The Effectiveness of Chest Ultrasonography in Differentiating Empyema from Simple Parapneumonic Effusion

Objective: To retrospectively evaluate the effectiveness of chest ultrasonography in differentiating empyema from simple parapneumonic effusion in children. Materials and Methods: We retrospectively studied pediatric patients with a diagnosis of pneumonia with pleural effusion who had undergone thoracocentesis from January 2000 to August 2007 at the Changhua Christian Hospital, Taiwan. The diagnosis of pneumonia with pleural effusion was based on chest X-ray and ultrasonographic findings. Indications for pleural drainage included persistent high-grade fever (＞38℃) for more than 24 hr after parenteral antibiotic treatment or respiratory distress. Pleural effusion was drained via pigtail catheter within 24 hr after ultrasonic examination. All related laboratory data were recorded. Results: A total of 58 patients were studied. The presence of fibrins or septations on ultrasonographic images has a high specificity (92%; 23/25) and positive predictive value (92.5%; 25/27) for differentiating between empyema and simple parapneumonic effusion in pediatric patients in the ICU. The sensitivity of the presence of those abnormalities in differentiating between empyema and simple parapneumonic effusion is moderate (75.7%; 25/33). Conclusion: Fibrin formations or septations identified on chest ultrasonography are highly predictive of the presence of empyema. The clinical doctor handles the aspect of parapneumonic effusion to use sonography is practice and reasonable.