What is a DVT?
A deep vein thrombosis (DVT) occurs when a blood clot forms in one of the veins in your body, the most common site for this is usually in your legs. These clots can become very serious and dislodge and go to your lungs which can then cause a blockage of blood flow (this is then called a pulmonary embolism). More than 200,000 people per year experience DVT’s and of those patients, 50,000 experience complications from a pulmonary embolism (Larkin, Mitchell & Petrie, 2012).
What are symptoms of a DVT?
Some common symptoms of a DVT are:
- Swelling in the affected leg
- Feeling of warmth on the skin
- DVT’s can also occur with no symptoms
What are common causes of a DVT?
The blood clots of DVT’s can be caused by anything that prevents your blood from circulating or clotting normally, such as injury to a vein, surgery, certain medications and limited movement.
- Pregnancy increases the pressure in the veins in your pelvis and legs. The risk of blood clots from pregnancy can continue for up to six weeks after you have your baby.
- Birth control pills or hormone replacement therapy increase your blood’s ability to clot.
- Smoking affects blood clotting and circulation, which can increase your risk of DVT.
- Sitting for long periods of time, such as when driving or flying. When your legs remain still for hours, your calf muscles don’t contract, which normally helps blood circulate. Blood clots can form in the calves of your legs if your calf muscles don’t move for long periods.
What are SCD’s and what are they used for?
A Sequential Compression Device (SCD) is a safe non-invasive therapy for the prevention of a DVT. The SCD sleeve is wrapped around the calf muscle and provides a gentle compression or squeeze to promote the flow of blood back to your heart. The Sequential Compression keeps the blood moving and helps to prevent it from clotting. The SCD mimics the contraction of the calf during walking. The units are to be used while resting or in bed and are placed on patients during surgery to help prevent DVT’s as well. SCD devices sequentially inflate and deflate air-filled sleeves on the lower extremities. With knee-high sleeves, pressure starts at the ankle and moves toward the knee; pressure is approximately 45 mm Hg at the ankle and 35 mm Hg at the knee. With thigh-high sleeves, pressure at the thigh is 30 mm Hg. Each compression lasts approximately 11 seconds.
How to properly apply a SCD?
- Make sure the ankle lines up with the ankle indication on the sleeve.
- Wrap the sleeve around the patient’s leg and secure it.
- Place two fingers between the patient’s leg and the sleeve to ensure a correct fit.
- Attach the sleeve to the mechanical pump unit.
- To check connections, note the arrows that indicate accurate insertions from sleeve to pump on the pump side and on the patient side of the pump hose.
- Turn on the mechanical pump and confirm it’s working properly.
- Stay with the patient to assess sleeve inflation and deflation through one full cycle.
- Remove the sleeve once every 8 hours to assess skin integrity and neurovascular status of the extremity and to reinforce patient education.
- Know that the sleeve should be removed during bathing and when the patient ambulates.
- Instruct the patient to call for assistance when preparing to ambulate.
- Caution the patient never to ambulate with the sleeve in place due to the risk of falling.
- Make sure the sleeve is removed only for a short time daily.
What is some evidence supporting the use of SCD’s?
- In a study by Nagahiro et al that included 706 patients undergoing general thoracic surgery, 362 patients were given prophylactic sequential compression devices, and none of these patients developed a pulmonary embolism. Of the 344 patients who did not receive sequential compression prophylaxis, however, 7 developed a pulmonary embolism (Summerfield, 2006).
- The use of the SCD for the prevention of DVT is covered by most insurances as a post-operative take-home therapy.
- This method is effective in preventing thrombosis, and compares favorably with pharmacological prophylaxis.
- In a study done to compare different SCD systems the results yielded that there is no reason to believe that any particular compression is more or less effective in preventing DVT than any other system, Intermittent compression prevents DVT and prevents venous stasis (Morris & Woodcock, 2004).
SCD’s in the media
A new trend in professional athletes has been utilizing the use of compression devices to help mobilize fluid and speed recovery. This technology has been modeled from the SCD’s that can be seen in hospitals and other healthcare facilities. An example of this brand is “Normatec”, the theory is that it provides graded compression in a circumferential manner, it brings away cell metabolites such as lactic acid that can make your muscles feel sore but it also brings increased blood flow to help quicken recovery. There is still more data needed on the research of this product. The trend has spread throughout professional sports such as the NFL and NBA where this product can be seen being used, Good Morning America also did a segment on Normatec and highlighted a few professional athletes such as Lebron James as being an athlete who is actively using this product. While it is apparent the usefulness that SCD’s have provided in preventing DVT’s it is very exciting that there are now products out there that could help to improve professional athletes overall recovery and performance! Technology is continuing to rapidly improve and grow so it will be interesting to see how these devices progress into the future.
Some useful links and resources for more information!
Morris, R. J., & Woodcock, J. P. (2004). Evidence-Based Compression: Prevention of Stasis and Deep Vein Thrombosis. Annals of Surgery, 239(2), 162–171. http://doi.org/10.1097/01.sla.0000109149.77194.6c
Ashworth, S. C. (2014). Sequential Compression Devices and Clots. Critical Care Nurse, 34(6), 68-69. doi:10.4037/ccn2014264
Larkin, B. G., Mitchell, K. M., & Petrie, K. (2012). Translating evidence to practice for mechanical venous thromboembolism prophylaxis. AORN Journal, 96(5), 513-527. doi:10.1016/j.aorn.2012.07.011
Summerfield, D. (2006). Decreasing the incidence of deep vein thrombosis through the use of prophylaxis. AORN Journal, 84(4), 642-645. doi:10.1016/S0001-2092(06)63943-4