Free BCEN Certified Emergency Nurse (CEN) Practice Question

Chest ultrasonography is the most appropriate initial diagnostic test for suspected pleural effusion. It is highly sensitive and specific, can be performed at the bedside, and does not expose the patient to radiation. Ultrasound can detect as little as 20 mL of pleural fluid and can also help guide thoracentesis if needed. While chest X-ray can detect pleural effusions, it requires at least 200-300 mL of fluid to be visible and may not detect smaller effusions. CT scan, although highly accurate, involves radiation exposure and is usually reserved for more complex cases or when other pathologies are suspected. Pulmonary function tests are not typically used for acute diagnosis of pleural effusion and would not provide immediate information about fluid in the pleural space.