PURPOSE: A proper evaluation of the size of a parapneumonic effusion (PPE) in hospitalized patients with community-acquired pnuemonia (CAP) is essential for optimal management. Diagnostic thoracentesis of a PPE is recommended in patients with CAP when the level of the effusion on a lateral decubitus chest radiograph measures >1 cm. The aim of this study was to identify potentially clinically significant associations or correlations between lateral decubitus chest radiographs measuring >1 cm and measurements of PPEs obtained on chest postero-anterior and lateral radiographs (PA/LAT)and chest CT scan.
METHODS: A multidisciplinary panel of 7 infectious diseases and pulmonary specialists from the University of Louisville reviewed clinical and imaging data of 70 hospitalized CAP patients with PPE. All images were projected from the hospital computer onto a screen. Measurements of PPE were performed in centimeters of the area with the largest accumulation of fluid using a ruler incorporated into the imaging software (CPRS Vista Imaging system, Veterans Affairs Hospital). Comparisons were performed using data from lateral decubitus chest films as baseline.
RESULTS: The presence of PPE measuring >1 cm on lateral decubitus chest films was generally associated with the presence of >5 cm of PPE measured on the upright lateral chest films (measured from the deepest point of the posterior costophrenic angle to the upper margin of the fluid level), and with >3 cm height on supine chest CT scan.
CONCLUSION: This study suggests that when a lateral decubitus chest film is not available, diagnostic thoracentesis of the PPE in hospitalized patients with CAP should be considered if on the upright lateral chest film the height of the pleural effusion is >5 cm or if on the supine chest CT scan the height of the fluid is >3 cm.
CLINICAL IMPLICATIONS: Simple computed tomography of the chest and upright lateral chest radiographs may be regarded as appropriate substitutions for lateral decubitus chest films during work-up of PPEs.
DISCLOSURE: Ervin Anaya, No Financial Disclosure Information; No Product/Research Disclosure Information