Pericardial effusion may lead to increased pressure around the heart. When this pressure increases to a level comparable to that of the right and left atria, restricted cardiac filling and reduced cardiac output may be triggered. In severe cases, this may lead to pulseless electrical activity in the heart, at which point a diagnosis of cardiac tamponade can be made. The classic presentation of cardiac tamponade, known as Beck’s triad, is a distend of the jugular vein, distant heart sounds, and hypotension. Patients with cardiac tamponade may present with severe respiratory distress, agitation, tachycardia, and hypotension, followed by rapid progression to occlusion, bradycardia, and pulseless electrical activity [1] . Emergency pericardiocentesis is a lifesaving clinical procedure that can quickly extract pericardial fluid, thereby rapidly restoring normal cardiac function and peripheral blood flow [2] . In clinical work, for patients with cardiac tamponade who need emergency treatment, timely completion of emergency pericardiocentesis can relieve the threat to the patient’s life, and save valuable time for patients who need emergency thoracotomy and pericardial window drainage [3] [4] .

Pericardiocentesis is a necessary clinical skill for residents in standardized training. According to the “Management Measures for Standardized Training of Residents (Trial)”, the standardized training students should master the basic knowledge and skills commonly used in clinical general medicine, such as the principle of clinical rational use of blood, cardiopulmonary resuscitation technology, pre-hospital emergency care for sudden diseases, palliative care, prevention and treatment knowledge of key and regional infectious diseases and the correct treatment process. In the first year of training, the basic clinical knowledge and skills of students should meet the requirements of medical licensing examination. In addition, “The Contents and Standards of Standardized Training for Residents (2022 Edition)” issued by the Chinese Medical Doctor Association in 2022 stipulates that surgical residents should be proficient in the operation points of pericardiocentesis after the standardized training, and complete pericardiocentesis under the guidance of superior doctors. Emergency pericardiocentesis techniques also require frequent review for clinicians who have practiced for many years, as pericardiocentesis is usually performed by sonographers. Emergency pericardiocentesis can be performed in patients with cardiac tamponade if clinicians are skilled in this technique [5] . In addition, the preliminary survey showed that most of the nursing staff had not received relevant teaching and training on emergency pericardiocentesis. Therefore, if nurses are familiar with this technology, they can better assist clinicians to perform this operation [6] .

In order to make the trainees in the standardized training of residents quickly master the theoretical knowledge of emergency pericardiocentesis, make the clinicians who have been working in medicine for many years more familiar with this technology, and make the nursing staff assist doctors to implement this technology more smoothly, we designed a “1 + 1 + 1” teaching method for the theoretical teaching of emergency pericardiocentesis. Briefly, that method is one English video overview, one English video detailed explanation and one summary extension. This method is based on problem-based learning theory. The problem-based learning theory was developed to address the problem of undergraduate medical students perceiving the first few years of the curriculum as impractical because of the difficulty of seeing the relevance of topics such as anatomy and physiology to their future careers as clinicians, and this approach, which seeks to demonstrate the topics’ Relevance. Most studies indicate that problem-based learning is generally well received and confers more confidence in graduates’ social and communication skills. After careful consideration of the thought processes developed by problem-based learning, there has been an increase in the number of people adopting this approach, thus making it a mainstay of medical education. Its effectiveness is also increasingly recognized [7] . The overall effect of this teaching method was evaluated by comparing the mastery of medical staff with different levels before and after the teaching.

Specifically, the “1 + 1 + 1” teaching method is as follows: 1) One English video overview. Before watching the English video, the key English words in the video are briefly explained, and then watch the video. 2) One English video detailed explanation. After playing a short part of the English video, the content of the part was accurately explained in detail. 3) One summary extension. Summarizes the content of the video, highlights the key and difficult points, and extends appropriately according to the content of the video.

Post-graduation medical education is an important part of medical education, and it is a key stage for medical students and doctors to further integrate theory with clinical practice. The main task of medical education is to select scientific and effective teaching methods so that residents can learn more clinical knowledge and become proficient in a variety of clinical skills within a limited period of time [8] .

In this theoretical teaching, we innovatively used the teaching method of “1 + 1 + 1”, which is a specific application of problem-based learning (PBL) in the teaching of clinical operation skills, and is the expansion and supplementation of previous teaching methods [9] [10] . At the same time, we chose English videos as teaching materials, which is similar to microclass material teaching [11] [12] , and is also an attempt and exploration in the bilingual teaching of clinical operation skills. This lays a certain foundation for further improving clinicians’ English application ability in medical specialties, expanding a wider scope of selecting bilingual teaching materials, as well as strict selection criteria for bilingual teaching materials, which is of certain reference significance [13] . The results of this study suggest that this teaching method is applicable to the population attending the lectures and is more effective within less senior medical staff. This may be due to the fact that the less senior medical staff themselves did not have as much theoretical knowledge of emergency pericardiocentesis as the more senior medical staff, and that. The method used in this instance was different from that used in undergraduate medical education, which may have been more appealing to the less senior medical staff and allowed them to concentrate more on their theoretical knowledge [14] . At the same time, this allows residents to form their own logical thinking with proficient theoretical knowledge, deepen their understanding of the nature of diseases and corresponding clinical dispositions, and fully utilize their knowledge to accurately identify and rationally solve clinical problems [15] . In addition, the “1 + 1 + 1” teaching method is also applicable to the theoretical teaching of other clinical operation skills.

However, this study only evaluated the effectiveness of the “1 + 1 + 1” teaching method and did not compare it with current widely used teaching methods, so it can only show that this method has a certain degree of teaching effectiveness, and cannot judge the superiority or inferiority of this method compared with other teaching methods. In addition, due to the small number of participants, although the lectures were effective, the differences in most of the statistical results were not statistically significant. In addition, due to the limitation of time and space, this teaching method only covers the theoretical knowledge of emergency pericardiocentesis, and only evaluates the degree of mastery of theoretical knowledge, and the effectness of practical skill was not evaluated.

In general, in post-graduation medical education, there is no single teaching method that can fully meet the needs of clinical education [16] [17] . We must adopt a reasonable and comprehensive teaching method based on the combination of key points of clinical knowledge, characteristics of diseases, and patients’ realities in order to enable trainees in standardized residency training to accurately, proficiently, and rapidly master clinical knowledge and clinical skills, and to rapidly grow up to be a qualified clinician [18] - [20] .

The “1 + 1 + 1” teaching method is effective in improving the mastery level of medical staff’s theoretical knowledge of emergency pericardiocentesis, and is also likely to improve its practical skills.

Medical rank: Beginner Intermediate Associate seniors and above

The answers to the following question has four alternatives, of which only one is the most suitable.

1) Indications for emergency pericardiocentesis

A) Cardiac tamponade B) Pericardial effusion

C) Pleural effusion D) Pneumothorax

2) Contraindications to emergency pericardiocentesis

A) Traumatic pericardial effusion B) Pleural effusion

C) Acute myocardial infarction (AMI) D) Rib fracture

3) The most commonly used method of emergency pericardiocentesis

A) Ultrasound-guided B) Blind puncture

C) Cardiac monitoring-guided D) Others

4) Common complications of emergency pericardiocentesis

A) Arrhythmia B) Diaphragmatic injury

C) Peritoneal perforation D) Death

*These authors contributed equally to this work and share first authorship.

^#Corresponding author.