Global Focused Assessment with Sonography for Trauma (Global FAST) combines abdominal FAST (AFAST), thoracic FAST (TFAST), and Vet BLUE into a single 15-point point-of-care ultrasound examination performed cageside as an extension of the physical exam. It is low-impact, radiation-sparing, requires no shaving, and provides real-time information on free fluid and soft tissue abnormalities of the abdomen, heart, and lung that are missed or only suspected by physical examination, blood work, and radiography.Veterinary Clin…+1
Before imaging, the dyspneic patient requires immediate clinical stabilization. Oxygen is administered immediately via flow-by, mask, hood, nasal, or oxygen cage techniques.MSD Vet Manuals Stressful procedures — including radiographs — can cause rapid decompensation in the respiratory patient, so thoracic radiography is performed only when the animal can tolerate it and must not delay therapy.MSD Vet Manuals Global FAST is specifically advantageous here because it is cageside and low-impact, making it safer than radiography in the unstable patient.Veterinary Clin…
TFAST evaluates the pleural space and pericardium. In the dyspneic patient, TFAST screens for pleural effusion, pneumothorax, and pericardial effusion, and includes assessment of the left atrial to aortic ratio — a ratio below 1.7 is normal.Journal of the… Diffuse coalescing B-lines bilaterally on TFAST indicate pulmonary parenchymal disease rather than pleural space disease.Journal of the… Distinguishing pleural space from parenchymal disease is clinically critical because it directs therapy: pleural space disease is treated with thoracocentesis, while parenchymal disease is treated with oxygen supplementation and sedation directed at the underlying cause.MSD Vet Manuals
TFAST reliably detects pleural free fluid but is not a reliable method to diagnose pneumothorax. Agreement between TFAST and CT for pleural effusion detection is fair to moderate. Agreement between TFAST and CT for pneumothorax detection is poor.Journal of Vete… When pneumothorax is a primary concern following trauma, CT is the definitive imaging modality.Journal of Vete…
AFAST evaluates the peritoneal cavity for free fluid. Agreement between AFAST and CT for detection of free peritoneal fluid is moderate to excellent.Journal of Vete… AFAST is therefore a reliable first-line screen for hemoabdomen or uroabdomen in the trauma patient.
Global FAST is used to stage localized versus disseminated disease by integrating findings from both cavities across all 15 imaging points, which reduces interpretation errors including satisfaction of search error and confirmation bias that occur with selective point-of-care ultrasound imaging.Veterinary Clin… This staging is both diagnostically and prognostically useful for patient workup.Veterinary Clin…
Catastrophic pleural space disease presenting with rapid cardiovascular decompensation, absent lung sounds throughout the thorax, and a barrel-shaped thorax indicates tension pneumothorax, which requires an intercostal incision or placement of a large-bore catheter — routine thoracocentesis is often inadequate.MSD Vet Manuals
| Exam Component | What It Detects | Agreement with CT | Key Caveat |
|---|---|---|---|
| AFAST | Free peritoneal fluid | Moderate to excellent | Reliable first-line screen for hemoabdomen |
| TFAST — pleural | Pleural free fluid | Fair to moderate | Adequate for clinical screening |
| TFAST — pneumothorax | Pneumothorax | Poor | CT required for definitive diagnosis |
| Vet BLUE / TFAST B-lines | Parenchymal disease | Not reported vs. CT | Diffuse bilateral B-lines indicate pulmonary edema or similar parenchymal pathology |
| LA:Ao ratio | Left atrial enlargement | Not reported vs. CT | < 1.7 is normal |
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