Lifeblood - E- Thrombosis
by Professor Beverley Hunt
REDUCING THE RISK OF E-THROMBOSIS
E-thrombosis is a new term, coined by a group of doctors in New Zealand led by Prof Richard Beasley, for the association between prolonged sitting working on a PC and the development of deep vein thrombosis (DVT) and then pulmonary embolism.
DVT is due to blood clots in the deep veins of the legs and can involve the calf and also thigh veins. Once a clot had entered the thigh, there is about a 10% chance of the clot breaking off and travelling up into the right side of the heart and then through into the lung artery, where it will block blood flow to the lungs. A large pulmonary embolism can block the entire blood supply to the lungs and thus is fatal. A smaller one can cause breathlessness and pain and even coughing up blood.
The association between prolonged sitting and deep vein thrombosis was first recognised in London during the blitz in World War II, when many people slept overnight in deck chairs. The added pressure of the wooden rung of the deck chair pressing on the back of the leg probably contributed. Travellers’ thrombosis is also due to prolonged immobility and indeed is more common in very tall and short individuals as well as those with other risk factors such as using the combined oral contraceptive pill, or travelling when unwell. Professor Beasley has also used the term “seated immobility syndrome” to cover e-thrombosis, travellers thrombosis and other conditions where immobility causes DVT. A recent study showed that just sitting immobile for an hour and a half reduces the blood flow in the popliteal vein (behind the knee) by 50%. This would predispose to DVT.
The first case of e-thrombosis described by Professor Beasley’s group was in a 32 year old man who developed a DVT and pulmonary embolism after sitting at for prolonged periods at work and at home in front of his PC. He regularly sat for 12 hours and sometimes for 18 hours; on occasion he did not get up and move around for 6 hours at a time. There has also been a recent legal case in the United States where a man won substantial damages from a large corporation after his 47 year old wife succumbed to a pulmonary embolism following a marathon 10 hour session at her PC meeting a deadline. Whilst this case did involved other risk factors for developing thrombosis, it was judged that it was the extended period of immobility brought about by pressure of work to complete a project which had lead to the pulmonary embolism and, subsequently her untimely death.
There have also been fatalities in a man who spent 72 hours in an internet café on a PC playing games. More recently a 20 year old man, Chris Staniforth, who regularly spent 12+ hours at a time gaming on-line with collaborators from across the world died from a pulmonary embolism which was deemed by the coroner to have been brought about by his marathon gaming sessions. Chris’ father, David, has set up an information website which brings together information about Chris’ death and to highlight the risks of developing DVT and pulmonary embolism at http://www.take-time-out.info We are currently working in collaboration with David to urge the gaming industry to put warnings about the risks of developing thrombosis from prolonged periods of immobility on their games, rather than on their websites which is current practice.
The incidence of e-thrombosis is not known, but may be quite substantial in view of the widespread use of computers at work and at home. In the U.S. in 2005 half of all employees use a PC at work and half had a PC at home, with increasing access to the Internet. There have been several recent articles linking our increasingly sedentary lifestyles to pulmonary embolism and the reality is that we are spending more and more time, both at work and in our leisure time, sitting immobile for long periods.
As a charity we have also had contact with people who have developed DVT and pulmonary embolism as a result of spending many hours at their PCs, either meeting deadlines or playing games. There have been several articles in the press related to this phenomenon and there has also been a US study published in the BMJ recently linking sedentary lifestyles to an increased incidence in pulmonary embolism, especially in women. It found that women who sat for a long time every day had double or even triple the risk of a dangerous blood clot.
New research has shown that the blood flow through your popliteal vein (behind the knee) falls off by 50% in only 90 minutes if you sit immobile. As yet the incidence of e-thrombosis is not yet known, but it is of increasing concern as more people spends many hours a day immobile looking at screens.
It would therefore seem prudent that if you spend long periods on a PC or a games console that regular foot and leg exercises are undertaken and regular exercise breaks are taken away from the PC every 90 minutes. It is also important to stay well hydrated with regular drinks, as dehydration is another risk factor for DVT.
Beasley R et al. eThrombosis: the 21st Century variant of venous thromboembolism associated with immobility. Eur Resp J 2003; 21: 374-376.
Kabrhel C, Varraso R, Goldhaber SZ, Rimm E, Camargo CA Jr.Physical inactivity and idiopathic pulmonary embolism in women: prospective study. BMJ. 2011 Jul 4;343:d3867. doi: 10.1136/bmj.d3867.