CLINICIAN’S CAPSULE
What is known about the topic?
Ultrasound simulation is an invaluable resource in medical education. However, the equipment required is often prohibitively expensive.
What did this study ask?
Does the use of a low-cost ultrasound simulator in trauma simulation improve diagnostic capabilities?
What did this study find?
Study participants experienced improvements in diagnostic accuracy, confidence, and precision following the use of this ultrasound simulator.
Why does this study matter to clinicians?
This low-cost ultrasound simulator provides an alternative to current technology and can easily be implemented into medical simulations.
INTRODUCTION
In trauma and critical care, clinicians are required to assess and initiate treatment for time-critical, often life-threatening injuries. One of the most versatile approaches used in this setting is ultrasonography. Point-of-care ultrasound (POCUS), an ultrasound exam performed and interpreted at the bedside by a primary care provider,Reference Atkinson, Ross and Henneberry1 is invaluable in rapidly diagnosing patients presenting with trauma.Reference Boulanger, McLellan and Brenneman2 Perhaps one of the most widely used POCUS scanning protocols in this setting is the extended focused assessment with sonography for trauma (E-FAST), which includes views into the abdomen, pelvis, and chest to assess for evidence of hemoperitoneum, hemothorax, or pneumothorax.Reference Williams, Perera and Gharahbaghian3
High-fidelity simulation, which makes use of technologically advanced mannequins in simulations that mimic clinic practice, is becoming increasingly popular in medical education.Reference Girzadas, Antonis and Zerth4 Further, hybrid simulation, which integrates POCUS into high-fidelity simulation, can lead to higher satisfaction amongst learners, and increase the overall fidelity of the simulation.Reference Girzadas, Antonis and Zerth4 The ultrasound simulator used in this study, the emergency department ultrasound simulatorReference Paul Kulyk5 (edus2), is an example of a low-cost device that allows learners to perform real-time scans during high-fidelity simulation.Reference Olszynski, Harris and Renihan6
Equipment for medical simulation can be prohibitively expensive. This study looked at whether the addition of a low-cost ultrasound simulator to high-fidelity trauma simulation was associated with an improvement in diagnostic accuracy, confidence, and precision.
METHODS
This prospective observational study was conducted at an urban regional hospital. The population consisted of resident (PGY1-3) and attending physicians. This study was approved by the Horizon Health Network Research Ethics Board.
All participants received standardized didactic and hands-on-training with the edus2. This simulator consists of radiofrequency identification chips tagged with pre-recorded videos of ultrasound scans, which are placed under the skin of a Laerdal SimMan 3G mannequin. When a simulated ultrasound probe is passed over the chips, the video is played on an adjacent screen (Supplementary Appendix 1).
Participants were given a brief case presentation and performed a history and physical exam of the mannequin. From this, they generated a list of up to five possible diagnoses with corresponding confidence (from 1% to 100%) that a given diagnosis matched the correct pathology. Participants then completed an E-FAST scan using the edus2 and subsequently recorded a new differential diagnosis list.
Following testing, a brief questionnaire regarding perceptions of realism and educational utility of the edus2 was completed by each participant (Supplementary Appendix 2).
RESULTS
Twelve residents and 20 attending physicians completed up to 6 simulations each, for a total of 114 scenarios. Table 1 presents the descriptive statistics for both residents and attending physicians on frequency of correct primary diagnoses, diagnostic accuracy, confidence, and precision, both before and after using the edus2.
Table 1. Performance of residents and attending physicians before and after POCUS
The diagnostic accuracy was assessed by comparing the total of number of correct primary diagnoses before and after the ultrasound. Following the use of the edus2, participants were more likely to rank the correct diagnosis at the top of their differential list (p<0.0001). This improvement was seen for residents (p<0.0001) and attending physicians (p=0.0116).
For a diagnostic rank score, if participants ranked the correct diagnosis as their first choice, they received five points; if second, they received four points, and so on. Following an ultrasound, it was more likely that participants would rank the correct diagnosis higher on their differential diagnosis lists (p<0.0001) (Supplementary Appendix 3). The same finding was true for resident (p=0.001) and attending physicians (p=0.0098).
The diagnostic confidence was defined as the percent confidence (from 1% to 100%) indicated with the correct diagnosis. Overall, participants reported higher percentages of confidence in their diagnoses following an ultrasound (p<0.0001) (Supplementary Appendix 4). Specifically, residents’ (p<0.0001) and attending physicians’ (p<0.0001) confidence also increased.
The diagnostic precision refers to the size of the differential diagnosis list, with less items considered more precise. Overall, participants narrowed their differential diagnosis list following POCUS (p<0.0001) (Supplementary Appendix 5). Again, this reduction was significant in both residents (p<0.0001) and attending physicians (p<0.0001).
Lastly, on the questionnaire, participants rated the realism and the potential impact of the edus2 future medical education to be very high (median rating of 4 out of 5 for all items assessed).
DISCUSSION
We have found that there were statistically significant increases in the number of correct primary diagnoses made, diagnostic rank score, confidence in the correct diagnosis, and diagnostic precision following the use of an ultrasound simulator.
Recent studies have found similar improvements in diagnostic capabilities following POCUS. Parks et al.Reference Parks, Verheul, Leblanc-Duchin and Atkinson7 found an improvement in medical learner’s diagnostic accuracy, confidence, and precision when an ultrasound was introduced into simulated cardiorespiratory scenarios. Similarly, in the clinical setting, Jones et al. found that physicians improved their diagnostic precision and proportion of correct primary diagnoses after using ultrasound in patients presenting with undifferentiated hypotension.Reference Jones, Tayal, Sullivan and Kline8
One limitation of this study is that the edus2 simulator requires users to pass the scanner only near the locations of the E-FAST scan to generate a perfect image. It does not simulate body habitus or variations in anatomy. In addition, without a control group, we can report on associated improvements in diagnostic capabilities but cannot suggest causation.
CONCLUSIONS
Given the ever-increasing cost of medical simulation equipment, simulators such as the edus2 are important low-cost alternatives. One study has shown that this simulator costs less than CAD$150 to assemble.Reference Damjonovic, Goebel and Fischer9 Considering the cost, ease of use, and associated improved diagnostic capabilities, the edus2 could easily be integrated into simulation programs across the country. In the future, we hope to compare the edus2 to other high-fidelity ultrasound simulators to assess for differences in impact on diagnostic capabilities, or in user perception of educational utility.
Acknowledgements
We thank all study participants for volunteering their time to contribute to this study. Additionally, we thank Susan Benjamin and the New Brunswick Trauma Program for their continued guidance and support.
Competing interests
None declared. This study received funding from the New Brunswick Trauma Program (2013) and the Health Innovation Research Fund (2013).
SUPPLEMENTARY MATERIAL
To view supplementary material for this article, please visit https://doi.org/10.1017/cem.2018.56
