Determining the Learning Curve for Acquiring Core Sonographic Skills for Ultrasound-Guided Axillary Brachial Plexus Block

Background and Objectives The objectives of this study were to determine the learning curve for capturing sonograms and identifying anatomical structures relevant to ultrasound-guided axillary brachial plexus block and to determine if massed was superior to distributed practice for this core sonographic skill. Methods Ten University of Melbourne, third- or fourth-year Doctor of Medicine students were randomized to massed or distributed practice. Participants performed 15 supervised learning sessions comprising scanning followed by feedback. A "sonographic proficiency score" was calculated by summing parameters in acquiring and interpreting the sonogram, and identifying relevant anatomical structures. Results Between the 1st and 10th sessions, the proficiency scores increased (P = 0.043). Except for one, all participants had relatively rapid increases in their "sonographic proficiency scores." There was no difference in proficiency scores between the 15th and 10th sessions (P > 0.05). There was no difference in scores between groups for the first session, (P = 0.40), 15th session (P = 0.10), or at any time. There was no difference in the slope of the increase in "sonographic proficiency score" over the first 10 scanning sessions between groups [massed, 1.1 (0.32); distributed, 0.90 (0.15); P = 0.22) presented as mean (SD)]. The 95% confidence interval for the difference in slopes between massed and distributed groups was -0.15 to 0.56. Conclusions The proficiency of participants in capturing sonograms and identifying anatomical structures improved significantly over 8 to 10 learning sessions. Because of sample size issues, we cannot make a firm conclusion regarding massed versus distributed practice for this core sonographic skill.