US Journal Club May, 2019: FAST Exam

Association Between a Positive ED FAST Examination and Therapeutic Laparotomy in Normotensive Blunt Trauma Patients

Moylan, Mark et al. Journal of Emergency Medicine, Volume 33, Issue 3, 265 – 271 

Full Text

  • Introduction and background information
    • Patients presenting to the ED with blunt trauma undergo FAST exams to determine presence of free fluid and therefore operative management
    • Hemodynamically stable patients with positive FAST exam → CT scan
    • Hemodynamically unstable patients with positive FAST exam → emergent exploratory laparotomy
  • What was the primary objective of this study?
    • To assess the association between positive ED FAST exam and therapeutic laparotomy in normotensive blunt trauma patients  
  • Methods and study design
    • Retrospective cohort design of patients presenting to two level 1 trauma centers
    • Inclusion criteria:
      • Age > 16 years old
      • Met trauma activation criteria
      • ED SBP > 100 mmHg (even if patient was initially hypotensive in prehospital setting)
      • ED FAST exam by senior resident or attending physician
      • Imaging findings confirmed by either ED attending with ultrasound fellowship training, CT findings or intraoperative findings
    • Exclusion criteria:
      • Penetrating injuries
  • What was the primary outcome?
    • Therapeutic laparotomy within 2 days of presentation to the ED
  • Results
    • Total of 3,350 eligible trauma patients
    • 1,636 included for analysis
      • 4% of patients had a positive FAST exam
      • 2% of patients underwent therapeutic laparotomy
      • Odds ratio was 116 between positive FAST and therapeutic laparotomy (OR 44.6 after adjusting for confounding variables)
      • Authors calculated a sensitivity of 75.8%, specificity of 97.4% for positive FAST exam and therapeutic laparotomy    
  • Discussion
    • In patients with a low pretest probability for laparotomy, a negative FAST reduces the likelihood of requiring laparotomy in the setting of blunt abdominal trauma
    • On the other hand, a positive FAST, even in normotensive blunt trauma patients, should be seen as a strong predictor for need of laparotomy
    • This may be of particular significance to low resource settings or EDs without readily available CT imaging capability
  • Were there any limitations?
    • All FAST exams were performed by experienced operators which may limit generalizability
    • Study did not perform serial FAST exams which may have changed sensitivity and specificity
  • Take home points
    • All blunt trauma patients should receive a FAST exam
    • In patients with a low pretest probability for laparotomy, a negative FAST is reassuring
    • A positive FAST, even with hemodynamic stability, predicts a high likelihood for emergent surgical management 

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