by: Romulo Babasa III, MD, FPCEM

Gone is the time when the stethoscope was considered as the most important diagnostic armamentarium of an emergency physician. ER doctors globally are slowly realizing that one can obtain more information from analysing images and shadows than by listening to clicks and gushing air right at the patient’s bedside. Welcome to the advent of visual medicine... the era of the bedside emergency ultrasonography.

At present, the use of bedside ultrasonography in the ED of tertiary hospitals in the Philippines is still in its infancy. An informal local telephone survey of 30 EM consultants from 6 training programs on ED ultrasound use revealed little to no experience at all among the respondents. Ultrasound-related course is not integrated in the curricular program of the EM residency training.

Several factors have contributed to the lack of utilization of bedside ultrasound by EM physicians. Availability of the ultrasound machines is difficult and quite expensive. Hospitals may be reluctant to invest in a machine solely dedicated to the ED, where risk to equipment theft and improper handling is very high. Secondly, the lack of expertise among the training faculty and the absence of a standard curricular program must also be addressed. Lastly and most importantly, other specialists may not be aware of the clinical utility of the bedside ultrasound during the critical decision-making that an EM physician must perform.  Even while ultrasonography may traditionally be the expertise of radiologists, the emergency physician can enhance his skills and harness this remarkable piece of technology to impact on his clinical practice. 

The following are guidelines which may be referred to.

Focused Assessment with Sonography for Trauma (FAST) a term first coined in 1996 is an integrated, goal-directed bedside examination to detect fluid, which is likely to be hemorrhage in a trauma setting. It scans for free fluid in the peritoneum, the pelvis, pleural cavity and the pericardium, which are the most critical locations of bleeding in traumatic injury. A FAST examination can be done in less than 5 minutes and has a sensitivity of 73 to 99%, a specificity of 94 to 98% and an overall accuracy of 90 to 98% in clinically significant intraabdominal traumatic injury. It augments the EP’s examination of the trauma patient leading to reduced time to appropriate intervention that results to shorter hospital stay, lower medical costs and lower mortality.

Rapid Ultrasound in Shock (RUSH) first described in 2007, is another integrated bedside ultrasound examination that is used to evaluate an undifferentiated hypotensive patient. The protocol provides an anatomic and physiologic assessment of a hypotensive or poorly perfused patient by focused evaluation of any pathology in the heart (pericardial tamponade, right ventricular failure and left ventricular dysfunction), inferior vena cava (hypovolemia and hypervolemia), Morrison’s pouch/splenorenal/pelvic area (intraabdominal bleeding), aorta (ruptured aortic aneurysm) and the chest wall (pneumothorax). The findings gathered from this examination not only enable the emergency physician to delineate the distinctive shock state but also direct proper intervention and monitor the patient’s response.

The Basic Lung Ultrasound in Emergency (BLUE) protocol is a recently developed ultrasound-based bedside examination that aids in the evaluation and diagnosis of acute respiratory failure. Developed and proposed by renowned intensivist Professor Daniel Lichtenstein in 2007, the BLUE protocol consists of sectored scanning of both lung fields for the presence of lung sliding, ultrasound air artifacts and interstitial syndrome. The absence of lung sliding signifies the presence of pneumothorax, while air artifacts like B-lines suggest the presence of interstitial disease indicating a possible pneumonic process or pulmonary congestion. The BLUE protocol in Professor Lichtenstein’s study provided immediate diagnosis of respiratory failure in 90.5% of cases studied. The clinical utility of lung ultrasound was further validated in studies by Volpicelli (2008) who utilized the presence of B-lines to prognosticate patients with heart failure, and Liteplo (2009) who concluded that lung ultrasonography is comparable to NT-proBNP in diagnosing congestive heart failure.

Integrated scans, however, are not the only useful applications of emergency ultrasonography. Many invasive procedures such as central vein cannulation, abscess incision and drainage, endotracheal intubation and surgical airway benefit from real time imaging and guidance by ultrasound thus providing a safer way for physicians to perform these procedures. The use of bedside ultrasound in screening patients for deep venous thrombosis and aortic aneurysms will enable emergency physicians to make appropriate and timely decisions for their patients. This can significantly reduce the need to perform additional diagnostic modalities which are more expensive and time consuming.

Emergency ultrasonography has been around for only a little more than a decade. To assure competent use, the emergency physician will have to undergo appropriate training and credentialing.  The quality and safety parameters must be set and followed.  Collaboration with other specialists like radiology, cardiology and surgery both in training and in clinical practice will help derive the maximal benefit from emergency ultrasound. It is not meant to replace diagnostic ultrasound as the former is a more focused and non- exhaustive examination with a clearly defined emergency indication that directly impacts clinical decision-making.

In 1834, an article was published in the London Times about a new tool in the examination of a patient.  It stated that the tool “will never come into general use”, because “its beneficial application requires much time and gives a good bit of trouble both to the patient and the practitioner; its hue and character are foreign and opposed to all our habits and associations”.  The tool that the article was referring to was the stethoscope. And much like the stethoscope in its heyday, emergency ultrasonography in the coming years will have more widespread acceptance and utilization.  This will help decrease medical errors, provide more efficient real-time diagnosis, and supplement or even replace more advanced imaging in appropriate situations in the ER. As an innovative tool in the assessment of the ER patient, the ultrasound extends the emergency physician’s vision effectively beyond their stethoscope and fingertips, albeit in an image that is black and white.

(The author is the speaker and trainer in the training course: Basic Emergency Sonography for Trauma which will be held at the Asian Hospital and Medical Center on April 4, 2013 from 8am to 4pm.  For registration inquiries you may contact the PCEM secretariat at 746-71-81 or at the St. Luke’s Medical Center, QC at 7252328.  Fo more information on the emergency ultrasonography course you may contact the author through email: This e-mail address is being protected from spambots. You need JavaScript enabled to view it )


References:

1. Babasa R. Telephone Survey of Local EM Training Programs on Emergency Ultrasound Use. March 2011

2. Moore, C. and Copel, J. Current Concepts: Point-of-Care Ultrasonography. The New England Journal of Medicine, 2011; 364:749-57

3. Perera, P., Mailhot, T., et al. The RUSH Exam 2012: Rapid Ultrasound in Shock in the Evaluation of the Critically Ill Patient. Ultrasound Clinics, 2012; 7:255-78

4. Lichtenstein, D. Lung Ultrasound in Acute Respiratory Failure: An Introduction to the BLUE-Protocol. Minerva Anestesiologica, 2009; 75: 213-7

5. Noble, V., and Nelson, B. Manual of Emergency and Critical Care Ultrasound 2nd Edition. 2012, pp 198-202. Cambridge University Press.

6. Kendall, J. Emergency Medicine Imaging For The 21st Century: Where Does Ultrasound Fit In? Emergency Medicine Practice article, April 2001, Vol 3; 4: 1-24

7. Reiser, S. The Medical Influence of the Stethoscope. Scientific American, February 1979, 240; pp 148-56

 

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