SAEM newsletter

The current issue of SAEM’s resident newsletter features an interview with Bret Nelson regarding ultrasound training. He and Beatrice Hoffman, MD, PhD, RDMS (Director of Ultrasound Education for the Department of Emergency Medicine at Johns Hopkins School of Medicine) are featured.

They describe their path towards emergency ultrasound, the value of fellowship training, advice for residents, the role of research, and more.

Aneurysm screening

Sweep through large AAA from Sinai EM Ultrasound on Vimeo.

Abdominal aortic aneurysm (AAA) affects 5-10% of males age 65-79, and among males over 55 years of age represents the 14th leading cause of death. Ruptured aortic aneurysm is associated with a very high mortality rate. Up to 80% of patients die by the time they reach the hospital, and half die during emergent operative repair.

Evaluation of the abdominal aorta by emergency physicians using point-of-care sonography has been a core indication since ACEP’s first ultrasound guidelines were published in 2001. Several studies have demonstrated sensitivity and specificity for aneurysm which approach those of Radiology Department performed ultrasounds, and even CT scans.

While many providers have adopted a point-of-care assessment strategy in patients where AAA is suspected, it is debatable whether emergency physicians should engage in screening asymptomatic patients for AAA. Several ED-based studies have found aneurysms in 5-7% of asymptomatic male patients over the age of 65. Screening has been shown to reduce mortality from AAA, and is recommended by the U.S. Preventive Services Task Force. A single screening examination for asymptomatic males over age 65 is covered by many insurers in the United States including Medicare (Medicare requires that you have smoked over 100 cigarettes or have a family history of AAA to qualify for coverage).

So there is evidence that emergency physicians are capable of screening for aneurysm, and there is evidence to support that someone should be screening selected elder patients. Whether emergency physicians should engage in screening will depend on ED resources available. Many departments across the country have screening programs for HIV, abuse, and other pathology. There is a balance between using limited resources to diagnose and treat acute illness and deploying resources to impact the long-term health of a population which might otherwise be lost to follow up.

So you decide!

Further reading:

  • Tayal VS, Graf CD, Gibbs MA. Prospective study of accuracy and outcome of emergency ultrasound for abdominal aortic aneurysm over two years. Acad Emerg Med 2003 (PMID: 12896888)
  • Costantino TG, Bruno EC, Handly N, Dean AJ. Accuracy of emergency medicine ultrasound in the evaluation of abdominal aortic aneurysm. J Emerg Med 2005 (PMID: 16243207)
  • Knaut AL, Kendall JL, Patten R, Ray C. Ultrasonographic measurement of aortic diameter by emergency physicians approximates results obtained by computed tomography. J Emerg Med 2005 (PMID: 15707804)
  • Salen P, Melanson S, Buro D. ED screening to identify abdominal aortic aneurysms in asymptomatic geriatric patients. Am J Emerg Med 2003 (PMID: 12671815)
  • Moore CL, Holiday RS, Hwang JQ, Osborne MR. Screening for abdominal aortic aneurysm in asymptomatic at-risk patients using emergency ultrasound. Am J Emerg Med 2008 (PMID: 18926345)
  • Cosford PA, Leng GC. Screening for abdominal aortic aneurysm. Cochrane Database Syst Rev. 2007 (PMID: 17443519)
  • Hoffmann B, Um P, Bessman ES, Ding R, Kelen GD, McCarthy ML. Routine screening for asymptomatic abdominal aortic aneurysm in high-risk patients is not recommended in emergency departments that are frequently crowded. Acad Emerg Med. 2009 (PMID: 20053243)

Haiti 2012

 

In early May, emergency ultrasound fellow Leila PoSaw and two Mount Sinai senior Emergency Medicine residents on the ultrasound track, Swathi Nadindla and Micah Nite, traveled to Haiti for an ultrasound education project.

This project was at the Bernard Mevs/ Project Medishare hospital in Port-au-Prince, which is the only trauma, critical care, and rehabilitation hospital in an entire country of ten million people. This hospital is responsible for providing lifesaving care to Haiti’s sickest adults, children and premature infants. The hospital treats 200 to 300 patients daily in the outpatient clinic and 50 inpatients daily.  Two years after the earthquake of Jan 12, 2010, Project Medishare has moved to a capacity-building stage of empowering Haitians to create and sustain their own healthcare system through training, education, and employment of local medical professionals.

 

The goals of the project were to assess the feasibility of a permanent ultrasound program run by Haitian doctors.  In such a program, Haitian doctors would use point of care bedside ultrasound to make life-changing medical decisions for their patients.

Is there a need? Is this possible?

We aimed to perform a needs assessment as an important part of the planning process to clarify and identify appropriate interventions. We also aimed to teach a mini-ultrasound course to any and all who might be interested to learn.

Two years after the earthquake we found the city to still be in a state of disrepair. We developed a flat tire on this extremely bumpy road strewn with debris.  This was formerly the busy down town area. Now it looks like a ghost town.

Though there are still tents around the destroyed National Palace (which is due for demolition), many of the tents have been moved away from the center to the outskirts.

There is a single guarded gate that leads into the Bernard Mevs hospital.  The clinics are open weekdays and have long wait lines. Not surprisingly, we found that the OB clinic could use an ultrasound machine!

The ultrasound course was a huge success. It was held in the cafeteria/dining hall. A total of 14 medical students and 7 staff doctors attended, including Drs. Marlon and Jerry Bitar in the blue surgical caps, and Dr. Toni Eyssallenne, the medical director.

Special thanks to Dr. Marc Jean-Baptiste, driver and navigator, Dr. Alice Baptiste, Dr. Julie Kanter, Dr. Swathi Nadindla and Dr. Micah Nite, without whom this project would never have happened.

There is no doubt that ultrasound has a lot of potential in resource-limited settings. We used ultrasound to diagnose and confirm several interesting cases, which will be highlighted on this site soon!

Jennifer Huang

We are very pleased to welcome the newest member of the Mount Sinai Emergency Ultrasound Division, Dr. Jennifer Huang!

Dr. Huang completed her residency training at Highland Hospital in Oakland, California and an emergency ultrasound fellowship at the SUNY Downstate / Kings County Hospital in Brooklyn, New York.  She has led emergency ultrasound courses and lectured both nationally and internationally.  She has also been an instructor for the ultrasound guided regional anesthesia course at ACEP since 2010.  Her interests include ultrasound education, ultrasound guided regional anesthesia, and critical care ultrasound.

Sonogames 2012

The inaugural SonoGames were held at the SAEM Scientific Assembly in Chicago this week. Thirty-eight residency programs were represented at the event, organized by Resa Lewiss and SAEM’s Academy of Emergency Ultrasound. Three rounds separated the dabblers from the master sonographers. In order to win, teams had to demonstrate ultrasound knowledge on tests and then complete feats such as blindfolded scanning and replicating sample images.

Here are the results:

Winner: Boston Medical Center

Team members: Derek Wayman, Joseph Pare, and Neil Hadfield. Faculty: Kristin Carmody.

They share The Cup, and each take home a copy of The Manual of Emergency and Critical care Ultrasound

Runner-up: University of Texas-Houston

Semi-Finalists: University of Michigan, University of Connecticut, Carolinas Med Center

Arcuate Vessels

Arcuate vessels are commonly seen on ultrasound evaluation of the uterus. Occasionally they can be confused with subchorionic hemorrhage, ovaries, and other structures so it’s worth looking at their characteristic appearance.

Once again, thanks to Dr. Gray for his lovely, copyright-free images:

Here we see the Uterine venous plexus giving rise to the helicine branches, aka arcuate vessels. They run circumstantially through the outer margin of the myometrium.

In the images below, anechoic areas are visible in the posterior aspect of the myometrium (arrows in top two images). The bottom two images reveal the same structures with and without color flow, demonstrating their vascularity. These vessels are normal anatomic variations, and can become more engorged during pregnancy as uterine bloodflow increases.

 

This is again visible posteriorly in this video of a gravid uterus:

 

Cavitation

microbubbles form behind propeller, courtesy of U.S. Navy

Rounding out our recent trifecta of biosafety posts is a description of cavitation. Cavitation is the formation of microbubbles in liquid which has been subjected to rapid pressure changes. This can happen from a variety of causes from beating Dolphin tails, propellers, cracking your knuckles, and with ultrasound. The Mechanical Index is used to represent the risk of cavitation in tissue during ultrasound evaluation, though most authorities do not think cavitation occurs in the normal operating parameters of diagnostic ultrasound.

During rarefaction (the low pressure portion of the ultrasound pressure wave) air-filled structures expand. They then quickly contract again during the remaining phases of the sound wave. Cavitation is deliberately employed in lithotrypsy, as well as non-medical applications such as metal cleaning.

According to Wikipedia:

The physical process of cavitation inception is similar to boiling. The major difference between the two is the thermodynamic paths that precede the formation of the vapor. Boiling occurs when the local vapor pressure of the liquid rises above its local ambient pressure and sufficient energy is present to cause the phase change to a gas. Cavitation inception occurs when the local pressure falls sufficiently far below the saturated vapor pressure, a value given by the tensile strength of the liquid at a certain temperature.

So there are two major bioeffects of ultrsound: Heat and cavitation. The risks of either are vanishingly small with normal diagnostic ultrasound use. No studies have demonstrated any ill effects of diagnostic ultrasound in humans or even fetuses. But understanding these processes at least helps us recognize the issues behind bioeffect concerns.