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Focused Assessment with Sonography for Trauma - Document ultrasound findings and get clinical recommendations
| View | Probe Position | What to Look For | Positive Finding |
|---|---|---|---|
| RUQ (Hepatorenal) | Right mid-axillary line, 8-11th rib | Morrison's pouch, subphrenic space | Anechoic fluid between liver and kidney |
| LUQ (Splenorenal) | Left posterior axillary line, 6-9th rib | Splenorenal recess, subphrenic space | Anechoic fluid between spleen and kidney |
| Pelvic | Suprapubic, transverse and sagittal | Pouch of Douglas (F), rectovesical (M) | Anechoic fluid around bladder |
| Pericardial | Subxiphoid or parasternal long | Pericardial space | Anechoic fluid in pericardium |
| Right Thorax (E-FAST) | Right mid-axillary, 4-5th intercostal | Pleural space, lung sliding | Anechoic fluid or absent lung sliding |
| Left Thorax (E-FAST) | Left mid-axillary, 4-5th intercostal | Pleural space, lung sliding | Anechoic fluid or absent lung sliding |
FAST (Focused Assessment with Sonography for Trauma) is a rapid bedside ultrasound examination used to detect free intraperitoneal or pericardial fluid in trauma patients. It typically takes 2-3 minutes to perform and helps guide urgent management decisions.
Standard FAST includes 4 views (RUQ, LUQ, pelvic, and pericardial) to detect intraperitoneal and pericardial fluid. E-FAST (Extended FAST) adds bilateral thoracic views to detect hemothorax and pneumothorax, making it more comprehensive for chest trauma.
FAST has high specificity (95-100%) but variable sensitivity (73-88%). Sensitivity increases with the volume of free fluid (typically requires 400-500mL to detect). It's less sensitive early after injury, and serial exams may be needed. FAST does not reliably detect solid organ injuries without free fluid.
FAST should be performed in all hemodynamically unstable trauma patients during the primary survey. It's particularly useful for blunt abdominal trauma and penetrating torso trauma. In stable patients, CT imaging may be more appropriate for comprehensive evaluation.
A negative FAST does not exclude injury. If clinical suspicion remains high, consider: (1) repeat FAST in 15-30 minutes, (2) CT imaging if hemodynamically stable, (3) diagnostic peritoneal lavage if unstable, or (4) close observation with serial abdominal exams.
Common pitfalls include: mistaking ascites or physiologic pelvic fluid for traumatic hemorrhage, poor image quality from obesity or subcutaneous air, missing retroperitoneal injuries (FAST only detects intraperitoneal fluid), and false negatives early after injury before significant fluid accumulation.
This FAST exam calculator is for educational and clinical documentation purposes only. FAST results must be interpreted in the clinical context of the patient's hemodynamic status, mechanism of injury, and physical examination findings. A negative FAST does not exclude injury. Always follow ATLS protocols and institutional trauma guidelines. This tool does not replace clinical judgment or formal ultrasound interpretation.