A medical student learning ultrasound techniques for vein differentiation.

Ultrasound Training for Medical Students: Mastering Vein Differentiation

Theo Raines in Health & Wellness August 2025 • 4 min read.

"A Simple Guide to Ultrasound-Based Techniques for Central Venous Catheter Placement Training"

Central venous catheters (CVCs) are essential in modern medicine but carry risks, particularly when placed in the subclavian vein. Traditional methods can lead to complications such as pneumothorax or hemothorax. The introduction of ultrasound-guided CVC (US-CVC) techniques has significantly improved safety, allowing doctors to visualize the vessels and guide the catheter more precisely.

However, mastering US-CVC requires training and skill. Medical students and those new to the procedure often struggle with differentiating between subclavian veins and arteries using ultrasound – a critical first step. This challenge prompted researchers at Osaka Medical College to investigate the subjective difficulty of various ultrasound-based differentiation methods.

This article breaks down their findings, offering insights that can help medical students and educators focus on the most effective techniques for learning and teaching ultrasound-guided vein differentiation. By understanding the perceived difficulty of each method, training programs can be tailored to improve learning outcomes and patient safety.

Understanding Ultrasound Techniques for Vein Differentiation

A medical student learning ultrasound techniques for vein differentiation.

The Osaka Medical College study involved 42 fifth-year medical students with no prior experience in subclavian vein ultrasound imaging. As part of their training, they were introduced to four common ultrasound techniques to differentiate between the subclavian artery and vein:

Each method relies on different visual cues to help distinguish between the vessels:

Arterial Pulse (Pulse): Assessing the pulsatility of the vessel to identify arteries.
Color Doppler: Using color Doppler imaging to visualize blood flow, with arteries showing pulsatile flow and veins showing more continuous flow.
Compression (Vein Reduction): Observing how the vessel responds to gentle pressure from the ultrasound probe; veins typically compress more easily than arteries.
Valsalva (Vein Expansion): Asking the patient to perform the Valsalva maneuver (attempting to exhale against a closed airway) to increase pressure in the veins, causing them to expand.

After training, the students rated the difficulty of each method on a visual analog scale (VAS), where 0 mm represented 'extremely easy' and 100 mm represented 'extremely difficult.' This subjective feedback provided valuable insights into the usability of each technique for novice learners.

Key Takeaways and Implications for Training

The study revealed significant differences in the perceived difficulty of the ultrasound techniques. Compression was rated as the easiest method, while arterial pulse and color Doppler were considered more challenging. The Valsalva maneuver, while still easier than pulse and color Doppler, presented its own set of difficulties, potentially due to the subtle expansion of the subclavian vein.

These findings suggest that training programs should prioritize the compression method as an initial approach for teaching vein differentiation. Focusing on the easily observable compression characteristic can build confidence and provide a foundation for understanding more complex techniques like color Doppler and pulse assessment.

Combining compression with other methods may further enhance novice doctors' ability to confidently differentiate between the subclavian vein and artery. Future research could explore optimal combinations and training protocols to maximize learning efficiency and improve the safety of CVC placements.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1016/j.jclinane.2018.12.002, Alternate LINK

Title: Subclavian Artery And Vein Differentiation Methods Using Ultrasound Imaging Among Medical Students

Subject: Anesthesiology and Pain Medicine

Journal: Journal of Clinical Anesthesia

Publisher: Elsevier BV

Authors: Nobuyasu Komasawa, Mamiko Higashida, Yuichi Noda, Toshiaki Minami

Published: 2019-05-01

Everything You Need To Know

Why is using Ultrasound-guided CVC (US-CVC) techniques important?

The use of Ultrasound-guided CVC (US-CVC) techniques is crucial because it enhances the safety of inserting Central Venous Catheters (CVCs). Traditional methods, such as those not using ultrasound, can result in complications like pneumothorax or hemothorax. US-CVC allows for visualization of the vessels, improving the precision of catheter placement and decreasing the risk of these adverse outcomes. This is especially important in the subclavian vein.

What are the different ultrasound techniques mentioned for differentiating between vessels?

The study mentions four techniques: Arterial Pulse, Color Doppler, Compression, and Valsalva. Arterial Pulse involves assessing the pulsatility of the vessel. Color Doppler uses color imaging to visualize blood flow. Compression observes the response to pressure from the probe. Valsalva involves the patient performing the Valsalva maneuver to increase vein pressure and expansion. Each method employs different visual cues to help differentiate between the subclavian artery and subclavian vein.

Why is it important to differentiate between the subclavian artery and vein?

Differentiating between the subclavian artery and the subclavian vein is a critical first step in ultrasound-guided CVC procedures. Accurate identification ensures the catheter is placed correctly into the vein, avoiding accidental arterial puncture. The study emphasizes the importance of mastering these differentiation techniques for safer patient outcomes, particularly in the context of the subclavian vein.

Which techniques were found to be easier or more difficult by the students in the study?

The Osaka Medical College study found that Compression was rated as the easiest method for differentiating between the subclavian artery and subclavian vein. Color Doppler and Arterial Pulse were considered more challenging for the novice learners. Valsalva presented its own set of difficulties, potentially because the expansion of the subclavian vein may not be readily apparent.

What are the implications of these findings for training?

The implications of the study's findings include the potential to tailor ultrasound training programs. By recognizing the perceived difficulty of each technique, educators can focus on the most effective methods for teaching ultrasound-guided vein differentiation. This targeted approach is designed to enhance learning outcomes and improve patient safety. This targeted approach is important for medical students and others new to the US-CVC procedure, with the ultimate goal of increasing the safety of Central Venous Catheter (CVC) placement.