Evaluation of the accuracy of portable ultrasound (eFAST) for detection of pneumothorax

Background: Pneumothorax, is a common complication of chest trauma. The purpose of this study was to assess the accuracy of sonographic detection of pneumothorax as a part of extended focused assessment with sonography for trauma (eFAST).

Materials and Methods: In a prospective study, a sonographic search for pneumothoraxes was performed as part of a standard FAST examination. Each lung field was scanned at the second to fourth anterior intercostal spaces and the sixth to eighth midaxillary line intercostals 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). The data was analyzed by Chi Square test.

Results: A total of 280 lung fields in 140 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 72 pneumothoraxes (51.4%). On chest radiography, 56 pneumothoraxes (40%) were identified. Extended FAST identified 64 pneumothoraxes (46.4%). Compared with CT, eFAST had sensitivity of 85%, specificity of 95.5%, a positive predictive value of 95.5%, a negative predictive value of 85.5%and accuracy 90%. Five small pneumothoraxes missed by eFAST did not require drainage during the hospitalization period. Average time to do eFAST in trauma room was 1.5 to 5 minutes.

Conclusions: Extended FAST performed by emergency specialist is an accurate and efficient tool for early detection of clinically important pneumothoraxes. In this study ultrasound was more sensitive than supine chest radiography and as sensitive as CT in the detection of traumatic pneumothoraxes.