Prevention of DVT (deep vein thrombosis) mainly involves using the foot pump and calf muscle pump to stimulate blood flow through the deep veins.
Blood is taken down to the feet through arteries and taken back to the lungs and heart via veins. About 90% of the venous blood is returned via the deep veins which are situated inside the calf and thigh muscles.
The foot pump involves squeezing of blood through a complicated venous plexus in the foot and the blood is then further squeezed towards the heart via calf and thigh muscle action on the deep veins.
When we sit for long periods the foot pump and calf muscle pump are inactive and this can lead to pooling of the blood (venous stasis) which in turn can cause a DVT. In a worst case scenario a piece of the blood clot (thrombus) can break off and block the main arteries to the lungs causing a pulmonary embolus (PE). A small PE may not even be noticed but a large PE can cause dramatic symptoms of severe chest pain, shortness of breath or coughing blood. In these circumstances a PE could be fatal so you need to get urgent attention by dialling 111.
Although small DVT's are quite common and usually don't cause symptoms, larger DVT's can cause calf or thigh pain and swelling of the leg. These symptoms should always be checked by ultrasound.
DVT's are more likely if you have long periods of sitting eg long car travel or long flights over 4 hours duration or if you have had recent surgery or a prolonged illness requiring bed rest. If you have had a DVT before or a superficial thrombophlebitis you may be at greater risk of a further DVT. It is worth having a thrombophilia screen if your doctor is concerned about a strong family history of DVT.
Prevention of DVT's can include:
1. wearing class 1 or 2 compression hosiery.
2. working the foot and calf to stimulate venous return.
3. getting up and walking around regularly if you are sitting for long periods.
4. keeping well hydrated on flights and avoid alcohol on flights.
5. the foot pump works better in people who do not have flat feet or high arches. If you suffer from these problems a good orthotic device will improve venous return.
6. varicose veins may increase the liklihood of DVT so having your varicose veins treated may be a good long term solution.
7. there is no evidence that aspirin reduces the risk of DVT