Introducing a Fresh Cadaver Model for Ultrasound-guided Central Venous Access Training in Undergraduate Medical Education

Abstract

Introduction: Over the past decade, medical students have witnessed a decline in the opportunities to perform technical skills during their clinical years. Ultrasound-guided central venous access (USG-CVA) is a critical procedure commonly performed by emergency medicine, anesthesia, and general surgery residents, often during their first month of residency. However, the acquisition of skills required to safely perform this procedure is often deficient upon graduation from medical school. To ameliorate this lack of technical proficiency, ultrasound simulation models have been introduced into undergraduate medical education to train venous access skills. Criticisms of simulation models are the innate lack of realistic tactile qualities, as well as the lack of anatomical variances when compared to living patients. The purpose of our investigation was to design and evaluate a life-like and reproducible training model for USG-CVA using a fresh cadaver.

Methods: This was a cross-sectional study at an urban academic medical center. An 18-point procedural knowledge tool and an 18-point procedural skill evaluation tool were administered during a cadaver lab at the beginning and end of the surgical clerkship. During the fresh cadaver lab, procedure naïve third-year medical students were trained on how to perform ultrasound-guided central venous access of the femoral and internal jugular vessels. Preparation of the fresh cadaver model involved placement of a thin-walled latex tubing in the anatomic location of the femoral and internal jugular vein respectively.

Results: Fifty-six third-year medical students participated in this study during their surgical clerkship. The fresh cadaver model provided high quality and lifelike ultrasound images despite numerous cannulation attempts. Technical skill scores improved from an average score of 3 to 12 (p<0.001) and procedural knowledge scores improved from an average score of 4 to 8 (p<0.001).

Conclusion: The use of this novel cadaver model prevented extravasation of fluid, maintained ultrasound-imaging quality, and proved to be an effective educational model allowing third-year medical students to improve and maintain their technical skills.

Figure 1

1A) Femoral line model: The clamp is tunneled into the deep subcutaneous tissue midway between the ASIS and pubic tubercle, the bony landmarks are annotated by X’s; 1B) The latex tube has been tunneled into the femoral tissues immediately overlying the femoral sheath to replicate the native vessel anatomy. ASIS, anterior superior iliac spine

Figure 2

2A) Internal jugular vein model: The two heads of the sternocleidomastoid (SCM) are drawn (in purple) to demonstrate the anterior triangle of the neck. The first incision is made between the two heads of the SCM just above the supraclavicular line (blue arrow). The second incision is made at the submandibular line (red arrow) 2B) A long clamp is used to tunnel through the anterior triangle at the level of the fascia from inferior to superior incision points. A length of latex tubing is clamped and pulled through the tunnel to replicate the IJV. IJV, internal jugular vein

Figure 3

A drape is used to hide the exposed latex tubing and Toomey syringe. The model is now ready for implementation.

Figure 4

The latex tubing provides an anechoic, compressible vessel clone that is durable enough to withstand multiple “sticks” without extravasation.