Abstract: Objective This study aimed to investigate the construction of standardized training resident’ learning curves for qualitative ultrasound assessment of gastric content and to determine the amount of training a resident would need to achieve competence in the ultrasound technique,so as to provide the reference basis for the training course development,the practice training and formulating the criterion of the qualifications to practice the ultrasound assessment of gastric content. Methods Ten residents underwent a teaching intervention including lectures and an workshop on live models of ultrasound assessment of gastric content. Lectures include reading articles,picture library,and how to perform a systematic qualitative assessment. Ten residents were divided into two groups and five residents were scheduled six training practice per group. Five volunteers were randomly assigned to five different operating areas at training practice. Each resident performed ultrasound sequentially and the results were recorded. Every resident assessed 30 separate sets of data and the results were recorded randomization allocation with random number method was conducted by an independent nurse into “empty” group,“clear fluid” group and “solid” group,with ten cases per group. Use the accrual and method to construct an individual learning curve; then learning curves and a predictive model were constructed through the cumulative sum method and nonlinear regression. Results The overall correct diagnosis rate of qualitative ultrasound assessment of gastric content was 70.7% (212/300) in the standardized training of the anesthesia department. The overall correct diagnosis rate was 59% (59/100) in the “empty” group,and was 74% (74/100) and 79% (79/100) in the “clear fluid” group and the “solid” group respectively. When comparing to “empty” group,the “solid” group showed a significantly higher failure rate (P<0.05). Although the learning curves of the five standardized training residents exceeded the acceptable failure rate of 10%,they were still beyond the cut-off point of unacceptable failure rate of less than 30%. The average number of cases required to achieve 90% and 95% success rates was estimated to be 24 and 28,respectively. Conclusions The learning curve and the predict model could not only evaluate the training process of achieving the learning objectives,but also assess the feasibility of establishing a new standardized training program. This study suggests that 24 and 28 are the average numbers of cases required to achieve 90% and 95% correct rates of qualitative ultrasound assessment of gastric content respectively. As the required number and the long cycle of training,a more convenient and effective training method is needed to be established.

Key words: Learning curve, Ultrasonography, Gastric content, Resident, Training