eFAST for Chest Trauma

By: Annemarie Daecher, MD

Reviewed by: Jonathan Kaplan, MD

Paper #1

Diagnostic accuracy of eFAST in the trauma patient: a systematic review and meta-analysis

Netherton S, Milenkovic V, Taylor M, Davis PJ. CJEM. 2019 Nov; 21(6):727-738. doi: 10.1017/cem.2019.381. PMID: 31317856. 


Introduction and Background: 

  • Traumatic injuries are the most common cause of morbidity and mortality in young adults, with incidence increasing over time
  • eFAST is a widely accepted part of the trauma   assessment to identify pneumothorax, pericardial effusion, intra-abdominal free fluid → early findings can lead to early intervention
  • Many studies on eFAST in trauma with variable sensitivities and specificities, and prior to this there has been no comprehensive systematic review examining the accuracy of all components of eFAST


  • there are a wide range of sensitivities/specificities reported for components of eFAST in trauma. The objective of this study was to review pooled sensitivities and specificities for components of eFAST 

Why is this important? 

  • the eFAST is a commonly used part of the trauma assessment, important to understand limitations as well as strengths 


  • searched Medline and Embase up to October 2018 for studies examining eFAST sensitivity/specificity 
    • 767 records, 119 underwent full text review
    • 75 studies with 24,530 patients satisfied selection criteria 
    • Pooled sensitivities and specificities calculated for pericardial effusion, pneumothorax, intra-abdominal free fluid 
    • Sub-group analysis for intra-abdominal free fluid in hypotensive patients, adult normotensive patients, and pediatric patients 

Study selection:

  • Population of interest: trauma patients (blunt, penetrating, poly) who were assessed in an ED or trauma center, underwent US initially and then underwent gold standard test 
    • US positive for pneumothorax if no lung sliding present or a lung point was seen, gold standard CT
    • US positive for pericardial effusion or intra-abdominal free fluid if hypoechoic fluid present in appropriate anatomic location 
      • For pericardial effusion, gold standard was a CT scan or positive intra-op findings
      • For intra-abdominal free fluid, gold standard was CT scan, positive laparotomy, or positive DPL/DPA
  • Exclusion criteria: studies performed in wrong setting (pre-hospital), in nontrauma patients, if they did not have gold standard comparisons done, or had incomplete data 
  • Primary outcome: Sensitivity and specificity of eFAST


  • 767 studies yielded from search, 119 underwent full text review, 75 papers met inclusion criteria
    • 17 studies examined pneumothorax detection, 9 examined pericardial effusion detection, 52 examined intra-abdominal free fluid detection
  • Studies examining pneumothorax included 3653 patients with 4816 data points (some studies used each lung as a data point, 2 data points per patient)
    • Avg. age 39.8 years, 75% male, predominantly blunt trauma
    • Pooled sensitivity for detecting pneumothorax via eFAST was 0.694 (95% CI 0.66-0.72), pooled specificity 0.99 (95% CI 0.98-0.99)
  • Studies examining pericardial effusion included 1031 patients 
    • Avg. age 30 years, 80.6% male, only penetrating trauma 
    • Pooled sensitivity for detecting pericardial effusion via eFAST was 0.912 (95% CI 0.87-0.94) and pooled specificity 0.941 (95% CI 0.922 – 0.957)
  • Studies examining intra-abdominal free fluid included 19,666 patients
    • Avg. age 33.3 years, 68.4% male
    • Of these studies, 6 included only pediatric patients, 8 included patients of all ages (peds and adults), 5 included only hypotensive patients and 1 included only pregnant patients (46% in third trimester)
    • Overall pooled sensitivity for detecting intra-abdominal free fluid via eFAST was 0.742 (95% CI 0.726 – 0.758) and pooled specificity was 0.976 (95% CI 0.973-0.978)
    • Only pediatric patients:
      • Sensitivity for detecting intra-abdominal free fluid via eFAST was 0.709 (95% CI 0.615-0.792) and specificity was 0.951 (95% CI 0.933-0.965)
    • Only hypotensive patients:
      • Sensitivity for detecting intra-abdominal free fluid via eFAST was 0.743 (95% CI 0.681-0.799) and specificity was 0.949 (95% CI 0.926-0.966) 
    • Only adult normotensive patients:
      • Sensitivity for detecting intra-abdominal free fluid via eFAST was 0.76 (95% CI 0.739-0.781) and specificity was 0.98 (95% CI 0.975-0.981)


  • Identification of pneumothorax using eFAST:
    • Moderate sensitivity (69.4%), good specificity (99%)
    • Positive likelihood ratio 62.57, negative likelihood ratio 0.256
    • Use for rule in, not rule out
  • Identification of pericardial effusion using eFAST: 
    • Excellent sensitivity (98.2%) and specificity (98.5%) with the removal of outlying studies 
    • Positive likelihood ratio 34.0169, negative likelihood ratio 0.110
  • Identification of intra-abdominal free fluid using eFAST:
    • Moderate sensitivity (74.2%), excellent specificity (97.6%)
    • Positive likelihood ratio 20.3, negative likelihood ratio of 0.25 (not much different between pediatric, hypotensive, adult normotensive groups)
  • Two additional recent reviews evaluated parts of the eFAST, reaching similar conclusions
    • Straub et al: detecting of PTX and hemothorax: sensitivity 81%, specificity 98%
    • Stengel et al: examined use of US in blunt thoracoabdominal trauma patients, found sensitivity was 68%/specificity 95% for detecting FF, organ injury, vascular injury; sensitivity 78%/specificity 97% for abdominal FF, intra-abdominal free air 


  • eFAST is a helpful tool to rule in pneumothorax, pericardial effusion, and intra-abdominal free fluid but is not sensitive enough to rule out these disease processes 


  • Publication bias, only positive studies published; however studies included low sensitivities/specificities 

Paper #2 

Value of point of care ultrasonography compared with CT scan in detecting potential life-threatening conditions in blunt chest trauma patients 

Jahanshir, A., Moghari, S.M., Ahmadi, A. et al. Ultrasound J. 2020; 12:36. https://doi.org/10.1186/s13089-020-00183-6

Introduction and Background:

  • Thoracic injury accounts fo 20-25% trauma mortality preventable by early diagnosis 
  • Role of ultrasound in trauma: diagnosing early, diagnosing in unstable patients unable to go to CT, reduction of radiation


  • evaluated caveats of point of care ultrasound in diagnosis of pneumothorax, hemothorax, and contusion


  • prospective study performed in 157 patients with blunt chest trauma in 3 university hospitals 
  • Ultrasounds performed by 2 EM attendings and a EM PGY3
  • Patients included: 18 years + with acute chest trauma (blunt chest trauma isolated to chest/back and multiple trauma patients)
  • Patient with old chest trauma, history of lung fibrosis or those that didn’t undergo CT were excluded (unless they had a chest tube placed to confirm diagnosis)
  • Each lung scanned in at least 4 spaces for evidence of pneumothorax, hemothorax, contusion by B and M modes 
  • Compared PoCUS to CT scan


  • 157 patients, 134 were men, mean age 38.3 years old
    • Most common mechanisms: MVC, falls
  • lung ultrasonography and physical exam: accuracy of 91.8%
  • Pneumothorax: PoCUS sensitivity 75%, specificity 100%, PPV 100%, NPV 94.9%
  • Hemothorax: PoCUS sensitivity 45.4%, specificity 100%, PPV 100%, NPV 91.8%
  • Lung contusion: PoCUS sensitivity 51.8%, specificity 100%, PPV 100%, NPV 86.3%
  • Interestingly, combined physical exam and sonography sensitivity was increased to 91.5% for the diagnosis of pneumothorax, hemothorax, contusion and the specificity decreased to 90.8%

Analysis of false-negatives

  • Pneumothorax:
    • Subcutaneous emphysema = clue to suspect PTX but disrupts US signal via scattering
    • Occult PTXs (very small, only seen by CT scan) = clinically significant?
      • Data suggests US doesn’t miss clinically significant PTX
  • Hemothorax: 
    • False negatives can be due to minimal amounts of blood, blood located posteriorly 
    • Concomitant subcutaneous emphysema
  • Pulmonary Contusion:
    • Finding various signs of lung contusion improves US sensitivity
    • Falsely diagnosed in ARDS, cardiogenic pulmonary edema 
    • Contusion can be falsely interpreted in presence of large PTX due  to presence of collapsed lung


  • US is specific enough to rule in diagnosis but not sensitive enough to rule out, use US in conjunction with physical exam, clinical findings


  • didn’t include patients with pulmonary fibrosis, excluding patients with underlying disease will skew results 
  • need larger sample sizes 

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