The advances in interventional radiology tools and techniques have propelled Image Guided Therapy (IGT) to become a major core in providing improved patient treatment and care. On the forefront, stands the mainstay of modern interventional radiology practice – Central Venous Access. Central venous access encapsulates three approaches: 1. Insertion of implantable ports 2. Insertion of peripherally inserted central catheters 3. Placement of central venous catheters (CVCs). This project will focus specifically on CVCs with an emphasis on their functional features tailored for various clinical indications. Additionally, the procedure and precautions aimed to minimise potential complications shall be discussed.
In brief, CVCs involve using fluoroscopic guidance to advance a catheter through the right internal jugular vein using a peel-away sheath and dilator assembly. This advancement proceeds until the tip of the catheter rests at the cavo-atrial junction – the junction of the SVC and right atrium.
Placement of CVCs has become commonplace in the IGT suite since their importance is echoed in both the therapeutic and diagnostic fields. In particular, they are appropriate if long-term, continuous venous access is required. This applies to the administration of total parenteral nutrition, prolonged antibiotic treatment and chemotherapy. However, one of their other therapeutic abilities is to enable dialysis and apheresis. From a diagnostic standpoint, CVCs play an integral role in haemodynamic monitoring.
Prior to each procedure, considerations must be made regarding the types of tools needed along with the appropriate size depending on age. Guidewires, for example, can be best classified according to their length, wire tip, stiffness, and diameter. Certain guidewires may possess a hydrophilic coating which makes them remarkably slippery and frictionless and this allows them to cross the narrowest of stenosis. A plethora of catheters are also available, which are generally made from silicone or polyurethane materials. They may possess a single double or triple lumen and can be designed to have special tips to meet the therapeutic demands and flow rates. Haemodialysis catheters, for example, require very high flow rates averaging at about 350mL/min with minimal recirculation. These highlights are just a fraction of the variables involved regarding CVC placement. Overall, a myriad of improved designs and techniques are continuously emerging, all serving to elevate patient care.