Table 8.

Factors Associated with Outcomes and Indication for Drainage of Parapneumonic Effusions

Size of effusion	Bacteriology	Risk of poor outcome	Tube drainage with or without fibrinolysis or VATSa
Small: <10 mm on lateral decubitus radiograph or opacifies less than one-fourth of hemithorax	Bacterial culture and Gram stain results unknown or negative	Low	No; sampling of pleural fluid is not routinely required
Moderate: >10-mm rim of fluid but opacifies less than half of the hemithorax	Bacterial culture and/or Gram stain results negative or positive (empyema)	Low to moderate	No if the patient has no respiratory compromise and the pleural fluid is not consistent with empyema (sampling of pleural fluid by simple thoracentesis may help determine presence or absence of empyema and need for a drainage procedure, and sampling with a drainage catheter may provide both diagnostic and therapeutic benefit); Yes, if the patient has respiratory compromise or if pleural fluid is consistent with empyema if the patient has respiratory compromise or if pleural fluid is consistent with empyema
Large: opacifies more than half of the hemithorax	Bacterial culture and/or Gram stain results positive (empyema)	High	Yes in most cases

^aVATS, video-assisted thoracoscopic surgery.