Pulmonary Embolism II: Diagnostic Studies and Interprofessional Care

CT angiography (CTA) is the preferred diagnostic tool, using intravenous contrast to visualize the pulmonary vasculature and identify emboli. A ventilation-perfusion (V/Q) scan is an alternative for patients unable to receive contrast, combining perfusion imaging with technetium-99m and ventilation imaging using radioactive gas inhalation to assess lung circulation and air distribution.

The D-dimer test measures cross-linked fibrin fragments to indicate abnormal clotting activity. Arterial blood gas (ABG) analysis reveals low PaO2 levels due to inadequate oxygenation from blocked pulmonary vessels. These tests support imaging findings and help confirm PE diagnosis when combined with clinical assessment.

Stable PE patients receive anticoagulant therapy as the cornerstone treatment, using low-molecular-weight heparin, unfractionated heparin, or fondaparinux to prevent further clot formation. Long-term management transitions to oral anticoagulants like warfarin or direct oral anticoagulants, typically continued for at least three months with regular INR monitoring.

Unstable PE patients with hypotension or shock require thrombolytic therapy using tissue plasminogen activators like alteplase to rapidly dissolve clots. Supportive measures include supplemental oxygen for hypoxemia, opioids for pleuritic chest pain, cautious IV fluids to avoid right ventricular overload, and vasopressors such as norepinephrine to maintain blood pressure.

For massive PE patients with contraindications to thrombolytics, pulmonary embolectomy removes emboli through vascular catheter or surgical intervention to reduce right ventricular afterload. Other moderately invasive options include ultrasound-guided catheter thrombolysis and aspiration thrombectomy to restore pulmonary circulation and improve patient outcomes.

An inferior vena cava (IVC) filter may be considered for patients experiencing recurrent PE despite effective anticoagulation. The filter permits normal blood flow while capturing large emboli from the pelvis or lower extremities, preventing them from reaching the lungs. IVC filters are not recommended as initial treatment and should be avoided in patients already receiving anticoagulants.

Chest X-rays may reveal nonspecific signs like atelectasis and pleural effusion. Electrocardiograms (ECGs) can show ST segment and T wave changes, while some patients display sinus tachycardia. These clinical manifestations and diagnostic studies help establish PE diagnosis and guide treatment decisions.