Travel News Monkey

When you think of ailments caused by flying, what do you think of? Jet Lag? Travel sickness? Deep Vein Thrombosis, or DVT, is another ailment that has received a fair bit of attention this decade, especially by those who travel by plane. While it’s not caused just by air travel, with over a billion passengers flying each year, excluding corporate flyers, it’s not surprising the focus has been on flight-induced DVT.

What Is Deep Vein Thrombosis (DVT)?

Deep Vein Thrombosis refers to blood clots formed in the deep veins of the leg, which can occur during long period of cramped seating – such as on a bus, train or airplane. The condition has been declared relatively rare, occuring in only one or two of a thousand people. Preexisting risk factors determine the actual likelihood of getting DVT. The two veins most likely to be affected are the femoral and popliteal veins, both in the leg.
While it is still considered fairly rare, it can be a serious health risk for air travellers, especially those on regular long-haul flights. Frequent flyers are at even greater risk due to increased exposure to specific risk factors.

Why Does It Occur?

DVT can happen for a number of reasons, though there is a strong correlation to air travel. Some of the risk factors are as follows.

1. Extended bed rest or sitting. Long flights are a particular contributor.
2. Low humidity of pressurized air cabins. This causes dehydration, which thickens the blood and thus increases the risk of blood clots.
3. Virchow’s Triad: (1) decreased blood flow; (2) increased thickness of the blood; (3) damage to blood vessel walls.
4. Obesity.
5. Cancer.
6. Use of oral contraceptives.
7. Smoking. Especially amongst women taking oral contraceptives.
8. Recent miscarriage, giving birth afer 35, or being on estrogen therapy.
9. Varicose veins.
10. Family history of blood clots.
11. Past a certain age. Advice varies, and this milestone has been variably indicated as 40, 50 or 60 years.
12. Recent surgery or trauma, especially in the abdomen, and or legs – especially hips or knees.
13. Hormone replacement therapy.
14. Circulation or heart problems.
15. History of inflammatory bowel disease.

A fairly length list of factors is available at BJSPH.

Who Does It Affect?

Since celebrities and politicians are most likely to fly frequently and thus be exposed more often to some of the risk factors of DVT, they are more susceptible to it. Starlet Anna Nicole Smith’s son, who died of a massive heart attack at the age of 20, shortly before Smith’s own death, might have had DVT. One theory is that she died of a blood clot, given that women over 35 who give birth are more susceptible to doing so, and having given birth recently. US Vice President Dick Cheney, who recently completed a 25,000 mile tour through Asia, was diagnosed with DVT after complaining of pain in the left leg. In addition to sitting on a plane for 65 hours over nine days, he has a history of blood clotting and has suffered four heart attacks.

That said, anyone who flies frequently or on long-haul flights is susceptible to DVT, especially if various risk factors are present. While only 1-3 people per 1000 in the UK are reportedly developing DVT, thousands of people each year in the UK might be dying of DVT directly or indirectly, whether or not related to flight. Flight-related clots might also be misdiagnosed or autopsies may not show the cause of a clot. It’s quite possible that due to some (American) airlines’ insistence on remaining seated with your seatbelt fastened, more people may be suffering from DVT than actually being diagnosed. Early symptoms do not always show clearly, or a connection with them and DVT is not always drawn.

What Are Some DVT Symptoms Or Aftereffects?

While DVT may be linked with certain symptoms, the presence of these symptoms alone is not always sufficient to indicate DVT. Symptoms and aftereffects of DVT include:

1. Swelling of one ankle and not the other.
2. Swelling of a calf or thigh. Usually the swelling occurs below the clot, moving along the deep leg veins.
3. Localized pain or tenderness in calf or thigh, or soreness in the joints.
4. Discoloration or redness of ankle, calf, thigh or feet.
5. Fever.
6. Cough.
7. Increased heart rate.
8. Breathlessness.
9. Chest pain.
10. Palpitations.
11. Ulcers from blood pooling in the lower leg.
12. Blood clots
13. Death from pulmonary embolism (PE), which has a connection to DVT

People do not die of DVT per se, but the complications from DVT can be fatal. Presence of any symptoms are not sufficient to conclude that someone has DVT. Rather, family and personal medical history, and travel history, have to be taken into account as well.

How To Avoid DVT

Here are some tips for avoiding DVT. (Prevention really is the best cure in this case.) While the tips are aimed at air passengers, most apply for other modes of travel as well.

1. Comfort.Wear loose clothing for comfort, and to prevent constriction.
2. More leg room.Get a seat with lots of leg room. Sometimes this means getting to the bus station or airport early. DVT is sometimes called the economy class syndrome, affecting travellers in cramped seats. Airlines seem unconcerned about the chances of DVT due to cramped seating. If you are susceptible to blood clots, you may need to purchase an upgraded seat for more leg room. Some planes may have movie theatre-style flip seats, which may help.
3. Movement.Get up and walk around, especially on long flights. Your legs need to be exercised at least once every one or two hours. Stretch your body in-seat as well, but don’t cross your legs as that compresses veins. Arm bends, forward abdomen bends, and other simple exercises [PDF, 1 pg] will help circulation.
4. Elevate your feet.Put a piece of baggage under your feet while flying, to relieve stress on your lower back. Generally, make sure your blood is circulating while sitting, even if you can only wiggle your toes and do heel raises or foot pumps. Only massage your legs if you are not susceptible to blood clots, else this might dislodge a clot.
5. Avoid sleeping pills.Avoid any medication that wil leave you motionless during travel, whether you are asleep or not.
6. Hydrate.Pressurized cabins make the air during a flight dry. Drinking water before and during flight keeps you hydrated. Avoid coffee, tea, soft drinks and alcohol.
7. Use DVT socks/ support hose.Aka compression socks or stockings. These apply maximum pressure lower down the leg, and minimum pressure up higher, thus reducing the chance of blood clots. Here are a couple of Google Videos explaining the use of compression stockings.
8. Anti-coagulants and blood thinners.Aspirin, Heparin and Warfarin are sometimes prescribed to prevent DVT. Check with your doctor before you fly.
9. Quit smoking.This is especially important if you take oral contraceptives or for any of the other reasons that you may be more susceptible to clotting.
10. Split up trips.
    Australia tends to be one of the few destinations where most inbound flights are long-haul trips because of geography. Aside from that destination, split up your trips into separate legs, possibly using some alternate transportation, or at least with stopovers.
11. Have surgery.
    Ian Anderson of British folk rock band Jethro Tull tells a story of how he tore an ACL in his leg but continued to tour for several weeks instead of having immediate surgery. This resulted in painful swelling, which he eventually had to have treated during a stopover in Australia.
12. Exercise between flights.If you are a frequent flyer like US Vice President Dick Cheney, make sure that you get leg exercise between flights. As mentioned above, Cheney spent 65 hours on a plane over nine days, and was later diagnosed with DVT.

How To Treat DVT

Diagnosis of DVT is typically done using either an ultrasound or venography X-ray. Most treatments are to either prevent the enlargement of a clot, to prevent its breaking, or to prevent additional clots. Common treatments are anticoagulants and blood thinners. Anti-coagulants are typically taken before DVT occurs, as they cannot break down existing clots. Blood thinners are prescribed after the fact, and usually for 3-6 months for the average patient (lifelong if the patient is prone to recurrence). If blood thinners cannot be taken, a filter may be installed in the inferior vena cava leading to the heart, to prevent a clot from reaching the heart or lungs. Excercise is part of the treatment regimen as well.

Summary

While DVT or Deep Vein Thrombosis is supposedly rare, the condition may be more common than diagnosed, especially for frequent flyers and/or those people bearing certain risk factors. Travel insurance should be a consideration, as medical costs can be significant. Check with a doctor pre-flight before taking any preventive medications, even aspirin.

This entry was posted on Tuesday, March 20th, 2007 at 5:25 am and is filed under Airlines. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.