Abstract
BACKGROUND: Eye-tracking measures attention patterns, which may offer insight into evaluating procedural expertise. The purpose of this study was to determine the feasibility of using eye tracking to assess visual fixation patterns when performing an ultrasound-guided regional anesthesia procedure and to assess for differences between experienced, intermediate, and novice practitioners. METHODS: Participants performed an ultrasound-guided sciatic nerve block 3 times on a fresh cadaver model while wearing eye-tracking glasses. Gaze fixation and dwell time on each location were compared between participants. Eye-gaze paths were used to derive a measure of entropy, or how often participants switched gaze fixations between locations. RESULTS: Five attending anesthesiologists, 5 third-year anesthesiology residents with prior ultrasound-guided regional anesthesia experience, and 5 medical students completed the study. Individuals with more experience were more likely to successfully perform the sciatic nerve block (5/5 attendings, 5/5 residents, 0/5 students; P = .002) and performed the procedure faster (average: attendings 62.6 seconds, residents 106.4 seconds, students 134.4 seconds; P = .089). Participants were progressively faster with practice (Trial 1: 41.8 seconds, Trial 2: 29.2 seconds, Trial 3: 28.9 seconds; P = .012), and the average number of eye shifts per trial decreased from 10.8 to 6.5 to 6 (P = .010). Attending physicians spent significantly less time fixating on the ultrasound monitor compared to trainees (P = .035). Average visual entropy progressively decreased from Trial 1 to Trial 3 (P = .03) and with greater experience (P = .15). There was a strong correlation between entropy and time on task (r(16) = 0.826, P = .001). CONCLUSIONS: Experienced providers make fewer back-and-forth visual fixations, spend less time in the procedure, and demonstrate less entropy during ultrasound-guided regional anesthesia procedures. Mobile eye-tracking has the potential to provide additional objective measures of performance that may help not only determine procedural competence but also distinguish between levels of proficiency.