Postoperative pleural effusions are common in patients who undergo cardiac surgery [1-13]. Most of these effusions develop as a consequence of the surgical procedure itself ("nonspecific pleural effusions") and follow a generally benign course. Postoperative pleural effusions may also occur with postpericardiotomy syndrome (PPCS, also known as the postcardiac injury syndrome or Dressler's syndrome), or as the initial manifestation of a potentially serious complicating event, such as heart failure or pulmonary embolism (table 1).
The extent of the evaluation required for a postoperative pleural effusion depends upon the presence of associated cardiovascular symptoms and the volume, timing of onset, progression, and persistence of the pleural effusion. Effusions with the following characteristics almost invariably represent nonspecific pleural effusions, and require only observation:
- Small to moderate in size
- Present within one to two days after surgery and not progressive
- Not associated with respiratory symptoms
On the other hand, symptomatic, large, or progressive pleural effusions require thoracentesis with pleural fluid analysis, and, in some instances, further evaluation with serum brain natriuretic peptide (BNP), echocardiography, helical chest CT, or other diagnostic studies. Postoperative pleural effusions can also be caused by hemothorax, pneumonia, pleural infections, central venous catheter erosion, mediastinitis, or chylothorax [14-16]. (See "Diagnostic evaluation of a pleural effusion in adults: Initial testing".)
NONSPECIFIC PLEURAL EFFUSIONS
Pleural effusions of a generally benign nature occur after cardiac transplantation, coronary artery bypass grafting (CABG), and, less often, mitral and aortic valve replacement surgery [2-13,16-18]. These effusions can occur in the early (≤30 days) or late (>30 days) postoperative period.