In what situation would a thoracentesis be indicated?

A thoracentesis is primarily indicated to relieve pleural effusion. This procedure involves the insertion of a needle into the pleural space to remove excess fluid that may be accumulating due to various conditions, such as heart failure, pneumonia, or malignancy. By draining this fluid, thoracentesis can help alleviate symptoms such as shortness of breath, chest pain, and cough associated with the pressure of the fluid on the lungs.

The other options involve procedures or actions that do not specifically relate to treating pleural effusion. For example, obtaining a lung biopsy is typically done through methods like bronchoscopy or needle aspiration, which target lung tissue rather than fluid in the pleural space. Administering medication might involve different routes or techniques unrelated to the pleural space, and performing pulmonary function tests assesses lung capacity and airflow without direct intervention in the pleura. Thus, the indication for thoracentesis is firmly centered on managing pleural effusion.