Course highlights:

• Basic to advanced topics covered
• Organ system-based approach to bedside ultrasound use
• Faculty with international experience in ultrasound education
• Diagnostic applications as well as procedure guidance covered

Both experienced sonographers and neophytes will benefit from small group sizes and an interactive course design.

Additional information is available on the CME Course Page, or download our Mount Sinai Ultrasound CME course brochure 2012.

Registration for the course is open!

If you can spot tamponade clinically in a hypotensive, tachycardic patient with muffled heart tones and JVD, congratulations! You may pass your boards, save a simulated patient, or impress a junior medical student. But how does one diagnose this condition a bit earlier in its natural history?

Pulsus parodoxus is not as hard to assess as it sounds- inflate a blood pressure cuff as you normally would. Slowly deflate the cuff and listen for Korotkoff sounds. If they are present during inspiration and expiration, there is no pulsus parodoxus and you are done. If you only hear Korotkoff sounds during expiration, note the pressure reading and keep slowly deflating until they are present throughout the respiratory cycle. What is the pressure difference between sounds during expiration only and sounds throughout the entire cycle? If it is greater than 10 mmHg, pulsus paradoxus is present.

But you read this far down because you want to know how to find tamponade using ultrasound, right? There are some earlier findings of cardiac tamponade which are detectable with ultrasound before hemodynamic instability ensues. They are:

1. Pericardial effusion
• Hard to have tamponade without this
2. Diastolic collapse of right atrium and right ventricle
• Ideally diastole can be recognized with EKG monitoring on ultrasound, or using M-Mode
3. Inferior Vena cava plethora
• Dilated IVC with loss of respiratory variation
4. Atrio-ventricular valve Doppler inflow velocities
• If these words are unfamilar, use the first three findings instead! Respiratory variation in inflow across the atrioventricular valves (like a valvular pulsus parodoxus) can be a sign of early tamponade physiology. However this is an advanced technique.

The video below shows the first three findings nicely:

Large Pericardial Effusion from Sinai EM Ultrasound on Vimeo.

Note the subxiphoid view with large effusion, followed by the parasternal long axis view. Finally, a transverse view of the IVC demonstrates dilatation and loss of respiratory variation.

 Further Reading:

• Schairer JR, Biswas S, Keteyian SJ, et al. A systematic approach to evaluation of pericardial effusion and cardiac tamponade. Cardiol Rev. 2011 Sep-Oct;19(5):233-8.
• Nagdev A, Stone MB. Point-of-care ultrasound evaluation of pericardial effusions: does this patient have cardiac tamponade? Resuscitation. 2011 Jun;82(6):671-3.

We already know what to look for without ultrasound (thanks to Greyson Orlando and Wikipedia for the GIF):

By directing the beam of a high-frequency linear array transducer through the plane of the iris, you can obtain the following image (while shining a light through the closed eyelid of the same or contralateral eye):

It takes a bit of practice to align both planes, and not worth the trouble if the patient can open their eyes.

Placing a Tegaderm over the closed eye prior to applying gel can make cleanup much easier afterwards (a useful tip for any type of ocular ultrasound).

Further reading:

• Sargsyan AE, Hamilton DR, Melton SL, et al. Ultrasonic evaluation of pupillary light reflex. Critical Ultrasound Journal. 2009 1(2): 53-57.
• Harries A, Shah S, Teismann N, Price D, Nagdev A. Ultrasound assessment of extraocular movements and pupillary light reflex in ocular trauma. Am J Emerg Med. 2010 Oct; 28(8):956-9.

Thus, when novice ultrasound users attempt to discern images created with sound, it can be confusing that bone and air both create bright white signal as well as shadow. The purpose of this brief post is to describe very subjectively how sound behaves as it crosses media of different densities. In the real world of physics this would be referred to as Snell’s Law (unless you want to give more credit to Ibn Sahl or Descartes).

For a very concise and well-animated description of Snell’s Law please see Dr. Dan Russells’ excellent website. The basic premise is that  sound (like light) will bend depending on the density of the medium it is traveling in. The greater the change in density from one medium to another, the greater the bend. For our purposes, that also means the more scattering of ultrasound waves back towards the transducer and less acoustic energy propagating forwards.

For practical purposes, we always start with liquid density in clinical sonography. That is because the transducer and acoustic gel are roughly water-dense, and so is the skin (bear with this oversimplification a moment).  Thus, we really only have three scenarios to think about. Going from liquid to air, liquid to liquid, and liquid to bone.

As illustrated above, the great density differences from liquid to air or bone create lots of scatter (and therefore bright white signal on the screen), and leave little or no acoustic energy to travel deeper into the tissue (thus the distal shadowing). When liquid-dense structures are encountered, relatively little energy is lost (attenuated), and the beam continues to send signal deeper into the body. Thus, liquid structures such as liver, spleen, kidney, bladder make good acoustic windows. They allow lots of ultrasound energy to propagate into the body. Bone and air make poor windows, as it is difficult to see past them.

In addition to the expected excellent lectures and educational sessions, there was a new needle guidance system being demonstrated which may be of benefit to clinicians performing ultrasound-guided procedures.

The SonixGPS system by Ultrasonix uses a sensor in the ultrasound transducer and another in the needle to track the needle’s trajectory and tip placement. The system can work in any direction: in-plane or out-of-plane. Needle trajectory is displayed as a graphic on the main screen, and orientation with respect to the transducer is modeled in the lower right. The system promises the ability to plan out their trajectory before needle placement as well, thus facilitating decisions regarding optimal entry points.

Please note that no members of our ultrasound division have a financial relationship with Ultrasonix.

Thanks to Dr. Wasserman, Ms. Thomas and all the folks at Beth Israel Newark Medical Center Emergency Medicine.  It was a pleasure to visit your shop today and talk about ultrasound in cardiac arrest.  As promised, you will find below a pdf of the handout, a revised RUSH in Arrest algorithm and a full set of references.  When I get a chance to record the lecture, I’ll post that here as well.

Thanks again.

Media:

Handout

Recorded Lecture (pending)

Algorithm:

References:

Atkinson, P R T, D J McAuley, R J Kendall, O Abeyakoon, C G Reid, J Connolly, and D Lewis. “Abdominal and Cardiac Evaluation with Sonography in Shock (ACES): An Approach by Emergency Physicians for the Use of Ultrasound in Patients with Undifferentiated Hypotension.” Emergency medicine journal : EMJ 26, no. 2 (2009): doi:10.1136/emj.2007.056242.

Blaivas, M, and J C Fox. “Outcome in Cardiac Arrest Patients Found to Have Cardiac Standstill on the Bedside Emergency Department Echocardiogram.” Academic emergency medicine : official journal of the Society for Academic Emergency Medicine 8, no. 6 (2001): 616-21.

Breitkreutz, Raoul, Susanna Price, Holger V Steiger, Florian H Seeger, Hendrik Ilper, Hanns Ackermann, Marcus Rudolph, and others. “Focused Echocardiographic Evaluation in Life Support and Peri-Resuscitation of Emergency Patients: A Prospective Trial.” Resuscitation 81, no. 11 (2010): doi:10.1016/j.resuscitation.2010.07.013.

Hernandez, C, K Shuler, H Hannan, C Sonyika, A Likourezos, and J Marshall. “C.A.U.S.E.: Cardiac Arrest Ultra-Sound Exam–A Better Approach to Managing Patients in Primary Non-Arrhythmogenic Cardiac Arrest.” Resuscitation 76, no. 2 (2008): 198-206.

Jones, A E, V S Tayal, D M Sullivan, and J A Kline. “Randomized, Controlled Trial of Immediate Versus Delayed Goal-Directed Ultrasound to Identify the Cause of Nontraumatic Hypotension in Emergency Department Patients*.” Critical care medicine 32, no. 8 (2004): doi:10.1097/01.CCM.0000133017.34137.82.

Lichtenstein, Daniel A, and Gilbert A Mezière. “Relevance of Lung Ultrasound in the Diagnosis of Acute Respiratory Failure: The BLUE Protocol.” Chest 134, no. 1 (2008): doi:10.1378/chest.07-2800.

Rose, J S, A E Bair, D Mandavia, and D J Kinser. “The UHP Ultrasound Protocol: A Novel Ultrasound Approach to the Empiric Evaluation of the Undifferentiated Hypotensive Patient.” The American journal of emergency medicine 19, no. 4 (2001): 299-302. 

Salen, Philip, Larry Melniker, Carolyn Chooljian, John S Rose, Janet Alteveer, James Reed, and Michael Heller. “Does the Presence or Absence of Sonographically Identified Cardiac Activity Predict Resuscitation Outcomes of Cardiac Arrest Patients?” The American journal of emergency medicine 23, no. 4 (2005): 459-62.

Weingart, Scott, Duque, Daniel and Nelson, Bret. “The RUSH Exam – Rapid Ultrasound for Shock / Hypotension.” http://www.webcitation.org/5vyzOaPYU (accessed January 9, 2011).

AIUM Officially Recognizes ACEP Emergency Ultrasound Guidelines
November 17, 2011

In keeping with the AIUM’s overarching mission of advancing the safe and effective use of ultrasound in medicine through education, research, and development of guidelines, the AIUM recognizes the American College of Emergency Physicians (ACEP) Policy Statement Emergency Ultrasound Guidelines as meeting the qualifications for performing ultrasound in the emergency setting. These guidelines describe the education and training required by emergency physicians to achieve competency for the performance of focused emergency ultrasound applications in clinical practice.

AIUM President Alfred Z. Abuhamad, MD, expanded on the importance of this resolution, stating, “Recognition of the ACEP Emergency Ultrasound Guidelines by the AIUM helps ensure that focused emergency ultrasound examinations are performed safely and that physicians performing the ultrasound examinations have met a minimum level of competency as hereby defined. AIUM recognition of the ACEP guidelines can pave the way for collaboration between the two organizations. Furthermore, AIUM recognition provides support and standardization for hospital credentialing of emergency physicians in the performance of the focused emergency ultrasound examination.”

Focused emergency ultrasound examinations are performed at the bedside to diagnose acute life-threatening conditions, guide invasive procedures, and treat emergency medical conditions. Focused emergency ultrasound has been proven to improve the care and expedite treatment of countless patients worldwide.

Michael Blaivas, MD, emergency physician and chair of the AIUM Emergency and Critical Care Ultrasound Community stated:“The recognition by the AIUM is a major milestone for both societies as well as point-of-care ultrasound in general. The AIUM has been able to adapt and grow, not only in membership but also in diversity, by embracing and helping the spread of ultrasound into the point-of-care practice setting for a wide range of clinical applications. The ultimate beneficiaries of this recognition are our patients as ultrasound spreads more widely to help patients who are suffering from acute and chronic illness or undergoing potentially dangerous or painful procedures.”

The AIUM anticipates future collaborative efforts with the ACEP on the use of ultrasound in the emergency medicine setting.

Sonopalpation of the tender area revealed the following:

Untitled from Sinai EM Ultrasound on Vimeo.

The chest x-ray was read as negative for atypical pneumonia and the rib X-ray series reported as negative.   The ultrasound image reveals a bright white cortex (horizontal line halfway down screen) with an obvious discontinuity. This is a classic appearance of fracture (cortical break) on ultrasound. The patient was prescribed analgesia, given instructions for caring for a rib fracture, and did well.

Further reading:

The SAEM Resident Education Committee for Bedside Ultrasonography has published a series of modules designed to used for resident education.  This is another excellent resource out there for anyone teaching bedside ultrasound, and amounts to a mini-textbook.

Take a look here.

Questions:

1. What’s inside the bladder?
2. What’s the bladder volume?
3. How is that catheter working?
4. What’s that bright echogenic arc coming of the superficial aspect of the Foley bulb?

Discussion:

The catheter was irrigated, and began to drain normally again after a blood clot was pushed out. The patient felt better, the urine flow cleared, and discharge with a leg bag and close urology follow up was arranged.

1. A Foley bulb (bright echogenic circular structure) is visible inside the bladder
2. Here’s an easy bladder volume calculation: Length x Width x Height x 0.75. Most machines will calculate volume based on your caliper measurements, but 3/4 of a cuboid isn’t that hard to remember
3. Two ways to tell the catheter isn’t working:
1. The bladder is pretty full despite a properly placed Foley bulb
2. Your clinical acumen. Poor urine output, suprapubic discomfort…
4. Grating lobe artifact. Note that the echogenic line is parallel to the curve of the transducer, and extends from a bright reflector out laterally from the main beam. Turning down the gain (especially the fair field gain) might reduce this a bit. Here’s a nice quick artifacts review.