Purpose: Medical schools are shifting from a time-based approach to a competency-based education approach. A competency-based approach requires continuous observation and evaluation of trainees. The goal of Central Line Tutor is to be able to provide instruction and real-time feedback for trainees learning the procedure of central venous catheterization, without requiring a continuous expert observer. The purpose of this study is to test the accuracy of the workflow detection method of Central Line Tutor. This study also looks at the effectiveness of object recognition from a webcam video for workflow detection. Methods: Five trials of the procedure were recorded from Central Line Tutor. Five reviewers were asked to identify the timestamp of the transition points in each recording. Reviewer timestamps were compared to those identified by Central Line Tutor. Differences between these values were used to calculate average transitional delay. Results: Central Line Tutor was able to identify 100% of transition points in the procedure with an average transitional delay of -1.46 ± 0.81s. The average transitional delay of EM and webcam tracked steps were -0.35 ± 2.51s and -2.46 ± 3.57s respectively. Conclusions: Central line tutor was able to detect completion of all workflow tasks with minimal delay and may be used to provide trainees with real-time feedback. The results also show that object recognition from a webcam video is an effective method for detecting workflow tasks in the procedure of central venous catheterization.
PURPOSE: Under ultrasound guidance, procedures that have been traditionally performed using landmark approaches have become safer and more efficient. However, inexperienced trainees struggle with coordinating probe handling and needle insertion. We aimed to establish learning curves to identify the rate of acquisition of in-plane and out-of-plane vascular access skill in novice medical trainees. METHODS: Thirty-eight novice participants were randomly assigned to perform either in-plane or out-of-plane insertions. Participants underwent baseline testing, four practice insertions (with 3D visualization assistance), and final testing; performance metrics were computed for all procedures. Five expert participants performed insertions in both approaches to establish expert performance metric benchmarks. RESULTS: In-plane novices (n=19) demonstrated significant final reductions in needle path inefficiency (45.8 vs. 127.1, p<0.05), needle path length (41.1 mm vs. 58.0 mm, p<0.05), probe path length (11.6 mm vs. 43.8 mm, p<0.01), and maximal distance between needle and ultrasound plane (3.1 mm vs. 5.5 mm, p<0.05) and surpassed expert benchmarks in average and maximal rotational error. Out-of-plane novices (n=19) demonstrated significant final reductions in all performance metrics, including needle path inefficiency (54.4 vs. 1102, p<0.01), maximum distance of needle past plane (0.0 mm vs. 7.3 mm, p<0.01), and total time of needle past plane (0.0 s vs. 3.4 s, p<0.01) and surpassed expert benchmarks in maximum distance and time of needle past plane. CONCLUSION: Our learning curves quantify improvement in in-plane and out-of-plane vascular access skill with 3D visualization over multiple attempts. The training session enables more than half of novices to approach expert performance benchmarks.