DVT and flying
What about DVT following plane flights? (Economy class syndrome)
Recently, there has been a lot of publicity about people having venous thrombosis after travelling, particularly after plane flights. In fact there is nothing new about this. If you are immobile for long periods this increases the risk of DVT, similarly if you are dehydrated this also increases the risk (See Why does DVT happen?).
Both immobility and dehydration can occur on long journeys. There is probably nothing special about aeroplane travel itself. For example, you could just as easily get a DVT on a long coach journey. In general, the longer the flight the greater the risk. Although DVT can occur on plane flights, it is rare for people to develop blood clots which cause trouble or spread to the lung after a flight. You do not need to cancel your holiday! However there are some simple things that can be done to reduce the risk:
- Keep mobile. Make sure you move your ankles and legs to get the leg muscles working and pump blood through the veins. Stand up and stretch or go for a walk up the aisle from time to time;
- Wear some "flight stockings". These increase the speed of flow through the deep veins and help reduce the chances of a clot. It is important that they fit well and are comfortable. They only need to come up to the knee not the whole of the leg;
- Avoid dehydration. The air is very dry at altitude and it is easy to get dehydrated without recognising it. Drink plenty of water. Go easy on the duty free booze as this tends to cause dehydration;
- Aspirin? Taking 75mg (a quarter of a normal 300mg tablet) some hours before your flight may reduce your chances of a DVT slightly (but remember that Aspirin can sometimes cause indigestion in people with a tendency to it, if in doubt ask your GP);
- Special cases. For most people the risk of a DVT is extremely small and the common sense precautions above reduce it still further. A few people are at especially high risk, for example if they have had lots of blood clots already or if they have an abnormal clotting system. If you are one of these it would be sensible to obtain specialist advice prior to flying. You might benefit from covering the journey with injections of low molecular weight Heparin.