Central venous catheter

Central venous catheters (CVC), also known as central venous lines (CVL), refer to a wide range of catheters that are inserted so that their distal tips lie in a central vein. Central venous access devices can broadly be divided into four categories. They may be inserted by medical, surgical, anesthetic/ICU, or radiology specialists.

Classification

• peripherally inserted central catheters (PICC)

• non-tunneled CVCs

  • e.g. used in ICU or ED for emergent or short-term (<7-10 days) access

  • e.g. Vascath is used for haemodialysis, apheresis, stem cell collection, etc.

• tunneled CVCs

  • e.g. Hickman catheters, Groshong catheter, Broviac line, Permcath

• implantable ports

  • e.g. Port-a-Cath, Infus-a-Port

  • may be located in the chest or arm (brachial)

  • may be a single or dual lumen

Site

Central venous catheters can be inserted into a variety of veins, most commonly including:

• internal jugular vein (see: jugular venous catheters)

• subclavian vein

• femoral vein (typically only short-term access)

• brachial, basilic or cephalic veins (for PICCs and implantable ports)

Placement

Policy varies by institution but tip placement for neck/thoracic/upper limb CVCs in the superior vena cava or at the cavoatrial junction is generally acceptable. There is a limited differential of left paramediastinal catheter positions.

Ultrasound-guided CVL insertion is proposed to reduce the number of complications and to increase the safety and quality of central venous catheter (CVC) placement.

Complications  

• pneumothorax

• hemothorax

• infusothorax

• arrhythmia

• infection

• mediastinal hematoma

• arterial placement

• perforation of vein needing a stent

• pinch off syndrome

• retained guidewire

• guidewire shearing and fragment embolization

• sheared fragment of catheter

• malposition of port and or tip

• azygos termination

• retained hub

• downhill esophageal varices

Intravenous contrast injection

Contrast injection through a central venous catheter is safe with complication rate of 1% if a strict protocol is followed. Among the complications are ⁴:

• catheter rupture leading to contrast extravasation

• loss of vascular access

• embolization of catheter fragments

• catheter obstruction

• mediastinal contrast extravasation

• mediastinal hematoma

• cardiac arrhythmia.

Catheters more than 3 months old have increased risk of rupture. Automatic power injection or hand injection of contrast media poses the same risk of catheter rupture ⁴.

Safety protocols when using CVC as intravenous contrast injection site are ⁵:

• aspirating blood before the injection of contrast media

• localizing the the position of CVC before and after the injection

• ensuring no kinking of the CVC

• using sterile syringes

• making sure CVC is patent after scanning

Slow injection rate of 2ml s^-1 only minimally compromise the image quality. Meanwhile, high flow rates have higher risk of catheter rupture with uncertain gurantee of image quality ^4,5.