The risk of surgical patients developing a blood clot is higher than previously thought, according to a study published in the journal BMJ late last year. U.K. researchers found that surgical patients overall were as much as 70 times more likely to be hospitalized for a blood clot than non-surgical patients. Although the risk was found to be lower among outpatients — they're 10 times more likely than non-surgical patients to develop clots — deep vein thrombosis is still a complication you should be concerned and proactive about. Failing to prevent, recognize and treat DVT before the clot travels to the lungs and causes a pulmonary embolism can prove fatal.

You may encounter several of the risk factors associated with post-operative DVT on a daily basis at your facility if, for example, you do a lot of lower extremity or abdominal procedures or treat a lot of elderly or obese patients. The best way to prevent DVT is to have patients up and moving around as soon as possible after surgery, but in some cases — even in the outpatient setting — that's not an option. The first preventive step you can take is to use pre-op interviews and the patient's medical history to assess the patient's relative risk of developing a blood clot. The degree of the risk (low, high or medium) will determine the level of prophylactic intervention needed, as well as whether and how long you should continue it after surgery.

Make sure you're well stocked with the supplies you'll need for anti-DVT prophylaxis, including anticoagulant medications, compression stockings and mechanical compression devices. Your staff should also be well-trained to identify patients and scenarios that will increase the risk of DVT, to position patients properly to avoid cutting off circulation in the legs and to follow-up with patients to make sure they aren't exhibiting any of the warning signs of a clot. While your facility is not likely to play a role in diagnosing and treating patients for DVT, which would typically develop days after they've already gone home, you can play a role in educating patients about the symptoms and what to do if they suspect a clot.

Use the step-by-step guide on the next page to help staff identify patients at risk for DVT and use the appropriate interventions to prevent post-op clotting. OSM

Step 1: Identify At-Risk Patients
Does the patient have any of the following risk factors?

• Personal or family history of circulation problems, DVT or pulmonary embolism
• Elderly
• Aged 40 or over and suffering from circulation problems
• Overweight or obese
• Cancer patient
• Varicose veins, compressed veins or swollen legs
• Prolonged immobility, such as a recent long hospital stay or bed rest
• Pregnant, has recently given birth or has a history of miscarriage
• Recent physical trauma
• History of heart failure

Does the procedure have any of the following risk factors?

• Operation of the lower extremities, abdomen or pelvis (limits post-operative mobility)
• Procedure lasting 45 minutes or longer
• General anesthesia

How high is the risk? Assess the number and severity of risk factors for each patient to determine whether he's at risk for DVT and, if so, whether the risk is low, medium or high. A DVT risk assessment tool is available online at www.perinatology.com/protocols/DVT%20Riskprint.htm.

Step 2: Administer Anti-DVT Prophylaxis
Depending on the patient's risk level, use 1 or more of the following strategies to prevent post-operative clotting.

• Anticoagulants administered at least 1 hour before the procedure and continued post-operatively. Patients with a history of clotting or circulatory issues may already be on blood-thinning medications such as warfarin or heparin. Low-molecular weight heparin (Lovenox) is a popular option in the surgical setting.
• Compression stockings worn intra- and post-operatively. As long as they don't interfere with the anatomy being operated on, these stockings, donned before surgery, are a simple way to promote circulation in the leg and therefore prevent clotting. Patients at high risk can continue to wear them at home until they're back to normal activity.
• Mechanical compression device. These devices go a step further than the stockings, pumping air into booties or sleeves that squeeze the leg to keep the blood flowing throughout the operation.
• Proper patient positioning. Avoid putting pressure on the back of the knee — the site of the popliteal vein — when positioning patients for surgery, as that can cut off circulation in the leg.
• Post-operative ambulation. The best way to prevent clotting is to have patients up and moving around as soon as is safe and possible after the surgical procedure. Patients undergoing operations on the lower extremities or abdomen are less mobile post-operatively, so may need to continue the interventions listed above to prevent clotting.

Step 3: Monitor, Detect and Treat Clots Early
In the case of most outpatient procedures, it's fairly unlikely that the warning signs of a blood clot will manifest while the patient is still in your facility. Usually a clot will form over the course of several days. But your staff should act quickly if patients complain of the following symptoms either in PACU or in post-op follow-up calls.

• Pain, swelling, redness or inflammation of the legs, ankles or feet. Signs of potential DVT.
• Chest pain or shortness of breath. Signs the clot may have progressed to the pulmonary embolism stage.

Instruct patients who have any of these symptoms to either call a physician or go to the emergency room immediately, depending on the level of perceived risk. Excessive swelling and inflammation of the calf or entire leg and all of the signs of pulmonary embolism should be treated as emergencies.