Focused assessment with sonography for trauma

Focused assessment with sonography in trauma (commonly abbreviated as FAST) is a rapid bedside ultrasound examination performed by surgeons, emergency physicians, and paramedics as a screening test for blood around the heart (pericardial effusion) or abdominal organs (hemoperitoneum) after trauma. There is also the extended FAST (eFAST) which includes some additional ultrasound views to assess for pneumothorax. The four classic areas that are examined for free fluid are the perihepatic space (including Morison's pouch or the hepatorenal recess), perisplenic space, pericardium, and the pelvis. With this technique it is possible to identify the presence of intraperitoneal or pericardial free fluid. In the context of traumatic injury, this fluid will usually be due to bleeding. Reasons a FAST or eFAST would be performed would be: Blunt abdominal trauma Penetrating abdominal trauma Blunt thoracic trauma Penetrating thoracic trauma Undifferentiated shock (low blood pressure) Since the FAST/eFAST is performed with ultrasound, there is very little risk to the patient as ultrasounds only emit sound waves and record the echo to create a picture. The most common contraindication would be delay of definitive care such as surgical intervention in the setting of obvious trauma or resuscitative efforts in an extreme scenario. The eFAST allows for the examination of both lungs by adding bilateral anterior thoracic sonography to the FAST exam. This allows for the detection of a pneumothorax with the absence of normal ‘lung-sliding’ and ‘comet-tail’ artifact (seen on the ultrasound screen). Compared with supine chest radiography, with CT or clinical course as the gold standard, bedside sonography has superior sensitivity (49–99% versus 27–75%), similar specificity (95–100%), and can be performed in under a minute. Several recent prospective studies have validated its use in the setting of trauma resuscitation, and have also shown that ultrasound can provide an accurate estimation of pneumothorax size.