Chest Abdominal-Focused Assessment Sonography for Trauma during the primary survey in the Emergency Department: the CA-FAST protocol.

PURPOSE: To evaluate the feasibility of a new protocol, Chest Abdominal-Focused Assessment Sonography for Trauma (CA-FAST), during the primary survey and to estimate its diagnostic accuracy when compared with thoracoabdominal computed tomography (CT) scan.

METHODS: A prospective accuracy study was performed from November 2012 to November 2013 at the Emergency Department. Only adult trauma patients who underwent a CA-FAST examination prior to a thoracoabdominal CT scan were enrolled. In addition to standard patterns detected by Extended-FAST (E-FAST) such as pneumothorax (PTX), hemothorax (HTX), pericardial and intraabdominal effusion, CA-FAST protocol also included the research of lung contusions (LCs).

RESULTS: Six hundred and one patients were enrolled. The mean time for protocol execution was 7 ± 3 min. Chest ultrasonography showed the following results (all p < 0.001): LCs sensitivity 59 %, specificity 98 %, positive predictive value (PPV) 92 %, negative predictive value (NPV) 86 %, accuracy 87 %; PTX sensitivity 84 %, specificity 98 %, PPV 93 %, NPV 95 %, accuracy 95 %; HTX sensitivity 82 %, specificity 97 %, PPV 87 %, NPV 95 %, accuracy 94 %. The standard 4-views FAST examination showed a diagnostic accuracy of 91 % with a sensitivity of 75 %, specificity of 96 %, PPV of 81 % and NPV of 94 %.

CONCLUSION: According to our results CA-FAST protocol proved to be a rapid bedside method, with good accuracy and high NPV in detection of ultrasonographic patterns suggestive of serious injury in trauma patients; moreover, the additional research of LCs did not cause a delay in the diagnosis. Ultrasonography should be used as initial investigation during the primary survey, sending to further diagnostic studies (CT scan) only those patients not clearly classified.