Focused Assessment with Sonography for Trauma (FAST)
FAST results alone should not dictate the decision to operate, and negative FAST does not exclude injury. This calculator is meant to help with interpretation of FAST findings, which are at least partially dependent on the user's sonographic technique.
- FAST should be used liberally in the evaluation of trauma patients.
- Especially useful in patients with penetrating thoracic trauma and in unstable patients after blunt abdominal trauma.
- Assesses for fluid in the pericardium or abdomen (hemopericardium or hemoperitoneum, respectively).
- The traditional four views consist of a subxiphoid view of the heart and pericardium, right and left upper quadrant windows, and the pelvis.
- More recently, the extended FAST (eFAST) has entered into clinical practice with the addition of bilateral thoracic views to assess for pneumo- and hemothoraces.
- Negative FAST does not exclude injury. Ultrasound is user dependent; therefore, clinicians should be cautious in interpretation of negative FAST. Sensitivities of abdominal and suprapubic views in FAST vary widely, with ranges of 22–98% reported in recent literature (Richards 2017, Carter 2015).
- In penetrating thoracic trauma, pericardial view sensitivity approaches 100% (Matsushima 2017, Ball 2009, Rozycki 1999) but can miss cardiac injury if there is concomitant pericardial laceration allowing decompression into the left chest (Ball 2009).
- If clinical suspicion for injury persists despite negative FAST, FAST should be repeated, additional investigations should be performed, or intervention should be pursued, depending on patient’s clinical condition.
- For tips on ultrasound technique, see Next Steps > Advice.
- FAST is a rapid, non-invasive, and repeatable imaging modality that can guide the surgeon in the decision to operate.
- Performed in trauma bay (does not require patient transport out of the emergency department, which is risky in unstable patients).
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- FAST results alone should not determine the decision to operate. However, FAST can be a helpful adjunct in clinical decision making, particularly in an unstable blunt trauma patient in order to rapidly assess the chest and abdomen for potential causes of hypotension.
- Most clinicians use the low frequency phased array ultrasound probe (a.k.a. cardiac probe), to obtain all windows in FAST.
- Pericardial: place probe in the subxiphoid area and orient towards patient's left shoulder. Apply downward pressure to look under the costal margin and towards the heart. The heart and pericardium will come into view, allowing inspection for hemopericardium and ultrasound findings of cardiac tamponade.
- Right upper quadrant: place probe in right anterior to mid axillary line (between 11th–12th ribs). Visualization of the hepatorenal recess (Morison's pouch) allows the assessment for hemoperitoneum in the right upper quadrant. Blood most likely accumulates here if hemoperitoneum is present.
- Left upper quadrant: apply transducer firmly onto the skin in left posterior axillary line (between the 9th–10th ribs) to visualize splenorenal and subphrenic spaces.
- In practice, it is important to remember that the right and left upper quadrant views are often more posterior than anticipated. It can be helpful to bring the probe all the way down to the stretcher in order to best visualize these windows.
- Suprapubic: place transducer superior to pubic symphysis and fan probe inferiorly to visualize the bladder.
Suggested management (clinician must consider additional clinical information including hemodynamic stability and clinical suspicion for injury):
Pericardial FAST (penetrating thoracic trauma)
- Positive: emergent surgical intervention recommended. Median sternotomy preferred if the patient is stable; otherwise, use left anterolateral thoracotomy.
- Equivocal: pericardial window or formal transthoracic echocardiography (TTE) recommended.
- Negative: close clinical monitoring or discharge recommended, according to clinical suspicion for injury.
Abdominal FAST (blunt abdominal trauma)
- Positive: in the unstable patient, emergent exploratory laparotomy is recommended. In the stable patient, cross-sectional imaging (CT scan) in recommended.
- Equivocal: in the unstable patient, diagnostic peritoneal aspiration (DPA) is recommended. In the stable patient, cross-sectional imaging (CT scan) is recommended.
- Negative: in the unstable patient, diagnostic peritoneal aspiration (DPA) is recommended if clinical suspicion for intra-abdominal bleeding exists. In the stable patient, CT scan, close clinical monitoring, or discharge is recommended, according to clinical suspicion for injury.
- Repeating FAST while preparing to perform diagnostic peritoneal aspiration is useful to quickly reassess unstable patients with blunt abdominal trauma with initially negative FAST. Intra-abdominal hemorrhage may not be significant enough on presentation to be FAST-positive initially.
- Be cautious if pericardial FAST is negative in patients with penetrating thoracic trauma, especially if unstable. Cardiac injuries can decompress through the injured pericardium, most commonly into the left hemithorax, resulting in negative pericardial FAST (Ball 2009). Therefore, unstable patients with this mechanism of injury and FAST finding should undergo a chest x-ray. If it reveals a hemothorax, a chest tube must be placed. Ongoing or high-volume chest tube output in this clinical context may be from cardiac injury.
Using bedside ultrasound, assess for fluid in each of the following areas:
Right upper quadrant (Morison’s pouch) fluid
Left upper quadrant (splenorenal recess) fluid
Facts & Figures
- If pericardial fluid is seen in the subxiphoid view, surgical intervention is warranted.
- If intra-abdominal fluid is seen in any of the three abdominal views, emergent laparotomy is indicated in unstable patients.
- Stable patients with intra-abdominal fluid should proceed to cross-sectional imaging.
See Next Steps > Management for suggested algorithm.
The original study conducted by Rozycki et al in 1993 utilized FAST in patients ≥16 years after blunt or penetrating trauma (n = 476). When compared to gold standards of CT scan, diagnostic peritoneal lavage (DPL), and/or operative findings, FAST had a sensitivity of 79% and specificity of 96%. FAST was further validated in 1998 in a much larger study (n = 1,540) by the same group. This showed that FAST is most sensitive and specific in patients with penetrating precordial wounds (sensitivity 100%, specificity 99%) and in hypotensive patients after blunt abdominal trauma (sensitivity 100%, specificity 100%). They concluded that the accuracy of FAST in these clinical scenarios justified surgical intervention on the basis of the FAST findings in these trauma patients. With the application of FAST outside of study protocols by non-experts and non-radiologists, the contemporary diagnostic yield of FAST ranges more broadly. Recent studies quote a sensitivity of 22–98% for FAST in the detection of hemoperitoneum (Richards 2017, Carter 2015).
More recently, thoracic views have been added to the FAST exam and termed eFAST. These windows assess the chest bilaterally for pneumo- and hemothoraces. In some series, the reported sensitivities of eFAST (86–100%) are superior to that of chest x-ray (27–83%) in the detection of pneumothoraces (Governatori 2015, Nandipati 2011, Wilkerson 2010).
Original/Primary ReferenceRozycki GS, Ochsner MG, Jaffin JH, Champion HR. Prospective evaluation of surgeons' use of ultrasound in the evaluation of trauma patients. J Trauma. 1993 Apr;34(4):516-26.
ValidationRozycki GS, Ballard RB, Feliciano DV, Schmidt JA, Pennington SD. Surgeon-performed ultrasound for the assessment of truncal injuries: lessons learned from 1540 patients. Ann Surg. 1998 Oct;228(4):557-567.Rozycki GS, Ochsner MG, Schmidt JA, et al. A prospective study of surgeon-performed ultrasound as the primary adjuvant modality for injured patient assessment. J Trauma. 1995 Sep;39(3):492-8.Rozycki GS, Feliciano DV, Ochsner MG, et al. The Role of Ultrasound in Patients with Possible Penetrating Cardiac Wounds: A Prospective Multicenter Study. J Trauma. 1999 Apr;46(4):543-51.
Other ReferencesRichards JR, McGahan JP. Focused Assessment with Sonography in Trauma (FAST) in 2017: What Radiologist Can Learn. Radiology. 2017 Apr;283(1):30-48.Ball CG, Williams BH, Wyrzykowski AD, et al. A Caveat to the Performance of Pericardial Ultrasound in Patients with Penetrating Cardiac Wounds. J Trauma. 2009 Nov;67(5):1123-4.Nandipati KC, Allamaneni S, Kakarla R, et al. Extended Focused Assessment with Sonography for Trauma (EFAST) in the Diagnosis of Pneumothorax: Experience at a Community Based Level I Trauma Center. Injury. 2011 May;42(5):511-4.Governatori NJ, Saul T, Siadecki SD, et al. Ultrasound in the Evaluation of Penetrating Thoraco-Abdominal Trauma: A Review of the Literature. Med Ultrason. 2015 Dec;17(4):528-34.Wilkerson RG, Stone MB. Sensitivity of Bedside Ultrasound and Supine Anteroposterior Chest Radiographs for the Identification of Pneumothorax After Blunt Trauma. Acad Emerg Med. 2010 Jan;17(1):11-7.Matsushima K, Khor D, Berona K, Antoku D, Dollbaum R, Khan M, Demetriades D. Double Jeopardy in Penetrating Trauma: Get FAST, Get It Right. World J Surg. 2017 Aug 4. [Epub ahead of print]Carter JW, Falco MH, Chopko MS, Flyn WJ Jr, Wiles Iii CE, Guo WA. Do we really rely on fast for decision-making in the management of blunt abdominal trauma?. Injury. 2015 May;26(5):817-21.
About the Creator
Grace Rozycki, MD, MBA, is chief of surgery at Indiana University’s Methodist Hospital and the Willis D. Gatch Professor of Surgery and associate chair of the department of surgery at Indiana University School of Medicine. She previously served as chief of trauma and critical care at Grady Memorial Hospital in Atlanta. Dr. Rozycki has pioneered research on the application of surgeon-performed ultrasound in patients with post-trauma hemothorax, cardiac tamponade, hemoperitoneum, solid organ injuries, intra-abdominal abscesses, and femoral deep venous thrombosis.
To view Dr. Grace Rozycki's publications, visit PubMed
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- Morgan Schellenberg, MD, MPH
- Kenji Inaba, MD, FRCSC, FACS