This study aims to investigate medical students' mastery of radial artery puncture and catheterization skills guided by the midline on ultrasound when using scenario simulation combined with intermittent training, and to compare this approach with traditional teaching methods.

With the continuous advancement of modern anesthesiology and critical care medicine, arterial monitoring has become an integral part of clinical anesthesia management. During anesthesia, functions such as arterial blood pressure monitoring and arterial blood gas analysis enable real-time surveillance of vital signs, playing a crucial role particularly in the anesthesia management and postoperative monitoring of high-risk patients. The radial artery, being a superficial and easily accessible vessel, has become one of the commonly used arterial puncture sites in clinical practice. Furthermore, this technique is a mandatory skill for residents in standardized training programs within anesthesiology departments. However, as an invasive procedure, it demands high proficiency from the operator and carries significant risks of complications such as infection, hematoma, thrombosis, and arterial spasm. Radial artery catheterization poses a challenge for residents, making it essential to establish a straightforward and clear teaching strategy.The success rate of ultrasound-guided radial artery puncture is influenced by operator experience, particularly among resident physicians. Although ultrasound with a "midline" feature can assist in puncture, catheter placement remains challenging, and the effectiveness of their mastery requires further study. Current training programs exhibit gaps, with clinical settings predominantly relying on intensive learning sessions that yield poor skill retention. Interval learning, despite its advantages, is underutilized. Given the clinical workload constraints of residents, sustained practice after intensive training is challenging. Therefore, designing and implementing an intermittent training program for ultrasound-guided radial artery catheterization is highly significant. This approach aims to combine the strengths of both intensive and intermittent training to enhance residents' skills, reduce complications, ensure patient safety, and provide departments with a new, effective training method.

Inclusion and Exclusion Criteria for Study Participants (Resident Trainees) I. Inclusion Criteria Identity and Qualifications: Resident physicians undergoing standardized training in this department.

Training Stage: Resident physicians who have not yet independently performed ultrasound-guided radial artery puncture and catheterization procedures.

Willingness to Learn: Voluntary participation in this "Ultrasound-Guided Radial Artery Catheterization" training program with full understanding of the research content.

Informed Consent: Have signed a written informed consent form agreeing to participate in this study and comply with protocol requirements.

Basic Requirements: Possess good hand-eye coordination and learning ability, capable of cooperating to complete the entire training course and data collection.

II. Exclusion Criteria Prior Experience: Residents who have previously independently completed more than 5 cases or have systematically studied ultrasound-guided radial artery puncture and catheterization techniques.

Skill Level: Residents who achieved a high pre-test performance score or demonstrated consistent success in performing ultrasound-guided radial artery catheterization prior to the study.

Cognitive or Motor Impairment: Residents with severe cognitive dysfunction, motor impairment, or a history of psychiatric disorders that may compromise training efficacy assessment.

Time Commitment and Compliance: Individuals unable to guarantee completion of the prescribed training program, practical exercises, and follow-up evaluations.

Other Conditions: Participants deemed unsuitable for this study by the investigator due to other reasons (e.g., rotation schedule conflicts, inability to coordinate personal time, etc.).

Inclusion and Exclusion Criteria for Study Subjects (Patients Undergoing Radial Artery Catheterization)

I. Inclusion Criteria

Age: Generally ≥18 years old. Clinical Indications: Patients requiring invasive arterial pressure monitoring via radial artery puncture and catheterization due to surgical procedures, critical condition monitoring, or blood gas analysis.

Vascular Criteria: Palpable radial artery pulse on the puncture side, negative modified Allen test (or adequate ulnar artery compensation as determined by current guidelines).

Informed Consent: Patient or authorized family member fully understands the study purpose and procedures, and has signed a written informed consent form.

Cooperation Capacity: Able to cooperate throughout the radial artery puncture and catheterization procedure.

II. Exclusion Criteria Contraindications for Puncture: History of thrombosis, aneurysm, or arteriovenous fistula at the puncture site; skin infection, laceration, burn, or severe scar tissue at the puncture site.

Circulatory Impairment: Severe shock, hypovolemic state, or anticipated difficulty with radial artery puncture.

Coagulation Abnormalities: Significant bleeding tendency, marked thrombocytopenia, or ongoing anticoagulant/antiplatelet therapy without discontinuation.

Abnormal vascular anatomy: Preliminary ultrasound assessment indicates severe tortuosity, malformation, excessively narrow diameter, or other significant anatomical variations in the radial artery that may compromise puncture success or safety.

Special circumstances: Requirement for simultaneous bilateral radial artery catheterization; or other situations deemed unsuitable for this teaching procedure by the investigator.