SonoTips & Tricks: The FAST scan: The Cardiac views #FOAMed

Finishing the ultrasound QA sessions that we do every week at Stanford, I was reminded about how bedside ultrasound is a tool that helps when resources were limited. If you hadn’t heard, there was an Asiana Airlines plane crash at San Francisco International Airport with over 180 patients requiring medical care, 55+ of which came to Stanford. Luckily, we just added 4 new SonoSite EDGE ultrasound machines to our 4 MTurbos and 3 GE Vscan systems the week before – and they sure were used well! The FAST scan was used as a screening tool and to help prioritize those who would go to the CT scanner. Once, again, it is important to know how to do it and do it well.  Our latest insert in the ACEP Ultrasound Section newsletter is below – on the FAST scan – the Cardiac sections. The prior entry was on the FAST scan: The Upper Quadrants ( go here. ) – And Ultrasound Podcast recorded with Cliff Reid about it this week too!

I’ll start with what I’ve said before: “2013 is the YEAR OF ULTRASOUND – and for good reason – there are only a few tools that give us such immediate information that can save a life. The ACEP US Section is the go-to site for everything you want to know about starting an US program, credentialing in ultrasound, the policies and politics, and is the home of SonoGuide - an amazing educational resource for bedside ultrasound, and the EMSONO: Ultrasound Test. It is also where we add our entries for their newsletter that goes over tips and tricks, cases, and all things ultrasound in the news. We recently wrote an article for the ACEP Ultrasound Section Newsletter - which is available for all members of the ACEP US Section – and I highly recommend becoming a member – it’s totally worth it.”

It was a TRUE pleasure to record a podcast recently with Dr. Scott Weingart (aka, my hero) on EMCrit (twitter: EMCrit), and writing this article with our ultrasound fellow, Dr. Viveta Lobo, describes some of what was spoken about.

By Viveta Lobo, MD and Laleh Gharahbaghian, MD, FACEP

As discussed in our last entry, the FAST exam is undoubtedly the most widely used bedside ultrasound application used in emergency medicine. Its incorporation in the ATLS revised protocol, the RUSH exam, and several other published protocols, makes it an invaluable screening tool for intra abdominal injury causing hemoperitoneum, cardiac injury with pericardial effusion, and unexplained hypotension.

We will continue our discussion of the FAST scan by reviewing the cardiac views, and relay some tips and tricks for each. Refer to the previous newsletter for tips onscanning the right upper quadrant (RUQ) and left upper quadrant (LUQ).

The Cardiac Views:

The traditional cardiac view obtained as part of the FAST exam is the subxiphoid view. The main focus of this view in the FAST exam is to evaluate for evidence of cardiac injury by evaluating for pericardial effusion and/or cardiac tamponade. The phased array probe is placed in the subxiphoid space medially, applying pressure to go under the xiphoid process and flattening out the probe while aiming caudally.

Tips for the Subxiphoid View: 

TT1 1. Use your liver as an acoustic window. 
TT2
Sound waves will travel through liver to the heart, allowing you to visualize the heart. Often one can even place the probe slightly to the right of the xiphoid process, to allow for better liver visualization, and then adjust your depth to be able to look past the liver to the heart. Without the liver in view, gas scatter will affect your image acquisition.


2. Visualize both the inferior and superior pericardial borders, to completely evaluate for pericardial effusion or, rarely, loculated pericardial effusions. It is possible for one area to have pericardial effusion and not the other. Click Here for a Video.

3. Have the patient take a deep breath and hold it. When you notice that the heart is far from the probe, and you find yourself adjusting your depth to more than 20cm, having your patient take a deep breath will lower the heart closer to the probe, improving visualization. Click Here for a Video.

TT3

Despite the subxiphoid view being the traditional view for the FAST exam, the parasternal long view is becoming more of the ‘go-to’ window to evaluate for pericardial effusion. This may be due to several very relevant clinical factors: You simply cannot get a good subxiphoid view. An injury, foreign body, or abdominal pain does not allow for subxiphoid probe placement/pressure. Or you can differentiate pericardial fluid from pleural fluid in the parasternal long view

Tips for Parasternal Long View:
As far as patient positioning, if you’ve already evaluated the RUQ and LUQ (so as to not affect free fluid evaluation) and the patient is able to turn into a left lateral decubitus position, it will help bring the heart closer to the chest wall for visualization. This can be difficult, or impossible, in trauma patients, so the below tips may help:

TT4 1. Start high and start medial - Place your phased array probe just next to the sternum, starting just under the clavicle. If you don’t see the heart there, slide down a rib space, and fan through that space to find the heart. Continue sliding down rib spaces, until you find it.

2. Slowly change the angle of your probe (up and down) when you’re assessing each rib space as described above. ‘Slowly’ is the key word here. If you’re angling downward too much in a rib space and see the PSL heart, you may need to just slide down a rib space. If that makes the image worse, slide back up.

3. Slowly rotate your probe while keeping the angle described above (clockwise/counterclockwise depending on whether you use the right shoulder or the left hip to direct your probe marker). Rotate until you visualize the longitudinal view of the left side of the heart.

4. Slide your probe medially/laterally only if you need to in order to center the aortic and mitral valves on your screen.

5. Ensure adequate depth in order to distinguish a left sided pleural effusion from a pericardial effusion. This will allow visualization of the descending thoracic aorta seen in its transverse view just deep to the heart, which is your landmark in differentiating pleural effusion from pericardial effusion. Pleural effusion will travel posterior to the aorta while pericardial effusion will travel anterior to it (and possibly circumferentially around the heart).TT5
TT6

TT7Lastly, it can be very difficult in both subxiphoid and parasternal long views to differentiate epicardial fat pad from pericardial effusion. One tip: epicardial fat is seen anteriorly and has echogenicity within it, while pericardial effusion is seen posteriorly or inferiorly and is anechoic, but can travel anteriorly if large enough to become a circumferential pericardial fluid collection. Despite this tip, clinical correlation is needed.

Look out for Part 3 of the FAST Exam: The Pelvis, in the next newsletter. Until next time, happy scanning!

For a set of links to online education in bedside ultrasound, go here. Another post on Social Media in EM Ultrasound and the amazing tools out there to learn it for free, go here.”

References
1. Ma OJ, Mateer JR, Ogata M, et al. Prospective analysis of a rapid trauma ultrasound examination performed by emergency physicians. J Trauma. 1995; 38:879-85.
2. Wherrett LJ, Boulanger BR, McLellan BA, et al. Hypotension after blunt abdominal trauma: the role of emergent abdominal sonography in surgical triage. J Trauma. 1996;41:815-20.
3. Schiavone WA, Ghumrawi BK, Catalano DR, et al. The use of echocardiography in the emergency management of nonpenetraing traumatic cardiac rupture. Ann Emerg Med. 1991;20:1248-50.
4. 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;46:543-52.

 

 

 

SonoTips & Tricks: The upper quadrants of the FAST scan #FOAMed

Happy Monday everyone! I mean, Tuesday!! Ugh! Well, if you were wondering where I’ve been, or even if you didn’t notice, I’ve had a busy couple weeks. From the many shifts that was full of interesting ultrasound cases (which you know I’ll share with you soon!) to graduating another stellar group of emergency residents, credentialing them in EM Ultrasound after 3 great years of training and a competency test, and hopefully soon to hear about the amazing pick-ups and lives saved in their future careers with the use of their great clinical judgement and bedside ultrasound. Im sure you love those busy weeks as much as we do, so i thought I would post something that would be a bit of positivity and highlight a group that I believe in: ACEP Ultrasound Section.

I’ll start with what I’ve said before: “2013 is the YEAR OF ULTRASOUND – and for good reason – there are only a few tools that give us such immediate information that can save a life. The ACEP US Section is the go-to site for everything you want to know about starting an US program, credentialing in ultrasound, the policies and politics, and is the home of SonoGuide - an amazing educational resource for bedside ultrasound, and the EMSONO: Ultrasound Test. It is also where we add our entries for their newsletter that goes over tips and tricks, cases, and all things ultrasound in the news. We recently wrote an article for the ACEP Ultrasound Section Newsletter - which is available for all members of the ACEP US Section – and I highly recommend becoming a member – it’s totally worth it. To continue to entice you, i will include our latest entry below – with a few additions in the end. For a set of links to online education in bedside ultrasound, go here. And, for our last entry into the Newsletter on Social Media in EM Ultrasound and the amazing tools out there to learn it for free, go here.”

Now, let’s talk about the FAST scan. It was a TRUE pleasure to record a podcast recently with Dr. Scott Weingart (aka, my hero) on EMCrit (twitter: EMCrit), and writing this article with our ultrasound fellow, Dr. Viveta Lobo, describes some of what was spoken about.

The focused assessment with sonography in trauma, or FAST exam, is undoubtedly the most widely used bedside ultrasound application in emergency medicine. With its incorporation into the ATLS trauma protocol, the FAST exam is performed immediately after the primary survey simultaneously with other resuscitative efforts. It is also a component of the RUSH protocol for patients with unexplained shock. Trauma patients often present with multiple injuries, and significant bleeding can occur without obvious changes in vitals signs. Medical patients can present intoxicated, altered, delirious, or demented all of which will limit the physical exam. The primary purpose of the FAST exam is to rapidly detect free fluid and hemorrhage in the peritoneal, pericardial and pleural spaces. There may be difficulties in obtaining adequate views, and we hope to discuss a few pearls to minimize them.

As with all ultrasound applications, familiarity with technique and patient anatomy, knowledge of common pitfalls, practice, and appreciating technical limitations are important errors to avoid. In general, the FAST exam is not “fast” – it can take up to 3-4 minutes to perform.1 The patient should be supine (or Trendelenberg) with low ambient light, with a low frequency probe used (the phased array probe provides the additional benefit of visualizing between the ribs and getting into the subxiphoid region more easily for the cardiac view). Even with the best technique, the FAST scan will only visualize 25 cc or more of thoracic free fluid and 500cc or more of intraperitoneal free fluid.2

The Right Upper Quadrant (RUQ)

RUQ

The RUQ is the most sensitive region for free fluid in comparison to the other FAST views.3 In my view, the RUQ should be divided into 3 zones.

1. Above/Below the diaphragm,
2. Morrison’s pouch (hepato-renal recess)
3. Paracolic gutter: Around the inferior hepatic edge/inferior pole of kidney

The key is to know your landmarks, and STOP, STAY and widely FAN through each zone well, adjusting your depth as necessary to keep the area of interest centered on your screen. Click Here for a Video. Start high to stay and fan (anterior to posterior) around the diaphragm. Then, SLIDE down into another rib space, stop, stay and fan around the entire kidney. An additional rib space may be necessary to evaluate the paracolic gutter.

Tips for RUQ Diaphragm View :

The liver may be easily seen, but the diaphragm can be more difficult, especially if it’s behind a rib shadow. Have the patient take in a deep breath. This lowers the diaphragm into your view and allows visualization of the thoracic cavity for hemothorax/pleural fluid as well as sub-diaphragmatic peritoneal fluid. Visualization of the spine shadow travelling in the lower part of the screen will normally stop at the diaphragm with a mirror image artifact illustrated in the thoracic cavity.

2-TT Imagespineshadow

However, if the spine is able to been seen above the diaphragm– this is pathognomonic of pleural fluid, and also known as the “V-line.”4Click Here for a Video.

3-TT Imagevline

Tips for RUQ Morrison’s Pouch (Hepato-Renal Recess) View:

If rib shadows get in the way, using the same trick above of patient inspiration can help. There are also a few false positive “traps” here.

First, the double line sign, seen around the kidney capsule as hyperechoic double lines with hypoechoic material in between, can be mistaken for free fluid.5 However, free fluid will not be surrounded by hyperechoic lines and will not be in a contained structure.

4-TT ImageVine
Second, edge artifact from the liver/kidney interface occurs due to ultrasound physics and sound wave transmission between structures of different densities. It is seen as a dark thin line tracing off the edge of this interface extending to the bottom of the screen. Click Here for a Video. This differentiates it from free fluid, which will not extend past the liver.Click Here for a Video.

5-TT ImageRUQFFinMP

Tips for RUQ Paracolic Gutter View:

This is where free fluid can be seen first amongst all the different zones of the RUQ view.6The most important tip is to not forget to view this area. You will often have to slide your probe more inferior to obtain this view. Decrease the depth to look around the hepatic edge and inferior kidney pole, and evaluate the region with slow fanning. Click Here for a Video.

6-TT ImageParaCOlicFF

The Left Upper Quadrant (LUQ)

The LUQ is less sensitive for free fluid than the RUQ for varying reasons. First, the LUQ is opposite the side of the sonographer, which can make it technically difficult to obtain an adequate view. Also, the spleen is smaller than the liver and, thus, the acoustic window is lessened.

7-TT Imagestomachsabotage

The stomach commonly obstructs the view as well. The LUQ should also be divided into 3 zones:

1. Above/Below the diaphragm,
2. Spleno-Renal recess,
3. Paracolic gutter: Around the inferior pole of kidney

Tips for the LUQ view
In addition to the various RUQ view tips and tricks as stated above, the LUQ diaphragm view also requires tips to avoid “stomach sabotage”. There are two ways around this: oblique the probe to have the indicator angled toward the gurney and/or slide your probe to the posterior-axillary line away from the plane of the stomach.

8-TT ImageLUQFFAbove

Look out for Part 2 of FAST Tips and Tricks, in the next newsletter where we talk about maximizing your cardiac views.

For additional material, images, and cases on the E-FAST, go here.

Another great review of FAST with excellent references here.

And, of course, saving the best for last – Cliff Reid and The Ultrasound Podcast discusses how to “earn your vaginal stripes” about the EFAST – go here.

References
1.     Boulanger BR, McLellan BA, Brenneman FD, et al. Emergent abdominal sonography as a screening test in a new diagnostic algorithm for blunt trauma.
J Trauma. Jun 1996;40(6):867-    874.
2.     Branney SW, Wolfe RE, Moore EE, et al. Quantitative sensitivity of ultrasound in detecting free intraperitoneal fluidJ Trauma. Aug 1995;39(2):375-380.
3.     Chambers JA, Pilbrow WJ. Ultrasound in abdominal trauma: an alternative to peritoneal lavageArchEmerg Med. Mar 1988;5(1):26-33.
4.     Atkinson P, Milne J, Loubani O, et al. The V-line: a sonographic aid for the confirmation of pleural fluidCrit Ultrasound J. 2012;4(1):19.
5.     Sierzenski PR, Schofer JM, Bauman MJ, et al.
The double-line sign: A false positive finding on the focused assessment with sonography for trauma (FAST) examinationJ Emerg Med. 2011;40(2):188-189.
6.     Rozycki GS, Ochsner MG, Feliciano DV, et al. Early detection of hemoperitoneum by ultrasound examination of the right upper quadrant: a multicenter study.
J Trauma. Nov 1998;45 (5):878-883.

SonoTip&Trick: “I can’t get a good RUQ view for my FAST!” – Really? Well, try this…

The “F” in FAST does not mean “fast”; it stands for “focused”. The good thing is that everyone agrees to that, but we so often forget. This week has turned into the right upper quadrant (RUQ) view of the FAST week! I actually don’t mind that at all and I love it – as too many incomplete FAST scans are done (and accepted). It’s tragic, actually. I get it, and I’ve been there – you feel rushed because you either have too many patients to see, others need the ultrasound machine, or your consultants or surgeons are yelling at you to hurry up because they want to roll the patient or get that life-saving chest radiograph (don’t get me started!). It needs to be a complete, deliberate, and dedicated study. You should know when and how to do the FAST, especially the RUQ as it is one of the most accurate, and how to do it well. After having shown you several cases and images of real patients, some (including me) still have a hard time getting the perfect views of each of the sections of the RUQ (yes, there are “sections” of the RUQ) even though everything is done the right way. Well, thankfully, there are some little tricks to improve your image quality  - so that you feel confident about telling that consultant the FAST results with your voice confident, back straight, chest out and shoulders back. You may even want to add a “booya” at the end of it. Continue reading

SonoTip&Trick: “I can’t tell if there is normal lung sliding.” Here’s a quick tip….

All of us have had that case where we had a thoracic trauma victim or an acutely short of breath patient who we want to evaluate for pneumothorax. We use the ultrasound machine since it’s quick and more accurate than chest XRay. We place the linear probe on the anterior chest wall, indicator toward the head at the 2nd intercostal space and midclavicular line, and see this:

Continue reading

SonoTip&Trick: There’s a left pneumothorax! Really? check again…

Whenever you are performing an E-FAST exam on your trauma patient or a thoracic US in those with unexplained shock or shortness of breath, your sphincter tightens when you see fluid in the belly or when there is no lung sliding. Ever placed your probe on the left anterior chest wall and have been surprised after noticing there is no lung sliding? Or, that you see this weird movement of “the lung” on the left side, which surely isn’t normal and definitely deeper than the pleural line and you think, “There’s a left pneumothorax!” Well, guess what guys and gals, it just could be the heart. Continue reading

SonoTip&Trick: “I can never get a nice subxiphoid view!” Really? Well try this…

You get a patient who has gradual onset of shortness of breath with a history of cancer, a patient with sudden severe exertional chest pressure and new orthopnea, a patient with known pericarditis with worse pain or breathing difficulty, or a trauma patient with a penetrating stab wound to the chest and you want to evaluate whether they have a pericardial effusion, signs of tamponade, or poor contractility through a bedside echo, but you just can’t seem to obtain a great subxiphoid (SX) view. The SX view of the heart seems like it would be easy to obtain. I mean, it is right there! – right by the probe, and the patient is alive so you know he has a heart! Well, sometimes it’s not so easy. There are several reasons for this: your probe positioning, not seeing the liver, and the patient’s thoracic cage.

Continue reading

SonoTip: Da Spine Sign: Dont miss that Pleural Effusion on the FAST scan!

I call it “Da Spine Sign” (insert any accent here – trust me, its funny). So, fluid is the lover of ultrasound, right? And air is the enemy. Typically you will not see the spine passed the diaphragm when looking at your RUQ view for your FAST scan in normal patients, but oh when you do, BAM! You know there’s fluid in the thorax. Here’s an image showing exactly that, as well as a little somethin’ somethin’ in the intraperitoneal space… so, don’t forget to look above the diaphragm in your FAST scan views! By the way – it’s also called the V-Line - I like my name better :)