Role of E-FAST in Assessing Suspected Trauma
E-FAST should be performed in all patients with suspected severe trauma as it allows rapid identification of potential life-threatening injuries and guides immediate treatment decisions. 1
Primary Functions of E-FAST in Trauma Assessment
E-FAST serves as a critical initial imaging tool compatible with ongoing resuscitation efforts when CT scanning is not immediately possible due to hemodynamic instability 1
E-FAST allows rapid detection of free fluid in the peritoneal, pleural, and pericardial spaces, helping to identify the source of bleeding in trauma patients 1
When combined with chest X-ray, E-FAST enables appropriate urgent intervention decisions (tube thoracostomy, emergency thoracotomy, pelvic angiography/embolization, emergency laparotomy) with 98% accuracy in hemodynamically unstable patients 1
Diagnostic Performance in Trauma
E-FAST has high specificity (91-100%) for detecting thoracic injuries but variable sensitivity depending on the specific condition being evaluated 2
For intra-abdominal bleeding detection in pelvic trauma associated with severe abdominal trauma, E-FAST has a positive predictive value of 97% 1
The negative predictive value of E-FAST is 97% in patients with shock, making it valuable for ruling out certain injuries 1
E-FAST has lower sensitivity for detecting pneumothorax (22%), hemothorax (36%), and pericardial fluid (47%) in penetrating thoracic trauma 2
Clinical Decision-Making Based on E-FAST Results
When E-FAST and chest X-ray rule out extra-pelvic causes of hemorrhagic shock in pelvic trauma, patients should undergo body CT scan with intravenous contrast followed by angiography/embolization 1
The abundance of hemoperitoneum detected on E-FAST correlates with the need for laparotomy - 3 positive E-FAST sites is associated with 61% appropriate laparotomies, while 2 positive sites correlates with 26% 1
In rare cases of uncontrollable hemorrhagic shock, angiography/embolization can be performed immediately after E-FAST and chest X-ray to rule out non-pelvic massive hemorrhage 1
Integration with Other Imaging Modalities
In hemodynamically stable patients, E-FAST should be followed by a thoraco-abdomino-pelvic CT scan with contrast for complete injury assessment 1
In hemodynamically unstable patients, E-FAST combined with pelvic and chest X-rays may be the only imaging workup possible during ongoing resuscitation 1
E-FAST can potentially replace plain radiography in stable trauma patients, reducing time spent in the trauma bay (25 vs. 38 minutes), radiation exposure, and costs 3
Limitations and Pitfalls
E-FAST performance may be diminished by false positives such as suffusion of a hemoretroperitoneum or intra-peritoneal bladder rupture 1
The sensitivity of E-FAST for detecting pneumothorax is particularly low when performed by clinicians with variable levels of ultrasound training 4
E-FAST is not recommended as the primary tool for diagnosing duodeno-pancreatic trauma, though it is effective for detecting free fluid and solid organ injury 1
Urgent interventions are frequently required in patients with false-negative E-FAST studies, highlighting the importance of not relying solely on E-FAST when clinical suspicion is high 2
Special Populations
In pediatric patients and pregnant women, E-FAST can be used as an alternative to CT scan when hemodynamically stable, reducing radiation exposure 1
In children with mild symptoms, minimal clinical findings, and hematuria <50 RBCs/HPF, ultrasound techniques including E-FAST may be adopted for initial evaluation 1