383 The Effect of Display Size on Ultrasound Interpretation

Abstract

Ultrasound (U/S) has become an essential component of emergency department patient care. Since the 1990s, U/S systems have become smaller and more affordable. In fact, recent technological advances have heralded the development of handheld ultrasound (HHU) systems, placing the technology within the pockets of practitioners. However, miniaturization may come with consequences, particularly regarding the ability to accurately interpret examinations on a smaller screen. This study aims to assess how display size affects the ability of emergency providers to accurately interpret U/S videos. A prospective convenience sample of emergency physicians were enrolled. Participants completed an initial survey assessing training level and previous experience with HHU, as well as their perception of whether display size may affect U/S interpretation. Participants were then randomized to begin the study on a phone-sized screen (Apple® iPhone® XS Max - 6.5”, 2688x1242 pixel resolution) versus a laptop-sized screen (Apple® MacBook Pro® - 13.3”, 2560x1600 pixel resolution). 50 unique U/S videos were chosen for inclusion in the study, with 25 displayed per device. Each video depicted right upper quadrant views of the Focused Assessment with Sonography in Trauma (FAST) examination, half containing free fluid and the other half not. The videos were 6 seconds in length and continuously looped during the assessment. Participants answered “Yes” or “No” in response to whether they identified free fluid, above and/or below the diaphragm. The time that each participant used per device was also recorded. Following the assessment, participants were asked whether they felt that the display size affected their ability to accurately interpret the videos. 52 emergency physicians were enrolled in the study: 19 attendings with U/S fellowship training, 8 attendings without U/S fellowship training, 3 U/S fellows, 1 PGY4 resident, 8 PGY3 residents, 7 PGY2 residents, and 6 PGY1 residents. 67.3% of participants reported no current use of HHU, while the remainder reported a combination of academic and clinical use (23.1% academic, 9.6% academic and clinical). Prior to study initiation, 50% of participants felt that display size would affect accuracy, 42.3% were unsure, and 7.7% felt it would not. The accuracy of U/S interpretation for phone versus laptop display was 87.3% and 87.6%, respectively (p=0.84). The mean time spent with phone versus laptop display was 293s and 290s, respectively (p=0.66). Following completion of the study, 48.1% of participants felt that display size affected their ability to interpret the videos, 38.5% felt it did not and 13.5% were unsure. The study found no statistically significant difference in the accuracy of interpretation when ultrasounds were reviewed on a phone-sized versus a laptop-sized display. Furthermore, the time spent interpreting videos was nearly equivalent between devices. Finally, the results suggest that, overall, participants felt more confident in their ability to interpret videos on the smaller screen following the study. This study suggests that the accuracy of U/S interpretation may not significantly depend upon the size of the display utilized. A limitation of this study is that the interpretations were limited to one application: the FAST examination. Future studies will be needed to further assess other applications.