Emergency Ultrasound Section Newsletter - December 2008, Vol 13, # 1
Message from the Chair
Lawrence A. Melniker, MD, MS, FACEP
It is with great pleasure that I assumed the position of Chair of the Emergency Ultrasound Section of the American College of Emergency Physicians this past October in Chicago. I could reminisce about the "early days" or the "origins" of the Section, but quite frankly there is too much to discuss and much more work to do.
The past year for the Section under the leadership of Vivek Tayal has been nothing short of extraordinary. While updating the "ACEP Emergency Ultrasound Guidelines," Vivek set the bar for the stewardship of a College Section. He completed a major overhaul of our Section, from a large body under mostly central senior-level control to a highly democratic multifunctional organization with 10 Standing Committees and 6 more subcommittees. A few highlights of committee reports and announcements from the October meeting:
- Accreditation Committee, under the leadership of Jerry Chiricolo, completed a roadmap for a College accreditation system for ultrasound services in the emergency department (ED). Should the need arise for Emergency Ultrasound programs to be accredited; ACEP has acknowledged that it is the sole organization appropriate and capable of this task. The committee developed a multistage system that can be phased in over a period of years. The Board of Directors recognizes the role of our Section in the defense of the independent practice of emergency medicine.
- Industry Communications Committee, under the leadership of Christopher Moore, organized an Industry Roundtable on the Sunday prior to the start of Scientific Assembly that was well-attended and represented by most major companies. The discussions were broad-based and led to an expanding dialogue regarding the development of industry-wide standards for reporting, image storage, and data management.
- Medical Student Education Committee, under the leadership of Michael Stone, secured an ACEP Section Grant this year for the development of an educational assessment tool for emergency ultrasound. The tool will permit objective testing of the training and development of medical students and our future residents as clinical sonographers.
- Emergency Ultrasound Management Course Committee, under the leadership of Troy Foster, hosted the annual EUS Management Course. Again, the course was very well-attended and evaluations were excellent. The committee will formulate a plan for the ongoing development and scheduling of the course.
- Sonoguide Committee, under the leadership of Beatrice Hoffmann, discussed the successful roll-out of the website, acep.org/sonoguide, which is getting thousands of visits each day. A conference call in late November was conducted to discuss future updates and upgrades to the site. Dr. Hoffmann was presented with a special award of appreciation from the Section for this extraordinary achievement.
- Elections: Gerardo Chiricolo was elected Chair-elect for the current year and will assume leadership of the Section during the annual section meeting at Scientific Assembly in Boston in October 2009.
- The Emergency Ultrasound Section Operational Guidelines were approved and call for electronic voting for all elected Section Officers. One section member, one vote - from this time forward.
For the current year, I have 3 major items on the agenda. The new Operational Guidelines for the Section were approved at the meeting in Chicago; the primary objective of our Section is "To promote the development of the specialty of emergency medicine across the world and the use of ultrasound to improve the practice of emergency medicine."
To fully implement this goal, we must re-commit ourselves to promoting the best practice of emergency ultrasound in order to maximize patient safety and quality of care, while minimizing medical errors. In the years since the publication of the "IOM Report on Medical Errors," several layers of regulatory oversight have been added to Continuous Quality Management (CQM). When a medical error is uncovered, the routine has become to complete a Root Cause Analysis (RCA), a retrospective review of what occurred and why – post hoc, in hindsight. More recently, a new requirement has been added, Failure Mode & Effects Analysis (FMEA). This analysis requires foresight – a priori evaluation of potential errors that may occur in the future.
In order to meet our primary objective, we must articulate the relationship between emergency ultrasound practice and CQM in emergency medicine. Highlighting situations in which ultrasound made the difference, where the lack of ultrasound may have led to medical error (RCA), and how ultrasound use may prevent future errors (FMEA) is essential to defining and promoting that relationship. During this year, we will prepare a white paper entitled, "Improving Patient Safety and Quality of Care with the Use of Ultrasound during Central Venous Cannulation: A Failure Mode and Effects Analysis."
The second agenda item for the year involves expanding on the development of our Section under Dr. Tayal’s leadership. The leadership will assist the standing and subcommittee chairs in determining which of each group’s goals can be completed in time for the Society for Academic Emergency Medicine (SAEM) Annual Meeting in New Orleans in May 2009 (half-year goals), which can be completed for Scientific Assembly 2009 in Boston (full-year goals), and which will require a longer timeline and additional resources, such as funding, to complete. The Section leadership will facilitate attaining such needs. In order to promote membership involvement and leadership development, each standing and subcommittee shall select a successor to the current chair prior to the SAEM Annual Meeting and a plan of mentorship will be instituted to provide the next chair all the skills needed by the ACEP SA 2009.
Third, as stated earlier, the successful Industry Roundtable and work of the Industry Communications Committee has led to a call from our corporate colleagues for the development of industry-wide standards or minimum requirements for clinician-performed ultrasound examinations, including, but not limited to, imaging standards, reporting requirements, image/video formatting & storage, and data management & transmission. We cannot ignore this call to action and it shall be the goal of our Section to outline these standards for discussion by ACEP SA 2009.
Call for "Section Grants Proposals" – all proposals should be forwarded to the section leadership no later than December 15, 2008.
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Call for Section Grants for 2008-2009 Section Grant Cycle
The application process for the 2008-09 Section Grant program began November 7. Complete information about applying for Section Grants can be found at: https://www.acep.org/ACEPmembership.aspx?id=31962&ekmensel=c580fa7b_86_142_31962_2
Section Grants are designed to meet sections’ needs in educating the public and furthering the advancement of emergency medicine.
- Projects funded by Section Grants must demonstrate a time commitment from members of the section.
- The project coordinator must be a section member.
- The Section Grant letter of intent and full proposal must be reviewed, approved, and signed by the section chair.
The timeline for submissions is below.
| December 31, 2008
||Dr. Melniker would like to review your Letter of Intent
| February 16, 2009
||Postmark, e-mail, or fax deadline for Letters of Intent
|April 3, 2009
||Section Chair and Project Coordinator notified of results of the Letter of Intent review. Full proposals requested. Section Grant Task Force Chair provides feedback to sections with unsuccessful Letters of Intent
|May 4, 2009
||Postmark, e-mail, or fax deadline for Final Applications
|June 24, 2009
||Sections notified of awards
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To the Editor
In our Procedure Center at Cedars-Sinai Medical Center in Los Angeles, California, we are now using ultrasound to assist with almost all of our lumbar punctures (over 400 cases annually) and have found it to be an extremely useful tool. When we first started performing LPs for the entire institution in 2004, we limited the use of ultrasound mapping to the more difficult cases. However, more recently we noted its benefits even for those patients with good anatomic landmarks.
Figure 1 illustrates the power of ultrasound to help guide the procedure, as well as to reinforce the importance of proper positioning. The top pair of pictures ("relaxed") demonstrates a cranial-caudal (longitudinal) ultrasound view of the interspinous space with the patient in a straight-backed position, knees flexed at 90 degrees. Note the width of the interspinous space to be 0.61cm. The bottom pair of pictures ("curled") is the same ultrasound window, now with the patient curled into a fetal position. With this simple change in position, the interspinous space has increased three-fold to 1.92cm, making it a clearly bigger target for the proceduralist.
As has been described previously, this imaging provides the basis for ultrasound-guided LPs: A transverse skin indentation would be made over the interspinous space (underneath and across the ultrasound probe). Then, the probe would be rotated 90 degrees (transversely across the back--not pictured) over a nearby spinous process, allowing for the creation of a longitudinal indentation at the midline (again underneath and across the ultrasound probe). The resultant crosshair would then mark the spot for an optimal entry point once the patient is sterilely prepped and draped.
We would like to make two points. First of all, with or without the use of ultrasound, simple attention to proper positioning can maximize the chances of procedural success, as evidenced by Figure I. We have used these simple but effective images as an educational tool for residents, as well as to emphasize to our Procedure Center nursing staff (who assist us with all procedures) the importance of a proper curl. Second, while we recognize that the use of ultrasound to assist with lumbar puncture is not currently the standard of care (or evenly commonly used), its potential benefit is easy to see. Our experience has been that the minimal amount of time required (<3 minutes) to map the optimal anatomic landmarks is easily offset by a more expedient procedure and reduction in the number of needle passes. Therefore, in the interest of efficiency and patient comfort, we would encourage our colleagues who have access to a portable ultrasound machine to avail themselves of this simple yet valuable technique, and to correspond with us regarding their experiences.
Mark J. Ault, MD, FACEP
Bradley T. Rosen, MD, MBA
Cedars-Sinai Medical Center
Los Angeles, California
Please send correspondence to: Mark.Ault@cshs.org
- Lin, M; Ultrasound-Guided Lumbar Puncture; Courtney Washington, BA. ACEP News. Feb 2007.p 23
- Nomura JT, Leech SJ, Shenbagamurthi S, et al. A randomized controlled trial of ultrasound-assisted lumbar puncture. J Ultrasound Med. 2007; 26:1341-1348.
- Stiffler KA, Jwayyed S, Robinson A, et al. Use of Ultrasound to Identify Pertinent Landmarks for Lumbar Puncture. Ann Emerg Med. 2005; 46(3)(Supplement):S28.
|Lumbar Puncture Positioning-Relaxed
|Lumbar Puncture Postioning-Curled
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ACOG Practice Bulletin
Lisa D. Mills, MD, FACEP
ACOG. ACOG Practice Bulletin: Clinical Management Guidelines for Obstetrician-Gynecologists. Ultrasonography in Pregnancy. Obstetrics and Gynecology. 2008. 112(4):951-961.
ACOG updated their recommendations for the use of US in pregnancy, replacing guidelines from 1998. The guidelines address indications for use of ultrasound in pregnancy, recommendations for the scope of the studies, accreditation for use of ultrasonography, quality assurance, transducer cleaning, and safety of ultrasound. The new guidelines do not present a major paradigm shift in the approach to OB ultrasonography.
The indications for US in first and second trimester pregnancy continue to include those clinical scenarios that we see in the emergency department. They include, but are not limited to, confirming intra-uterine pregnancy, evaluating for ectopic pregnancy, evaluation of vaginal bleeding and pelvic pain, confirming fetal cardiac activity, evaluating pelvic masses, evaluation for hydatidiform mole, estimating gestational age, and examination for placental abruption.
The guidelines report that no evidence of fetal injury from US has been identified. However, they suggest the possibility of physical effects on the fetus from US. ACOG recommends that US be utilized "only when there is a valid medical indication." They cite the FDA statement that "the promotion, sale or lease of ultrasound equipment for making ‘keepsake’ fetal videos as an unapproved use of a medical device." Utilization of US for medical purposes is recommendation by ACOG.
ACOG continues to espouse the two level cleaning system for US transducers. They stat that transabdominal transducers can be adequately cleaned by wiping with an antiseptic towelette. They recommend that transvaginal transducer undergo "high-level" disinfection between each use. Statement by the CDC and FDA are used to support this recommendation.
These recommendations do not represent a major shift in the ED utilization of US in pregnancy. The recommendation to perform "high-level" cleaning of the cavitary transducer is not well-supported by the FDA and CDC documents. These documents recommend high-level cleaning for medical equipment in direct contact with mucus membranes and cavities. They do not clearly address the cleaning of equipment that is introduced with a cover. This continues to be a topic of controversy for the ED.
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Annual Meeting Minutes
Members in attendance for all or part of the meeting included: Over one hundred seventy members and guests.
Others participating for all or part of the meeting included: Andrew Sama, MD, FACEP, Board Liaison; and Marilyn Bromley, RN, Staff Liaison.
Ratify Operational Guidelines
Clinical Commentary on Therapeutic US
New Ultrasound guidelines
New Chair comments
Major Points Discussed
US Section meeting
- Lunch was graciously sponsored by Ultrasonix
- New Section Operation guidelines were approved
- Chair-elect - Jerry Chiricolo, MD, FACEP of Northshore Hospital in NY won the election. We appreciate the willingness of both candidates to run, and look forward to the leadership of both Dr. Chericolo and Resa E. Lewiss, MD, in the coming years.
- Featured Presentation –
- Due to a family death last weekend, Dr. George Shaw was not able to lecture on therapeutic ultrasound. We sent our condolences to him and his family regarding their loss.
- Dr. Paul Sierzenski, with very little notice, spoke on a clinical perspective on therapeutic ultrasound. His lecture was taped with a grant from Zonare, and it will be put on the ACEP website sometime after Scientific Assembly. His talk was extremely interesting and thought provoking as ultrasound moves from diagnosis to actual therapy.
- New Emergency Ultrasound Guidelines – Dr. Vivek Tayal gave a short perspective on the new ultrasound guidelines, highlighting the different sections. The guidelines should be available from ACEP, once they are formatted.
- Plan Ultrasound Accreditation – Dr. Tayal provided background, and then a synopsis of a plan presented the ACEP Board.
- Subcommittee reports
Verbal reports were given by chairs of the subcommittees. Written reports can be seen in the next newsletter.
- Liaison Reports
- CTAF – Dr. Diku Mandavia gave an exciting recount of what really can be described as "the battle at CTAF." It was remarkable and again kudos to all those that contribute to his efforts and, of course Diku, for his considerable skills that won the day.
- NQF – Dr. Paul Sierzenski, who represented ACEP and not just the section, gave a summary of the current efforts of NQF in regards consensus on imaging issues
- Critical Care – Dr. Mike Blaivas reported briefly on developments of hopefully an ally in clinical ultrasound.
- AIUM – Dr. Dave Bahner reminded us of the positive developments of 2007-2008 including the joint FAST guidelines, more emergency courses at the AIUM annual meeting, the upcoming US forum on MSK/procedural guidance, and the 2009 AIUM meeting in NY.
- ASE – Dr. Vicki Noble discussed the ongoing effort of a consensus paper with the American Society of Echocardiography (ASE), and the current strategy toward consensus.
- Emergency Ultrasound Award – Dr. Beatrice Hoffman won the Emergency Ultrasound Award for her efforts on Sonoguide, an internet-based ultrasound learning site, initiated by an ACEP Section grant. The site has had close to a million server requests since its launch in May. The site speaks for itself and Dr. Hoffman’s considerable efforts and talent in education and US. www.acep.org/sonoguide
- Julie Dill and Marilyn Bromley were thanked for their service to the section and presented with a gift card as a token of the section leaders’appreciation for their assistance on the various section projects.
The ACEP Ultrasound Section meeting adjourned. SAEM Special Interest Group then provided an update on their activities and issues.
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Sonographic Findings of Incarcerated Abdominal Wall Hernias
William T. Hosek, MD, FACEP
A 45 year old female presents with acute onset of lower abdominal pain. She denies nausea, vomiting or diarrhea. She is afebrile and has stable vital signs. The physical exam is significant for a large abdomen which is soft and has bowel sounds. A focal area of tenderness and swelling is identified in the midline abdominal wall 4 centimeters below the umbilicus. The overlying skin appears normal and is without erythema or warmth. The patient’s white blood count, basic metabolic panel and lactate level are all normal. A bedside ultrasound of her abdominal wall is performed with a high frequency linear transducer (see image A).
Four sonographic signs have been identified as useful in distinguishing between incarcerated and non-incarcerated hernias. They are (1) free fluid within the hernia sac, (2) wall thickening of the herniated bowel (greater than or equal to 4 mm), (3) fluid within the herniated bowel, and (4) dilated bowel loops within the abdomen. In a study of 149 consecutive abdominal wall hernias, the combination of at least two of these four signs detected incarceration with a 100% sensitivity.1 The image from this patient’s ultrasound shows an anechoic mass (representing a fluid-filled hernia sac) containing an echogenic loop of bowel with a dark center (fluid within the bowel). The maximum cross sectional diameter of the bowel loop was measured at 4mm (see image B). The fluid accumulation, along with the bowel wall thickening and transudative effusion around the outside of the loop, was suggestive of a prolonged period of incarceration with possible strangulation. Because of these ultrasound findings, bedside reduction of the hernia was not attempted. A diagnosis of incarcerated hernia was confirmed by CT and the patient was taken to the OR.
In the OR, the hernia sac was found to contain approximately 10 cc of fluid and an incarcerated loop of small bowel with areas of necrosis. The patient received a segmental enterectomy with primary anastomosis, tolerated the procedure well and was discharged three days later.
1. Rettenbacher T, Hollerweger A, Macheiner P, et al. Abdominal Wall Hernias: Cross-Sectional Imaging Signs of Incarceration Determined with Sonography. AJR. 2001; 177: 1061-1066.
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Ultrasound Classified Ad
EM Ultrasound Faculty Opportunity in Tucson, AZ We are currently seeking an additional emergency ultrasound faculty member to join one RDMS credentialed emergency physician to assist in the expansion of our teaching and research programs, and possible future fellowship, at the University of Arizona in Tucson, Arizona. You would join the faculty of an excellent emergency medicine residency program which has been in existence since 1982 and a relatively new combined emergency medicine/pediatric residency. We staff two academic emergency departments with a combined volume of 90,000. Outstanding research division with excellent opportunities for mentoring. Highly desirable university town in the awesome Southwest.
Please contact Albert Fiorello, MD, Director of Emergency Medicine Ultrasound, 520.626.1554, firstname.lastname@example.org, or Sam Keim, MD, Vice Head and Residency Director, 520.626.5034, email@example.com for more information.
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Susan Cameron, MD
Greg Press, MD, RDMS
Sarah Miller, MD
A 39-year-old male with a history of intravenous drug abuse presented to our ED with confusion and altered mental status. The patient complained of a four day history of malaise, fever, myalgias, joint pain, rash on his palms and soles, and swelling of the fingers, elbows, knees and ankles.
The patient’s temperature was 100.5o F. He had a heart rate of 120 bpm, a blood pressure of 95/68 mmHg, and respiratory rate of 20. On physical examination, he was found to be confused, lethargic and incontinent of urine. Non-tender small macules on his palms and soles were present. He had numerous non-blanching petechiae on his extremities. Painful red nodules on his fingers and thin vertical hemorrhagic lines under his nails were noted. Cardiac auscultation revealed tachycardia and a 2/6 systolic ejection murmur at the apex. On both upper extremities, the patient had small linear scars consistent with the track marks of intravenous drug use.
ECG revealed sinus tachycardia. Chest x-ray and CT of the head were normal. Bedside transthoracic ultrasound was performed by the emergency physician, which revealed a floppy vegetation on the mitral valve (Figure 1). The diagnosis of infective endocarditis was made.
Infective endocarditis (IE) is a disease process in which infective vegetations form on cardiac valves. These vegetations can embolize and cause systemic disease. Risk factors for IE include IV drug abuse, congenital heart defects, rheumatic heart disease, and prosthetic valves. The presentation of IE can be variable, and the classic findings of fever, heart murmur and embolic effects may not be seen in early presentations. Ultrasound combined with Duke’s criteria can aid in the diagnosis of IE.
EPs have reliably utilized cardiac ultrasound in the setting of chest trauma, pericardial effusions and cardiac arrest. Transthoracic echocardiography can identify vegetations as small as 5 mm, with a sensitivity of 30% to 100%.[4, 5] To our knowledge, this is the second case report of endocarditis diagnosed by an EP using bedside ultrasound.
The patient was admitted to the cardiac ICU. Transesophageal echocardiography showed a large, highly mobile 2.7 cm x 0.7 cm echogenic mass attached to the anterior mitral leaflet most consistent with a vegetation. Blood cultures were positive for Staphylococcus aureus. The patient was taken emergently by cardiovascular surgery to the operating room for a mitral valve replacement with a St. Jude mechanical valve.
- Ciccone TJ. Cardiac ultrasound. Emerg Med Clin North Am. 2004; 22(3): 621-640.
- Dunmire SM. Infective endocarditis and acquired valvular heart disease. In: Rosen P, Barkin R, editors. Emergency medicine: concepts and clinical practice. St. Louis (MO): Mosby; 1998. p. 1745-`754.
- Durack DT, Lukes AS, Bright DK. New criteria for diagnosis of infective endocarditis: utilization of specific echocardiographic findings. Am J Med. 1994;96:200-209.
- Wellford AL, Snoey ER. Emergency medicine applications of echocardiography. Emerg Med Clin N Am. 1995;13(4):831-854.
- Sachdev M, Peterson GE, Jollis JG. Imaging techniques for diagnosis of infective endocarditis. Infect Dis Clin N Am. 2002;16:319-337.
- Kulstad E, Konicki J. Diagnosis of endocarditis by bedside echocardiography. Internet J Emerg Med. 2004;2(1).
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Journal Watch December 2008
Reviewer: Jehangir Meer, MD, RDMS, FACEP
Rose J, Norbutas C. A randomized controlled trial comparing one-operator versus two-operator technique in ultrasound-guided basilic vein cannulation.J Emerg Med. 2008.;35(4):431-435.
Methods: Prospective randomized controlled trial comparing one-person versus two-person technique in basilic vein cannulation by novice operators, defined as emergency medicine residents with limited ultrasound guided catheter experience (<10 cannulations). Healthy adult volunteer subjects were recruited; each volunteer underwent both techniques, one technique on each arm. The initial arm and technique was selected using computerized block randomization. In the single operator technique, the operator held the transducer in transverse axis while attempting cannulation using a 20-gauge 1.88-inch catheter. In the two-person technique, the second operator held the transducer in transverse axis while the first operator attempted cannulation. The primary outcome variable was first-attempt cannulation success. Secondary outcome variables included overall success, number of attempts, time to cannulation, complications, and self-rated ease of technique by the operators.
Results: 32 subjects were enrolled. Single-operator first-attempt success was 56% (18/32) versus 65% (21/32) for two-operator technique: this was not statistically significant difference however (CI crossed 0). Overall success was statistically similar for one operator 72% (23/32) versus 75% (24/32) for two-operator technique. Median number of attempts was similar; 1.6 for single-operator versus 1.4 for two-operator (p=0.8). Time to cannulation was similar; 57s for one-operator versus 44s for two-operator (p=0.33). Ease of use score was similar as well; 4.3 for one-operator versus 3.6 for two-operator (p=0.26). There were no complications reported in either group.
Discussion: This paper demonstrates that novice operators can reliably perform ultrasound guided basilic vein cannulation. This is the first paper to compare one-person versus two person technique for ultrasound guided peripheral IV access, and no differences were shown. Limitations of this study included small sample size and study was not powered for secondary outcome variables. Additionally subjects were healthy volunteers and the results may not be applicable in patients with difficult vascular access issues.
Reviewer: Clifford J. Fields, DO
Blaivas M. Transesophageal Echocardiography during Cardiopulmonary Arrest in the Emergency Department.Resuscitation. 2008; 78:135-140.
Dr. Blaivas presents a provocative case series demonstrating the feasibility of using transesophageal echocardiography (TEE) during cardiac arrest to aid in diagnosing the etiology of the arrest state and monitoring the efficacy of the interventions in the emergency department (ED). Six cases are chosen from a series of 15 cases over 6 months (presumably a convenience sample) that demonstrates the potential utility of TEE (over transthoracic echocardiography [TTE]) in CPR. The cases are worth reading but the major concept is that TEE allows superior visualization and hence better decision making when compared to TTE. Highlights of the cases are listed below.
- TTE demonstrated no cardiac movement in one case while the TEE demonstrated organized cardiac movement. (case 1)
- TTE demonstrated no cardiac movement while the TEE demonstrated ventricular fibrillation. (case 2)
- TEE allowed monitoring the effectiveness of CPR without interrupting compressions. (case 3)
- TEE allowed visualization of a right ventricular thrombus not visualized on TTE and in an interesting case demonstrated the presence of a PICC tip in the right atrium. (cases 3 and 4)
- TEE allowed visualization of an aortic dissection not visible on TTE. (case 5)
- TEE allowed better visualization of the right side of the heart, in one case demonstrating normal sized chambers, while the TTE suggested large chambers suggestive of a pulmonary embolism. (case 6)
In all of the presented cases, clinical management was profoundly altered by the TEE findings. In two cases TTE suggested asystole while one patient had organized cardiac activity and the other had ventricular fibrillation.
Comments: This is the first report of emergency physicians using TEE to guide resuscitation of patients in cardiopulmonary arrest. The cases are provocative and suggest further study of the use of TEE by emergency physicians should be performed. The two cases of TTE suggesting cardiac standstill which were then shown by TEE to be NSR and VF are particularly disturbing in that this challenges a widely held belief that the absence of mechanical activity on TTE precludes any meaningful survival and should signal the end of the resuscitation in such patients.
Reviewers: Andrew Liteplo, MD, RDMS; Ben Attwood, MD
Stone MS, Wang R, Price D. Ultrasound-guided supraclavicular brachial plexus nerve block vs procedural sedation for the treatment of upper extremity emergencies.Am J Emerg Med. 2008; 26: 706-710.
Methods: This prospective study of a convenience sample of patients compared ultrasound-guided supraclavicular nerve blocks (USNB) to procedural sedation (PS) in patients with regards to length of stay in the emergency department (ED). Patients presenting to the ED requiring procedures of the upper extremity (ie, abscess drainage, fracture or dislocation reduction) were randomized to receive either standard PS or an USNB. The primary outcome was length of stay (LOS) in the ED.
Results: 12 patients were enrolled in the study. 7 received an USNB, and 5 received PS. The average time to initiation of the procedure and LOS in the USNB group were 20 and 106 minutes respectively, and in the PS group were 199 and 285 minutes respectively. No complications were reported. The authors concluded that an USNB significantly decreases the LOS in these patients when compared to PS (p<.01).
Discussion: This article is one of few to study ultrasound-guided nerve blocks in the emergency department and as such represents an important step in broadening the realm of researched emergency ultrasound applications. Despite the statistically significant finding of a decreased LOS, however, there are numerous limitations which may limit the generalizability of the findings. Firstly, as admitted by the authors, there is an extremely small study population. Although the results are statistically significant, with such a small size it is difficult to draw any valid conclusions from the study. Secondly, the authors themselves also admit that most difference in the ED LOS derives from the preprocedural phase, likely due to bed availability and/or staffing constraints (PS at their institution needs to be carried out in a certain part of the ED, where bed availability was often scarce.) In fact, the time of the actual procedure was identical (an average of 86 minutes in each group). And finally, there was no follow-up of the patients after their procedure. Whether or not there were any complications from the USNB (ie, intravascular injection, neurotoxicity, damage to adjacent structures, or infection) is unknown.
While it is of interest to investigate the comparison of USNB versus PS in this context, it is important to be aware that the conclusions of this study cannot be extrapolated to the overall ED population, which makes the findings limited. As the authors state themselves, further trials are necessary to prove ultrasound technique both in efficacy and safety before it could be advocated as a preferable alternative to current treatment.
Reviewers: Vicki Noble, MD, RDMS, FACEP; Andrew Liteplo, MD, RDMS.
Moore CL, Holiday RS, Hwang J, et al. Screening for Abdominal Aortic Aneurysm in Asymptomatic At- Risk Patients Using Emergency Ultrasound. Am J Emerg Med. 2008; 26: 883-887.
Methods: This study was designed to look at the feasibility and prevalence of abdominal aortic aneurysms in asymptomatic emergency department (ED) patients with >1 risk factor for the disease. The study restricted enrollment to those ED patients who presented with chief complaints other than those that required formal imaging to evaluate for abdominal aneurysm.
Results: 12/179 patients enrolled were found to have abdominal aneurysms > 3 cm for a prevalence rate of 6.7%. 11/12 were followed up and 3/12 had surgical repair recommended. All scans took less than 3 minutes to perform. However, the authors reported that only 62.6% of patients were able to have complete scans performed (defined as imaging of the aorta in two planes from the celiac axis to the iliac bifurcation). In 4.5% of patients the aorta was not visualized at all and in the remaining 32.9% the aorta was imaged only in part.
Discussion: This study is well-designed and suggests a few interesting take home points to ponder. Previous studies have suggested almost 100% test feasibility for screening ultrasound evaluations of the abdominal aorta. However, test feasibility in this study is only 62.6% despite the experience of the sonographers (all had met the American College of Emergency Physician’s credentialing requirements). The reasons for this wide variation in test feasibility deserve further evaluation.
In addition, this study raises the question of screening for disease in asymptomatic patients in the emergency department. While the benefits of a quick, low-risk, relatively easy to perform test to screen for lethal disease are not disputed, this study does not evaluate the cost-benefit implications of screening for a disease with a prevalence rate of 6.7% (or only 1.7% if prevalence is defined as only those patients who were referred for surgical treatment). And as the authors themselves point out, widespread implementation of screening programs would depend on many factors, including "availability of EP physicians with ability to perform aortic ultrasounds, finding time to perform the exam in an overcrowded ED, and motivation to perform the examination, including reimbursement."
The question is whether the most effective method for utilizing the power of point of care ultrasound in this instance may be in teaching this technique to primary care providers. These physicians already have systems in place to help assist patients with referrals to specialists, have the ability to select patients at high risk for disease based on known past medical history, and may be the only care providers able to pay for the costs of such a screening program, given that Medicare reimbursement is limited to patients in the first six months of Medicare enrollment.
The cost-benefit analysis for abdominal aorta screening deserves further evaluation but this study raises thought-provoking questions about where the opportunity for diagnosing disease lies and who should take on the responsibility for making the most of this opportunity.
Reviewers: Heidi Kimberly, MD; Andrew Liteplo, MD, RDMS
Nicholls SE, Sweeney TW, Ferre RM, et al. Bedside sonography by emergency physicians for the rapid identification of landmarks relevant to cricothyrotomy.Am J Emerg Med. 2008; 26: 852-856.
Methods: In this two-part prospective observational trial, the investigators sought firstly to develop a sonographic technique for visualization of relevant landmarks for crichothyrotomy, and then to test the feasibility of locating these landmarks in real patients. First, using ultrasound they located and marked the boundaries of the cricothyroid membrane (CM) on the necks of 4 cadaveric models. They then dissected the cadaver necks to confirm the accuracy of the sonographic images.
In the second part of the study, the investigators (an attending EP and 3rd year EM resident, both with prior ultrasound experience) performed sonographic evaluation of relevant cricothyrotomy anatomy on a convenience sample 50 ED patients. They studied the mean time needed to identify the landmarks, and also compared difficulty of ultrasound to palpation.
Results: The mean time to visualization of the CM was 24 seconds. There was no relationship between BMI or tissue depth and time to visualization of the CM. A significant relationship existed between physician perceptions of landmark palpation difficulty with increasing BMI. The investigators concluded that this technique could be used for teaching relevant anatomy and as an adjunct when a difficult airway is anticipated.
Discussion: Cricothyrotomy is an infrequently performed but critical procedure in emergency medicine. Current technique involves palpation of landmarks which can be challenging in obese patients or those with distorted neck anatomy. This is an interesting article describing the use of ultrasound in identifying the cricothyroid membrane. The authors do not describe the technique or the ultrasonographic appearance of the CM, minimizing the usefulness to the reader. Also, the study is limited by the absence of a gold standard, as it does not appear that any images were reviewed by a third party, and no patients had a cricothyrotomy performed. Despite these limitations, the authors describe a technique which could have a benefit in the rare occasions when a cricothyrotomy is necessary. It would seem to be most practical to sonographically identify and mark the CM in any patient with an anticipated difficult airway, before the RSI is performed. The exact role of applying this technique has not been studied but would be an interesting area of future research.
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