Patterns of skills acquisition in anesthesiologists during simulated interscalene block training on the soft embalmed Thiel cadaver (Preprint)

BACKGROUND Demand for regional anesthesia for major surgery has increased considerably but only a small number of anesthesiologists can provide such care. Simulation may improve clinical performance, but opportunities to rehearse procedures are limited and not formalised. Clinical educational outcomes prescribed by the Royal College of Anesthesiologists training curriculum 2021 are difficult to attain. Educational paradigms such as mastery learning and dedicated practice are increasingly used to teach technical skills in order to enhance skills acquisition. Moreover, high fidelity resilient cadaver simulators are now available: the soft embalmed Thiel cadaver shows similar physical characteristics and functional alignment to patients. The elasticity of tissues results in resolution of perineural fluid injection and enables hundreds of repeated injections without damage. However, learning curves, and their intra- and inter-individual dynamics, have not hitherto been measured on the Thiel cadaver simulator using the mastery learning and dedicated practice educational paradigm coupled with validated, quantitative metrics, such as checklists, eye tracking metrics and self-rating scores. OBJECTIVE Our primary objective was to measure the times taken to complete the scanning and needling phases of interscalene block conducted repeatedly on the soft embalmed Thiel cadaver over a 3-hour period of training. The primary outcome was the best-fit linear slope of log-log transformed time to complete the scanning and needling phases of repetitive, simulated interscalene block. METHODS Thirty anesthesiologists, with a wide range of experience, conducted up to 60 ultrasound-guided interscalene blocks over 3h on the left side of two soft embalmed Thiel cadavers. The duration of scanning and needling phases was defined as the time taken to perform all steps correctly. Our secondary objectives were to: measure pre-procedural psychometrics; describe deviations from the learning slope; correlate scanning and needling phase data; characterize skills according to clinical grade; re-test a sub-group of participants 2 to 3 months after training; measure learning curves using objective eye gaze tracking and subjective self-rating measures; and use these to discriminate between levels of scanning and needling performance RESULTS The median (IQR (range]) log-log learning slopes were -0.47 (-0.62 - -0.32 [-0.96 - 0.30]) and -0.23 (-0.34 - -0.19 [-0.71 - 0.27]) during the scanning and needling phases respectively. Loess curves showed wide variability in within-participant performance. The learning slopes of the scanning and needling phases correlated; rho 0.55 (0.23 - 0.76), P<.001; and rho -0.72 (-0.46 - -0.87), P<.001 respectively. Eye gaze fixation count and glance count during scanning and needling phases best reflected block duration. Using clustering techniques, fixation count and glance identified four distinct patterns of learning behaviour. CONCLUSIONS We quantified the rate or slope of learning by log-log transformation of learning curves and identified intra- and inter-individual patterns of variability. CLINICALTRIAL N/A