The most nerve-racking step of central line placement for the inexperienced practitioner is accessing the vein. My preferred way to safely access the vein for central line placement is to use the Modified Seldinger Technique.
In some studies for ultrasound-guided internal jugular vein catheterization, the modified Seldinger technique
showed superiority over the Seldinger technique in terms of successful catheterization and guidewire insertion on the
first attempt.
The Seldinger Technique:
In the Seldinger technique, a steel needle is used to introduce a wire into a vessel. It was first introduced in 1953 by a Swedish interventional radiologist. The vessel being accessed can be either an artery or a vein depending on the procedure. The Seldinger technique a very versatile technique and is used throughout healthcare for:
- venous access for central venous catheters
- venous or arterial access for cardiology procedures
- venous or arterial access for interventional radiology procedures
- insertion of chest tubes and drains
- insertion of PEG tubes
Steps in the Seldinger Technique
Step 1: A steel hollow bore needle is used to puncture the vessel or cavity being accessed.
- Place the needle bevel up relative to the skin on your syringe.
- Enter the skin at a 45-degree angle if possible. In some patients, the angle will vary depending on patient anatomy.
- Once the needle has passed through the skin, apply a gentle suction by withdrawing the plunger between the pointer and middle finger and pressing down with the thumb on the flange.
- Continue to advance the needle with gentle suction until blood starts to fill the syringe or the tip of your needle is past the vessel on ultrasound.
- PRO TIP: “bounce” the needle as you advance so the needle “pops” into the vessel. Watch this video to see how.
- Once the blood fills the syringe, without moving the tip of the needle in any direction, carefully remove the syringe from the needle and place your thumb over the hub of the needle to prevent a potential air embolus.
KEY POINT #1: All we know, at this point is that the tip of our needle is in the lumen of some vessel. At this time, we don’t know if this vessel is an artery or a vein.
The rate of arterial puncture with central line placement is 0.2 – 2%. If you hit the artery at this step, it’s not great, but it’s also generally not life-threatening for the patient. Don’t assume that the needle tip is in the vein’s lumen until you confirm the position with either ultrasound or manometry.
To learn more about how to confirm that your needle is in a vein, see our post: Central Line Placement: Ultrasound vs. Manometry
Advance your needle at a constant angle until you hit the vessel. If you miss the vessel withdraw the needle to just below the skin surface and advance again.
KEY POINT #2: If you adjust your needle angle as you advance, you will tent the tissues and create a Z-track underneath the skin through which the wire will pass. This Z-track makes it difficult to dilate and advance the catheter over the wire.
See this image on how a z-track is created.
Step 2: A guidewire with a soft curved tip is inserted through the needle and advanced into the lumen of the vessel or cavity
- While stabilizing the steel needle, insert your guidewire through the needle’s hub and advance the wire.
- Please pay close attention to the wire’s feel; it should advance smoothly without resistance as it passes from the lumen of the needle into the lumen of the vessel.
- If you feel any resistance, stop advancing, withdraw the wire and place your syringe back on the needle and apply gentle suction to confirm that the tip of your needle is still in the lumen of the vessel. Blood should withdraw easily. If it does, reinsert your wire again.
- Advance the wire to the appropriate depth. In most cases, there is no need to advance the wire past the 20cm mark. In some cases, you may not want to advance the wire even that deep.
Step 3: The guidewire is held firmly in place while the steel needle is withdrawn from the vessel or cavity over the wire
- Once your guidewire has advanced, hold it firmly and remove your hollow bore needle over the wire.
- place the needle in a sharps management device to prevent a needle stick
- PRO TIP: Never let go of the wire, especially in a spontaneously ventilating patient. The negative inspiratory pressure created by spontaneous ventilation can suck the wire into the patient. It can also cause an air embolism if you did not position your patient with the insertion site below the heart level.
Step 4: A sheath/cannula/dilator/catheter is passed over the guidewire into the lumen of the vessel or cavity
For a standard 7fr triple lumen catheter, while still holding the guidewire, pass your dilator over the wire to expand the tissues and make the passage of the catheter easier.
If you are using an introducer, the dilator is part of the catheter, and the dilator and catheter are placed in a single step.
Step 5: The guidewire is removed from the sheath/cannula/catheter leaving the sheath/cannula/catheter in the lumen of the vessel or cavity that was originally accessed with the steel needle.
Once your catheter is in place remove your wire from the catheter.
Hand on the Wire Pearl: It’s important always to have a hand on the wire to prevent wire mishaps!
- Keeping a hand on the wire can help prevent you from placing the wire too deep and causing cardiac arrhythmias.
- Keeping a hand on the wire reminds you to pull the wire out when placing the catheter.
Risks and Benefits of the Seldinger Technique
The Seldinger technique is the gold standard when it comes to gaining access to a vessel lumen. Whenever I have a challenging central line placement, I defer back using the steel needle and the Seldinger technique.
It is not without risks, however, and it requires proper skills for verification and confirmation of the needle in the venous vessel lumen to prevent arterial injury.
Using manometry with the Seldinger technique, you either need to hold the needle extremely still (an advanced skill). You need to insert your wire and then place an angiocath and transduce manometry off the catheter. The extra step of having to place the angiocatheter is why many anesthesiologists default to using the Modified Seldinger Technique from the start.
