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Difference between the single wall and the double wall technique
- The single wall and double wall techniques are two different approaches used in the placement of central venous catheters, such as a subclavian or jugular catheter.
Here’s an overview of the differences between the single wall and double wall technique:
Single Wall Technique:
- Insertion: In the single wall technique, the catheter is inserted through a single puncture site in the vein wall.
- Dilator Use: A dilator may or may not be used during the insertion to enlarge the puncture site.
- Catheter Placement: The catheter is advanced through the puncture site and positioned within the vein.
- Suture: Once the catheter is in place, a single suture is used to secure it to the skin.
Double Wall Technique:
- Insertion: In the double wall technique, the catheter is inserted through two separate puncture sites in the vein wall.
- Dilator Use: A dilator is typically used for each puncture site to create larger openings in the vein wall.
- Catheter Placement: Two separate catheters are inserted through the respective puncture sites and advanced into the vein.
- Suture: After catheter placement, each catheter is individually sutured to the skin using separate sutures.
Key Difference between the single wall and the double wall technique
- Number of Puncture Sites: The single wall technique involves a single puncture site, while the double wall technique requires two separate puncture sites.
- Dilator Use: In the single wall technique, the use of a dilator may or may not be necessary, whereas the double wall technique involves the use of dilators at each puncture site.
- Catheter Placement: The single wall technique utilizes a single catheter inserted through the puncture site, while the double wall technique involves the placement of two separate catheters through their respective puncture sites.
- Suturing: In the single wall technique, a single suture is used to secure the catheter, whereas the double wall technique involves individual sutures for each catheter.
What is a single wall technique?
A single wall technique shall be used for radiography whenever practical. To perform a single-wall technique, only the ventral wall of the vessel is punctured to gain entry to the vessel.
What is a double wall technique?
When it is not practical to use a single wall technique, a double walled technique shall be used. A double-wall puncture (Seldinger technique) is performed by puncturing the dorsal and ventral walls of the vessel and subsequently withdrawing the needle.
When pulsatile blood is encountered, the tip of the needle is in an intraluminal position, and a guidewire can be placed safely.
What is Seldinger technique?
The Seldinger technique, named after Dr. Sven-Ivar Seldinger, is a medical procedure used to safely and percutaneously access blood vessels or other hollow structures in the body. It is commonly used in various medical fields, including interventional radiology, cardiology, and vascular surgery.
The Seldinger technique involves the following steps:
- Needle Puncture: A small puncture is made in the skin at the desired insertion site, typically guided by imaging techniques such as ultrasound or fluoroscopy.
- Insertion of a Guidewire: A flexible guidewire is inserted through the needle and advanced into the vessel or hollow structure. The needle is then removed, leaving the guidewire in place.
- Dilatation: A dilator or a series of dilators of increasing size may be introduced over the guidewire to create a tract and facilitate the subsequent insertion of the catheter or other devices.
- Insertion of Catheter or Device: Once the tract has been dilated, a catheter, sheath, or other devices can be inserted over the guidewire and advanced into the desired location within the blood vessel or hollow structure.
- Removal of the Guidewire: After the catheter or device is in place, the guidewire is carefully removed.
The Seldinger technique is advantageous because it minimizes the risk of complications associated with direct puncture of blood vessels. It allows for precise and controlled access, reduces the risk of damage to surrounding structures, and enables the introduction of various diagnostic or therapeutic tools into the body.
The Seldinger technique is widely used in procedures such as central venous catheterization, arterial catheterization, angiography, percutaneous drainage procedures, and various other minimally invasive interventions. It has become a fundamental technique in modern medical practice for gaining safe and reliable access to blood vessels or other hollow structures.
Seldinger technique (thin-wall needle technique) is commonly used procedure to obtain safe access to central vein.
The desired vessel is punctured with a sharp hollow needle, syringe is detached and guidewire is advanced through the lumen of the needle, and then the needle is withdrawn.
After desired vessel puncture, guiding sheath is instantly slid over the needle into the vessel.
The needle is withdrawn, guidewire is advanced through the guiding sheath, central catheter is placed into the vessel.
Needle puncture with subsequent guidewire introduction into vessel through needle; needle exchanged for sheath/catheter over wire•
The Seldinger technique for venous cutdown can also use a small, 1- to 2-mm, venotomy and a Seldinger wire-guided catheter (found in prepackaged central line set).
Central catheter is then passed over the guidewire into the vessel.
Contrarily, modified Seldinger technique(guiding sheath-over-the-needle technique) use needle that is covered with guiding sheath.
The Seldinger unit comes assembled with dilator and catheter.
The catheter-over-needle is advanced through the skin, 1 cm distal to the incision and then through the venotomy. The needle is removed and the wire advanced into the vein through the catheter.
Available access routes○
Internal/external jugular vein○
Common femoral vein○
Subclavian vein○
Popliteal vein○
Greater/lesser saphenous vein○
Translumbar IVC○
Transhepatic IVC or portal vein
Preprocedure
Review indications to determine best route of access•
Review prior imaging for patency of planned route of access
Procedure
US guidance is preferred during needle access○
21-g needle for 0.018″ wire/micropuncture○
18-g needle for direct 0.035″ system•
Confirm venous blood return through needle•
Introduce wire fluoroscopically○
Place microaccess sheath; upsize wire to 0.035″•
Place desired sheath/catheter
Post-Procedure
•Obtain hemostasis•
Observe for location-specific potential complications
Outcomes
•Nearly 100% success rate for image-guided access○
5-13% failure rate for blind access•
Complications:
- Pneumothorax
- arterial puncture
- air embolism
- venous perforation
