Thromboembolism IT training Presentation Midwifery update Marie Lewis

The risk factors for thrombosis  major operations  trauma (fractures)  medical conditions  cancer and its treatment  stroke or paralysis  previous DVT  immobility/lack of movement  severe varicose veins  increasing age  pregnancy  some oral contraceptives  being very overweight  smoking  thrombophilia  long journeys

Major operations Major operations increase the risk of deep-vein thrombosis, particularly if the operation involves the lower half of the body (abdomen, pelvis and legs). During pelvis, hip or knee surgery, for example, the vein wall may be injured and this can promote thrombosis. Other factors that may increase the risk of DVT include the type of surgical procedure used, the duration of the operation, the type of anaesthetic, whether a long-term venous catheter (a tube used to introduce fluid into the veins) was required, and how long you have to remain in bed after the operation.

Medical conditions Certain medical conditions are associated with increased risk of deep- vein thrombosis (DVT). These include heart attack, varicose veins and inflammatory diseases. Poor circulation and immobility during prolonged bed rest are two important factors that increase the risk of DVT in patients who have these medical conditions.

Previous deep-vein thrombosis women who have already had deep-vein thrombosis (DVT), are more likely to get it again than someone who has never had this condition. This may be because they inherited some factors from their parents that make them susceptible to DVT, or because the previous episode of DVT altered the structure of the veins in some way to make another episode of DVT more likely.

Being very overweight Women who are seriously overweight, or obese, are at greater risk of developing deep-vein thrombosis (DVT). Weight is an important risk factor, particularly if you also have other risk factors. For example, seriously overweight patients are more likely to develop DVT after a major operation than patients who are not overweight. Smoking Although more scientific research is necessary, it may be that smokers are at greater risk of deep-vein thrombosis (DVT) than non-smokers. If you are a smoker, and you are also obese, your risk of DVT is increased still further.

There are a variety of medications and device options available to prevent or treat thrombosis.

Possible options for prevention or treatment include:  mechanical devices (e.g. elastic stockings, intermittent pneumatic compression)  low-molecular-weight heparin (LMWH)  unfractionated heparin (UFH)  low-dose aspirin  oral anticoagulants (e.g. warfarin)

Mechanical devices that have been shown to be effective in the prevention of deep-vein thrombosis (DVT) in patients at risk of DVT include elastic graduated compression stockings and intermittent pneumatic compression. They are most often used after a surgical operation. Elastic graduated compression stockings increase the rate of blood flow through the veins in your legs. Pneumatic compression is achieved by wearing a plastic stocking that intermittently fills with air and squeezes your leg. This compression enhances blood flow in the deep veins and stimulates your body to produce factors that help to dissolve small blood clots. These methods are particularly useful in patients with a high risk of serious bleeding. Mechanical devices Side effects no significant side effects. Potential drug interactions not applicable. Monitoring of therapy your physician will ensure that you know how to apply these mechanical devices correctly, and that you are aware of when and for how long you should wear them. Mechanical devices that have been shown to be effective in the prevention of deep-vein thrombosis (DVT) in patients at risk of DVT include elastic graduated compression stockings and intermittent pneumatic compression. They are most often used after a surgical operation. Elastic graduated compression stockings increase the rate of blood flow through the veins in your legs. Pneumatic compression is achieved by wearing a plastic stocking that intermittently fills with air and squeezes your leg. This compression enhances blood flow in the deep veins and stimulates your body to produce factors that help to dissolve small blood clots. These methods are particularly useful in patients with a high risk of serious bleeding. Mechanical devices Side effects no significant side effects. Potential drug interactions not applicable. Monitoring of therapy your physician will ensure that you know how to apply these mechanical devices correctly, and that you are aware of when and for how long you should wear them. Mechanical devices that have been shown to be effective in the prevention of deep-vein thrombosis (DVT) in patients at risk of DVT include elastic graduated compression stockings and intermittent pneumatic compression. They are most often used after a surgical operation. Elastic graduated compression stockings increase the rate of blood flow through the veins in your legs. Pneumatic compression is achieved by wearing a plastic stocking that intermittently fills with air and squeezes your leg. This compression enhances blood flow in the deep veins and stimulates your body to produce factors that help to dissolve small blood clots. These methods are particularly useful in patients with a high risk of serious bleeding. Side effects no significant side effects. Potential drug interactions not applicable. Monitoring of therapy your physician will ensure that you know how to apply these mechanical devices correctly, and that you are aware of when and for how long you should wear them.

Many patients with deep-vein thrombosis (DVT) have no obvious symptoms, although some may, for example, experience: swelling tenderness pain redness in their leg A further problem is that many other conditions produce similar symptoms to those seen with DVT, these include skin infections in particular, and muscle strains.

Diagnosing DVT and PE There are a variety of tests that your doctors can use if he/she suspects that a woman has have DVT or PE. Some of these tests require injection of a dye (contrast agent) to be injected into a vein, in order for your blood flow to be visualized.

Diagnosing Deep-vein thrombosis Doppler ultrasonography (B-mode sonography) Doppler ultrasonography (also known as B-mode sonography) is a non-invasive and painless method of diagnosing DVT. It is easy to perform and provides reliable results. Doppler ultrasonography uses sound waves to measure the flow rate of your blood. Your physician will place an ultrasound probe on your skin over a deep vein in your leg and will apply gentle pressure to compress the vein and halt the blood flow. When the compressed vein is released the blood flow will greatly increase. The changes in ultrasound that occur will provide information about the ease of passage of blood through the vein and hence will indicate whether blood clots are present

D-dimer testing D-dimer testing is a blood test, detecting the levels of D-dimer, a substance that is found after an important constituent of blood clots called fibrin has been produced and broken down. These tests provide results in a relatively short amount of time and they are used to rule out deep-vein thrombosis or pulmonary embolism, or confirm the results of other tests such as duplex scanning.

Duplex scanning Duplex scanning combines two forms of ultrasonography (Doppler ultrasonography and real-time B-mode ultrasonography) and provides more reliable results than either of these methods alone. A probe is placed on your skin over a deep vein in your leg and the operator will gently press down on (compress) the vein. If your vein is compressible, this indicates that there is no blood clot. If your vein resists compression, the inability to compress the vein indicates a blood clot. Real-time ultrasonography can help to visualize the blood clot through the use of a computer, which creates a two-dimensional image of your veins and any blood clots on a computer screen. For the diagnosis of clots in the calf of the leg and, in some conditions, Duplex scanning may give a false 'positive' result which would need to be confirmed by other tests. However, this is a painless and convenient test, which is readily available and is not expensive.

What can you do to decrease your risk? There are several actions you can take to decrease your risk of developing thrombosis.

Alert your physician of previous deep-vein thrombosis (DVT) You should alert your physician of any previous DVT if you: are about to undergo major surgery suffer a bone fracture are diagnosed with a medical condition, such as heart disease or cancer are prescribed prolonged bed rest or immobility are pregnant are in any other situation that increases your risk of DVT

Improving your circulation Make a habit of sitting with your legs together rather than crossed and perform leg exercises as often as possible while seated (e.g. squeezing your calf muscles, pointing and flexing your feet and wiggling your toes). Keep mobile as much as possible, for example, try to walk around for a few minutes every hour. Avoid wearing tight clothing that could restrict the flow of blood in your legs or arms. If your legs feel swollen and heavy at any time, have a lie-down with your feet higher than the rest of your body. This should decrease the swelling and discomfort.

Further reading Please spend some time looking at the RCOG guidelines..