Diagnostic Value of Sonography in Detecting Hemothorax and Determining its Size in Blunt Trauma Patients

Background: Hemothorax is among the most prevalent complications after thoracic trauma. Extended focused assessment with sonography for trauma (e-FAST) is one of the diagnostic methods for hemothorax assessment. However, there are still limited data about its diagnostic value, especially in determining the size of the hemothorax. Objective: This study aimed to assess the diagnostic value of e-FAST in detecting hemothorax and determining its size among patients with blunt thoracic trauma. Methods: This cross-sectional diagnostic assessment study was conducted on 400 adult patients with blunt trauma who needed chest CT-scan. Chest X-ray (CXR), sonography and chest CT-scan were performed and hemothorax size was assessed with sonography and CT-scan. Sensitivity, specificity, and positive and negative predictive values of sonography and CXR were calculated. Hemothorax size on sonography was compared with the results of CT-scan as gold standard. Findings: Mean age of participants was 43.67±22.03. Based on CT-scan findings, 176 participants (44%) had a hemothorax. The sensitivity, specificity, positive and negative predictive values, and correct classification rate of sonography were 79%, 99.1%, 98.6%, 85.7%, and 90.2%, respectively. Sonography detected accurately 97.1% of small hemothoraxes, 46.9% of medium hemothoraxes and 33.3% of large hemothoraxes. Conclusion: Sonography is a sensitive diagnostic modality for the detection of hemothorax in multiple trauma patients, but tends to underestimate moderate to large sized hemothoraxes. Chest sonography can be an acceptable imaging modality, if CT-scan is not available or desired.