@article {Moffeterj00045-2011, author = {B.K. Moffet and T.S. Panchabhai and I. Anaya and R. Nakamatsu and F.W. Arnold and P. Peyrani and T. Wiemken and J. Guardiola and J.A. Ramirez}, title = {Computed tomography measurements of parapneumonic effusion indicative of thoracentesis}, elocation-id = {erj00045-2011}, year = {2011}, doi = {10.1183/09031936.00004511}, publisher = {European Respiratory Society}, abstract = {Patients with parapneumonic effusions (PPE) that measure \<1 cm by lateral decubitus radiograph (LDR) or \<5 cm by lateral erect radiograph (LER) do not require thoracentesis. No such data exists for chest computed tomography (CCT). The objective of this study was to identify a PPE measurement by CCT that indicates the need for thoracentesis.A secondary data analysis of two pneumonia databases was conducted to identify patients with PPE. Measurements of PPE using LDR, LER, and CCT were correlated by linear regression analysis. The clinical outcome of community acquired pneumonia patients managed with the newly defined CCT measurement was evaluated.PPE was identified in 419 of 1,460 patients with possible pneumonia. PPE measurements by LDR of 1.00 cm and 5.00 cm by LER correlated with a measurement of 2.5 cm by CCT. Out of 95 patients with CCT measurements \<2.50 cm, 31 poor clinical outcomes occurred: 1 outcome was PPE related, 26 were PPE unrelated, and 4 were unevaluable. The single case of a poor outcome also measured \<1.00 cm by LDR.This study indicates that patients with CAP and a PPE measuring \<2.50 cm by CCT can be managed without the need for thoracentesis.}, issn = {0903-1936}, URL = {https://erj.ersjournals.com/content/early/2011/05/26/09031936.00004511}, eprint = {https://erj.ersjournals.com/content/early/2011/05/26/09031936.00004511.full.pdf}, journal = {European Respiratory Journal} }