In the USA, one million patients diagnosed with pneumonia are admitted each year and among these, 32,000 patients develop empyema (1,2). Empyema is associated with a high morbidity and mortality (2,3).

Empyema was first described by Hippocrates 2,400 years ago. He also performed the first pleural drainage when he created a burr hole to drain the infected fluids and performed daily irrigation (4).

Thoracic empyema is defined as either presence of bacterial organisms and/or presence of grossly purulent fluid in the pleural cavity. A positive culture is not required for diagnosis of patients previously on antibiotics. As well, in the case when a sampling was taken of the inflammatory fluid from around the infected empyema fluid, or in anaerobic bacterial infections which are difficult to be cultured.