View source for Medicine:Focused assessment with sonography for trauma

{{short description|Fluid accumulation screening}}
{{Infobox diagnostic
| name            = Focused assessment with sonography in trauma, a.k.a. FAST
| image           = Ultrasound image of spleen 110314102702 1031200.jpg
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| caption         = Ultrasound image of a normal spleen that may be seen in part of the eFAST
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| eMedicine       = 104363
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'''Focused assessment with sonography in trauma''' (commonly abbreviated as '''FAST''')  is a rapid bedside ultrasound examination performed by surgeons, emergency physicians, and paramedics as a screening test for blood around the heart (pericardial effusion) or abdominal organs ([[Medicine:Hemoperitoneum|hemoperitoneum]]) after trauma.<ref>{{cite web |url=http://www.sonoguide.com/FAST.html |title=Ultrasound in Trauma - The FAST Exam Focused Assessment with Sonography in Trauma |website=www.sonoguide.com |url-status=dead |archive-url=https://web.archive.org/web/20080914011833/http://www.sonoguide.com/FAST.html |archive-date=2008-09-14}}</ref> There is also the extended FAST (eFAST) which includes some additional ultrasound views to assess for pneumothorax.<ref name="NCBI eFAST" />

The four classic areas that are examined for free fluid are the perihepatic space (including Morison's pouch or the hepatorenal recess), peri[[Biology:Spleen|splenic]] space, pericardium, and the pelvis.  With this technique it is possible to identify the presence of intraperitoneal or pericardial free fluid. In the context of traumatic injury, this fluid will usually be due to bleeding.

== Indications ==
Reasons a FAST or eFAST would be performed would be:
#Blunt abdominal trauma
#Penetrating abdominal trauma
#Blunt thoracic trauma
#Penetrating thoracic trauma
#Undifferentiated shock (low blood pressure)<ref name="NCBI eFAST">{{cite journal |last1=Bloom |first1=Benjamin A. |last2=Gibbons |first2=Ryan C. |title=Focused Assessment with Sonography for Trauma |url=https://www.ncbi.nlm.nih.gov/books/NBK470479/ |website=StatPearls |publisher=StatPearls Publishing |date=2022|pmid=29261902 }}</ref>

== Contraindications ==
Since the FAST/eFAST is performed with ultrasound, there is very little risk to the patient as ultrasounds only emit sound waves and record the echo to create a picture.<ref>{{cite web |title=Ultrasound |url=https://www.nibib.nih.gov/science-education/science-topics/ultrasound |website=National Institute of Biomedical Imaging and Bioengineering |language=en}}</ref> The most common contraindication would be delay of definitive care such as surgical intervention in the setting of obvious trauma or resuscitative efforts in an extreme scenario.<ref name="NCBI eFAST" />

== Extended FAST ==
The eFAST allows for the examination of both lungs by adding bilateral anterior thoracic sonography to the FAST exam. This allows for the detection of a [[Medicine:Pneumothorax|pneumothorax]] with the absence of normal ‘lung-sliding’ and ‘comet-tail’ artifact (seen on the ultrasound screen). Compared with supine chest radiography, with CT or clinical course as the gold standard, bedside sonography has superior [[Sensitivity and specificity|sensitivity]] (49–99% versus 27–75%), similar [[Sensitivity and specificity|specificity]] (95–100%), and can be performed in under a minute.<ref>Kirkpatrick AW, Sirois M, Laupland KB, et al., J Trauma, 2004;57(2):288–95.</ref> Several recent prospective studies have validated its use in the setting of trauma resuscitation, and have also shown that ultrasound can provide an accurate estimation of pneumothorax size.<ref>Zhang M, Liu ZH, Yang JX, et al., Crit Care, 2006;10(4):R112.</ref><ref>Blaivas M, Lyon M, Duggal SA, Acad Emerg Med, 2005;12(9):844–9.</ref> Although radiography or CT scanning is generally feasible, immediate bedside detection of a pneumothorax confirms what are often ambiguous physical findings in unstable patients, and guides immediate [[Medicine:Chest tube|chest decompression]]. In addition, in the patient undergoing positive-pressure ventilation, the detection of an otherwise ‘occult’ pneumothorax prior to CT scanning may hasten treatment and subsequently prevent development of a tension pneumothorax, a deadly complication if not treated immediately, and deterioration in the [[Medicine:Radiology|radiology]] suite (in the CT scanner).<ref>Davis JA, et al. Critical Diagnosis in Bedside Ultrasonography. Diagnostics & Imaging. 2007.</ref>

=== Components of the Examination ===
There are five components to the eFAST exam:

# Right Upper Quadrant of the abdomen (Perihepatic view). Right upper quadrant is examined by working your probe down the midaxillary line starting at the right 8th rib to the 11th rib. This examines for free fluid around the kidney and liver.
# Left Upper Quadrant of the abdomen (Perisplenic view). Left upper quadrant is examined by working your probe down the midaxillary line starting at the left 8th rib to the 11th rib. This examines for free fluid around the kidney and spleen.
# Pelvic views (Long and transverse axis). The suprapubic view helps assess for free fluid in the pelvic cavity.
# Cardiac view. The pericardial component is assessed using the subxiphoid view.
# Lung views (Right and Left, Long axis). These final views help determine if a pneumothorax is present.<ref>[https://jomi.com/article/299.6/Extended-Focused-Assessment-with-Sonography-for-Trauma-(EFAST)-Exam], Patel D, Lewis K, Peterson A, Hafez M. Extended Focused Assessment with Sonography for Trauma (EFAST) Exam. J Med Ins. ;(299.6) doi:https://jomi.com/article/299.6</ref>

===Findings===
eFAST (extended focused assessment with sonography for trauma) allows an emergency physician or a surgeon the ability to determine whether a patient has [[Medicine:Pneumothorax|pneumothorax]], [[Medicine:Hemothorax|hemothorax]], pleural effusion, mass/tumor, or a lodged foreign body. The exam allows for visualization of the echogenic tissue, ribs, and lung tissue. Few radiographic signs are important in any trauma and they include the ''stratosphere sign'', the ''sliding or seashore sign'', and the ''sinusoid sign.''

''Stratosphere sign'' is a clinical medical [[Physics:Ultrasound|ultrasound]] finding usually in an eFAST examination that can prove presence of a [[Medicine:Pneumothorax|pneumothorax]]. The sign is an imaging finding using a 3.5–7.5 [[Hertz|MHz]] ultrasound probe in the fourth and fifth intercostal spaces in the anterior clavicular line using the M-Mode of the machine. This finding is seen in the M-mode tracing as pleura and lung being indistinguishable as linear hyperechogenic lines and is fairly reliable for diagnosis of a pneumothorax. Even though the stratospheric sign can be an indication of pneumothorax its absence is not at all reliable to rule out pneumothorax as definitive diagnosis usually requires X-ray or [[CT scan|CT]] of thorax.<ref name=ein>{{cite book|title=Visual Diagnosis in Emergency and Critical Care Medicine|author1=Christopher P. Holstege|author2=Alexander B. Baer|author3=Jesse M. Pines|author4=William J. Brady|publisher=Wiley-Blackwell|year=2011|pages=95–7|isbn=9781444397987|url=https://books.google.com/books?id=ordt647fOR8C&q=stratosphere+sign+ultrasound&pg=PA97}}</ref><ref name=do>{{cite book|title=Clinical chest ultrasound: from the ICU to the bronchoscopy suite|author1=Christoph T. Bolliger|author2=F. J. F. Herth|author3=P. Mayo|author4=T. Miyazawa|author5=J. Beamis|publisher=Karger Publishers|year=2009|pages=86–8|isbn=9783805586429|url=https://books.google.com/books?id=OF4SS1mgZRkC&q=stratosphere+sign+ultrasound&pg=PA86}}</ref><ref name=tar>{{cite book|title=Tarascon Adult Emergency Pocketbook|author=Steven G. Rothrock (M.D.)|publisher=Tarascon|year=2009|page=144}}</ref>

''Seashore sign'' is another eFAST finding usually in the lungs in the M-mode that depicts the glandular echogenicity of the lung abutted by the linear appearance of the visceral pleura. This sign is a normal finding. In absence of a seashore sign or presence of a stratosphere sign, pneumothorax is likely. '''B-lines''' or "comet trails" are echogenic bright linear reflections beneath the pleura that are usually lost with any air between the probe and the lung tissue and therefore whose presence with seashore sign indicates absence of a pneumothorax.<ref name=ein/><ref name=tar/>

''Sinusoid sign'' is another M-mode finding indicating presence of pleural effusion. Due to the cyclical movement of the lung in inspiration and expiration, the motion-time tracing (M-mode) ultrasound shows a sinusoid appearance between the fluid and the line tissue. This finding indicates a possible pleural effusion, [[Medicine:Empyema|empyema]], blood in pleural space (hemothorax).<ref name=ein/><ref name=do/>

==Advantages==
 
FAST is less invasive than diagnostic peritoneal lavage, involves no exposure to radiation and is cheaper compared to computed tomography, but achieves a similar accuracy.<ref>{{cite journal|vauthors=Rozycki G, Shackford S| title=Ultrasound, what every trauma surgeon should know| journal=J Trauma| volume=40| issue=1| pages=1–4| year=1996| pmid=8576968| doi=10.1097/00005373-199601000-00001}}</ref>

Numerous studies have shown FAST is useful in evaluating trauma patients.<ref>{{cite journal| title=2,576 ultrasounds for blunt abdominal trauma|vauthors=Dolich MO, McKenney MG, Varela JE, Compton RP, McKenney KL, Cohn SM| journal=Journal of Trauma|date=Jan 2001| volume=50| pages=108–12| pmid=11231679| issue=1| doi=10.1097/00005373-200101000-00019}}</ref><ref>{{cite journal| title=Hypotensive patients with blunt abdominal trauma: performance of screening US|vauthors=Farahmand N, Sirlin CB, Brown MA, Shragg GP, Fortlage D, Hoyt DB, Casola G| journal=Radiology|date=May 2005| volume=235| pages=436–43| pmid=15798158| issue=2| doi=10.1148/radiol.2352040583}}</ref><ref>{{cite journal| title=Blunt abdominal trauma: clinical value of negative screening US scans|vauthors=Sirlin CB, Brown MA, Andrade-Barreto OA, Deutsch R, Fortlage DA, Hoyt DB, Casola G| journal=Radiology|date=Mar 2004| volume=230| pages=661–8| pmid=14990832| issue=3| doi=10.1148/radiol.2303021707}}</ref><ref>{{cite journal| title=Association between a positive ED FAST examination and therapeutic laparotomy in normotensive blunt trauma patients|vauthors=Moylan M, Newgard CD, Ma OJ, Sabbaj A, Rogers T, Douglass R| journal=Journal of Emergency Medicine|date=Oct 2007| volume=33| pages=265–71| pmid=17976554| issue=3| doi=10.1016/j.jemermed.2007.02.030}}</ref> It also appears to make [[Medicine:Emergency department|emergency department]] care faster and better.<ref>{{cite journal| title=Randomized controlled clinical trial of point-of-care, limited ultrasonography for trauma in the emergency department: the first sonography outcomes assessment program trial|vauthors=Melniker LA, Leibner E, McKenney MG, Lopez P, Briggs WM, Mancuso CA| journal=Annals of Emergency Medicine|date=Sep 2006| volume=48| pages=227–35| pmid=16934640| issue=3| doi=10.1016/j.annemergmed.2006.01.008}}</ref><ref>{{cite journal| title=Prospective study to evaluate the influence of FAST on trauma patient management|vauthors=Ollerton JE, Sugrue M, Balogh Z, D'Amours SK, Giles A, Wyllie P| journal=Journal of Trauma|date=Apr 2006| volume=60| pages=785–91| pmid=16612298| issue=4| doi=10.1097/01.ta.0000214583.21492.e8}}</ref>

<gallery>
File:UOTW 18 - Ultrasound of the Week 1.webm|Negative FAST but full stomach<ref name=UOTW18>{{cite web|title=UOTW #18 - Ultrasound of the Week|url=https://www.ultrasoundoftheweek.com/uotw-18/|website=Ultrasound of the Week|access-date=27 May 2017|date=17 September 2014}}</ref>

File:UOTW 18 - Ultrasound of the Week 2.webm|Negative FAST but full stomach<ref name=UOTW18/>

File:UOTW 18 - Ultrasound of the Week 3.webm|Negative FAST but full stomach<ref name=UOTW18/>

</gallery>

==Interpretation==
[[File:FAST Algorithm.svg|thumb|FAST Algorithm]]
FAST is most useful in trauma patients who are hemodynamically unstable. A positive FAST result is defined as the appearance of a dark ("anechoic") strip in the dependent areas of the peritoneum. In the right upper quadrant this typically appears in Morison's Pouch (between the [[Biology:Liver|liver]] and kidney). This location is most useful as it is the place where fluid will collect with a supine patient. In the left upper quadrant, blood may collect anywhere around the [[Biology:Spleen|spleen]] (perisplenic space). In the pelvis, blood generally pools behind the [[Biology:Bladder|bladder]] (in the rectovesicular space). A positive result suggests hemoperitoneum; often [[CT scan]] will be performed if the patient is stable<ref name="Scalea">{{cite journal|vauthors=Scalea T, Rodriguez A, Chiu W, Brenneman F, Fallon W, Kato K, McKenney M, Nerlich M, Ochsner M, Yoshii H| title=Focused Assessment with Sonography for Trauma (FAST): results from an international consensus conference| journal=Journal of Trauma| volume=46| issue=3| pages=466–72| year=1999| pmid=10088853| doi=10.1097/00005373-199903000-00022| doi-access=free}}</ref> or a laparotomy if unstable. In those with a negative FAST result, a search for extra-abdominal sources of bleeding may still need to be performed.

==See also==
*HEART scan

==References==
{{reflist}}

;Further reading
* {{cite journal|last=Gillman|first=Lawrence M|author2=Ball, Chad G|author3=Panebianco, Nova|author4=Al-Kadi, Azzam|author5= Kirkpatrick, Andrew W|title=Clinician performed resuscitative ultrasonography for the initial evaluation and resuscitation of trauma|journal=Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine|date=2009|volume=17|issue=1|pages=34|doi=10.1186/1757-7241-17-34|pmc=2734531|pmid=19660123 |doi-access=free }}

==External links==
* [http://www.acep.org/Clinical---Practice-Management/Focus-On--EFAST---Extended-Focused-Assessment-With-Sonography-for-Trauma/ Focus On: EFAST - Extended Focused Assessment With Sonography for Trauma]: American College of Emergency Physicians (ACEP)
* [http://www.emedicine.com/MED/topic2804.htm eMedicine: Blunt abdominal trauma]
* [http://sinaiem.us/tutorials/fast FAST exam tutorial] {{Webarchive|url=https://web.archive.org/web/20180903004934/http://sinaiem.us/tutorials/fast |date=2018-09-03 }}
* [http://www.trauma.org/archive/radiology/FASTfast.html The FAST examination] {{Webarchive|url=https://web.archive.org/web/20110720045630/http://www.trauma.org/archive/radiology/FASTfast.html |date=2011-07-20 }} from Trauma.org, includes tutorial videos.
*[https://www.youtube.com/watch?v=VBHCmw8iHCc Trauma FAST Exam - LUQ Exam] 
* [http://www.criticalecho.com/content/tutorial-9-lung-ultrasound Lung ultrasound]: ICU Sonography
* [https://www.amazon.ca/FOB-Doc-Doctor-Front-Afghanistan-ebook/dp/B008V43N60/ref=pd_sim_351_5?ie=UTF8&dpID=5161VPfMsCL&dpSrc=sims&preST=_OU15_AC_UL160_SR107%2C160_&refRID=7GFWZ8Q2CH6M532AN904 ''FOB Doc'']: Capt Ray Wiss, MD. By a pioneering teacher of FAST to ER and first responders, civilian and military.

{{Medical imaging}}
{{Trauma|state=autocollapse}}

[[Category:Medical ultrasonography]]
[[Category:Traumatology]]

{{Sourceattribution|Focused assessment with sonography for trauma}}