How good is bedside ultrasound in emergency departments? So good that there aren't many randomized studies to prove it. That would mean a control group, and why make any patients miss the opportunity for helpful scanning to demonstrate such an obvious point?
A positive FAST exam...Image Tools
Actually, there is at least one good reason: to stop all the debate, according to some of those who rely on ultrasonography in emergency medicine. “Much work remains to be performed, and with proper planning, studies should be able to evaluate ultrasound impact on outcome and efficiency without compromising patient care or individual clinicians' dependence on the technology,” wrote Srikar Adhikari, MD, and Michael Blaivas, MD, in Evidence-Based Emergency Medicine. (Oxford, UK: Wiley-Blackwell, BMJ Books; 2009.)
The pair, who note that the paucity of double-blind, crossover trials often comes as a “shocking surprise to some novice ultrasound investigators,” nonetheless quite powerfully stress its merits for placing central venous cannula, evaluating blunt abdominal trauma, and detecting aortic aneurysm. Their confidence in reaching this conclusion seems to rest on two developments: compact point-of-care systems that yield more precise visualization now and fairly recent medical education programs aimed at honing user skill, particularly during residency.
It has only been a decade since the first official statement of use on ultrasound was published by the American College of Emergency Physicians (http://bit.ly/USacep), but somehow ultrasound as a modality in emergency departments is still a source of argument. (EMN 2011;33:36; http://bit.ly/VNoble.) Much of the discussion centers on whether most of the current training programs truly prepare emergency physicians for effective clinical use and how much the technology itself has evolved to allow broader but still appropriate and accurate applications.
The benefits of ultrasound are well established, even if placebo-controlled cross-over studies are lacking. Two years ago, for example, when the Society for Academic Emergency Medicine published a consensus paper calling for ultrasound to be introduced early in every emergency medicine training program — a recommendation that came from the Council of Emergency Medicine Residency Directors conference — the simple introductory statement, a sentence saying that ultrasound improves the care of ED patients, was supported by 26 citations. (Acad Emerg Med 2009 Dec 16;Suppl 2:S32.)
And those anecdotal patient histories make a powerful case for its use, and in particular, for emergency medicine residents to be trained in its use. In Manhassett, NY, a case of H1N1-related acute myocarditis was diagnosed with point-of-care sonography in the emergency department — by residents. The patient, whose chief symptom was abdominal pain, was referred to the ED by her pediatrician. (J Ultrasound Med 2010;29:1361.) Within the hour, she became light-headed and hypotensive. She received immediate care after receiving Focused Abdominal Sonography in Trauma (FAST) in the emergency department, pending an abdominal ultrasound by radiology as ordered by her treating physician, but Robert Bramante, MD, a resident in emergency medicine, didn't think the little girl had time to wait for that.
“I was an emergency medicine resident, and ultrasound is a required component of ED physician training,” he recalled. “The other two physicians who were with me were also EM-trained, and had both completed a fellowship in emergency ultrasound for additional training and expertise.” To Dr. Bramante, the incident doesn't just illustrate how important access to ultrasound in emergency medicine is, but also how essential it is to have the kind of training that allows it to be utilized in such situations.
“It is a tool that is useful, and it decreases time to diagnosis and treatment,” said Vicki E. Noble, MD, the director of emergency ultrasound at Massachusetts General Hospital in Boston. “The question should be: How do we do it better?” rather than debating the merits of it, she said, calling that a “misplaced controversy.” And asking whether the educational process is good enough is like asking: “How do we know everyone is learning CPR well enough?” Guidelines for good training are in place, but more effective ways for assessing competency are essential.
In a handful of medical colleges, ultrasound training occurs from the first year on, and that early training may become more common, she pointed out. The University of California, Irvine, School of Medicine, for instance, instituted an ultrasound clerkship among medical students that appears to have resulted in substantially more use of ultrasonography in the ED. (West J Emerg Med 2010;11:31.) “Technology is only as good as your training,” Dr. Noble said.
Sometimes the advantage of that early exposure to ultrasound can come to light in a dramatic way, Dr. Noble explained. At her institution, medical students gain such exposure by asking waiting patients if they can practice point-of-care ultrasound on them.
When a third-year student scanned one such woman lying on a hallway gurney, a ruptured ectopic pregnancy was found. “I am sure it would have been found at some point, but this student absolutely made it happen more quickly, and recognized the abnormal findings immediately,” Dr. Noble said. “If you can teach that to a medical student, I think the debate over ultrasound's efficacy as a clinical diagnostic tool is pretty much settled.”
In general, European accident and emergency centers seem to be using ultrasound in new ways, and in ways similar to American EDs but with less controversy, even in helicopters, ambulances, and at the scene. In fact, one medical group that has been using ultrasound in such settings proposed that the mobile technology could improve triage in disasters. (Eur J Emerg Med 2010;17:254.)
Enthusiasm about the potential for ultrasonography is so high among some physicians that news about pending developments flies across the Internet on listservs, blogs, and enewsletters. One group of biomedical engineers and physicians with interest in the field currently confesses excitement about the arrival of a new transducer, which, if it lives up to its potential, will make even three-dimensional printouts possible. (http://medgadget.com.) And a BlackBerry-sized ultrasound scanner made news this year — the website article was accessed by a huge number in the medical field — when it was unveiled. The downsized technology, in a picture showing it being used to see a liver, featured a tiny fliptop screen that seemed to offer remarkable clarity. (http://cnet.co/GEvscan.)
There seems to be a disconnect between the way ultrasound is used in the real world and the way that some academic medicine ultrasound enthusiasts envision it, said Liam Yore, MD, a Seattle-area emergency physician. Only about half of his colleagues use it, he said, stressing, though, that he “loves it.” But he said he wonders how smaller emergency departments can justify it, or even how larger ones can with competing resource needs, for that matter. “It's a hassle to bill. Many payors don't pay ER docs for it. The value of the service as typically coded is low,” he said. “So all of that [affects] the business case for ultrasound,” he said.
But wider use of ultrasound in emergency medicine seems inevitable, to rule out conditions once subject to other kinds of testing, such as musculoskeletal conditions like infections and fractures, Dr. Noble said. Highly portable, user-friendly ultrasound systems have become more accessible, she added, with an average price tag between $10,000 and $30,000, quite an astonishing plummet over the past several years. Digital imaging also provides better definition and visualization, and wireless transmission makes a second opinion or consultation possible at the touch of the control panel. Probe-switching is now a thing of the past, and so are multiple control knobs. “Fewer levers and buttons make it much easier to use,” she said.
Fractures, alignment, effusions, and abscess already are fairly routinely detected with ultrasound, but the applications are bound to expand, she said. Such advances will help avoid the need for radiation-emitting CT, which is a concern, particularly in children. In fact, ensuring that ultrasound is part of a safe and effective treatment protocol may be the only limiting factor in its future use, Dr. Noble said.
Meanwhile, radiologists have been broadening its scope because it spares the patient radiation and performs as highly as other imaging approaches, depending on the user. Increasingly, radiation exposure is a point of discussion, even contentiousness, in the specialty — and an acknowledged case of risk-benefit ratio. (Radiology 2011;258:889.) Just this year, researchers from Stanford University demonstrated the effectiveness of staged ultrasonography in pediatric patients suspected of having appendicitis, when they limited CT imaging to an as-needed basis after ultrasound. Ultrasound provided an opportunity to substantially reduce radiation without running the risk of a missed diagnosis, and the finding was missed in less than one percent of 631 patients in the study. (Radiology 2011;259:231.)
The use is an advance but not a surprising one. Radiologists had found ultrasound to be a promising imaging method for appendicitis only a few years ago, and suggested more utilization of it for that purpose because more than a quarter million new cases of the abdominal disorder are diagnosed each year. (Radiol Clin North Am 2007;45:411.)
Other disciplines have followed suit, also touting the benefits of ultrasonography. Ear, nose, and throat specialists use it clinically as a cost-effective imaging tool beyond the physical exam. “The ability to palpate with the ultrasound probe provides unique information on a lesion's compressibility or stiffness not available with computerized tomography and magnetic resonance imaging,” wrote Michael Holtel, MD, of the Telemedicine Research Institute at the University of Hawaii in Honolulu. (Otolaryngol Clin North Am 2010;43:1267.)
This past spring a group of plastic surgeons showed that small nerves that have been injured can be reliably assessed by using an advanced ultrasound technique; they found it to be a “non-invasive efficient method to reliably predict whether a small nerve is actually severed.” (Plast Reconstr Surg 2011;127:100 [Abstract 183].) The use of ultrasound for rapid identification of esophageal and tracheal intubations also is being used by anesthesiologists. (J Ultrasound Med 2011;30:671.)
The possible uses of ultrasound may not be limited to medical settings if a conference in July of this year is any indication. Known as “Healthcare Unbound,” the meeting includes experts across disciplines who will discuss how imaging will be used in the future now that the U.S. Food and Drug Administration has approved a cell phone application for such scans. (http://bit.ly/HCunbound.)
Will such technology be used one day by emergency medical technicians from the floor or couch of a collapsed patient's residence prior to being transported to a hospital? Dr. Noble thinks that scenario doesn't go far enough. “Who says someday there won't be images sent to or from an African desert?”
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An Ultrasound Timeline
What medical school has an ultrasound machine in the student lounge next to the pool table? The University of California, Irvine (UCI), where students now get ultrasound training all four years. J. Christian Fox, MD, the professor of clinical emergency medicine who helped propel the program to national prominence, provides the following countdown of the decade in which it happened.
2002: UCI starts a fourth-year clerkship in emergency ultrasound. Student-doctor forums discuss the program online, giving it cross-country exposure.
2003: As word of the program spreads, students from around the United States start coming to UCI in their fourth year for the clerkship — about eight students a month.
2004: Ultrasound begins to be integrated into the anatomy curriculum for first-year medical students.
2005: Correlating anatomy is now being taught in lectures and on cadavers. The curriculum appears to be well received by students, and the training continues to grow in popularity over the next five years.
2010: Integrated ultrasound is now a part of the first- and second-year curriculum. This includes eight hours of lecture and 20 hours of hands-on use for first-year medical students and four hours of lecture with 10 hours of hands-on use for second-year medical students.
2011: A third-year elective in ultrasound use, begun the previous winter, gives the option of utilization in the intensive care unit as part of medical education. Students in the third-year clerkship of medicine and surgery are now using ultrasound on their patients during rounds.
2012: Fourth-year “emergency ultrasound elective” is changed to “bedside ultrasound elective,” which is now scheduled to include the ICU, outpatient care, and in various subspecialties. — AS
© 2011 Lippincott Williams & Wilkins, Inc.