Share this article on:

The Speed of Sound: ‘Triple Scan’ for Dyspneic Patients Improves Diagnostic Accuracy

Butts, Christine MD

doi: 10.1097/01.EEM.0000515685.67918.f7
The Speed of Sound

Dr. Buttsis the director of the division of emergency ultrasound and a clinical assistant professor of emergency medicine at Louisiana State University at New Orleans. Follow her on Twitter @EMNSpeedofSound, and read her past columns athttp://bit.ly/EMN-SpeedofSound.

dyspnea, ultrasound

dyspnea, ultrasound

Figure

Figure

In all deference to my medical school instructors, I can't remember the last time I attempted to elicit egophony in a patient I was evaluating for shortness of breath. The physical exam frequently comes down to a quick listen with my stethoscope while taking their history.

I'm certainly not alone. I'm not sure any of my residents can even spell egophony, let alone elicit it on exam. That said, shortness of breath can be a challenging complaint. Many patients may not be able to provide an extensive history because of their clinical status, and examination of the chest can be limited by patient effort or habitus. Treatment of these patients can't wait, however, and relies on making the correct clinical assessment. Should we give nebs and steroids? Diuretics? Antibiotics? All of the above?

A number of ultrasound-based algorithms has been proposed to evaluate the dyspneic patient. Many of them are lengthy and complicated. The “triple scan” is a simplified protocol that builds on components of the rapid ultrasound in shock and hypotension (RUSH) exam to identify the etiology when the complaint is shortness of breath. (West J Emerg Med 2016;17[1]:46.)

The triple scan entails a quick look at the heart to evaluate for overall left ventricular function, the presence or absence of pericardial effusion, and the presence or absence of right ventricular enlargement. This quick echo can be done with any of the standard views (parasternal long or short axis, apical, or subxiphoid), and typically only one view is needed. A quick assessment of the lungs follows to see whether there are predominantly A-lines (“dry” lungs) or B-lines (“wet” lungs), the presence or absence of pleural effusions, and the presence or absence of lung sliding. Lastly, the triple scan evaluates the inferior vena cava (IVC) for size and change with respiration, a marker of central venous pressure.

So is the triple scan helpful in evaluating these patients? The architects of the protocol analyzed its use in their ED over a 10-month period in patients presenting with shortness of breath. (West J Emerg Med 2016;17[1]:46.) Each patient underwent an initial history and physical. The examining physician was then asked to rank the three most likely diagnoses and his confidence in those diagnoses. A triple scan was then performed, with the results shown to the examining physician. The physician was then asked to rank his most likely diagnoses a second time, again grading his confidence in the diagnosis.

All of these findings were compared with the final diagnosis, based on chart review at a later time when all clinical data were available. This study found that diagnostic accuracy improved from 53 percent prior to the triple scan to 77 percent after. The physicians' initial impression changed in almost half of the cases based` on the scan, and their confidence in the most likely diagnosis also significantly improved.

Taking the time to add a quick ultrasound assessment in our patients with shortness of breath can point us toward the right diagnosis.

Share this article on Twitter and Facebook.

Access the links in EMN by reading this on our website or in our free iPad app, both available at www.EM-News.com.

Comments? Write to us at emn@lww.com.

Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.