Mount Sinai Emergency Medicine Ultrasound

Finding the right angle is critical to optimal imaging. In fact ‘right angle’ or perpendicular imaging is the best way to get a clear image. At 90 degrees, many more sound beams reflect back to the transducer than at more shallow angles.

In addition, the ultrasound energy is more spread out when it connects to the tissue at an angle, as seen above.
In this image of the kidney, notice the inferior aspect of the kidney (right arrow) is imaged at nearly 90 degrees. The white lines represent the plane of the kidney.

It has the sharpest border and is well-distinguished from the liver. The middle arrow represents the path of ultrasound energy hitting the the kidney off 90 degrees.  Not a bad image but doesn’t look as good as the one imaged at 90 degrees. Finally, the left arrow represents the beam hitting the kidney almost parallel. Note that the kidney-liver interface looks fuzzy and there is a great loss of detail. Most of the ultrasound energy is reflecting off the surface AWAY from the transducer- hardly any is available to reflect back towards the transducer and yield a good image.

Thus, angling the probe 90 degrees to the structure you want to image can increase resolution and improve your image quality.

Sinai’s own Dr. Lana Friedman, Pediatric Emergency Medicine Fellow, was just named one of three recipients of the prestigious SPR Fellow Clinical Research Award. Her abstract entitled, “Accuracy of Point-of-Care Ultrasound (PoCUS) by Novice Pediatric Emergency Sonologists in the Diagnosis of Skull Fractures,” was selected from a very competitive pool of submissions. She will present the abstract at the PAS meeting in Denver in April.
Congratulations to Dr. Friedman and her research advisor, Dr. Jim Tsung!

On November 17, 2011 Dr. Braden Hexom presented research organized by Mount Sinai and conducted at JFK Hospital in Liberia. The project,

Evaluation of Novel Obstetrics Ultrasound Curriculum for Local Healthcare Providers in Liberia

Bentley S, Hexom B, Nelson BP

described a novel ultrasound curriculum developed in concert with providers in Liberia after a needs assessment and analysis of various use models of ultrasound deployment in the area.

It was determined that among the highest-yield applications of point-of-care ultrasound was pregnancy evaluation, especially during the third trimester. According to the United Nations Population Fund, Liberia’s rate of maternal mortality is among the highest in sub-Saharan Africa (994 per 100,000 live births). Increasingly international organizations such as WINFOCUS have lauded ultrasound as a means of empowering patients and providers in under-resourced areas and improving the quality of care delivered.

A great presentation by Alberta Spreafico (Outreach and International Development Program Coordinator at Henry Ford Health Systems) highlights this topic in an eloquent and inspiring fashion. See below for her TED talk!

On March 22, 2012 the Division of Emergency Ultrasound will host its annual hands-on CME course at Mount Sinai. Targeted at clinicians in emergency and critical care settings, the course consists of presentations by national faculty and plenty of hands-on scanning with live models.

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!

One of the major indications for bedside cardiac ultrasound is the detection of pericardial effusion and its extreme form, cardiac tamponade. You may remember that Beck’s Triad (hypotension, jugular venous distension, and muffled or distant heart sounds) is pathognomonic for cardiac tamponade. You should also remember (to say to your colleagues who recite that tamponade is a clinical diagnosis) that the triad is present in about one-third of cases.

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.