Central venous catheterization technique is a compulsory clinical skill for anesthesia resident physician. Because it is difficult to operate and may cause serious complications, teaching this skill is a key and difficult point in clinical teaching of anesthesiology department.This project aims to observe the effect of video demonstration combined with video feedback teaching on the central venous catheterization time of junior residents and to obtain a better training method for central venous catheterization skills.

Central venous catheterization technology is a compulsory clinical skill for resident physicians. Because of its difficulty in operation and the possibility of serious complications, teaching this skill is a key and difficult point in clinical teaching in anesthesiology. This skill training has gone through the traditional "apprentice mode" teaching to the current video demonstration teaching, bedside feedback teaching, etc.. The attempts of multiple teaching modes are to help low-age resident doctors master the technology as soon as possible, improve the operation success rate, and reduce the incidence of complications.

The Department of Anesthesiology in our hospital is a key base for the standardized training of anesthesiologists in China. In recent years, the introduction of video demonstration methods for the central venous catheterization technology of low-age residents has achieved some results. Residents watch the demonstration operation videos specially recorded by the department, and perform operation exercises after passing the pre-operation assessment. The trainees self-reported that the teaching mode increased their confidence in learning this skill. However,in the actual training process, bedside comments (feedback teaching) were also involved, and it was discovered that it could cause panic and dissatisfaction of the patient, which was later improved into the paper-based feedback of the teacher.

The video demonstration teaching method was first applied to athletes' competitive training and was found to be effective in improving athletes' competitive skills.It was also used in medical education for surgical operation training, such as laparoscopic operation, which also obtained significant results. Feedback, as a method of attracting learners, has long been regarded as an important part of learning in medical education. We used bedside feedback teaching in the early stage, which was criticized by patients. Research has shown that video feedback may not only be superior to traditional verbal feedback methods alone, but it can also avoid problems from patients. When learners watch their own operation videos, video feedback will occur regardless of whether there is guidance from the instructor. Learners can watch these videos individually or with the teacher who can provide guidance at the same time. This teaching method is believed to be helpful for the assessment of skills. The use of video feedback originated from track and field sports learning. A large number of studies have found that video feedback teaching can be used as an effective means of medical communication skills training. Recently, it has also be used in clinical skills teaching. Current studies have confirmed that this teaching method can improve students' confidence in learning skills, but there is still relatively little research on skill acquisition.

In summary, video demonstration teaching and video feedback teaching are both useful in deliberate practice teaching (such as skill operation training). Skills operation training involves targeted repetitive exercises to improve skills, and feedback is the key to strengthening clinical learning. By video demonstrations, learners can observe and analyze the performance of experts (demonstrators) at key decision points under the guidance of the teacher. And video feedback can help promote self-assessment. It shows that the combination of the two may be more conducive to the integration of observational learning, imitation and self-evaluation, and speed up the progress of skill training. This joint teaching has been studied in sports research, while there are few studies in medical education. At present, a small study found that compared with oral feedback, the combined method can achieve better hernia repair skills, and there are recent research reports in peripheral vein indwelling operation training. But whether it is also suitable for the operation training of high-risk skills with greater difficulty coefficient, it needs to be confirmed by further research.

This project intends to observe the impact of video demonstration combined with video feedback teaching on the central venous catheterization time of low-age resident physicians, aiming to obtain a better method of central venous catheterization skills training, and to improve the learning confidence of students to better master this skill, improve the success rate of operation, reduce complications, and promote the application.

Inclusion Criteria:

• The target population will be junior residents of the Department of Anesthesiology, the Second Affiliated Hospital of Zhejiang University with < 3 previous encounters performing central vein operation

Exclusion Criteria:

• The target population will be junior residents of the Department of Anesthesiology, the Second Affiliated Hospital of Zhejiang University with ≥ 3 previous encounters performing central vein operation

Students and teachers are not blinded, but researchers and data evaluators are blinded.