A central venous catheter or central venous line is a temporary catheter placed into a large vein, with an intention to keep it for the required period and administer drugs, blood products, and other fluids and as well as to draw blood for investigation.
Insertion of a central venous catheter in a human was first reported by Werner Forssman, in 1929. Seldinger in 1953 developed a technique of putting these catheters into the lumen of veins and is quite popular as modified Seldinger technique now.
Central venous catheters are now common among critically ill patients or in patients who require venous access but do not have accessible peripheral veins [as in extensive burns].
Central venous catheters usually remain in place for a longer period than other peripheral venous access devices such as a cannula.
Types of Central Venous Catheters
Site of Insertion
- Internal jugular central venous catheter
- Subclavian central venous catheter
- Supraclavicular central venous catheter
- Femoral central venous catheter
- Peripherally Inserted Central Catheter (PICC)
Peditaric central line is a central venous catheter that is used in children and the most preferred site is femoral.
These catheters are Non-tunneled catheters are fixed in place at the site of insertion, with the catheter and attachments protruding directly. [Most of the catheters are inserted this way]
Tunneled catheters are passed under the skin from the insertion site to a separate exit site. For example internal jugular or subclavian is passed under the skin to emerge at the chest, making the access ports less visible than catheters that protrude directly from the neck. Passing the catheter under the skin helps to prevent infection and provides stability. Hickman catheters and Groshong catheters are examples of tunneled catheter.
When a tunneled catheter is left entirely under the skin, it is called port.Medicines are injected through the skin into the catheter. Some implanted ports contain a small reservoir that can be refilled in the same way. After being filled, the reservoir slowly releases the medicine into the bloodstream. An implanted port is less obvious, requires little daily care, easier to maintain and carry lesser risk of infection.
Ports are used on patients who require only occasional venous access but for a long duration course of therapy. They are not suitable when frequent venous access is required.
Lumen of Catheters
Depending on use, catheters may have a single lumen or multiple lumens. A catheter with two lumens is “biluminal”, three “triluminal”. Up to 4 or 5 lumens may be used.
Indications for Central venous catheters
- Central venous pressure monitoring
- Resuscitation requiring high volume or flow
- Emergency venous access
- Inability to obtain peripheral venous access
- Repetitive blood sampling
- Administration of
- Hyperalimentation [parentral nutrition esp when long term]
- Caustic agents
- Concentrated fluids
- Drugs that are prone to cause phlebitis in peripheral veins
- Calcium chloride
- Hypertonic saline
- Potassium chloride (KCl)
- Vasopressors (for example, epinephrine, dopamine)
- Long-term intravenous antibiotics
- Insertion of transvenous cardiac pacemakers
- Hemodialysis or plasmapheresis
- Insertion of pulmonary artery catheters
- Peripheral blood stem cell collections
- Frequent blood draws
- No peripheral access present in face of need for intravenous therapy
Contraindications to Central Venous Catheters
- Infection over the placement site
- Anatomic obstruction (thrombosis of target vein, other anatomic variance)
- Site-specific issue- e.g. trauma/fracture to ipsilateral clavicle or proximal ribs
- Preferentially use a compressible site such as the femoral location and avoid the internal jugular and subclavian.
- Distorted landmarks
- Congenital anomalies
- Prior vessel injury or procedures
- Morbid obesity
- Uncooperative patient
Insertion of Catheter
The detailed methods are given when individual catheters are discussed. Here the method is only briefly touched.
The area of skin over the planned insertion site is cleaned. A local anesthetic is infiltrated. if necessary.
The location of the vein is identified by landmarks or with the use of a small ultrasound device. A hollow needle is advanced through the skin until blood is aspirated.
The line is then inserted using the Seldinger technique [the most common technique used now]
A blunt guidewire is passed through the needle, then the needle is removed. After the guidewire is positioned in the vein, a dilator is passed over the guidewire to expand the tract and removed. Finally, the catheter is passed over the guidewire and positioned. The guidewire is now removed.
All the lumens of the line are aspirated and flushed with either saline or heparin.
Position of the catheter is confirmed by a chest X-ray. Chest x-ray also helps to find if there is a breach of pleura and presence of pneumothorax.
On anteroposterior X-rays, a catheter tip between 55 and 29 mm below the level of the carina [a ridge of cartilage in the trachea that occurs between the division of the two main bronchi].
Electromagnetic tracking can be to provide guidance during insertion and to verify tip placement and in such cases x-rays are not required.
The catheter is then secured in place by an adhesive dressing, suture, or staple and covered by an occlusive dressing. Regular flushing with saline or a heparin-containing solution is advidsed to keep the line open.
Some venous catheters are impregnated with antibiotics or silver-containing substances to reduce infection risk.
Complications of Central Venous Catheter
- Pneumothorax (more common with subclavian central line)
- Arterial puncture (more common with femoral)
- Catheter malposition
- Subcutaneous hematoma
- Catheter-related infection (more with femoral)
- Catheter-induced thrombosis
- Arrhythmia (usually from guidewire insertion)
- Venous air embolism (avoid with Trendelenburg position)