This is a summary of the paper:
‘Airline Travel: A randomised trial to assess the incidence of asymptomatic DVT and prevention by graduated compression stockings’
by J Scurr, SJ Machin SJ, S Bailey-King, IJ Mackie, S McDonald , Coleridge Smith PD, Lancet 12th May 2001.
The purpose of this study was to try to establish whether people flying long-haul developed clots in the leg. A lot of anecdotal information has been provided and there is now genuine concern that flying may cause clots, some of which can be very serious. Using a very sensitive technique we were able to detect very small clots in 12 out of 100 passengers flying long-haul. All these clots were small and in most passengers dissolved without treatment. In the remaining passengers anti-coagulants were given and the clots all dissolved before they became important. What this study has shown is that it is extremely common to develop small clots. We still do not know how many passengers will go on to get a bigger clot, either affecting the leg on a long-term basis, or travelling to the lung. At the same time we studied these passengers, a further 100 passengers were fitted with Medi-travel class 2 elastic stockings. these stockings squeezed the leg, promoting blood flow through the deep veins and preventing the deeper veins from enlarging during long periods of inactivity. We were unable to detect any clots in the deep veins in these 100 passengers, suggesting that the use of the Medi-travel elastic stockings is a very effective way of preventing the development of clot.
Four of the passengers wearing elastic stockings complained of pain in the superficial veins. These passengers had quite marked varicose veins. It is probable, therefore, that passengers with bad varicose veins are prone to the stocking rubbing on the veins and causing inflammation locally. Superficial thrombophlebitis is not a serious condition although it can be quite painful.
In summary, passengers who fly long-haul are at risk of developing small clots. It is probable that a number of these passengers will go on to develop bigger clots and more serious problems. The use of an elastic compression stocking (Medi-travel) is an effective way of reducing this risk.
Recommendations – Preventing Deep Vein Thrombosis:
Following this study and a proven link between air travel and the development of deep vein thrombosis, we would make the following recommendations: Any passenger with a history of clots or co-existing medical problems such as heart trouble, lung trouble, cancer or a recent operation should consult their own general practitioner before travelling. Your general practitioner can assess whether there is a real risk and advise you appropriately.
For Passengers in Good Health, We Would Make the Following Recommendations:
Before travelling obtain a pair of Medi-travel class 2 elastic stockings (mediuk.co.uk). These should be worn for the duration of the flight, both outbound and inbound. Before getting on the aeroplane take a reasonable amount of exercise and avoid drinking alcohol.
When on the aeroplane drink plenty of water and avoid excessive consumption of alcohol. Whilst you are sitting in your seat, move your feet up and down regularly and if you can get out of your seat, walk round the aeroplane. If you are not walking round your aeroplane and you are in your seat with your seatbelt fastened, moving the feet up and down does promote the flow of blood through the legs, particularly if you are wearing an elastic compression stocking.
We believe these simple measures are effective in reducing the risk of developing even a small blood clot, and certainly effective in reducing the risk of developing a large blood clot.