Peer-teaching cardiac ultrasound among medical students: A real option

Introduction
Teaching cardiac ultrasound (CU) image acquisition requires hands-on practice under qualified instructors supervision. We assessed the efficacy of teaching medical students by their previously trained classmates (teaching assistants [TAs]) compared to teaching by expert trainers (cardiologists or diagnostic medical sonographers.
Methods
Sixty-six students received 8-hour CU training: 4-hour lectures on ultrasound anatomy and imaging techniques of 6 main CU views (parasternal long [PLAV] and short axis [PSAV]; apical 4-chamber [4ch], 2-chamber [2ch], and 3-chamber [3ch]; and sub costal [SC]) followed by 4 hours of hands-on exercise in groups of ≤5 students under direct supervision of a TA (group A: 44 students) or a qualified trainer (group B: 22 students). Students’ proficiency was evaluated on a 6-minute test in which they were required to demonstrate 32 predetermined anatomic landmarks spread across the 6 views and ranked on a 0–100 scale according to a predetermined key.
Results
The 6-minute test final grade displayed superiority of group A over group B (54±17 vs. 39±21, respectively [p = 0.001]). This trend was continuous across all 6 main views: PLAV (69±18 vs. 54±23, respectively), PSAV (65±33 vs. 41±32, respectively), 4ch (57±19 vs. 43±26, respectively), 2ch (37±29 vs. 33±27, respectively), 3ch (48±23 vs. 35±25, respectively), and SC (36±27 vs. 24±28, respectively).
Conclusions
Teaching medical students CU imaging acquisition by qualified classmates is feasible. Moreover, students instructors were superior to senior instructors when comparing their students' capabilities in a practical test. Replacing experienced instructors with TAs could help medical schools teach ultrasound techniques with minimal dependence on highly qualified trainers.

引言
心脏超声（cardiac ultrasound, CU）图像采集教学需在合格导师的监督下开展实操练习。本研究对比了经前期培训的同班同学（即教学助理（teaching assistants, TAs)）与专家导师（心脏病学家或诊断医学超声技师）带教医学生的教学效果。

研究方法
本研究共纳入66名医学生，均接受8小时心脏超声培训：首先为4小时理论课程，讲解6种标准心脏超声切面的超声解剖与成像技术，包括胸骨旁长轴（parasternal long axis, PLAV）、胸骨旁短轴（parasternal short axis, PSAV）、心尖四腔心（apical 4-chamber, 4ch）、心尖二腔心（apical 2-chamber, 2ch）、心尖三腔心（apical 3-chamber, 3ch）及肋下切面（subcostal, SC）；随后为4小时实操练习，学生以≤5人为一组，分别在教学助理（A组，44名学生）或合格导师（B组，22名学生）的直接监督下完成训练。学生的操作熟练度通过6分钟考核进行评估：要求学员展示覆盖上述6种切面的32个预设解剖标志点，并依据预设评分标准以0-100分制进行打分。

研究结果
6分钟考核的最终评分显示，A组学生成绩显著优于B组（54±17 vs. 39±21，P=0.001）。该优势在全部6种标准切面中均有体现：胸骨旁长轴（69±18 vs. 54±23）、胸骨旁短轴（65±33 vs. 41±32）、心尖四腔心（57±19 vs. 43±26）、心尖二腔心（37±29 vs. 33±27）、心尖三腔心（48±23 vs. 35±25）及肋下切面（36±27 vs. 24±28）。

结论
由合格同班同学担任教学助理开展心脏超声图像采集教学是切实可行的。此外，在实操考核中，经教学助理带教的学生表现优于经资深导师带教的学生。以教学助理替代资深导师，可帮助医学院校在大幅降低对高水平专业导师依赖的前提下开展超声技术教学。