

Bus, train and automotive travel also carry a clotting risk if segments of the journey are prolonged and passenger movement is restricted. If swelling of legs, tenderness over veins or localized redness or heat occurs following prolonged non-stop travel, seek immediate medical evaluation.

Contact Clif Cleaveland at

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