5.11 Deep Vein Thrombosis

Overview

Deep vein thrombosis (DVT) is a clot that forms in a deep, peripheral vein. DVTs usually develop in the lower leg, thigh, or pelvis, but they can also occur in the arm.^[1] See Figure 5.33^[2] for an image of a DVT in the client’s right leg, indicated by unilateral redness and edema as compared to the left leg.

Three main pathophysiological mechanisms involved in the development of a DVT (often referred to as Virchow’s triad) are venous stasis, hypercoagulability, and injury to a vein.^[3] Venous stasis refers to slow blood flow, often caused by immobility, medication therapies, and heart failure. Hypercoagulability may occur due to deficient fluid volume, pregnancy, oral contraceptive use, or smoking. Injury to a vein is often caused by major surgery (particularly the abdomen, pelvis, hips, or legs), fracture, or severe muscle injury. Venous wall damage may occur due to venipuncture, certain medications, trauma, and surgery. Chronic disease like cancer, heart disease, and lung disease can also increase the risk for developing DVTs, as well as other factors such as obesity, central venous access devices, inherited clotting disorders, and a previous history or family history of DVTs.^[4],[5]

Assessment

The lower extremities of clients at risk for developing DVTs should be routinely assessed for unilateral extremity edema, redness, warmth, and calf pain. The bilateral extremities should be examined simultaneously because DVTs can initially cause minor signs that are easily missed. Although Homan’s sign was a traditional procedure used to assess for DVT, current research indicates it is not sensitive or specific for diagnosing DVT and is no longer considered a criterion for DVT.^[6] Any signs or symptoms suspicious for DVT should be immediately communicated to the health care provider for urgent diagnostic testing.

Pulmonary emboli (PE) are a potential complication of a DVT and can develop quickly, even without noticeable symptoms of a DVT. A pulmonary embolism can occur when a clot from elsewhere in the body travels through venous circulation and gets lodged in the blood vessels of the lungs. This impedes blood flow, and impacted lung tissue dies. PEs are medical emergencies that require emergent treatment. Signs and symptoms of a PE include the following^[7]:

• Sudden difficulty breathing
• Tachycardia and/or irregular heart rhythm
• Chest pain or discomfort, which usually worsens with a deep breath or coughing
• Hemoptysis (Coughing up blood)
• Very low blood pressure, lightheadedness, change in level of consciousness, or fainting
• Sudden anxiety

Diagnostic Testing

Diagnostic testing for a suspected DVT includes a D-dimer and a duplex ultrasound, with the results available within four hours if possible.^[8]

• D-dimer is a blood test that is a marker for the presence of blood clots, specifically the breakdown products of fibrin that result from the dissolution of a blood clot. Elevated levels of D-dimer may suggest the presence of an active blood clotting process in the body. If the D-dimer test is negative, it means that the client probably does not have a DVT.^[9],[10]
• Duplex ultrasonography is an imaging test that uses sound waves to look at the flow of blood in the veins. It can detect blockages or blood clots in the deep veins.^[11]

If a PE is suspected, additional diagnostic testing is performed, such as a computed tomographic pulmonary angiography (CTPA), a special type of X-ray test that includes injection of contrast material into a vein to provide images of the blood vessels in the lungs.

Nursing Diagnosis

Nursing diagnoses for clients with a DVT that can form life-threatening emboli are based on the client’s assessment data, medical history, and specific needs. Nursing priorities of care include preventing pulmonary embolism, managing pain, administering anticoagulant therapy, and providing health teaching.

Nursing diagnoses guide the development of individualized care plans and interventions. Examples of nursing diagnoses related to DVT include the following^[12]:

• Acute Pain
• Readiness for Enhanced Knowledge
• Risk for Impaired Tissue Perfusion
• Risk for Bleeding

Outcome Identification

Examples of outcome criteria for clients at risk for developing a DVT or PE are as follows:

• The client will not experience a DVT during hospitalization for other medical or surgical conditions.
• The client will not experience a pulmonary embolism, as evidenced by absence of dyspnea and chest pain.

Interventions

Medical Interventions

Medical interventions for DVTs typically include administration of anticoagulants. In severe or chronic cases, thrombolytic therapy, inferior vena cava filter, or surgery may be performed.

Medication Therapy

Anticoagulants

Anticoagulants reduce the ability of the blood to clot, preventing the clot from becoming larger while the body slowly reabsorbs it and reducing the risk of further clots developing. The most frequently used injectable anticoagulants are unfractionated heparin (administered intravenously), low-molecular weight heparin (LMWH), and fondaparinux (injected subcutaneously). Anticoagulants administered orally include warfarin, dabigatran, rivaroxaban, apixaban, and edoxaban.^[13] All anticoagulants can cause excessive bleeding, so nurses must closely monitor for unusual bleeding and implement bleeding precautions to clients receiving anticoagulants. Nurses and providers monitor laboratory results to help ensure therapeutic levels of anticoagulation medication is administered. Clients are typically started on heparin injections and transitioned to coumadin to ensure that therapeutic impact is achieved more quickly.

Thrombolytics

Thrombolytics (commonly referred to as “clot busters”) work by dissolving the clot. They have a high risk of excessive bleeding compared to the anticoagulants, so they are prescribed for severe cases.^[14] Tissue Plasminogen Activator (tPA), also known by the generic name alteplase, is administered intravenously to dissolve severe clots blocking tissue perfusion but are most commonly used to dissolve clots or emboli causing myocardial infarction, strokes, or pulmonary embolism.

Surgical Interventions

Inferior Vena Cava Filter

When anticoagulants cannot be used or clients develop chronic cases of DVTs, a filter can be inserted inside the inferior vena cava to trap an embolus before it reaches the lungs.^[15]

Thrombectomy/Embolectomy

In rare cases, a surgical procedure to remove the clot may be necessary for preservation of life or limb. Thrombectomy involves removal of the clot in a client with DVT, and embolectomy refers to removal of an embolus.^[16]

Nursing Interventions

Nursing interventions primarily focus on preventing DVTs and PEs for clients who are at risk. If a DVT is diagnosed, nurses administer anticoagulants and analgesics, implement bleeding precautions, and monitor for excessive bleeding.

Nursing Interventions to Prevent DVTs

For hospitalized clients at risk, the following interventions are commonly implemented to prevent the development of a DVT^[17]:

• Encourage early ambulation or frequent leg exercises in postoperative clients or those who are bed-bound.
• Apply mechanical measures to prevent venous stasis, as prescribed, such as sequential compression devices (SCDs) or compression stockings.
• Administer LMWH as prescribed to prevent the development of clots.

Health Teaching to Prevent DVTs

Nurses teach the following information to clients who are at risk for developing DVTs^[18]:

• Move around as soon as possible after having been confined to bed, such as after surgery, illness, or injury.
• When sitting for long periods of time, such as when traveling for more than four hours, get up and walk around every one to two hours.
• Exercise your legs while you’re sitting by raising and lowering your heels while keeping your toes on the floor and tightening and releasing your leg muscles.
• Wear loose-fitting clothes.
• Reduce your risk by stopping smoking, maintaining a healthy weight, and avoiding a sedentary lifestyle.

If a DVT is diagnosed, nurses administer prescribed anticoagulants and manage discomfort by administering analgesics as needed, while continuing to monitor for signs and symptoms of a PE. Bleeding precautions are implemented for clients receiving anticoagulants with routine monitoring for signs and symptoms of excessive bleeding.

Evaluation

During the evaluation stage, nurses determine the effectiveness of nursing interventions for a specific client. The previously identified expected outcomes are reviewed to determine if they were met, partially met, or not met by the time frames indicated. If outcomes are not met or only partially met by the time frame indicated, the nursing care plan is revised. Evaluation should occur every time the nurse implements interventions with a client, reviews updated laboratory or diagnostic test results, or discusses the care plan with other members of the interprofessional team.