Abstract: Objective To explore the minimum number of practice attempts required for undergraduate medical interns to master endotracheal extubation skills under the ″sandwich″ teaching method. Methods Fifteen fifth-year undergraduate clinical students from the Class of 2019 at Jiaxing University medical college, who completed a rotation in the Department of Anesthesiology at the Affiliated Hospital of Jiaxing University between June and September 2023, were enrolled in the study. The ″Sandwich″ teaching method was employed for training in tracheal extubation procedures. All bedside extubation practices were independently supervised and assessed by the same two senior attending physician. Each intern independently completed 30 cases of tracheal extubation (a total of 450 cases), The quality score of the operation was recorded using a scale validated by the Delphi method, and a learning curve was constructed using the Cumulative Sum (CUSUM) method. They fitted quadratic and cubic polynomial functions and compared the goodness of fit (R²). The derivative analysis method was used to analyze the slope of the fitted curve and determine the skill turning point. Results The cubic polynomial function has the best fitting effect on the learning curve (R²=0.914). Using polynomial fitting derivative analysis method, the 18th operation is the inflection point of the learning curve slope, indicating a significant slowdown in skill improvement speed and entering a stable plateau period. Conclusions The ″sandwich″ teaching method can serve as an effective approach for training interns in endotracheal extubation skills. Learning curve analysis indicated that the minimum number of practice attempts required to achieve skill mastery was 18, providing evidence-based support for setting teaching objectives and optimizing resource allocation.

Key words: Teaching, Tracheal extubation, ″Sandwich″ teaching, Learning curve, Undergraduate