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Emergency Ultrasound Section Newsletter - June 2013

circle_arrowFrom the Chair: Update on the Clinical Ultrasound Accreditation Program (CUAP) - Emergency Ultrasound Section Newsletter, June 2013
circle_arrowTips & Tricks: FAST Exam Cardiac Views - Part 2 - Emergency Ultrasound Section Newsletter, June 2013
circle_arrowAsk the Expert - Ultrasound Guided Nerve Blocks in the ED - Emergency Ultrasound Section Newsletter, June 2013
circle_arrowJournal Watch - Emergency Ultrasound Section Newsletter, June 2013
circle_arrowCase Report: To see or not to see…- Emergency Ultrasound Section Newsletter, June 2013
circle_arrowInterested in Contributing? - Emergency Ultrasound Section Newsletter, June 2013

From the Chair: Update on the Clinical Ultrasound Accreditation Program (CUAP) - Emergency Ultrasound Section Newsletter, June 2013

Raj Geria, MD, FACEP

The Clinical Ultrasound Accreditation Program (CUAP) is an ACEP governed entity that has been developed by the ACEP Accreditation Subcommittee of the Ultrasound Section over the past several years. The goal of CUAP is to establish a system of guidance for all emergency departments performing clinical point-of-care ultrasound to ensure quality, safety, communication, responsibility and clarity. It aims to ensure practice standards as described in the ACEP Ultrasound Guidelines.

CUAP will specifically address the following aspects of an ultrasound program:
• Administration
• Training & education
• Performance & quality assurance
• Equipment maintenance and cleaning
• Image acquisition and retention
• Report generation

CUAP will not accredit, certify or credential individual physicians but will evaluate and assist in developing the process by which credentialing and privileges are obtained. Individual institutional emergency departments can apply.

The application process will be solely Internet based. Applicants will upload specified documents providing evidence that program requirements are met. Sample documents are currently available on the ACEP Ultrasound Section website. Once the documents are received, they will be redacted and then reviewed by experts on the reviewer panel. We anticipate the application process to be painless with a price point much less than already existing accreditation programs. The term of accreditation will be 3 years and renewal will be simple and straightforward. The end result will be a quality product that will add value to your clinical ultrasound program.

We are currently completing the design of the online submission website and preparing for beta testing of this program.

This program has a core mission of emergency physicians helping other emergency physicians. Smaller and newer programs that often lack the resources of large academic centers can take advantage of expert experience and mentorship.

We hope to have major development with this program by the Scientific Assembly in Seattle this year. A special breakout session dedicated to Q&A regarding CUAP will be offered in a town hall format following the section meeting.

Thank you.


Tips & Tricks: FAST Exam Cardiac Views - Part 2 - Emergency Ultrasound Section Newsletter, June 2013

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:TT1
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: 
1. Use your liver as an acoustic window. 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.

TT22. 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

 

 

 

 TT4

 

 

 

 

 

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:
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.
TT5 TT6

 

 

 

 

 

 

 

 

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). 

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!

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.


Ask the Expert - Ultrasound Guided Nerve Blocks in the ED - Emergency Ultrasound Section Newsletter, June 2013

Robert Bramante, MD and Michael Zwank, MD, FACEP, talk to Lawrence Haines, MD, Emergency Ultrasound Director at Maimonides Medical Center.

"What is the most challenging part when performing US guided nerve blocks?

For me, the most challenging part of performing the nerve block is purely logistical as the actual nerve block is relatively easy to perform and takes less than a minute. The whole set up process of moving the ultrasound machine next to the bedside and having enough room around the patient for the machine and the nerve block set up can be quite a challenge in a crowded New York City ED. Juggling the time it takes to gather the supplies, to consent the patient, and to set up the sterile field with the flow of patient care on a busy shift is often almost prohibitive. However, I am always happy afterward when the patients are made so much more comfortable without the potential side effects of nausea, delirium, hypotension and respiratory depression from systemic opiate analgesia.

"What do you find is better, needle in plane/ out of plane with the transducer when performing these blocks?"

I prefer the in-plane technique as I am able to visualize the needle tip the entire time and can ensure that the tip is not too far from the nerve or lacerating through the nerve itself. The nerve is also very near the femoral artery and vein, so visualizing the needle tip allows for me to confidently inject the anesthetic without fear of intravascular injection.

"Which of the blocks works best for hip fractures?"

There are three nerves that provide sensory innervation to the hip, the sciatic nerve, the obturator nerve and the femoral nerve. Blocking the sciatic nerve in the ED for hip fracture is difficult because you have to place the patient prone and flex the hip to place an injection through the gluteus muscle. As you may imagine, this is extremely uncomfortable in the setting of acute hip fracture. Most of the attention in the ED setting has really been placed on blocking the femoral and obturator nerves because these can be accessed in the supine patient from an anterior approach.

The three types of nerve block that have been commonly described are the Femoral Nerve Block, the 3-in-1 Femoral Nerve Block and the Fascia Iliacus Block. I think that the jury is still out on which one is superior as there is a paucity of prospective, blinded, randomized controlled trials comparing the blocks head to head. There are a multitude of studies showing that each of the blocks are effective in reducing pain associated with hip fracture and that they are equal if not better than systemic analgesia.

"How do you deal with, or convince, our orthopedic colleagues to agree with this as a patient pain management plan?"

For the most part, the orthopedists at my institution were enthusiastic about this type of pain control. Some were even familiar with it as they had worked in institutions where the anesthesiologists used continuous nerve blocks in the peri-operative period. I did encounter a few dissenting voices who were concerned about losing the sensory exam prior to evaluation, or the possibility of increasing their post-operative infection rates. To address these issues, I allow for the in-house orthopedic resident to examine the hip fracture patient for a sensory exam prior to performing the block, and emphasized to the surgeons that the nerve block is not actually at the osseus structures of the hip. So far, we have been successful and they have all been on board.


Journal Watch - Emergency Ultrasound Section Newsletter, June 2013

Brian D. Euerle, MD, FACEP and Greg R. Bell, MD

Article: Bailey C, Carnell J, Vahidnia F, et al. Accuracy of emergency physicians using ultrasound measurement of crown-rump length to estimate gestational age in pregnant females. Am J Emerg Med. 2012;30(8):1627–1629.

Reviewer: Brian D. Euerle, MD, RDMS, FACEP

Objective: To determine the accuracy of emergency medicine providers in determining gestational age using crown-rump measurement in pregnant patients.

Methods: This was a prospective observational study performed in a hospital obstetrics clinic with a convenience sample of women who were in the 6th to 14th week of pregnancy. The patients first had a transabdominal ultrasound examination performed by an emergency care provider, who used crown-rump length to determine gestational age. The clinicians were a mix of senior medical students, emergency medicine residents, emergency ultrasound fellows, emergency department physician assistants, and emergency department attending physicians, all of whom had viewed a 5-minute instructional video about crown-rump measurement. Immediately following the initial ultrasound scan, comprehensive sonography was performed by either an ultrasound technician or an OB/Gyn physician. Their results served as the gold standard.

Results: One hundred five patients were enrolled. Comparison of the emergency medicine providers’ scans with the gold standard ultrasound showed an average correlation of 0.935 (0.911–0.959). When the published variance for crown-rump measurements (3 or 5 days) was used, the correlation was 0.947 (0.927–0.967). The average time for the emergency care providers to obtain a crown-rump measurement was 85 seconds.

Discussion: This study demonstrates that crown-rump length measurements can be obtained rapidly by emergency medicine providers and show good correlation with a gold standard measurement. A nice feature of this study is that the emergency scans were obtained not only by physicians but by a wide variety of providers, including medical students and physician assistants.

Article: Bloch AJ, Bloch SA, Lyon M. Correlation of ß-human chorionic gonadotropin with ultrasound diagnosis of ectopic pregnancy in the ED. Am J Emerg Med. 2013;31(5):876–877.

Reviewer: Laura Diegelmann, MD, RDMS

Objective: To determine the frequency of patients with ß-human chorionic gonadotropin (ß-hCG) levels less than 1500 mIU/mL who are diagnosed with an ectopic pregnancy by emergency ultrasound.

Methods: This retrospective chart review was conducted at an academic center by emergency medicine physicians trained and credentialed in transvaginal ultrasound (TVUS). Of the 3707 charts that were reviewed, 876 met the inclusion criteria. The charts were reviewed for the patient’s presenting complaint and any associated risk factors in women who were ultimately diagnosed with an ectopic pregnancy.

Results: Of those 876 patients, 47 were diagnosed with an ectopic pregnancy, with ß-hCG levels ranging from 125 to 68,138 mIU/mL. Overall, 15 women with ectopic pregnancies had ß-hCG levels less than 1500 mIU/mL, the value typically used as the discriminatory zone for diagnosing early pregnancy via TVUS. The most common presenting complaints were abdominal pain and vaginal bleeding (91.5% of the patients had abdominal pain and 57.4% had both abdominal pain and vaginal bleeding). Risk factors included previous ectopic pregnancy (17%) and history of a sexually transmitted disease.

Discussion: Emergency medicine physicians often choose not to perform TVUS when a patient’s ß-hCG level is below the discriminatory zone. If an intrauterine pregnancy is not found when the ß-hCG level is low, then two diagnoses are possible: ectopic pregnancy or early intrauterine pregnancy. Women with an ectopic pregnancy tend to have lower ß-hCG levels than women with an intrauterine pregnancy. This study shows that ectopic pregnancies can be diagnosed by emergency ultrasound at ß-hCG levels much lower than 1500 mIU/mL. The chart review confirmed that an ectopic pregnancy can be diagnosed by TVUS at ß-hCG levels below the discriminatory zone. When an emergency physician is planning the workup for a patient with a suspected ectopic pregnancy, the ß-hCG level should not be used to determine whether or not TVUS is needed. In this study, 32% of the patients with ectopic pregnancy had a ß-hCG level below 1500 mIU/mL. Since this was a retrospective chart review, it is possible that not all pertinent data were available because they were not recorded onto the charts.

Article: Saul T, Lewiss RE, Rivera M. Accuracy of emergency physician performed bedside ultrasound in determining gestational age in first trimester pregnancy. Crit Ultrasound J. 2012;4:22.

Reviewer: Brian D. Euerle, MD, RDMS, FACEP

Objective: To determine the accuracy of bedside ultrasound examinations by emergency physicians to estimate gestational age compared with ultrasound studies performed in a radiology department.

Methods: This prospective study evaluated stable patients in the first trimester of pregnancy presenting to a single emergency department. Eligible patients received a transabdominal or transvaginal ultrasound examination in the emergency department, performed by an emergency medicine resident or attending physician, as well as an ultrasound examination in the radiology department. All emergency physicians were given a brief didactic and practical session prior to the start of the study. Gestational age was determined by measurement of the maximal crown-rump length when a fetal pole was visualized or through the use of gestational sac diameter if no fetal pole was seen. Pearson’s product moment correlation coefficient was used to assess the correlation between ultrasound studies performed in the emergency department and the radiology department.

Results: Eighty-one patients were initially enrolled in the study; however, 13 did not undergo ultrasound examinations in the radiology department and therefore were excluded. Of the remaining 68 patients, a fetal pole was seen in 62. The data were analyzed in two ways: with all 68 patients together and with only the 62 patients in whom a fetal pole was seen. In the group of 62 patients, the median discrepancy of estimated gestational age was 2 days, with a correlation coefficient of 0.978. With all 68 patients, the median discrepancy was 3 days, with a correlation coefficient of 0.945.

Discussion: This study showed that emergency physicians, using bedside ultrasound after a brief period of training, are able to determine gestational age in the first trimester of pregnancy, corresponding closely with results of ultrasound examinations obtained in a radiology department.

Article: Benson CB, Doubilet PM, Peters HE, Frates MC. Intrauterine fluid with ectopic pregnancy: a reappraisal. J Ultrasound Med. 2013; 32:389–393.

Reviewer: Brian D. Euerle, MD, RDMS, FACEP

Objectives: To determine the incidence of intrauterine fluid seen on transvaginal sonography in women with proven ectopic pregnancies and to describe the sonographic characteristics of the fluid to help distinguish it from an early intrauterine gestational sac.

Methods: All transvaginal ultrasound examinations performed over a 3-year period at a single institution to “rule out ectopic pregnancy” were reviewed. Patients who ultimately were diagnosed with ectopic pregnancy were selected and included in the study. Any patient a heterotopic pregnancy was not included. Sonographic images and video clips were reviewed for the presence of intrauterine fluid collections. The fluid collections were characterized as either type A (pointy, complex, or clearly located within the intrauterine cavity) or type B (smooth walled and anechoic, with a location either in the decidua or uncertain). Type A fluid was not consistent with a gestational sac; type B could be a gestational sac.

Results: The study group consisted of 229 patients with the diagnosis of ectopic pregnancy. Thirty-eight of them (16.6%) had fluid visible in the central portion of the uterus. Of these 38 patients, 31 had fluid that was considered to be type A, and 7 had fluid characteristic of type B. The ultrasound scans also showed that 33 of the 38 patients had an adnexal mass separate from the ovary. Of the remaining five patients without an adnexal mass, three had type A fluid and two had type B. Combining their data with the estimated incidence of ectopic pregnancy in the United States, the authors determined that a patient with a positive pregnancy test, an intrauterine smooth-walled anechoic fluid collection, and no extrauterine adnexal mass has a 0.02% (1 in 5000) likelihood of having an ectopic pregnancy. Conversely, this patient would have a 99.98% (4999 in 5000) likelihood of having an intrauterine pregnancy.

Discussion: The authors discuss the origin of the term “pseudogestational sac” and how it can lead to the error of diagnosing a patient as having an ectopic pregnancy when she actually has an early intrauterine pregnancy. This error can lead to harm to the pregnancy (loss) if treatment for the incorrectly diagnosed ectopic pregnancy is instituted. This study provides important information that will be beneficial in the evaluation and management of these patients and will help prevent such errors.


Case Report: To see or not to see…- Emergency Ultrasound Section Newsletter, June 2013

Dina Seif, MD; Thomas Mailhot, MD, FACEP; Mikaela Chilstrom, MD; Tarina Kang MD, FACEP
From the LAC+USC Emergency Department, Los Angeles, CA
Eye1
Chief Complaint: Right eye swelling
Questions:

1. What pathology is shown in the image to the right? Click Here for Video.
2. What is the differential diagnosis for this disease?
3. What type of probe would produce the best image of this structure?

Case Presentation:
This is a 36 year-old male who presented to the emergency department (ED) with a history of atraumatic right eye swelling and redness. He was seen in the ED one-week prior for the same complaint, diagnosed with preseptal cellulitis and conjunctivitis, and discharged home with oral antibiotics. He initially improved on antibiotics, but awoke the morning of his second visit with recurrent swelling and pain in his right eye. In the ED he complained of tearing and itching in his eye, but denied fevers, chills, purulent drainage, or changes in his vision. He did not use contact lenses. On physical exam, he had significant swelling and erythema to the upper and lower eyelids. There was no crepitus. His extraocular muscle movements, vision, pupillary exam, and intraocular pressures were normal. He had no pain with extraocular muscle movements. His right eye exam was significant for conjunctival injection and copious tearing. The patient was given a diagnosis of preseptal cellulitis by the treating team. Given the degree of swelling, however, a bedside ultrasound of the eye was performed.

EyeArrowBedside ultrasound demonstrated a hypoechoic rim concerning for postseptal fluid (long arrow) with nonspecific thickening of the posterior segment of the eye (short arrow).

An orbital CT scan confirmed the diagnosis of orbital cellulitis. Ophthalmology was consulted and the patient was admitted for observation and IV antibiotics.

Role of Emergency Ultrasound in a patient with a swollen red eye:
Bedside ultrasound is useful in evaluating the skin and soft tissue for infection such as cellulitis, abscess formation, as well as foreign bodies and necrotizing fasciitis. Orbital cellulitis is an acute inflammation of the soft tissues of the eye posterior to the orbital septum. Expeditious diagnosis and management is of paramount importance to prevent potentially dangerous outcomes such as abscess formation, blindness, CNS infections, venous thrombosis, and death. Sinusitis and trauma to the face are the most common causes in adults. In this case, the patient had undergone a closed reduction and maxilla-mandibular fixation for a complex mandibular fracture, which was complicated by a post-operative infection requiring antibiotic therapy for four months prior to his presentation to the ED. Patients with orbital cellulitis typically present with painful eye movement, decreased vision, proptosis, and redness of the eyelid. In this case, the patient had significant eyelid erythema and swelling, but he did not have proptosis, abnormal vision, or other findings typical for a clinical diagnosis of orbital cellulitis. However, bedside ultrasound was helpful in detecting this disease, prompting a confirmatory CT scan and appropriate care.

Answers to Questions

1. What pathology is shown in the above image?
Ocular ultrasound in the axial plane was performed showing edema in the posterior septal space, with diffuse thickening of the posterior segment worrisome for orbital cellulitis.

2. What is the differential diagnosis for this disease?
Conditions to consider include infection, trauma, foreign bodies, inflammatory disease, endocrinopathies, malignancy, and idiopathic orbital inflammation, which can present in a similar fashion to orbital cellulitis. Infectious causes most commonly occur as a result of spread of a bacterial infection from adjacent soft tissue structures or sinuses, through the blood, or from prior trauma or surgery.

3. What type of probe would produce the best image of this structure?
Ocular ultrasound is performed using a high-frequency transducer (13-6 MHz). A transparent film barrier may be applied to the patient’s closed eye to prevent gel from entering the eye. To assess the retrobulbar space, the gain settings should be decreased. To assess the vitreous and central portion of the globe, the gain should be increased to appreciate subtle echoes.

References
1. Frazee BW, White DAE. Soft Tissue. Practical Guide to Emergency Ultrasound. Lippincott Williams and Wilkins. Philadelphia. Kendall and Cosby.
    2006. Pg. 331-333.
2. Mair MH, Geley T, Judmaier W, et al. Using orbital sonography to diagnose and monitor treatment of acute swelling of the eyelids in pediatric patients.
    AJR Am J Roentgenol. 2002;179(6):1529-34.


Interested in Contributing? - Emergency Ultrasound Section Newsletter, June 2013

Many thanks to all section editors. If you want to contribute to the next newsletter, then just email John Bailitz, MD, FACEP

 


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