Eye tracking technology differentiates novice and expert image interpretation for ultrasound-guided regional anesthesia. Borg L, Harrison TK, Kou A, Mariano ER, Udani AD, Kim TE, Shum C, Howard SK. Department of... [ view full abstract ]
Eye tracking technology differentiates novice and expert image interpretation for ultrasound-guided regional anesthesia.
Borg L, Harrison TK, Kou A, Mariano ER, Udani AD, Kim TE, Shum C, Howard SK.
Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine; Anesthesiology and Perioperative Care Service, Veterans Affairs Palo Alto Health Care System; Department of Anesthesiology, Duke University
Introduction
Historically, educational research has relied on test-retest and self-assessment methods to infer learning. Similarly, training programs use subjective evaluations from instructors to determine trainees’ milestone achievement and competence. Objective measures of learning are needed to guide the individual learner’s pathway from novice to expert. Eye tracking has been used in surgery, radiology, nursing, and athletics for both training and assessment. Based on a recent feasibility study in the field of ultrasound-guided regional anesthesia (UGRA), we designed this study to test the hypothesis that eye tracking may differentiate novices from experts in image interpretation for UGRA.
Materials and Methods
With IRB and VA research committee approval, we recruited 6 first-year anesthesiology residents and 6 experts in regional anesthesiology to participate. Novices completed a survey describing their previous experience with ultrasound-guided techniques. Participants were seated in front of a 50-inch screen and fitted with eye tracking glasses (Tobii, Karlsrovägen, Sweden). Glasses were calibrated to each individual participant. Room lighting and set-up were the same for each participant. A slideshow of 5 UGRA sonograms were serially projected onto the screen. Participants were asked a series of standardized anatomy-based questions related to each image while their eye movements were recorded. The answer to each question was a location on the ultrasound image defined as the “area of interest” (AOI; Figure 1). Gaze data was analyzed using Tobii Pro Lab Analyzer (Karlsrovägen, Sweden). The primary outcome was total gaze time in the AOI (sec). Secondary outcomes were total gaze time outside the AOI (sec), total time to answer questions (sec), and time to first fixation on the AOI (sec).
Results
One novice and one expert were excluded from the study due to prescription eyewear preventing successful calibration of the eye tracking glasses. All novices had performed ultrasound-guided line placement and observed UGRA; only one novice had performed any ultrasound-guided peripheral nerve blocks. While the gaze time (mean+/-SD) in the AOI was not different between groups (7+/-4 sec for Novice and 7+/-3 sec for Expert; p=0.150), gaze time in non-AOI was greater for Novice (75+/-18 sec) vs. 44+/-4 sec for Expert (p=0.005). Total time to answer standardized questions and total time to first fixation in the AOI were both shorter for Expert (Figures 2 and 3).
Discussion
Experts in UGRA take less time to identify sonoanatomy of interest and spend less time gazing away from a target compared to novices. Eye tracking is a potentially useful tool to differentiate novices from experts in the domain of ultrasound image interpretation, a key skill in field of UGRA, and may represent an objective measure to benchmark a trainee’s progress towards expertise.
