Venous Access

Authors: Dr Tuan Phan*
                            Dr Stuart Lyon *

What are the prerequisites for having a venous access device inserted?

Interventional radiologists are often asked to assist in achieving central venous access. This document outlines key decisions required in gaining assistance from an interventional radiologist in achieving the appropriate access for the clinical condition.

Venous access catheters can be tunnelled or non-tunnelled and are indicated for various conditions.

Peripherally-inserted central catheters and non-tunnelled central catheters are used for:

• Extended intravenous access for infusion of medications, intravenous fluids, recurrent transfusions, chemotherapeutic agents and total parenteral nutrition (TPN).
• Requirement for frequent blood sampling for patient comfort or lack of adequate peripheral venous access.

Tunnelled central catheters are used for:

• Extended intravenous access for infusion of medications, chemotherapeutic agents, bone marrow transplant protocols, high-volume blood exchanges and total parenteral nutrition.
• Requirement for frequent blood sampling for patient comfort or lack of adequate peripheral venous access.
• Longer-term requirement than PICC lines because of the nature of the tunnel.

Implanted ports:

• Prerequisites are the same as for tunnelled central catheters.

In addition, these provide better cosmesis compared to the previously mentioned catheters, because both the catheter portion and the port are beneath the skin surface. Consequently, these catheters also require less maintenance and are less prone to becoming infected.

What are the absolute contraindications for a venous access?

Long-term, active, systemic bacteraemia is an absolute contraindication.

What are the relative contraindications for venous access?

• Access site infection (cellulitis or dermatitis).
• Allergy to materials in the device.
• Central venous obstruction or thrombosis.

What are the adverse effects of a venous access?

Between 4% and 7% of venous access procedures have immediate complications. These are managed by the radiologist during or immediately after the procedure.

• bleeding (<2%);
• air embolism (1%);
• arterial puncture (<1%);
• pneumothorax (<1%);
• nerve injury (<1%);
• cardiac arrhythmia (<1%); or
• iodine contrast allergy (<1%).

Late complications:

Infection, local or systemic (5-15% of patients). This may result in the catheter being removed, hospitalisation, antibiotics or all three.

Catheter blockage. This may occur from kinking of the catheter or blockage within the catheter (fibrin sheath or thrombosis). Definitive treatment usually involves the exchange of the existing catheter for a new catheter or fibrin sheath stripping.

Central vein thrombosis. The majority of these occur at the access site vein and are asymptomatic. However occasionally these may cause headache, head and neck swelling, arm swelling and/or arm pain, and pulmonary embolism. Treatment of symptomatic thrombosis is initially with anticoagulation. Severe cases may require thrombolysis and removal of the catheter.

Catheter fracture – the development of a crack or break in the catheter (less than 1% of cases)

Long term catheter malfunction – including an obstruction in the catheter or movement or dislodgement of the catheter (10-35% of cases). The latter usually requires catheter repositioning in the angiography suite.

Are there alternative imaging tests, interventions or surgical procedures to a venous access?

Conventional intravenous access through the use of a cannula in a peripheral, superficial vein may be a viable short-term option, depending on the clinical situation. However, peripheral veins are prone to infusion phlebitis, which quickly leads to the depletion of accessible peripheral veins.

Alternative medical treatment may be considered, if relevant and appropriate, such as oral medications.

Further information about venous access:

How to care for a venous access catheter:

Within the packaging for each catheter used, there is a detailed patient information booklet, which should be given to the patient or carer. Detailed step-by-step instructions are given for maintenance procedures.

Generally, implantable ports should be flushed monthly with normal saline.

Tunnelled and non-tunnelled catheters and PICC lines should be flushed daily with saline. If a valved cap is used on a catheter, flushing may be carried out weekly. After aspirating blood from the catheter, 20mL of saline should be used for flushing. After flushing with saline, heparin should be injected into the catheter or implantable port with a volume equal to the capacity of the catheter.

What to look out for:

Central venous thrombosis. This presents as arm or neck swelling, or may be life-threatening, presenting as pulmonary embolism and shortness of breath. The patient should be immediately referred to have an ultrasound or CT scan, preferably to the institution where the venous catheter was originally inserted, where appropriate and active management can be carried out.

Infection. This can occur at the catheter skin exit site, along the tunnel or within the blood stream, resulting in bacteraemia and sepsis. Skin infections can present with tenderness at the skin entry site, with or without erythema or exudate. Similarly, infection along the tunnel can present with tenderness along the tunnel, with or without overlying erythema or exudate and wound dehiscence.

Bacteraemia can present with fever. Infection at the skin exit site may be treated with antibiotics alone, but deeper infections will also require removal of the catheter.

Malfunctioning central venous catheter. A catheter may not be flushing or aspirating normally. It may be partially or completely blocked with a clot, cracked, kinked, encapsulated by a fibrin sheath or migrated. The patient should be referred back to the institution where the venous access was carried out for assessment and further management

Useful websites about venous access:

Cardiovascular and Interventional Radiological Society of Europe:
http://cirse.org/index.php?pid=1078
Society of Interventional Radiology:
www.sirweb.org/patients/gastrostomy/

*The author has no conflict of interest with this topic.

Page last modified on 30/8/2018.