Sonographic detection of pneumothorax by radiology residents as part of extended focused assessment with sonography for trauma.

The purpose of this study was to assess the accuracy of sonographic pneumothorax detection by radiology residents as a part of extended focused assessment with sonography for trauma (eFAST). In a prospective study, a sonographic search for pneumothoraces was performed as part of a standard FAST examination by the on-call resident. Each lung field was scanned at the second to fourth anterior intercostal spaces and the sixth to eighth midaxillary line intercostal spaces. A normal pleural interface was identified by the presence of parietal-over-visceral pleural sliding with "comet tail" artifacts behind. Absence of these normal features indicated a pneumothorax. The sonographic diagnosis was correlated with supine chest radiography and chest computed tomography (CT). A total of 338 lung fields in 169 patients were included in the study. Patients underwent eFAST, chest radiography, and chest CT when clinically indicated. Chest CT was considered the reference standard examination. Computed tomography identified 43 pneumothoraces (13%): 34 small and 9 moderate. On chest radiography, 7 pneumothoraces (16%) were identified. Extended FAST identified 23 pneumothoraces (53%). Compared with CT, eFAST had sensitivity of 47%, specificity of 99%, a positive predictive value of 87%, and a negative predictive value of 93%. All of the moderate pneumothoraces were identified by eFAST. Twenty small pneumothoraces missed by eFAST did not require drainage during the hospitalization period. Extended FAST performed by residents is an accurate and efficient tool for early detection of clinically important pneumothoraces.