Moving the rear end in a combination of both the vertical and the horizontal plane makes it possible to place the needle tip freely throughout the 2D area

By adding the gradual forward movement to the vertical and horizontal movements, a 3D positioning of the needle tip becomes possible – this is the key goal of the DNTP technique

• A downward movement to the right will move the needle upwards and to the left
• A downward movement to the left will move the needle upwards and to the right
• An upward movement to the right will move the needle downwards and to the left
• An upward movement to the left will move the needle downwards and to the right

Click on the VIDEO CLIP button to view an animated illustration of the technique

When starting DNTP, insert the needle 1 cm from the transducer at an angle of 30-45 degrees or what is most appropriate in the situation

Use alternating movements of the needle and transducer for guiding the needle tip accurately into blood vessel

When the needle tip is inside the vessel, reduce the angle after each movement of the needle

Insert the entire needle using ultrasound guidance

Guiding the needle successfully requires good eye-hand coordination and three-dimensional visualization skills

Vascular phantoms provide a simple and often inexpensive method to learn the skills of ultrasound-guided needle placement, before clinical use on patients, thereby reducing patient discomfort and possible complications

Vascular phantoms need to mimic some properties of human tissue such as background echogenicity, the texture, and needle resistance; they should be visually opaque so the needle and the target cannot be seen from the outside

We use both commercial (Blue Phantom) and homemade gelatin vascular phantoms

The success of your training depends on how well prepared you are

This includes:

• Studying the previous e-learning modules thoroughly
• Finding the things needed – ultrasound machine, phantom, gel, and needle
• Placing yourself correctly in front of the ultrasound screen
• Resting your arms in the 4-point rest
• Moving the transducer and needle in small alternating steps

For some people with less developed “spatial intelligence” the needle guidance can become problematic if the plane of the ultrasound beam is not aligned with the face of the ultrasound screen

A setting where the ultrasound beam and the face of the ultrasound screen are perfectly aligned is the best starting point for performing the procedure, and is recommended whenever possible

Needle manipulation and needle tip control – left/right movements

It is crucial to understand that any sideways movements of the rear end of the needle moves the needle tip in the opposite direction

Moving the rear end sideways to the right will turn the needle tip to the left

Moving the rear end sideways to the left will turn the needle tip to the right

Before performing ultrasound guided vascular access in patients you must master complete needle control

You must practice “outside” the human body first

Moving the rear end in the vertical plane upwards and downwards is an essential skill for accurately positioning the needle tip

When the needle is in the tissue and the needle tip can be seen, an upward movement of the rear end of the needle will move the needle tip down

A downward movement of the rear end will move the needle tip up

The needle tip and shaft look the same on the ultrasound screen!

The needle tip is seen  as a white dot when it transects the ultrasound imaging plane

By carefully moving the needle in small (mm) steps in and out of the plane of the ultrasound beam  needle tip can be tracked into the tissue

Have in mind that is not possible to discriminate between the tip and the shaft of needle

Dynamic Needle Tip Positioning (DNTP) was invented as a simple, effective and safe technique of venous and arterial cannulation in order to either draw a blood sample or insert a catheter into a target blood vessel – typically in patients with difficult vascular access.

It has been practiced for several years at Aarhus University Hospital, and thousands of catheters have been placed using this method with high success rates, few complications and high patient satisfaction.

The method is further so simple that it can be learned by anyone with minimum training, and thereby has a potential for simplifying ALL vascular cannulation.

The principles of DNTP are presented in European Journal of Ultrasound, Ultraschall in Med 2012; 33: E321-E325

The principle of dynamic needle tip positioning (DNTP) is to track the needle tip continuously

Since both the needle tip and the needle shaft appear as a white dot on the ultrasound screen, the only way to ensure correct position of the needle tip is to keep track of the needle tip position at all times