The authors wish to acknowledge Dr. Annie Y. Chen and Ms. Linda Salas Mesa for their assistance with photography.

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. The patients provided written informed consent for participating in the study. Patient inclusion criteria: any patient with hemodynamic instability or abdominal pain/distension. Patient exclusion criteria: patient refusal.
1. Transducer selection
<ol>
	<li>Select a low-frequency linear transducer (1-5 MHz) (see Table of Materials) to visualize organs deeper than 6 cm in the body1,19.</li>
	<li>If available, select the curvilinear low-frequency probe as its wide footprint maximizes spatial resolution of intra-abdominal organs.</li>
	<li>If the curvilinear probe is not available, select any low-frequency probe such as a sector array probe (aka &#34;phased array probe&#34;, see Table of Materials). 
	NOTE: The sector array probe is sometimes colloquially called the &#34;phased array probe&#34;. However, this latter colloquial term is misleading because all modern ultrasound transducers (including even linear high-frequency transducers) use electronic phasing to steer the ultrasound beam20,21,22, so what distinguishes the sector array from other ultrasound probes is not that it is a &#34;phased array&#34; (all modern transducers are) but that this probe traces out a sector arc. But because many point-of-care ultrasound providers use the term &#34;phased array&#34; to refer to the sector array probe, this manuscript will mention both terms. However, to those interested in the mechanics of how ultrasound machines work, sector array probe is the technically accurate name and is already widely used by ultrasound experts outside of the point-of-care ultrasound world18,23,24,25,26.</li>
	<li>If the e-FAST exam is being performed and is being used to screen for pneumothorax, use a linear high-frequency probe (&#8805; 5 MHz, see Table of Materials) for that application and then resume using a low-frequency probe for the remainder of the FAST/e-FAST exam.</li>
</ol>
2. Machine settings and machine placement
<ol>
	<li>Mode
	<ol>
		<li>Select abdominal mode, which will place the indicator on the left screen and maximize spatial resolution while minimizing temporal resolution. 
		NOTE: In contrast to &#34;abdominal&#34; mode, &#34;cardiac&#34; mode will maximize temporal resolution at the expense of spatial resolution, settings that are optimal for visualizing the fast-moving structures within the heart but unhelpful for visualizing the slow-moving structures in the abdomen or screening for gross fluid in the pericardial sac.</li>
	</ol>
	</li>
	<li>Machine placement
	<ol>
		<li>Place the ultrasound machine on either the patient&#39;s left or right side but ensure that the sonographer has a direct line of sight to both the machine&#39;s screen and to the patient simultaneously so that the operator can manipulate both the ultrasound probe and the ultrasound machine settings concurrently.</li>
	</ol>
	</li>
	<li>Image acquisition preset
	<ol>
		<li>Set the ultrasound machine&#39;s image acquisition technique to prospective collection. If the operator prefers &#34;retrospective collection, &#34; they will need to reverse the order of any paired steps involving fanning the ultrasound probe and click Acquire before image acquisition.</li>
	</ol>
	</li>
</ol>
3. Patient positioning
<ol>
	<li>Position the patient supine with the chest and abdomen exposed1.</li>
	<li>For Right Upper Quadrant (RUQ) and Left Upper Quadrant (LUQ) views, abduct the patient&#39;s arms at least 5 inches away from their body to allow access for the ultrasound probe to reach the patient&#39;s flanks.</li>
</ol>
4. Scanning technique
<ol>
	<li>Apply gel to the ultrasound probe prior to attempting each view.</li>
	<li>Point indicator mark cranially for coronal or sagittal views and toward the patient&#39;s right side for transverse views.</li>
</ol>
5. FAST exam cardiac views
<ol>
	<li>Subxiphoid (aka subcostal) 4-chamber view
	<ol>
		<li>Place the probe on the anterior abdominal wall just caudal to the xiphoid process in the midline or slightly to the patient&#39;s right1.</li>
		<li>Orient the ultrasound beam transversely with the indicator to the patient&#39;s right and the probe nearly flat against the patient&#39;s abdomen and directed towards the patient&#39;s left shoulder1 (Figure 1).</li>
		<li>Adjust probe positioning and screen depth to obtain a view of the four cardiac chambers visualized in the center of the ultrasound image (Figure 2; Video 1).</li>
		<li>Adjust the gain until the intracardiac blood appears uniformly black (anechoic) with just a few specks of grey27.</li>
		<li>Click on Acquire.</li>
		<li>Inspect the circumference of the heart for a similar dark hypoechoic stripe around the myocardium (Figure 2; Video 2).</li>
	</ol>
	</li>
	<li>Parasternal long-axis view (optional) 
	NOTE: In some patients, the subxiphoid window may provide ambiguous findings or inadequate visualization of the pericardium due to abdominal obesity or distended/gas-filled stomach1. In these circumstances, the parasternal window may provide an alternative window to screen for pericardial effusion.
	<ol>
		<li>Place the probe along the left sternal border just caudal to the clavicle with the indicator mark pointing toward the patient&#39;s left hip (Figure 3). 
		NOTE: The transducer indicator mark is pointed toward the patient&#39;s left hip and not toward the right shoulder, as would be done when performing transthoracic cardiac ultrasound because the entire FAST exam is traditionally performed in &#34;abdominal&#34; rather than &#34;cardiac&#34; mode.</li>
		<li>While keeping the probe indicator pointed toward the patient&#39;s left hip, slide (translate) the probe caudally examining each rib interspace until the heart disappears and making a note of which interspaces provided a useful view of the heart.</li>
		<li>Slide (translate) the probe back cranially to the interspace or spaces that provide the best visualization of the heart.</li>
		<li>Adjust probe positioning to obtain a view with the following structures visible: descending thoracic aorta, left atrium, left ventricle, left ventricular outlow tract, right ventricle, and pericardium (Figure 4; Video 3).</li>
		<li>Adjust screen depth so that at least 3-6 cm of depth is visible deep to the descending thoracic aorta (Figure 4; Video 3; Video 4).</li>
		<li>Adjust gain as mentioned in step 5.1.4.</li>
		<li>Click on Acquire.</li>
		<li>Inspect the circumference of the heart for a dark hypoechoic stripe that dissects into the plane between the heart and the descending thoracic aorta (Figure 4).</li>
	</ol>
	</li>
</ol>
6. FAST exam abdominal windows
<ol>
	<li>Right upper quadrant (RUQ) window
	<ol>
		<li>Place the ultrasound probe in the coronal plane on the patient&#39;s right side along the mid-to-posterior axillary line in the 7th to 9th intracoastal space with the probe indicator towards the patient&#39;s head (Figure 5)1,28.</li>
		<li>Adjust the probe positioning to obtain a view containing the following structures: (1) liver; (2) right kidney; (3) hepato-renal interface (a potential space also called Morison&#39;s pouch) (Figure 6; Video 5)1.</li>
		<li>Adjust screen depth so that the hepato-renal interface occupies the middle third of the screen (Figure 6; Video 5).</li>
		<li>Adjust the gain until the liver and kidney appear slightly hyperechoic (tissue echogenicity) but not so dark as completely black and not so bright that they are indistinguishable from their hyperechoic capsules (Figure 6; Video 5). Click on Acquire.</li>
		<li>Fan through the hepato-renal interface anteriorly to posteriorly and back during the video acquisition (Video 6).</li>
		<li>Inspect the hepato-renal recess for a hypoechoic or anechoic stripe between the caudal-most tip of the liver and the inferior pole of the kidney, as this is the most sensitive site for detection of free peritoneal fluid in both the RUQ and usually the entire FAST exam in a supine patient29 (Figure 6; Video 7).</li>
		<li>If the initial view is negative, continue the search for fluid by sliding (translating) the probe caudally into the paracolic gutter and/or cranially to view the hepato-diaphragmatic space between the liver and the diaphragm28,29 (Video 8).
		<ol>
			<li>From the cranial-most RUQ view, visualize the right pleural space cranial to the diaphragm allowing the operator to easily perform this component of the e-FAST exam as a logical extension of the conventional FAST exam1,28,29 (Video 9).</li>
		</ol>
		</li>
	</ol>
	</li>
	<li>Left upper quadrant (LUQ) window
	<ol>
		<li>Place the ultrasound probe in the coronal plane on the patient&#39;s left flank along the mid-to-posterior axillary line in the 5th to 7th intracoastal space with the probe indicator towards the patient&#39;s head1,28(Figure 7).</li>
		<li>Adjust the probe positioning to obtain a view containing the following structures: (1) spleen; (2) diaphragm; and (3) if possible, the spleno-renal interface (Figure 8; Video 10).</li>
		<li>Adjust screen depth so that the spleno-diaphragmatic interface occupies the middle third of the screen (Figure 8; Video 10).</li>
		<li>Adjust gain as indicated in step 6.1.4, but replace liver with spleen in the instructions (Figure 8; Video 10). Click on Acquire.</li>
		<li>Fan through the interface between the spleen and diaphragm anteriorly to posteriorly and back during the video acquisition (Video 11).</li>
		<li>Inspect the interface for a hypoechoic or anechoic stripe between the spleen and diaphragm and between the spleen and left kidney (Figure 8; Video 12).</li>
		<li>If the spleno-renal interface was inadequately visualized in steps 6.2.5-6.2.7, slide (translate) the probe caudally until the spleno-renal interface is visualized and repeat steps 6.2.5-6.2.7 but this time focusing on the spleno-renal rather than the spleno-diaphragmatic interface (Video 13).</li>
		<li>To examine the left pleural space (i.e., if performing an e-FAST exam), slide (translate) the probe cranially until the view is centered on the diaphragm1,28 (Video 14).</li>
	</ol>
	</li>
	<li>Suprapubic (pelvic) window 
	NOTE: Since a fluid-filled bladder provides an excellent medium for the transmission of ultrasound waves, imaging the pelvis before insertion of a foley catheter or clamping the foley catheter to allow filling of the bladder can improve image acquisition1,28.
	<ol>
		<li>Transverse suprapubic (pelvic) view
		<ol>
			<li>Position the ultrasound probe in the transverse plane with the indicator mark pointing to the patient&#39;s right side, place the probe just cranial to the pubic symphysis, and angle the ultrasound beam 10-20 degrees caudally into the pelvis1,28 (Figure 9).</li>
			<li>Adjust the probe positioning to obtain a view containing the following sex-specific structures.</li>
			<li>If the patient is female:
			<ol>
				<li>Adjust the probe to visualize the following structures: (1) the bladder in its maximal dimension; (2) the uterus (if present); and (3) the space just posterior to the uterus (rectouterine pouch of Douglas)2&#160;(Figure 10).</li>
				<li>Adjust screen depth so that the uterus occupies the middle third of the screen (Figure 10; Video 15).</li>
				<li>Adjust screen gain so that the urine in the bladder appears relatively anechoic (black) and the space deep into the bladder is distinct from the posterior bladder wall (Figure 10; Video 15).</li>
			</ol>
			</li>
			<li>If the patient is male:
			<ol>
				<li>Adjust the probe to visualize the following structures: (1) the bladder in its maximal dimension and (2) the space just posterior to the bladder (recto-vesical pouch)2 (Figure 11; Video 16).</li>
				<li>Adjust screen depth so that the bladder occupies the middle third of the screen (Figure 11; Video 16).</li>
				<li>Adjust the screen gain so that the urine in the bladder appears relatively anechoic (black) and the space deep into the bladder is distinct from the posterior bladder wall (Figure 11; Video 16).</li>
			</ol>
			</li>
			<li>Click on Acquire. Fan across the pelvis posteriorly to anteriorly during the video acquisition (Video 17).</li>
			<li>Inspect the view for an anechoic stripe in the peri-uterine/rectouterine space if the patient is female (Figure 10B; Video 18) and in the recto-vesical space if the patient is male (Figure 11B; Video 19).</li>
		</ol>
		</li>
		<li>Sagittal suprapubic (pelvic) view
		<ol>
			<li>Starting with the transverse view above (6.3.1.1), rotate the ultrasound probe 90 degrees clockwise until the ultrasound beam is in the sagittal plane with the indicator mark pointing to the patient&#39;s head and keep the ultrasound beam angled 10-20 degrees caudally into the pelvis1,28&#160;(Figure 12).</li>
			<li>Adjust the probe positioning to obtain a view containing the following sex-specific structures.</li>
			<li>If the patient is female:
			<ol>
				<li>Adjust the probe to visualize the following structures: (1) the bladder in its maximal dimension; (2) the uterus (if present); and (3) the space just posterior to the uterus (rectouterine pouch of Douglas)2&#160;(Figure 13; Video 20).</li>
				<li>Adjust screen depth so that the uterus occupies the middle third of the screen (Figure 13; Video 20).</li>
				<li>Adjust screen gain so that the urine in the bladder appears relatively anechoic (black) and the space deep to the bladder is distinct from the posterior bladder wall (Figure 13; Video 20).</li>
			</ol>
			</li>
			<li>If the patient is male:
			<ol>
				<li>Adjust the probe to visualize the following structures: (1) the bladder in its maximal dimension and (2) the space just posterior to the bladder (recto-vesical pouch)2&#160;(Figure 14; Video 21).</li>
				<li>Adjust screen depth so that the bladder occupies the middle third of the screen (Figure 14; Video 21).</li>
				<li>Adjust the screen gain so that the urine in the bladder appears relatively anechoic (black) and the space deep into the bladder is distinct from the posterior bladder wall (Figure 14; Video 21).</li>
			</ol>
			</li>
			<li>Click on Acquire. Fan across the pelvis left-to-right and back during the video acquisition (Video 22).</li>
			<li>Inspect the view for an anechoic stripe in the peri-uterine/rectouterine space if the patient is female (Video 23) and in the recto-vesical space if the patient is male (Video 24).</li>
		</ol>
		</li>
	</ol>
	</li>
</ol>

YB is an Editor on the American Society of Anesthesiologists' Editorial Board on Point-of-Care Ultrasound and Section Editor for POCUS for OpenAnesthesia.org.

Traumatic injuries remain a leading cause of morbidity and mortality in the United States and worldwide. The rapid evaluation of the trauma patient and identification of injuries, including major hemorrhage, is a key component of reducing trauma morbidity. The FAST exam rapidly and non-invasively screens for potential sources of life-threatening hemorrhage. Critical steps to the success of the procedure are obtaining all of the views through the four primary ultrasonographic windows and, if necessary, using the alternati...

The Focused Assessment with Sonography for Trauma (FAST) exam is a diagnostic point-of-care ultrasound (POCUS) exam of the torso designed to rapidly assess potentially life-threatening hemorrhage in trauma patients1. The FAST exam was one of the earliest POCUS techniques to achieve widespread adoption: it was first developed in the 1980s in Europe and spread to the United States in the early 1990s. As POCUS became more commonly utilized in the evaluation of trauma patients, a consensus conference was held in 1997, which standardized the definition of the FAST exam and its role in the care of trauma patients. Over time, some authors have advocated for adding a focused ultrasound exam of the lung to the traditional FAST exam and have termed this multi-organ exam the extended FAST (e-FAST) exam2.
The primary role of both the classical FAST and its newer iteration, e-FAST, is in the initial evaluation of trauma patients3. Hemodynamic instability in traumatically injured patients is commonly caused by a limited number of conditions, including primary hemorrhage, cardiac tamponade, and tension pneumothorax3,4. As a part of the ACBDE steps of the Advanced Trauma Life Support(ATLS) primary survey, the Circulation step looks to identify and treat the life-threatening causes of hemodynamic instability in trauma patients3,5,6. This step includes ruling out cardiac tamponade and intracavitary bleeding in the pleural spaces and peritoneum, among other sources6,7. The FAST exam allows for visualization of free fluid in the pericardium and peritoneum, and with e-FAST views, bilateral pleural spaces3,6,7. In the clinical picture of hemodynamic instability after major trauma, this fluid is presumed to be blood until proven otherwise.
As a point-of-care ultrasound examination, the FAST/e-FAST exam offers several advantages. The exam can be performed using small portable ultrasound machines at the patient&#39;s bedside while other care is ongoing and without requiring the transport of the patient 3. The limited views using B-mode technique means that a complete examination can be obtained rapidly within a few minutes, and the noninvasive nature of the ultrasound exam means that the exam can be easily repeated if the patient&#39;s clinical picture changes3,8,9.
At the same time, the simple nature of the FAST exam has several limitations. Like any ultrasound examination, it is operator dependent to obtain appropriate views and accurate interpretation of the images in real-time9. Various patient factors, including obesity, and subcutaneous emphysema, may limit the ability to acquire adequate images. Additionally, the simplified views of the FAST/e-FAST exams do not look for specific organ injuries but rather screen for free fluid in the various body compartments. In the appropriately selected trauma patient, this free fluid is likely to represent blood from ongoing hemorrhage but may represent other fluid from traumatic or non-traumatic medical conditions.
Given the advantages and limitations of the FAST/e-FAST exams, their primary indication is in evaluating hemodynamically unstable patients who have suffered blunt trauma. For this patient population, the primary goal is to identify traumatic sources of hemodynamic instability, such as cardiac tamponade and intracavitary hemorrhage, which require immediate operative intervention. In this role, it has replaced diagnostic peritoneal lavage (DPL) as the primary modality for diagnosing intraperitoneal hemorrhage and physical examination and challenges the chest X-ray for diagnosing intrapleural hemorrhage and pneumothorax1. With their rapid and noninvasive nature, the FAST/e-FAST exams have been used in other trauma patients, including hemodynamically stable blunt trauma patients and penetrating trauma patients, both stable and unstable. However, the indications for and interpretation of these exams remain less clear.
Outside of the trauma setting, the FAST exam may have value in several different crisis management situations, including but not limited to any of the following: triaging the severity of obstetric hemorrhage10, searching for the location of perioperative bleeding, screening for peri-procedural bladder rupture, and as part of the preoperative assessment of patients with suspected but unconfirmed ascites scheduled for elective surgery11,12,13. In these non-trauma contexts, the providers available to perform the FAST exam are likely to come from specialties like obstetrics, anesthesiology, internal medicine, and critical care, for whom FAST exam training is highly variable in residency/fellowship curricula13,14,15,16. It is these non-trauma specialties that form the target audience of this review. Some of these non-trauma specialties tend to either have existing expertise in lung ultrasound (e.g., intensivists17) or have reasons to perform the abdominal views of the FAST exam in isolation (e.g., anesthesiologists and obstetricians)10. For these reasons and because the lung views of the e-FAST exam are already comprehensively covered in a separate manuscript18, this review will focus primarily on image acquisition for the abdominal views of the FAST exam. Despite this, it is worth emphasizing that, in the trauma setting, sonographic examination of the lung is, in many hospitals, considered a core part of the FAST protocol (i.e., e-FAST is the form of the FAST exam preferred by some trauma providers).

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Affiniti&#160; (including linear high-frequency, curvilinear, and sector array transducers)</td>
			<td>Philips</td>
			<td>n/a</td>
			<td>Used to obtain a subset of the Figures and Videos</td>
		</tr>
		<tr>
			<td>Edge 1 ultrasound machine (including linear high-frequency, curvilinear, and sector array transducers)</td>
			<td>SonoSite</td>
			<td>n/a</td>
			<td>Used to obtain a subset of the Figures and Videos</td>
		</tr>
		<tr>
			<td>M9 (including linear high-frequency, curvilinear, and sector array transducers)</td>
			<td>Mindray</td>
			<td>n/a</td>
			<td>Used to obtain a subset of the Figures and Videos</td>
		</tr>
		<tr>
			<td>Vivid iq&#160; (including linear high-frequency, curvilinear, and sector array transducers)</td>
			<td>GE</td>
			<td>n/a</td>
			<td>Used to obtain a subset of the Figures and Videos</td>
		</tr>
	</tbody>
</table>

focused assessment with sonography for trauma (fast) exam: image acquisition

Over the past twenty years, the Focused Assessment with Sonography for Trauma (FAST) exam has transformed the care of patients presenting with a combination of trauma (blunt or penetrating) and hypotension. In these hemodynamically unstable trauma patients, the FAST exam permits rapid and noninvasive screening for free pericardial or peritoneal fluid, the latter of which implicates intra-abdominal injury as a likely contributor to the hypotension and justifies emergent abdominal surgical exploration. Further, the abdominal portion of the FAST exam can also be used outside of the trauma setting to screen for free peritoneal fluid in patients who become hemodynamically unstable in any context, including after procedures that may inadvertently injure abdominal organs. These "non-trauma" situations of hemodynamic instability are often triaged by providers from specialties other than emergency medicine or trauma surgery who are not familiar with the FAST exam. Therefore, there is a need to promulgate knowledge about the FAST exam to all clinicians caring for critically ill patients. Toward this end, this article describes FAST exam image acquisition: patient positioning, transducer selection, image optimization, and exam limitations. Since the free fluid is likely to be found in specific anatomic locations that are unique for each canonical FAST exam view, this work centers on the unique image acquisition considerations for each window: subcostal, right upper quadrant, left upper quadrant, and pelvis.

Four sonographic windows are typically used to obtain the traditional FAST exam views19. The windows are subcostal 4-chamber (SC4C), right upper quadrant (RUQ), left upper quadrant (LUQ), and suprapubic/pelvic. Although the windows can be imaged in any order, the exam is typically performed in the following order: SC4C, RUQ, LUQ, and then suprapubic/pelvic1,19. This is because pericardial tamponade is usually more rapidly life-threatening ...

Watch this Scientific Journal Video about Focused Assessment with Sonography for Trauma FAST Exam: Image Acquisition at JoVE.com

Focused Assessment with Sonography for Trauma FAST Exam: Image Acquisition

The Focused Assessment with Sonography for Trauma (FAST) exam is a diagnostic point-of-care ultrasound examination used to screen for the presence of free fluid in the pericardium and peritoneum. Indications, techniques, and pitfalls of the procedure are discussed in this article.

Focused Assessment with Sonography for Trauma (FAST) Exam: Image Acquisition

Over the past twenty years, the Focused Assessment with Sonography for Trauma (FAST) exam has transformed the care of patients presenting with a ...

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4.6K Views.  Duke University Hospital. The Focused Assessment with Sonography for Trauma (FAST) exam is a diagnostic point-of-care ultrasound examination used to screen for the presence of free fluid in the pericardium and peritoneum. Indications, techniques, and pitfalls of the procedure are discussed in this article. 