Travelling overseas? Beware the window seat
The Australian Prescriber is a journal published four times a year and provides independent objective and up-to-date information about medicines to health care practitioners – doctors, dentists and pharmacists.
The latest issue (December 2009) discusses plane travel and the possible problems with DVT – deep venous thrombosis. The topic is timely with many travellers heading to and from Australia during the holiday season.
DVT is a condition in which a blood clot, or thrombus, develops in a deep vein – usually in the lower leg. Symptoms of DVT are principally pain, swelling and tenderness around the affected area. The good news is that DVT can be detected by medical testing and effectively treated.
However, if the DVT is not identified and treated, there is the risk of developing a so-called thromboembolism. This can occur when the blood clot breaks away from the vein in the leg and travels through the body to the lung, where it lodges and blocks blood flow. The chest pain and breathing difficulties from what is then known as a pulmonary embolism might be the early signs of a fatal outcome.
Some eight years ago, following the death of a young English woman returning home from a trip to Australia, the World Health Organization (WHO) initiated a study to determine the causes of and possible prevention strategies for DVT. This project was known as the WRIGHT study – or WHO Research Into Global Hazards of Travel.
The WRIGHT study showed that the risk of developing DVT nearly doubles after travel lasting four hours or more. But it seems the risk applies not only for travel by plane – train, bus and automobile passengers also have that same increased risk when they remain seated and immobile for more than four hours.
It all happens because periods of prolonged immobility cause stagnation of blood in the veins, thus promoting clot formation.
Interestingly, plane travellers who have the window seat are more likely to get a DVT. Apparently window seat occupants just hate to leave the view to exercise their legs.
Apart from immobility and duration of travel, there are a number of other factors which increase risk. These include being overweight, being very tall or very short (taller than 1.9 metres or shorter than 1.6 metres) having varicose veins and the use of so-called combination oral contraceptives.
One study within the project, which examined airline travel in particular, found that taking multiple flights over a short period of time also increases the risk. This is because the risk of DVT does not go away completely after the flight is over; the elevated risk remains for up to four weeks.
The Australian Prescriber article summarises a number of comparatively high risk factors. These include recent surgery, active cancer, and congestive heart failure; but prolonged immobility during long haul flights remains the major problem – and this risk factor is largely preventable.
Doing regular sprints through the cabin is not usually practical, but exercising the calf muscles with up and down movements of the feet at the ankle joint will keep the blood flowing – and you can certainly do that from your window seat.
For those of us in the low risk category for DVT, the best options are keeping mobile and keeping well hydrated – plenty of water and fruit juice – but we should limit our intake of alcohol and caffeine containing drinks.
There is no evidence that aspirin protects against DVT; but some studies have shown that wearing lower-leg compression stockings might help.
If you have a high risk factor, or even a combination of moderate risks, check with your doctor before travel; an injection of what’s known as low molecular weight heparin may be suitable.
It used to be called “economy class syndrome”, but if doesn’t really mater in which end of the plane you travel, if you don’t move around you risk a DVT.
So before you make your next move pick up the Travel Health fact card from your nearest Self Care pharmacy (locations are on the Pharmaceutical Society’s website at www.psa.org.au/selfcare). There’s more information about DVT and many other travel health issues as well.