FAST and TFAST are rapidly becoming an important part of the emergency assessment of veterinary trauma patients.
FAST & TFAST:
Traumatic abdominal injuries can be diagnostically challenging and may not manifest for hours or even days. Potential abdominal injuries caused by blunt-force trauma include:
- Organ bleeding (eg, hepatic, splenic)
- Large-vessel rupture
- Urinary or gallbladder rupture
- In humans, using physical examination to diagnose intraabdominal traumatic injury has been reported to be unreliable in 45% of cases.1
Focused assessment with sonography for trauma (FAST) and thoracic-focused assessment with sonography for trauma (TFAST) examinations were developed to assist emergency clinicians in the diagnosis of abdominal and thoracic hemorrhage and pneumothorax. They are also rapidly becoming an important part of the emergency assessment of veterinary trauma patients.
In 2004, Boysen and colleagues published the first veterinary study describing the use of the FAST examination in dogs after motor vehicular trauma.2 Subsequently, Lisciandro and coworkers published a FAST scoring system3 and an article evaluating the use of TFAST in traumatized dogs.4
FAST and TFAST examinations are indicated for evaluating veterinary patients after acute blunt trauma, such as that caused by motor vehicular accident, falls from heights, or crush injuries. Examinations are performed with or without clinical evidence of pleural, abdominal, or pericardial bleeding or pneumothorax. Specific protocols indicating patient positioning and probe sites to best visualize abdominal, pleural, and pericardial fluid and pleural air in dogs have been described.2,4
In addition to evaluation of trauma patients, FAST examination can be used to diagnose abdominal, pleural, and pericardial effusions caused by ascites, septic effusions, bile peritonitis, chylothorax, and neoplastic effusions. Although the techniques have been described only in dogs and humans, FAST and TFAST examinations can be used to detect cavitary effusions in other veterinary patients as well.
FAST and TFAST examinations do not take the place of a thorough physical examination, initiation of stabilization techniques, or rapid intervention when life-threatening respiratory distress or cardiovascular collapse due to cavitary bleeding is occurring.
Diagnosis & Monitoring
The primary advantage of using FAST and TFAST examinations in patients after a traumatic event is the ability to diagnose and monitor abdominal or thoracic effusions or a pneumothorax with relative ease and in a very short time (Figures 1 and 2).
Figure 1: Free abdominal fluid around the spleen visualized with an abdominal FAST examination