Travellers thrombosis (economy class syndrome) has
had a lot of coverage recently due to a number
of highly publicised deaths .It is estimated that over 2000
flyers each year die from the condition. This page hopes to
explain what this condition is and also give you some
practical advice to prevent it when undertaking a long
haul flight.
It has been known for many years that immobilisation can lead to the development of deep vein thrombosis (DVT) .This is a clot of blood that forms in the leg veins, when blood in the lower leg stops flowing when the calf muscle is not exercised. Long periods of immobilisation and the dehydrated atmosphere on board are thought to contribute to the problem.
Symptoms include a swollen and painful calf or thigh, an increase in skin temperature and skin discoloration (faint blue-red) at the site of the pain.
DVT is not dangerous in itself, but complications arising from it can be life threatening. If the clot breaks free from the veins and pass through the blood stream into the lungs (a condition called "pulmonary embolus") you could suffer from pain in the chest, which is worsened by breathing. Pulmonary embolus can also cause shortness of breath and the coughing up of small amounts of blood. If the blood clot is large enough, it can cause sudden death by travelling to the heart and lungs and interrupting the blood flow,
Research has brought peoples attention to the fact that air travel could increase the risk of developing DVT. Although more studies need to be carried out involving larger numbers of people, it is now believed that air travel can increase the risk of developing DVT if only because it increases both immobilisation and dehydration as mentioned above.
The blood oscillates between a fine balance of bleeding and
clotting. Flying pushes this balance in favour of clotting.
Whilst for the majority of passengers this does not cause a
problem, it could for some groups, including older
passengers and those with coexisting diseases. The real
problem is that people with genetic predispositions are not
easily identified and such defects probably account for the
small number of cases of DVT in young people.
 | Being immobile, especially in a seated position |
| Previous DVT |
| Hormonal treatment /contraceptive pill |
| Recent surgery or radiotherapy .Some experts advise that people who have had hip or knee replacements should postpone long haul flights for three months after surgery. If you have had this kind of surgery, talk to your family doctor, travel clinic staff or a member of the surgical team |
| Lower limb trauma |
| Abnormalities of blood clotting |
| Reduced oxygen and air pressure |
| Smoking |
| Pregnancy or recent parturition |
| Low humidity |
| Insufficient fluid intake |
| People over 40 years of age |
| Increased duration (4 hours or more) or frequency of travel |
| People suffering from cancer |
| People with heart disease |
| People with varicose veins |
| People over six feet tall, or under five feet tall because of the seated position |
It is important to remember that even if people have no apparent risk factors they are not immune from the possibility of developing DVT. Therefore, all travellers should take some basic precautions against DVT and those with known risk factors should take additional ones.
| Drink plenty of water at least two small glasses of water each hour |
| Avoid alcohol and caffeinated drinks |
| Move around the cabin as often as possible, at least once an hour |
| Flex legs, bending and straightening your legs, feet and toes while seated aprox every half-hour during the flight is advised to encourage blood flow |
| Do not sit with legs or ankles crossed .Do not use a footrest if it leaves your calves dangling or let your calves make prolonged contact with your seat. |
| Pressing the balls of your feet down hard against the floor will also help increase the blood flow in your legs. |
| take advantage of refueling stopovers where it may be possible to get off the plane and walk about |
| Wear loose fitting clothes |
| Consider wearing support stockings |
| Consider taking a pre-flight aspirin , avoid taking sleeping pills, which also cause immobility. |
| Do not sleep in an uncomfortable position |
| Breathe deeply at regular intervals to increase oxygen
intake
|
People at very high risk of DVT should consider either postponing their flight or the use of anticoagulation therapy .
General advice
All travellers should take some basic precautions against
developing DVT. This includes simple exercise such as
circling the ankles, pumping the feet, lifting the knees and
neck and shoulder rolls also keeping well hydrated
It is easy to become dehydrated on aeroplanes because
of the low humidity in cabins and because of eating and
drinking patterns people often adopt when flying.
Dehydration increases blood viscosity and hence the risk of
DVT. To avoid dehydration, travellers should be advised to
drink plenty of water and to minimise intake of alcohol,
caffeinated drinks and salty snacks. Some airlines are now
including this type of advice in in-flight
magazines. Make sure you have good medical insurance
for your trip. U.K citizens I travelling within the European
Economic Area, you may be eligible for an E111 form. This is
available from Post Offices or using the application form in
the Department of Health leaflet, Health Advice for
Travellers. This entitles you to free or
reduced-cost emergency treatment only, and therefore you must
also be insured.
Aspirin
Many experts advocate the use of preflight aspirin due
to its antiplatelet effect. A House of Lords report
recommends the use of pre-flight aspirin for people at
moderate risk of developing DVT, including people who take
the contraceptive pill or hormone replacement therapy.
The lack of clinical trial evidence for aspirin for
prevention of travel-related DVT meant that it was unclear
exactly what dose should be used. It has been suggested that
the dose should be between 75 and 150mg. One dose was
sufficient for all flight durations.
However, the Medicines Control Agency cautions that DVT is
an unlicensed indication for aspirin and it should be used
with caution in many patient groups including those with an
active peptic ulcer, asthma or on anticoagulation therapy.
People with known aspirin intolerance could ask their
general practitioner for clopidogrel. The use of heparin is
probably less suitable because of the practicalities of
patients administering it by injection just before a flight.
A natural alternative to aspirin is Pycnogenol a extract from pine bark with antioxidant and anti-inflammatory
properties .It can help and strengthen the connective tissue in blood vessels and the cardiovascular system.
Compression hosiery
Below the knee compression stockings e.g. Scholl, Activa are
available for preventing travel DVT. They offer the
equivalent of class I compression. . Class II stockings give
an unnecessary amount of compression for most people but
could be useful for people who fall in one of the risk
groups. Support tights are unlikely to be
beneficial.
People with arterial pathogenesis should not use
compression hosiery. In addition, people are occasionally
allergic to the components of stockings; this can be
overcome by wearing a cotton inner sock.
Scholl Flight Socks should be worn in place of normal socks throughout the flight. Always wear both socks and ensure that they are pulled up to just below the knee. The pack leaflet explains correct fitting and care of the socks. Scholl Flight Socks can also be worn at any time to improve leg comfort.
Not to be used if you have serious circulatory problems such as active arterial or venous disease.
- If you have a previous history of arterial or venous disease.
- lf you suffer from diabetes.
- lf you are currently using prescribed compression hosiery.
Three measurements are needed to ensure correct fitting:
1. Around the fullest part of the calf (B)
2. Around the ankle, just above the ankle bone (C)
3. The length of the foot (D)
Now use the table below to choose the size you need:
| Shoe Size Guide | 3-6 (35-39) | 6-9 (39-43) | 9-12 (43-47) |
| Calf (B) | 13-15" 33-39cm |
14-16" 35.5-41.5cm |
15-17" 38-44cm |
| Ankle (C) | 8.5-10.5" 21.5-26.5cm |
9.25-10.75" 23.5-28.5cm |
10-11.75" 25.5-30.5cm |
| Foot Length (D) | 9-9.5" 23-25cm |
10-10.5" 25.5-27.5cm |
10.5-11.5" 26.5-30.5cm |
Ultrafine Tactel Micro filaments with Lycra Soft for smooth stretching.
Three measurements are needed to ensure correct fitting:
1. Around the fullest part of the calf (B)
2. Around the ankle, just above the ankle bone (C)
3. The length of the foot (D)
Now use the table below to choose the size you need:
| Size | Small | Medium | Large | Extra Large |
| Calf (B) | 12-14.75" 30.5-37.5cm |
13-15.75" 33-40cm |
14-17.25" 35.5-43cm |
15-18.25" 38-46cm |
| Ankle (C) | 7.75-10" 19.5-25.5cm |
8.5-10.75" 21.5-27.5cm |
8.75-11.75" 22.5-29.5cm |
9-12.5" 23-32cm |
| Foot Length (D) | 8-9.5" 20.5-24cm |
9-10.25" 23-26cm |
10-11.5" 25.5-29.5cm |
10.5-12.75" 26.5-32.5cm |
retail
£9.25
Further information
The Lancet Volume 358, Number 9284 08 September 2001 Deep-vein thrombosis in long-haul flights
Department of health online site http://www.doh.gov.uk/dvt/
British Airways travel health online
http://www.britishairways.com/health/docs/during/travellers_thrombosis.shtml
page last updated 15th March 2002