Vascular access is crucial in nursing practice. The choice of the appropriate venous access device, such as the Midline or the PICC, and the insertion technique, whether the classic Seldinger technique or the Modified Seldinger, can significantly influence the preservation of venous capital and the effectiveness of treatment. This article explores the differences and similarities between both techniques and their application in Midline and PICC devices.
Here is a one minute overview of this article:
Venous Access Devices:
- Midline: Shorter catheter (8–20 cm), does not reach central circulation
- PICC: Longer and thinner catheter, designed to reach central circulation
Benefits of the Classic Seldinger Technique:
- Simplicity and lower cost.
- Ideal for Midline catheters in superficial veins with good calibre.
- Less invasive, suitable for patients with coagulation problems or low platelets.
Modified Seldinger Technique:
- Greater control and adaptability.
- Ideal for PICC catheters in deep and small calibre veins, such as in obese patients.
- Facilitates tunnelling and allows safer, more controlled access.
Comparison of techniques
- Classic Seldinger: Longer guidewire, dilation with removable dilator, catheter inserted through the guidewire.
- Modified Seldinger: Guidewire < 50 cm, dual-piece introduction (introducer and dilator), removal of guidewire and dilator, catheter inserted through peelable introducer.
- Common points: Ultrasound-guided insertion, 21G fine needle, flexible kink-resistant guidewire (nitinol).
Conclusion
- Midline: Classic Seldinger for its simplicity, speed, and suitability to the catheter type.
- PICC: Modified Seldinger for being safer, more precise, and less traumatic when inserting a longer and more delicate catheter.
Considering Vascular Access: Classic Seldinger Technique vs. Modified Seldinger Technique
Vascular access is of utmost importance in daily nursing practice, as at some point in life, most people have had a device inserted or a blood test performed.
Choosing one venous access device over another helps preserve veins, keeping them intact and usable.
There are different venous access devices to access suitable veins for PICC and Midline insertion.
Both devices are inserted using sterile ultrasound guidance with either the direct Seldinger or Modified Seldinger technique.
If we look for the origin of the Seldinger technique, we find it in the 1950s when a young radiologist, Sven-Ivar Seldinger, faced with arterial cannulation difficulties for diagnostic purposes, had the brilliant idea of using a wire after needle puncture to guide the catheter.
“I was struggling with the problem of developing a better catheterisation method with three objects in my hand: a needle, a wire, and a catheter, and in a fraction of a second I realised in what sequence I should use them. Insert the needle, place the wire inside, remove the needle, advance the catheter over the wire and remove the wire.”
This technique evolved into the current classic method, with the wire becoming a hydrophilic nitinol guidewire used for puncture, a 21G needle, and a dilator to ease catheter passage into the vein. It’s also used in pleural and pericardial drains.
The Seldinger Technique evolved over the years. Initially, a cannula was used to introduce the catheter. This led to the Modified Seldinger technique, which uses an introducer to guide the catheter correctly into the punctured vein and then insert it, with or without a stylet (most PICCs have a stylet to aid progression by adding rigidity). This introducer (often called a micro-introducer) contains a dilator that is removed to allow catheter insertion. The introducer is peelable and can be removed at the end of the procedure.
Comparing Techniques
Classic Seldinger:
- Longer guidewire.
- Dilation with removable dilator.
- Catheter inserted through guidewire, which is removed after insertion.
Modified Seldinger:
- Guidewire < 50 cm.
- Dual-piece introduction (introducer and dilator).
- Guidewire and dilator removed.
- Catheter inserted through introducer.
- Introducer peeled after catheter insertion.
Common Points:
- Ultrasound-guided insertion.
- 21G fine needle.
- Flexible kink-resistant guidewire (nitinol).
Classic Seldinger Technique
Based on this, we can say the Classic Seldinger, with its finer dilation, is less invasive, and most of the time does not require a scalpel.
Using the Classic Seldinger Technique for Midline Insertion
Thus, the Classic Seldinger Technique is known for its simplicity and lower cost, being a simpler and more economical option, especially effective for Midline. It is also less invasive, as it does not require an incision for dilator insertion, making it ideal for patients with coagulation issues or low platelets. It is notably effective in superficial veins, especially in patients with good calibre and superficial veins.
The guidewire needed must be longer than the catheter, the dilator used is shorter than the micro-introducer, which makes it suitable for the Midline and more superficial veins.
Using the Classic Seldinger Technique for PICC Insertion
A PICC is a longer catheter and to reach the vena cava a guidewire of about 90 cm is needed. Being longer, there may be problems maintaining sterility, making manipulation more complicated. In this case, manipulation is easier thanks to micropuncture, which is also longer and allows access to deeper veins.
To verify catheter tip location, intracavitary ECG is used, making it easier to insert the catheter through the introducer and connect the saline column.
The Classic Seldinger Technique is characterised by its simplicity and lower cost, being a simpler and more economical option, especially effective in the Midline. It is also less invasive, as it does not require an incision for dilator insertion, making it ideal for patients with coagulation problems or low platelets. Its effectiveness in superficial veins is notable, being more effective in patients with good calibre and superficial veins.
Modified Seldinger Technique
The Modified Seldinger Technique offers greater control and adaptability during the procedure. It is suitable for deep veins, being ideal for small calibre and deeper veins, such as in obese patients. It also facilitates tunnelling, as the peelable dilator allows more efficient direct and indirect tunnelling.
Using the Modified Seldinger Technique for Midline Insertion
The Midline is a shorter catheter (generally 8–20 cm) that does not reach central circulation. It requires less manipulation and usually does not need a peelable introducer. Its insertion is a simpler and quicker procedure, with less need for additional devices. In addition, the insertion procedure suits the Midline catheter structure well, which is generally more flexible and does not require large dilators.
Using the Modified Seldinger Technique for PICC Insertion
On the other hand, we have the PICC, which is a longer and thinner catheter, designed to reach central circulation. The modified technique allows safer and more controlled access, especially in smaller veins. Its peelable introducer prevents catheter damage and allows a cleaner skin seal. It also improves stability and control during insertion of longer and more fragile catheters.
Conclusion
The Classic Seldinger Technique is characterised by its simplicity and lower cost, being a simpler and more economical option, especially effective in the Midline. It is also less invasive, as it does not require an incision for dilator insertion, making it ideal for patients with coagulation problems or low platelets. Its effectiveness in superficial veins is notable, being more effective in patients with good calibre and superficial veins.
On the other hand, the Modified Seldinger Technique offers greater control and adaptability during the procedure. It is suitable for deep veins, being ideal for small calibre and deeper veins, such as in obese patients. It also facilitates tunnelling, as the peelable dilator allows more efficient direct and indirect tunnelling.
