What is DVT?
DVT is Deep Venous (Vein) Thrombosis, more commonly referred to as ‘economy class syndrome’ in the media. Of late, DVT has gained accelerated notoriety in the world’s press as the general public’s awareness of the problem has became more prevalent. The link between DVT and long haul air travel was first introduced in medical journals in the 1950s which highlighted the potential risk long periods of immobility during long haul flights presented. Even today, there remains a great deal of ignorance surrounding DVT, despite the fact that more people are flying than ever before.
First and foremost, DVT is not a problem restricted to air travellers, and anyone travelling for prolonged distances by car, bus or train are at equal risk. There is, in fact, no real evidence to suggest that air travel is responsible for an increased likelihood for DVT over any other situation where the condition may be arising.
In short, DVT is a result of extended periods of immobility (flights lasting in excess of five hours) which can lead to the development of a blood clot.
How to spot Deep Vein Thrombosis (DVT)?
DVT is very difficult to spot, as the symptoms tend to be similar to a number of conditions. Nevertheless, a type of ultrasound examination called a Doppler ultrasound, can show how fast the blood is flowing in a vessel, and can help to indicate whether a person may suffer from DVT.
Symptoms may occur a few hours after travelling, or even days later, though the majority of people experience the above symptoms during the flight. It is paramount to note, that many people naturally experience swelling of the ankles during a flight, which is not in any way associated with DVT.
As you can see, it is often difficult to recognise the symptoms of DVT until the occurrence of a pulmonary embolism. There may, however, be no symptoms at all until the pulmonary embolism occurs. In the majority of cases, there is a pain in the calf with redness, swelling and tenderness. It is important to note that DVT is distinguished from blood clots in superficial varicose veins in the legs, called phlebitis which is far less serious.
The Symptoms of Deep Vein Thrombosis
DVT is most common in the lower limbs, whereby pain, swelling and discoloration of the affected region may occur. The leg may also show a congestion of superficial veins.
Unfortunately, these are only general symptoms and in the majority of cases, symptoms are hard to initially discern. Clinical diagnosis of DVT is difficult, and a specialist is usually required to confirm diagnosis, as the symptoms of DVT can closely match a number of other medical conditions. In extreme cases, a pulmonary embolism may occur, which is the result of small pieces of the clot detaching and being carried through the blood stream to the heart and lungs. The product of an extensive clot in the leg, this may happen several days or hours after the formulation of the clot. This may result in chest pains, shortness of breath and even sudden death.
Our blood clots naturally as a means of protection against the severe blood loss from damage to veins and arteries. Blood is supposed to clot only when it is outside the blood vessel, however, in abnormal cases, the blood can clot while still in the blood vessel.
Those at Risk of DVT
More and more people are at risk of DVT today. With an ever increasing number of long haul flights every year, so through this natural growth, the number of individuals likely to be effected by DVT has inevitably also increased.
All passengers are susceptible to DVT, economy and first class flyers despite being dubbed ‘Economy Class Syndrome’ ( though cramped seating often found in economy class may compound the possibility of DVT occurring). DVT is not, however, exclusive to long haul travellers, and any mode of transport which entails long periods of immobility may be responsible for DVT. Every year DVT occurs in about 1 in 2000 people in the general population, ranging from less than 1 in 3000 in people under the age of 40 up to 1 in 500 in those over 80.
Some people are more susceptible to DVT than others. As a general rule, the risk of DVT automatically increases for those aged over 40, with less than 1 in 3,000 people aged under 40 effected by DVT, but 1 in 500 in those over 80. This can also be compounded by one or more of the following risk factors:
- Previous thrombotic episodes (especially pulmonary embolism)
- Documented thrombophilic abnormality
- Certain haematological disorders
- Prior history or currently suffering from malignant disease e.g. cancer
- Congestive heart failure
- Recent surgery (especially lower limbs)
- Pregnancy or recently had a baby
- Post-thrombotic Syndrome
- Chronic venous insufficiency
- Hormone treatment (including the oral contraceptive pill and oestrogen) containing hormone replacement therapy
- Recent major surgery or injury, particularly affecting the lower limbs or abdomen, especially hips or knees
- Research has also suggests that smoking, obesity and varicose veins can also compound your susceptibility to DVT.
In addition to the above, when flying DVT becomes more of a risk factor if you experience:
- Extended periods of immobility
- A cramped position for the duration of the flight (this may include keeping a seated posture for the duration of the flight)
- Dehydration as a result of alcohol intake.
- Compression of the popliteal vein by the edge of the seat.
It is vital to keep a level head, if you are concerned that DVT is a hindrance to flying. If you have any concerns or doubt, consult your local GP or travel clinic for expert advise.
The aviation industry still reluctantly admits a connection between the increased risk of DVT and flying. Above all with regard to the general public, those at greatest risk are travellers who fail to move about and exercise during the flight.
Preventing Deep Vein Thrombosis (DVT)
There are a number of ways to reduce the risk of DVT.
- Always drink plenty of water to avoid dehydration.
- Do not drink alcohol before or during the flight, as this can compound dehydration.
- Try and keep your thighs clear of the edge of your seat. Use foot rests as far as possible.
- Take a brisk walk for half an hour before the flight.
- Regularly go for a short walk to the restroom to keep your legs moving during the flight.
- Try a few simple exercises to keep your legs moving, by rotating your ankles, pointing your heel and toe alternately and lifting your knees whilst seated every half hour for a short period.
- Try and tense your leg muscles as regularly as possible throughout the flight.
- Wear elastic flight socks (elastic compression stockings) especially designed to reduce the risk of DVT. These are readily available at most pharmacies.
- The day before the flight, take a low dose of aspirin (100mg – 150mg), during the flight, and for three days following the flight.
It is possible to treat DVT with blood thinning drugs (anticoagulants), including warafin and heparin. Low doses of aspirin are believed to have a similar effect, though its effectiveness in preventing DVT remains disputed. The treatment of established DVT is carried out by administering an enzyme which can dissolve the clot – Tissue Plasimnogen Activator (TPA). If you are known to be a high risk patient of (click here for more information), then it possible to stop the blood from clotting, via the injection of low-molecular-weight heparin. This is a anticoagulant, which thins the blood. It cannot prevent DVT if a clot has already formed.
Despite the serious nature of DVT, it is vital to stress that occurrences of DVT are very rare, and only a very tiny minority will ever need to take medication during a flight to prevent DVT. The best advice for all travellers, is to regularly carry out a serious of series of simple leg exercises which keep the leg muscles moving throughout the duration of the flight.
DVT Flight Socks
In recent years, following the widening press coverage of DVT, there have been a number of efforts to introduce DVT-preventative devices.
Recognised by a number of health experts, these elastic compression stockings represent one of the most accessible steps towards the reduction of DVT. Ultimately, it would be hoped that all long-haul carriers provided them for free on all flights over five hours.
By applying a gentle pressure to the ankle, they help blood to flow around the body by squeezing it up towards the heart, which assists the body’s circulation.
At present, flight stockings can be purchased at good pharmacies for around £11 or $16. Their manufacturers claim that they can be worn up to 30 times, and are available in several sizes.