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