An older adult with a history of hypertension and atrial fibrillation develops a femoral neck fracture. What is the usual indication for a Greenfield filter?

A Greenfield filter, also known as an inferior vena cava (IVC) filter, is indicated primarily for the prevention of clot migration from the lower extremities to the pulmonary circulation, which can lead to a pulmonary embolism. In the case presented, the patient has a femoral neck fracture, which places them at increased risk of venous thromboembolism due to immobility and potential venous stasis. Therefore, the appropriate use of a Greenfield filter in this context would be to capture any thrombi that may form in the deep veins of the legs, preventing them from traveling to the lungs and causing a dangerous pulmonary embolism.

While cerebral embolism and atrial fibrillation are important considerations in patients with cardiovascular issues, the filter's primary purpose is not to prevent cerebral complications directly nor is it a standard intervention for atrial fibrillation. Similarly, while managing venous insufficiency is important in the care of an older adult, it does not relate to the specific role of an IVC filter. Thus, the focus of the Greenfield filter's use lies in preventing clot migration and subsequent pulmonary embolism, making this the correct choice.